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02cb3ff004
FROM clause terms that existed prior to version 3.39.0 for queries that contain no RIGHT or FULL JOINs. FossilOrigin-Name: 92d60b64ebfc2d1f0a9cabaa88e7bf0d11737ed01a77b627af10dd1b96a5321c
6404 lines
236 KiB
C
6404 lines
236 KiB
C
/*
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** 2001 September 15
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** This module contains C code that generates VDBE code used to process
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** the WHERE clause of SQL statements. This module is responsible for
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** generating the code that loops through a table looking for applicable
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** rows. Indices are selected and used to speed the search when doing
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** so is applicable. Because this module is responsible for selecting
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** indices, you might also think of this module as the "query optimizer".
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*/
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#include "sqliteInt.h"
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#include "whereInt.h"
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/*
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** Extra information appended to the end of sqlite3_index_info but not
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** visible to the xBestIndex function, at least not directly. The
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** sqlite3_vtab_collation() interface knows how to reach it, however.
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**
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** This object is not an API and can be changed from one release to the
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** next. As long as allocateIndexInfo() and sqlite3_vtab_collation()
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** agree on the structure, all will be well.
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*/
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typedef struct HiddenIndexInfo HiddenIndexInfo;
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struct HiddenIndexInfo {
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WhereClause *pWC; /* The Where clause being analyzed */
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Parse *pParse; /* The parsing context */
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int eDistinct; /* Value to return from sqlite3_vtab_distinct() */
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u32 mIn; /* Mask of terms that are <col> IN (...) */
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u32 mHandleIn; /* Terms that vtab will handle as <col> IN (...) */
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sqlite3_value *aRhs[1]; /* RHS values for constraints. MUST BE LAST
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** because extra space is allocated to hold up
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** to nTerm such values */
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};
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/* Forward declaration of methods */
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static int whereLoopResize(sqlite3*, WhereLoop*, int);
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/*
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** Return the estimated number of output rows from a WHERE clause
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*/
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LogEst sqlite3WhereOutputRowCount(WhereInfo *pWInfo){
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return pWInfo->nRowOut;
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}
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/*
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** Return one of the WHERE_DISTINCT_xxxxx values to indicate how this
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** WHERE clause returns outputs for DISTINCT processing.
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*/
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int sqlite3WhereIsDistinct(WhereInfo *pWInfo){
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return pWInfo->eDistinct;
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}
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/*
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** Return the number of ORDER BY terms that are satisfied by the
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** WHERE clause. A return of 0 means that the output must be
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** completely sorted. A return equal to the number of ORDER BY
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** terms means that no sorting is needed at all. A return that
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** is positive but less than the number of ORDER BY terms means that
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** block sorting is required.
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*/
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int sqlite3WhereIsOrdered(WhereInfo *pWInfo){
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return pWInfo->nOBSat;
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}
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/*
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** In the ORDER BY LIMIT optimization, if the inner-most loop is known
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** to emit rows in increasing order, and if the last row emitted by the
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** inner-most loop did not fit within the sorter, then we can skip all
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** subsequent rows for the current iteration of the inner loop (because they
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** will not fit in the sorter either) and continue with the second inner
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** loop - the loop immediately outside the inner-most.
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**
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** When a row does not fit in the sorter (because the sorter already
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** holds LIMIT+OFFSET rows that are smaller), then a jump is made to the
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** label returned by this function.
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**
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** If the ORDER BY LIMIT optimization applies, the jump destination should
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** be the continuation for the second-inner-most loop. If the ORDER BY
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** LIMIT optimization does not apply, then the jump destination should
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** be the continuation for the inner-most loop.
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**
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** It is always safe for this routine to return the continuation of the
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** inner-most loop, in the sense that a correct answer will result.
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** Returning the continuation the second inner loop is an optimization
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** that might make the code run a little faster, but should not change
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** the final answer.
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*/
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int sqlite3WhereOrderByLimitOptLabel(WhereInfo *pWInfo){
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WhereLevel *pInner;
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if( !pWInfo->bOrderedInnerLoop ){
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/* The ORDER BY LIMIT optimization does not apply. Jump to the
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** continuation of the inner-most loop. */
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return pWInfo->iContinue;
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}
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pInner = &pWInfo->a[pWInfo->nLevel-1];
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assert( pInner->addrNxt!=0 );
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return pInner->pRJ ? pWInfo->iContinue : pInner->addrNxt;
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}
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/*
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** While generating code for the min/max optimization, after handling
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** the aggregate-step call to min() or max(), check to see if any
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** additional looping is required. If the output order is such that
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** we are certain that the correct answer has already been found, then
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** code an OP_Goto to by pass subsequent processing.
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**
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** Any extra OP_Goto that is coded here is an optimization. The
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** correct answer should be obtained regardless. This OP_Goto just
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** makes the answer appear faster.
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*/
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void sqlite3WhereMinMaxOptEarlyOut(Vdbe *v, WhereInfo *pWInfo){
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WhereLevel *pInner;
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int i;
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if( !pWInfo->bOrderedInnerLoop ) return;
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if( pWInfo->nOBSat==0 ) return;
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for(i=pWInfo->nLevel-1; i>=0; i--){
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pInner = &pWInfo->a[i];
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if( (pInner->pWLoop->wsFlags & WHERE_COLUMN_IN)!=0 ){
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sqlite3VdbeGoto(v, pInner->addrNxt);
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return;
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}
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}
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sqlite3VdbeGoto(v, pWInfo->iBreak);
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}
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/*
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** Return the VDBE address or label to jump to in order to continue
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** immediately with the next row of a WHERE clause.
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*/
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int sqlite3WhereContinueLabel(WhereInfo *pWInfo){
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assert( pWInfo->iContinue!=0 );
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return pWInfo->iContinue;
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}
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/*
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** Return the VDBE address or label to jump to in order to break
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** out of a WHERE loop.
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*/
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int sqlite3WhereBreakLabel(WhereInfo *pWInfo){
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return pWInfo->iBreak;
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}
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/*
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** Return ONEPASS_OFF (0) if an UPDATE or DELETE statement is unable to
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** operate directly on the rowids returned by a WHERE clause. Return
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** ONEPASS_SINGLE (1) if the statement can operation directly because only
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** a single row is to be changed. Return ONEPASS_MULTI (2) if the one-pass
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** optimization can be used on multiple
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**
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** If the ONEPASS optimization is used (if this routine returns true)
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** then also write the indices of open cursors used by ONEPASS
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** into aiCur[0] and aiCur[1]. iaCur[0] gets the cursor of the data
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** table and iaCur[1] gets the cursor used by an auxiliary index.
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** Either value may be -1, indicating that cursor is not used.
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** Any cursors returned will have been opened for writing.
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**
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** aiCur[0] and aiCur[1] both get -1 if the where-clause logic is
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** unable to use the ONEPASS optimization.
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*/
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int sqlite3WhereOkOnePass(WhereInfo *pWInfo, int *aiCur){
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memcpy(aiCur, pWInfo->aiCurOnePass, sizeof(int)*2);
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#ifdef WHERETRACE_ENABLED
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if( sqlite3WhereTrace && pWInfo->eOnePass!=ONEPASS_OFF ){
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sqlite3DebugPrintf("%s cursors: %d %d\n",
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pWInfo->eOnePass==ONEPASS_SINGLE ? "ONEPASS_SINGLE" : "ONEPASS_MULTI",
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aiCur[0], aiCur[1]);
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}
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#endif
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return pWInfo->eOnePass;
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}
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/*
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** Return TRUE if the WHERE loop uses the OP_DeferredSeek opcode to move
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** the data cursor to the row selected by the index cursor.
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*/
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int sqlite3WhereUsesDeferredSeek(WhereInfo *pWInfo){
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return pWInfo->bDeferredSeek;
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}
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/*
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** Move the content of pSrc into pDest
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*/
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static void whereOrMove(WhereOrSet *pDest, WhereOrSet *pSrc){
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pDest->n = pSrc->n;
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memcpy(pDest->a, pSrc->a, pDest->n*sizeof(pDest->a[0]));
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}
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/*
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** Try to insert a new prerequisite/cost entry into the WhereOrSet pSet.
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**
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** The new entry might overwrite an existing entry, or it might be
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** appended, or it might be discarded. Do whatever is the right thing
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** so that pSet keeps the N_OR_COST best entries seen so far.
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*/
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static int whereOrInsert(
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WhereOrSet *pSet, /* The WhereOrSet to be updated */
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Bitmask prereq, /* Prerequisites of the new entry */
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LogEst rRun, /* Run-cost of the new entry */
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LogEst nOut /* Number of outputs for the new entry */
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){
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u16 i;
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WhereOrCost *p;
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for(i=pSet->n, p=pSet->a; i>0; i--, p++){
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if( rRun<=p->rRun && (prereq & p->prereq)==prereq ){
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goto whereOrInsert_done;
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}
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if( p->rRun<=rRun && (p->prereq & prereq)==p->prereq ){
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return 0;
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}
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}
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if( pSet->n<N_OR_COST ){
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p = &pSet->a[pSet->n++];
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p->nOut = nOut;
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}else{
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p = pSet->a;
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for(i=1; i<pSet->n; i++){
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if( p->rRun>pSet->a[i].rRun ) p = pSet->a + i;
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}
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if( p->rRun<=rRun ) return 0;
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}
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whereOrInsert_done:
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p->prereq = prereq;
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p->rRun = rRun;
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if( p->nOut>nOut ) p->nOut = nOut;
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return 1;
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}
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/*
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** Return the bitmask for the given cursor number. Return 0 if
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** iCursor is not in the set.
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*/
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Bitmask sqlite3WhereGetMask(WhereMaskSet *pMaskSet, int iCursor){
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int i;
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assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
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assert( pMaskSet->n>0 || pMaskSet->ix[0]<0 );
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assert( iCursor>=-1 );
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if( pMaskSet->ix[0]==iCursor ){
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return 1;
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}
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for(i=1; i<pMaskSet->n; i++){
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if( pMaskSet->ix[i]==iCursor ){
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return MASKBIT(i);
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}
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}
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return 0;
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}
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/* Allocate memory that is automatically freed when pWInfo is freed.
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*/
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void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte){
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WhereMemBlock *pBlock;
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pBlock = sqlite3DbMallocRawNN(pWInfo->pParse->db, nByte+sizeof(*pBlock));
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if( pBlock ){
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pBlock->pNext = pWInfo->pMemToFree;
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pBlock->sz = nByte;
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pWInfo->pMemToFree = pBlock;
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pBlock++;
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}
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return (void*)pBlock;
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}
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void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte){
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void *pNew = sqlite3WhereMalloc(pWInfo, nByte);
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if( pNew && pOld ){
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WhereMemBlock *pOldBlk = (WhereMemBlock*)pOld;
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pOldBlk--;
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assert( pOldBlk->sz<nByte );
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memcpy(pNew, pOld, pOldBlk->sz);
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}
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return pNew;
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}
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/*
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** Create a new mask for cursor iCursor.
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**
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** There is one cursor per table in the FROM clause. The number of
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** tables in the FROM clause is limited by a test early in the
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** sqlite3WhereBegin() routine. So we know that the pMaskSet->ix[]
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** array will never overflow.
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*/
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static void createMask(WhereMaskSet *pMaskSet, int iCursor){
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assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
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pMaskSet->ix[pMaskSet->n++] = iCursor;
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}
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/*
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** If the right-hand branch of the expression is a TK_COLUMN, then return
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** a pointer to the right-hand branch. Otherwise, return NULL.
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*/
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static Expr *whereRightSubexprIsColumn(Expr *p){
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p = sqlite3ExprSkipCollateAndLikely(p->pRight);
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if( ALWAYS(p!=0) && p->op==TK_COLUMN && !ExprHasProperty(p, EP_FixedCol) ){
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return p;
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}
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return 0;
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}
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/*
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** Advance to the next WhereTerm that matches according to the criteria
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** established when the pScan object was initialized by whereScanInit().
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** Return NULL if there are no more matching WhereTerms.
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*/
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static WhereTerm *whereScanNext(WhereScan *pScan){
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int iCur; /* The cursor on the LHS of the term */
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i16 iColumn; /* The column on the LHS of the term. -1 for IPK */
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Expr *pX; /* An expression being tested */
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WhereClause *pWC; /* Shorthand for pScan->pWC */
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WhereTerm *pTerm; /* The term being tested */
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int k = pScan->k; /* Where to start scanning */
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assert( pScan->iEquiv<=pScan->nEquiv );
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pWC = pScan->pWC;
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while(1){
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iColumn = pScan->aiColumn[pScan->iEquiv-1];
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iCur = pScan->aiCur[pScan->iEquiv-1];
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assert( pWC!=0 );
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assert( iCur>=0 );
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do{
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for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
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assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 || pTerm->leftCursor<0 );
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if( pTerm->leftCursor==iCur
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&& pTerm->u.x.leftColumn==iColumn
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&& (iColumn!=XN_EXPR
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|| sqlite3ExprCompareSkip(pTerm->pExpr->pLeft,
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pScan->pIdxExpr,iCur)==0)
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&& (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_OuterON))
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){
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if( (pTerm->eOperator & WO_EQUIV)!=0
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&& pScan->nEquiv<ArraySize(pScan->aiCur)
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&& (pX = whereRightSubexprIsColumn(pTerm->pExpr))!=0
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){
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int j;
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for(j=0; j<pScan->nEquiv; j++){
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if( pScan->aiCur[j]==pX->iTable
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&& pScan->aiColumn[j]==pX->iColumn ){
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break;
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}
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}
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if( j==pScan->nEquiv ){
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pScan->aiCur[j] = pX->iTable;
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pScan->aiColumn[j] = pX->iColumn;
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pScan->nEquiv++;
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}
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}
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if( (pTerm->eOperator & pScan->opMask)!=0 ){
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/* Verify the affinity and collating sequence match */
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if( pScan->zCollName && (pTerm->eOperator & WO_ISNULL)==0 ){
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CollSeq *pColl;
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Parse *pParse = pWC->pWInfo->pParse;
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pX = pTerm->pExpr;
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if( !sqlite3IndexAffinityOk(pX, pScan->idxaff) ){
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continue;
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}
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assert(pX->pLeft);
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pColl = sqlite3ExprCompareCollSeq(pParse, pX);
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if( pColl==0 ) pColl = pParse->db->pDfltColl;
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if( sqlite3StrICmp(pColl->zName, pScan->zCollName) ){
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continue;
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}
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}
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if( (pTerm->eOperator & (WO_EQ|WO_IS))!=0
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&& (pX = pTerm->pExpr->pRight, ALWAYS(pX!=0))
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&& pX->op==TK_COLUMN
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&& pX->iTable==pScan->aiCur[0]
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&& pX->iColumn==pScan->aiColumn[0]
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){
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testcase( pTerm->eOperator & WO_IS );
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continue;
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}
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pScan->pWC = pWC;
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pScan->k = k+1;
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#ifdef WHERETRACE_ENABLED
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if( sqlite3WhereTrace & 0x20000 ){
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int ii;
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sqlite3DebugPrintf("SCAN-TERM %p: nEquiv=%d",
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pTerm, pScan->nEquiv);
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for(ii=0; ii<pScan->nEquiv; ii++){
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sqlite3DebugPrintf(" {%d:%d}",
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pScan->aiCur[ii], pScan->aiColumn[ii]);
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}
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sqlite3DebugPrintf("\n");
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}
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#endif
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return pTerm;
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}
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}
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}
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pWC = pWC->pOuter;
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k = 0;
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}while( pWC!=0 );
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if( pScan->iEquiv>=pScan->nEquiv ) break;
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pWC = pScan->pOrigWC;
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k = 0;
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pScan->iEquiv++;
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}
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return 0;
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}
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/*
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** This is whereScanInit() for the case of an index on an expression.
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** It is factored out into a separate tail-recursion subroutine so that
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** the normal whereScanInit() routine, which is a high-runner, does not
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** need to push registers onto the stack as part of its prologue.
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*/
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static SQLITE_NOINLINE WhereTerm *whereScanInitIndexExpr(WhereScan *pScan){
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pScan->idxaff = sqlite3ExprAffinity(pScan->pIdxExpr);
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return whereScanNext(pScan);
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}
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|
|
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/*
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** Initialize a WHERE clause scanner object. Return a pointer to the
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** first match. Return NULL if there are no matches.
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**
|
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** The scanner will be searching the WHERE clause pWC. It will look
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** for terms of the form "X <op> <expr>" where X is column iColumn of table
|
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** iCur. Or if pIdx!=0 then X is column iColumn of index pIdx. pIdx
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** must be one of the indexes of table iCur.
|
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**
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** The <op> must be one of the operators described by opMask.
|
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**
|
|
** If the search is for X and the WHERE clause contains terms of the
|
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** form X=Y then this routine might also return terms of the form
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** "Y <op> <expr>". The number of levels of transitivity is limited,
|
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** but is enough to handle most commonly occurring SQL statements.
|
|
**
|
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** If X is not the INTEGER PRIMARY KEY then X must be compatible with
|
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** index pIdx.
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*/
|
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static WhereTerm *whereScanInit(
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WhereScan *pScan, /* The WhereScan object being initialized */
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WhereClause *pWC, /* The WHERE clause to be scanned */
|
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int iCur, /* Cursor to scan for */
|
|
int iColumn, /* Column to scan for */
|
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u32 opMask, /* Operator(s) to scan for */
|
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Index *pIdx /* Must be compatible with this index */
|
|
){
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pScan->pOrigWC = pWC;
|
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pScan->pWC = pWC;
|
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pScan->pIdxExpr = 0;
|
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pScan->idxaff = 0;
|
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pScan->zCollName = 0;
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pScan->opMask = opMask;
|
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pScan->k = 0;
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pScan->aiCur[0] = iCur;
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pScan->nEquiv = 1;
|
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pScan->iEquiv = 1;
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if( pIdx ){
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int j = iColumn;
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iColumn = pIdx->aiColumn[j];
|
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if( iColumn==pIdx->pTable->iPKey ){
|
|
iColumn = XN_ROWID;
|
|
}else if( iColumn>=0 ){
|
|
pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
|
|
pScan->zCollName = pIdx->azColl[j];
|
|
}else if( iColumn==XN_EXPR ){
|
|
pScan->pIdxExpr = pIdx->aColExpr->a[j].pExpr;
|
|
pScan->zCollName = pIdx->azColl[j];
|
|
pScan->aiColumn[0] = XN_EXPR;
|
|
return whereScanInitIndexExpr(pScan);
|
|
}
|
|
}else if( iColumn==XN_EXPR ){
|
|
return 0;
|
|
}
|
|
pScan->aiColumn[0] = iColumn;
|
|
return whereScanNext(pScan);
|
|
}
|
|
|
|
/*
|
|
** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
|
|
** where X is a reference to the iColumn of table iCur or of index pIdx
|
|
** if pIdx!=0 and <op> is one of the WO_xx operator codes specified by
|
|
** the op parameter. Return a pointer to the term. Return 0 if not found.
|
|
**
|
|
** If pIdx!=0 then it must be one of the indexes of table iCur.
|
|
** Search for terms matching the iColumn-th column of pIdx
|
|
** rather than the iColumn-th column of table iCur.
|
|
**
|
|
** The term returned might by Y=<expr> if there is another constraint in
|
|
** the WHERE clause that specifies that X=Y. Any such constraints will be
|
|
** identified by the WO_EQUIV bit in the pTerm->eOperator field. The
|
|
** aiCur[]/iaColumn[] arrays hold X and all its equivalents. There are 11
|
|
** slots in aiCur[]/aiColumn[] so that means we can look for X plus up to 10
|
|
** other equivalent values. Hence a search for X will return <expr> if X=A1
|
|
** and A1=A2 and A2=A3 and ... and A9=A10 and A10=<expr>.
|
|
**
|
|
** If there are multiple terms in the WHERE clause of the form "X <op> <expr>"
|
|
** then try for the one with no dependencies on <expr> - in other words where
|
|
** <expr> is a constant expression of some kind. Only return entries of
|
|
** the form "X <op> Y" where Y is a column in another table if no terms of
|
|
** the form "X <op> <const-expr>" exist. If no terms with a constant RHS
|
|
** exist, try to return a term that does not use WO_EQUIV.
|
|
*/
|
|
WhereTerm *sqlite3WhereFindTerm(
|
|
WhereClause *pWC, /* The WHERE clause to be searched */
|
|
int iCur, /* Cursor number of LHS */
|
|
int iColumn, /* Column number of LHS */
|
|
Bitmask notReady, /* RHS must not overlap with this mask */
|
|
u32 op, /* Mask of WO_xx values describing operator */
|
|
Index *pIdx /* Must be compatible with this index, if not NULL */
|
|
){
|
|
WhereTerm *pResult = 0;
|
|
WhereTerm *p;
|
|
WhereScan scan;
|
|
|
|
p = whereScanInit(&scan, pWC, iCur, iColumn, op, pIdx);
|
|
op &= WO_EQ|WO_IS;
|
|
while( p ){
|
|
if( (p->prereqRight & notReady)==0 ){
|
|
if( p->prereqRight==0 && (p->eOperator&op)!=0 ){
|
|
testcase( p->eOperator & WO_IS );
|
|
return p;
|
|
}
|
|
if( pResult==0 ) pResult = p;
|
|
}
|
|
p = whereScanNext(&scan);
|
|
}
|
|
return pResult;
|
|
}
|
|
|
|
/*
|
|
** This function searches pList for an entry that matches the iCol-th column
|
|
** of index pIdx.
|
|
**
|
|
** If such an expression is found, its index in pList->a[] is returned. If
|
|
** no expression is found, -1 is returned.
|
|
*/
|
|
static int findIndexCol(
|
|
Parse *pParse, /* Parse context */
|
|
ExprList *pList, /* Expression list to search */
|
|
int iBase, /* Cursor for table associated with pIdx */
|
|
Index *pIdx, /* Index to match column of */
|
|
int iCol /* Column of index to match */
|
|
){
|
|
int i;
|
|
const char *zColl = pIdx->azColl[iCol];
|
|
|
|
for(i=0; i<pList->nExpr; i++){
|
|
Expr *p = sqlite3ExprSkipCollateAndLikely(pList->a[i].pExpr);
|
|
if( ALWAYS(p!=0)
|
|
&& (p->op==TK_COLUMN || p->op==TK_AGG_COLUMN)
|
|
&& p->iColumn==pIdx->aiColumn[iCol]
|
|
&& p->iTable==iBase
|
|
){
|
|
CollSeq *pColl = sqlite3ExprNNCollSeq(pParse, pList->a[i].pExpr);
|
|
if( 0==sqlite3StrICmp(pColl->zName, zColl) ){
|
|
return i;
|
|
}
|
|
}
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
** Return TRUE if the iCol-th column of index pIdx is NOT NULL
|
|
*/
|
|
static int indexColumnNotNull(Index *pIdx, int iCol){
|
|
int j;
|
|
assert( pIdx!=0 );
|
|
assert( iCol>=0 && iCol<pIdx->nColumn );
|
|
j = pIdx->aiColumn[iCol];
|
|
if( j>=0 ){
|
|
return pIdx->pTable->aCol[j].notNull;
|
|
}else if( j==(-1) ){
|
|
return 1;
|
|
}else{
|
|
assert( j==(-2) );
|
|
return 0; /* Assume an indexed expression can always yield a NULL */
|
|
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Return true if the DISTINCT expression-list passed as the third argument
|
|
** is redundant.
|
|
**
|
|
** A DISTINCT list is redundant if any subset of the columns in the
|
|
** DISTINCT list are collectively unique and individually non-null.
|
|
*/
|
|
static int isDistinctRedundant(
|
|
Parse *pParse, /* Parsing context */
|
|
SrcList *pTabList, /* The FROM clause */
|
|
WhereClause *pWC, /* The WHERE clause */
|
|
ExprList *pDistinct /* The result set that needs to be DISTINCT */
|
|
){
|
|
Table *pTab;
|
|
Index *pIdx;
|
|
int i;
|
|
int iBase;
|
|
|
|
/* If there is more than one table or sub-select in the FROM clause of
|
|
** this query, then it will not be possible to show that the DISTINCT
|
|
** clause is redundant. */
|
|
if( pTabList->nSrc!=1 ) return 0;
|
|
iBase = pTabList->a[0].iCursor;
|
|
pTab = pTabList->a[0].pTab;
|
|
|
|
/* If any of the expressions is an IPK column on table iBase, then return
|
|
** true. Note: The (p->iTable==iBase) part of this test may be false if the
|
|
** current SELECT is a correlated sub-query.
|
|
*/
|
|
for(i=0; i<pDistinct->nExpr; i++){
|
|
Expr *p = sqlite3ExprSkipCollateAndLikely(pDistinct->a[i].pExpr);
|
|
if( NEVER(p==0) ) continue;
|
|
if( p->op!=TK_COLUMN && p->op!=TK_AGG_COLUMN ) continue;
|
|
if( p->iTable==iBase && p->iColumn<0 ) return 1;
|
|
}
|
|
|
|
/* Loop through all indices on the table, checking each to see if it makes
|
|
** the DISTINCT qualifier redundant. It does so if:
|
|
**
|
|
** 1. The index is itself UNIQUE, and
|
|
**
|
|
** 2. All of the columns in the index are either part of the pDistinct
|
|
** list, or else the WHERE clause contains a term of the form "col=X",
|
|
** where X is a constant value. The collation sequences of the
|
|
** comparison and select-list expressions must match those of the index.
|
|
**
|
|
** 3. All of those index columns for which the WHERE clause does not
|
|
** contain a "col=X" term are subject to a NOT NULL constraint.
|
|
*/
|
|
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
|
if( !IsUniqueIndex(pIdx) ) continue;
|
|
if( pIdx->pPartIdxWhere ) continue;
|
|
for(i=0; i<pIdx->nKeyCol; i++){
|
|
if( 0==sqlite3WhereFindTerm(pWC, iBase, i, ~(Bitmask)0, WO_EQ, pIdx) ){
|
|
if( findIndexCol(pParse, pDistinct, iBase, pIdx, i)<0 ) break;
|
|
if( indexColumnNotNull(pIdx, i)==0 ) break;
|
|
}
|
|
}
|
|
if( i==pIdx->nKeyCol ){
|
|
/* This index implies that the DISTINCT qualifier is redundant. */
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
** Estimate the logarithm of the input value to base 2.
|
|
*/
|
|
static LogEst estLog(LogEst N){
|
|
return N<=10 ? 0 : sqlite3LogEst(N) - 33;
|
|
}
|
|
|
|
/*
|
|
** Convert OP_Column opcodes to OP_Copy in previously generated code.
|
|
**
|
|
** This routine runs over generated VDBE code and translates OP_Column
|
|
** opcodes into OP_Copy when the table is being accessed via co-routine
|
|
** instead of via table lookup.
|
|
**
|
|
** If the iAutoidxCur is not zero, then any OP_Rowid instructions on
|
|
** cursor iTabCur are transformed into OP_Sequence opcode for the
|
|
** iAutoidxCur cursor, in order to generate unique rowids for the
|
|
** automatic index being generated.
|
|
*/
|
|
static void translateColumnToCopy(
|
|
Parse *pParse, /* Parsing context */
|
|
int iStart, /* Translate from this opcode to the end */
|
|
int iTabCur, /* OP_Column/OP_Rowid references to this table */
|
|
int iRegister, /* The first column is in this register */
|
|
int iAutoidxCur /* If non-zero, cursor of autoindex being generated */
|
|
){
|
|
Vdbe *v = pParse->pVdbe;
|
|
VdbeOp *pOp = sqlite3VdbeGetOp(v, iStart);
|
|
int iEnd = sqlite3VdbeCurrentAddr(v);
|
|
if( pParse->db->mallocFailed ) return;
|
|
for(; iStart<iEnd; iStart++, pOp++){
|
|
if( pOp->p1!=iTabCur ) continue;
|
|
if( pOp->opcode==OP_Column ){
|
|
pOp->opcode = OP_Copy;
|
|
pOp->p1 = pOp->p2 + iRegister;
|
|
pOp->p2 = pOp->p3;
|
|
pOp->p3 = 0;
|
|
pOp->p5 = 2; /* Cause the MEM_Subtype flag to be cleared */
|
|
}else if( pOp->opcode==OP_Rowid ){
|
|
pOp->opcode = OP_Sequence;
|
|
pOp->p1 = iAutoidxCur;
|
|
#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
|
|
if( iAutoidxCur==0 ){
|
|
pOp->opcode = OP_Null;
|
|
pOp->p3 = 0;
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Two routines for printing the content of an sqlite3_index_info
|
|
** structure. Used for testing and debugging only. If neither
|
|
** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
|
|
** are no-ops.
|
|
*/
|
|
#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(WHERETRACE_ENABLED)
|
|
static void whereTraceIndexInfoInputs(sqlite3_index_info *p){
|
|
int i;
|
|
if( !sqlite3WhereTrace ) return;
|
|
for(i=0; i<p->nConstraint; i++){
|
|
sqlite3DebugPrintf(
|
|
" constraint[%d]: col=%d termid=%d op=%d usabled=%d collseq=%s\n",
|
|
i,
|
|
p->aConstraint[i].iColumn,
|
|
p->aConstraint[i].iTermOffset,
|
|
p->aConstraint[i].op,
|
|
p->aConstraint[i].usable,
|
|
sqlite3_vtab_collation(p,i));
|
|
}
|
|
for(i=0; i<p->nOrderBy; i++){
|
|
sqlite3DebugPrintf(" orderby[%d]: col=%d desc=%d\n",
|
|
i,
|
|
p->aOrderBy[i].iColumn,
|
|
p->aOrderBy[i].desc);
|
|
}
|
|
}
|
|
static void whereTraceIndexInfoOutputs(sqlite3_index_info *p){
|
|
int i;
|
|
if( !sqlite3WhereTrace ) return;
|
|
for(i=0; i<p->nConstraint; i++){
|
|
sqlite3DebugPrintf(" usage[%d]: argvIdx=%d omit=%d\n",
|
|
i,
|
|
p->aConstraintUsage[i].argvIndex,
|
|
p->aConstraintUsage[i].omit);
|
|
}
|
|
sqlite3DebugPrintf(" idxNum=%d\n", p->idxNum);
|
|
sqlite3DebugPrintf(" idxStr=%s\n", p->idxStr);
|
|
sqlite3DebugPrintf(" orderByConsumed=%d\n", p->orderByConsumed);
|
|
sqlite3DebugPrintf(" estimatedCost=%g\n", p->estimatedCost);
|
|
sqlite3DebugPrintf(" estimatedRows=%lld\n", p->estimatedRows);
|
|
}
|
|
#else
|
|
#define whereTraceIndexInfoInputs(A)
|
|
#define whereTraceIndexInfoOutputs(A)
|
|
#endif
|
|
|
|
#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
|
|
/*
|
|
** Return TRUE if the WHERE clause term pTerm is of a form where it
|
|
** could be used with an index to access pSrc, assuming an appropriate
|
|
** index existed.
|
|
*/
|
|
static int termCanDriveIndex(
|
|
const WhereTerm *pTerm, /* WHERE clause term to check */
|
|
const SrcItem *pSrc, /* Table we are trying to access */
|
|
const Bitmask notReady /* Tables in outer loops of the join */
|
|
){
|
|
char aff;
|
|
if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
|
|
if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) return 0;
|
|
assert( (pSrc->fg.jointype & JT_RIGHT)==0 );
|
|
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0 ){
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LEFT );
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LTORJ );
|
|
testcase( ExprHasProperty(pTerm->pExpr, EP_OuterON) )
|
|
testcase( ExprHasProperty(pTerm->pExpr, EP_InnerON) );
|
|
if( !ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON)
|
|
|| pTerm->pExpr->w.iJoin != pSrc->iCursor
|
|
){
|
|
return 0; /* See tag-20191211-001 */
|
|
}
|
|
}
|
|
if( (pTerm->prereqRight & notReady)!=0 ) return 0;
|
|
assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
|
|
if( pTerm->u.x.leftColumn<0 ) return 0;
|
|
aff = pSrc->pTab->aCol[pTerm->u.x.leftColumn].affinity;
|
|
if( !sqlite3IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
|
|
testcase( pTerm->pExpr->op==TK_IS );
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
|
|
#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
|
|
/*
|
|
** Generate code to construct the Index object for an automatic index
|
|
** and to set up the WhereLevel object pLevel so that the code generator
|
|
** makes use of the automatic index.
|
|
*/
|
|
static SQLITE_NOINLINE void constructAutomaticIndex(
|
|
Parse *pParse, /* The parsing context */
|
|
const WhereClause *pWC, /* The WHERE clause */
|
|
const SrcItem *pSrc, /* The FROM clause term to get the next index */
|
|
const Bitmask notReady, /* Mask of cursors that are not available */
|
|
WhereLevel *pLevel /* Write new index here */
|
|
){
|
|
int nKeyCol; /* Number of columns in the constructed index */
|
|
WhereTerm *pTerm; /* A single term of the WHERE clause */
|
|
WhereTerm *pWCEnd; /* End of pWC->a[] */
|
|
Index *pIdx; /* Object describing the transient index */
|
|
Vdbe *v; /* Prepared statement under construction */
|
|
int addrInit; /* Address of the initialization bypass jump */
|
|
Table *pTable; /* The table being indexed */
|
|
int addrTop; /* Top of the index fill loop */
|
|
int regRecord; /* Register holding an index record */
|
|
int n; /* Column counter */
|
|
int i; /* Loop counter */
|
|
int mxBitCol; /* Maximum column in pSrc->colUsed */
|
|
CollSeq *pColl; /* Collating sequence to on a column */
|
|
WhereLoop *pLoop; /* The Loop object */
|
|
char *zNotUsed; /* Extra space on the end of pIdx */
|
|
Bitmask idxCols; /* Bitmap of columns used for indexing */
|
|
Bitmask extraCols; /* Bitmap of additional columns */
|
|
u8 sentWarning = 0; /* True if a warnning has been issued */
|
|
Expr *pPartial = 0; /* Partial Index Expression */
|
|
int iContinue = 0; /* Jump here to skip excluded rows */
|
|
SrcItem *pTabItem; /* FROM clause term being indexed */
|
|
int addrCounter = 0; /* Address where integer counter is initialized */
|
|
int regBase; /* Array of registers where record is assembled */
|
|
|
|
/* Generate code to skip over the creation and initialization of the
|
|
** transient index on 2nd and subsequent iterations of the loop. */
|
|
v = pParse->pVdbe;
|
|
assert( v!=0 );
|
|
addrInit = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
|
|
|
|
/* Count the number of columns that will be added to the index
|
|
** and used to match WHERE clause constraints */
|
|
nKeyCol = 0;
|
|
pTable = pSrc->pTab;
|
|
pWCEnd = &pWC->a[pWC->nTerm];
|
|
pLoop = pLevel->pWLoop;
|
|
idxCols = 0;
|
|
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
|
|
Expr *pExpr = pTerm->pExpr;
|
|
/* Make the automatic index a partial index if there are terms in the
|
|
** WHERE clause (or the ON clause of a LEFT join) that constrain which
|
|
** rows of the target table (pSrc) that can be used. */
|
|
if( (pTerm->wtFlags & TERM_VIRTUAL)==0
|
|
&& sqlite3ExprIsTableConstraint(pExpr, pSrc)
|
|
){
|
|
pPartial = sqlite3ExprAnd(pParse, pPartial,
|
|
sqlite3ExprDup(pParse->db, pExpr, 0));
|
|
}
|
|
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
|
|
int iCol;
|
|
Bitmask cMask;
|
|
assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
|
|
iCol = pTerm->u.x.leftColumn;
|
|
cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
|
|
testcase( iCol==BMS );
|
|
testcase( iCol==BMS-1 );
|
|
if( !sentWarning ){
|
|
sqlite3_log(SQLITE_WARNING_AUTOINDEX,
|
|
"automatic index on %s(%s)", pTable->zName,
|
|
pTable->aCol[iCol].zCnName);
|
|
sentWarning = 1;
|
|
}
|
|
if( (idxCols & cMask)==0 ){
|
|
if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ){
|
|
goto end_auto_index_create;
|
|
}
|
|
pLoop->aLTerm[nKeyCol++] = pTerm;
|
|
idxCols |= cMask;
|
|
}
|
|
}
|
|
}
|
|
assert( nKeyCol>0 || pParse->db->mallocFailed );
|
|
pLoop->u.btree.nEq = pLoop->nLTerm = nKeyCol;
|
|
pLoop->wsFlags = WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WHERE_INDEXED
|
|
| WHERE_AUTO_INDEX;
|
|
|
|
/* Count the number of additional columns needed to create a
|
|
** covering index. A "covering index" is an index that contains all
|
|
** columns that are needed by the query. With a covering index, the
|
|
** original table never needs to be accessed. Automatic indices must
|
|
** be a covering index because the index will not be updated if the
|
|
** original table changes and the index and table cannot both be used
|
|
** if they go out of sync.
|
|
*/
|
|
extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
|
|
mxBitCol = MIN(BMS-1,pTable->nCol);
|
|
testcase( pTable->nCol==BMS-1 );
|
|
testcase( pTable->nCol==BMS-2 );
|
|
for(i=0; i<mxBitCol; i++){
|
|
if( extraCols & MASKBIT(i) ) nKeyCol++;
|
|
}
|
|
if( pSrc->colUsed & MASKBIT(BMS-1) ){
|
|
nKeyCol += pTable->nCol - BMS + 1;
|
|
}
|
|
|
|
/* Construct the Index object to describe this index */
|
|
pIdx = sqlite3AllocateIndexObject(pParse->db, nKeyCol+1, 0, &zNotUsed);
|
|
if( pIdx==0 ) goto end_auto_index_create;
|
|
pLoop->u.btree.pIndex = pIdx;
|
|
pIdx->zName = "auto-index";
|
|
pIdx->pTable = pTable;
|
|
n = 0;
|
|
idxCols = 0;
|
|
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
|
|
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
|
|
int iCol;
|
|
Bitmask cMask;
|
|
assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
|
|
iCol = pTerm->u.x.leftColumn;
|
|
cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
|
|
testcase( iCol==BMS-1 );
|
|
testcase( iCol==BMS );
|
|
if( (idxCols & cMask)==0 ){
|
|
Expr *pX = pTerm->pExpr;
|
|
idxCols |= cMask;
|
|
pIdx->aiColumn[n] = pTerm->u.x.leftColumn;
|
|
pColl = sqlite3ExprCompareCollSeq(pParse, pX);
|
|
assert( pColl!=0 || pParse->nErr>0 ); /* TH3 collate01.800 */
|
|
pIdx->azColl[n] = pColl ? pColl->zName : sqlite3StrBINARY;
|
|
n++;
|
|
}
|
|
}
|
|
}
|
|
assert( (u32)n==pLoop->u.btree.nEq );
|
|
|
|
/* Add additional columns needed to make the automatic index into
|
|
** a covering index */
|
|
for(i=0; i<mxBitCol; i++){
|
|
if( extraCols & MASKBIT(i) ){
|
|
pIdx->aiColumn[n] = i;
|
|
pIdx->azColl[n] = sqlite3StrBINARY;
|
|
n++;
|
|
}
|
|
}
|
|
if( pSrc->colUsed & MASKBIT(BMS-1) ){
|
|
for(i=BMS-1; i<pTable->nCol; i++){
|
|
pIdx->aiColumn[n] = i;
|
|
pIdx->azColl[n] = sqlite3StrBINARY;
|
|
n++;
|
|
}
|
|
}
|
|
assert( n==nKeyCol );
|
|
pIdx->aiColumn[n] = XN_ROWID;
|
|
pIdx->azColl[n] = sqlite3StrBINARY;
|
|
|
|
/* Create the automatic index */
|
|
assert( pLevel->iIdxCur>=0 );
|
|
pLevel->iIdxCur = pParse->nTab++;
|
|
sqlite3VdbeAddOp2(v, OP_OpenAutoindex, pLevel->iIdxCur, nKeyCol+1);
|
|
sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
|
|
VdbeComment((v, "for %s", pTable->zName));
|
|
if( OptimizationEnabled(pParse->db, SQLITE_BloomFilter) ){
|
|
pLevel->regFilter = ++pParse->nMem;
|
|
sqlite3VdbeAddOp2(v, OP_Blob, 10000, pLevel->regFilter);
|
|
}
|
|
|
|
/* Fill the automatic index with content */
|
|
pTabItem = &pWC->pWInfo->pTabList->a[pLevel->iFrom];
|
|
if( pTabItem->fg.viaCoroutine ){
|
|
int regYield = pTabItem->regReturn;
|
|
addrCounter = sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
|
|
sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub);
|
|
addrTop = sqlite3VdbeAddOp1(v, OP_Yield, regYield);
|
|
VdbeCoverage(v);
|
|
VdbeComment((v, "next row of %s", pTabItem->pTab->zName));
|
|
}else{
|
|
addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur); VdbeCoverage(v);
|
|
}
|
|
if( pPartial ){
|
|
iContinue = sqlite3VdbeMakeLabel(pParse);
|
|
sqlite3ExprIfFalse(pParse, pPartial, iContinue, SQLITE_JUMPIFNULL);
|
|
pLoop->wsFlags |= WHERE_PARTIALIDX;
|
|
}
|
|
regRecord = sqlite3GetTempReg(pParse);
|
|
regBase = sqlite3GenerateIndexKey(
|
|
pParse, pIdx, pLevel->iTabCur, regRecord, 0, 0, 0, 0
|
|
);
|
|
if( pLevel->regFilter ){
|
|
sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0,
|
|
regBase, pLoop->u.btree.nEq);
|
|
}
|
|
sqlite3VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
|
|
sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
|
|
if( pPartial ) sqlite3VdbeResolveLabel(v, iContinue);
|
|
if( pTabItem->fg.viaCoroutine ){
|
|
sqlite3VdbeChangeP2(v, addrCounter, regBase+n);
|
|
testcase( pParse->db->mallocFailed );
|
|
assert( pLevel->iIdxCur>0 );
|
|
translateColumnToCopy(pParse, addrTop, pLevel->iTabCur,
|
|
pTabItem->regResult, pLevel->iIdxCur);
|
|
sqlite3VdbeGoto(v, addrTop);
|
|
pTabItem->fg.viaCoroutine = 0;
|
|
}else{
|
|
sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1); VdbeCoverage(v);
|
|
sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX);
|
|
}
|
|
sqlite3VdbeJumpHere(v, addrTop);
|
|
sqlite3ReleaseTempReg(pParse, regRecord);
|
|
|
|
/* Jump here when skipping the initialization */
|
|
sqlite3VdbeJumpHere(v, addrInit);
|
|
|
|
end_auto_index_create:
|
|
sqlite3ExprDelete(pParse->db, pPartial);
|
|
}
|
|
#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
|
|
|
|
/*
|
|
** Generate bytecode that will initialize a Bloom filter that is appropriate
|
|
** for pLevel.
|
|
**
|
|
** If there are inner loops within pLevel that have the WHERE_BLOOMFILTER
|
|
** flag set, initialize a Bloomfilter for them as well. Except don't do
|
|
** this recursive initialization if the SQLITE_BloomPulldown optimization has
|
|
** been turned off.
|
|
**
|
|
** When the Bloom filter is initialized, the WHERE_BLOOMFILTER flag is cleared
|
|
** from the loop, but the regFilter value is set to a register that implements
|
|
** the Bloom filter. When regFilter is positive, the
|
|
** sqlite3WhereCodeOneLoopStart() will generate code to test the Bloom filter
|
|
** and skip the subsequence B-Tree seek if the Bloom filter indicates that
|
|
** no matching rows exist.
|
|
**
|
|
** This routine may only be called if it has previously been determined that
|
|
** the loop would benefit from a Bloom filter, and the WHERE_BLOOMFILTER bit
|
|
** is set.
|
|
*/
|
|
static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
|
|
WhereInfo *pWInfo, /* The WHERE clause */
|
|
int iLevel, /* Index in pWInfo->a[] that is pLevel */
|
|
WhereLevel *pLevel, /* Make a Bloom filter for this FROM term */
|
|
Bitmask notReady /* Loops that are not ready */
|
|
){
|
|
int addrOnce; /* Address of opening OP_Once */
|
|
int addrTop; /* Address of OP_Rewind */
|
|
int addrCont; /* Jump here to skip a row */
|
|
const WhereTerm *pTerm; /* For looping over WHERE clause terms */
|
|
const WhereTerm *pWCEnd; /* Last WHERE clause term */
|
|
Parse *pParse = pWInfo->pParse; /* Parsing context */
|
|
Vdbe *v = pParse->pVdbe; /* VDBE under construction */
|
|
WhereLoop *pLoop = pLevel->pWLoop; /* The loop being coded */
|
|
int iCur; /* Cursor for table getting the filter */
|
|
|
|
assert( pLoop!=0 );
|
|
assert( v!=0 );
|
|
assert( pLoop->wsFlags & WHERE_BLOOMFILTER );
|
|
|
|
addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
|
|
do{
|
|
const SrcItem *pItem;
|
|
const Table *pTab;
|
|
u64 sz;
|
|
sqlite3WhereExplainBloomFilter(pParse, pWInfo, pLevel);
|
|
addrCont = sqlite3VdbeMakeLabel(pParse);
|
|
iCur = pLevel->iTabCur;
|
|
pLevel->regFilter = ++pParse->nMem;
|
|
|
|
/* The Bloom filter is a Blob held in a register. Initialize it
|
|
** to zero-filled blob of at least 80K bits, but maybe more if the
|
|
** estimated size of the table is larger. We could actually
|
|
** measure the size of the table at run-time using OP_Count with
|
|
** P3==1 and use that value to initialize the blob. But that makes
|
|
** testing complicated. By basing the blob size on the value in the
|
|
** sqlite_stat1 table, testing is much easier.
|
|
*/
|
|
pItem = &pWInfo->pTabList->a[pLevel->iFrom];
|
|
assert( pItem!=0 );
|
|
pTab = pItem->pTab;
|
|
assert( pTab!=0 );
|
|
sz = sqlite3LogEstToInt(pTab->nRowLogEst);
|
|
if( sz<10000 ){
|
|
sz = 10000;
|
|
}else if( sz>10000000 ){
|
|
sz = 10000000;
|
|
}
|
|
sqlite3VdbeAddOp2(v, OP_Blob, (int)sz, pLevel->regFilter);
|
|
|
|
addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
|
|
pWCEnd = &pWInfo->sWC.a[pWInfo->sWC.nTerm];
|
|
for(pTerm=pWInfo->sWC.a; pTerm<pWCEnd; pTerm++){
|
|
Expr *pExpr = pTerm->pExpr;
|
|
if( (pTerm->wtFlags & TERM_VIRTUAL)==0
|
|
&& sqlite3ExprIsTableConstraint(pExpr, pItem)
|
|
){
|
|
sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
|
|
}
|
|
}
|
|
if( pLoop->wsFlags & WHERE_IPK ){
|
|
int r1 = sqlite3GetTempReg(pParse);
|
|
sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
|
|
sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, 1);
|
|
sqlite3ReleaseTempReg(pParse, r1);
|
|
}else{
|
|
Index *pIdx = pLoop->u.btree.pIndex;
|
|
int n = pLoop->u.btree.nEq;
|
|
int r1 = sqlite3GetTempRange(pParse, n);
|
|
int jj;
|
|
for(jj=0; jj<n; jj++){
|
|
int iCol = pIdx->aiColumn[jj];
|
|
assert( pIdx->pTable==pItem->pTab );
|
|
sqlite3ExprCodeGetColumnOfTable(v, pIdx->pTable, iCur, iCol,r1+jj);
|
|
}
|
|
sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, n);
|
|
sqlite3ReleaseTempRange(pParse, r1, n);
|
|
}
|
|
sqlite3VdbeResolveLabel(v, addrCont);
|
|
sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
|
|
VdbeCoverage(v);
|
|
sqlite3VdbeJumpHere(v, addrTop);
|
|
pLoop->wsFlags &= ~WHERE_BLOOMFILTER;
|
|
if( OptimizationDisabled(pParse->db, SQLITE_BloomPulldown) ) break;
|
|
while( ++iLevel < pWInfo->nLevel ){
|
|
const SrcItem *pTabItem;
|
|
pLevel = &pWInfo->a[iLevel];
|
|
pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
|
|
if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ) ) continue;
|
|
pLoop = pLevel->pWLoop;
|
|
if( NEVER(pLoop==0) ) continue;
|
|
if( pLoop->prereq & notReady ) continue;
|
|
if( (pLoop->wsFlags & (WHERE_BLOOMFILTER|WHERE_COLUMN_IN))
|
|
==WHERE_BLOOMFILTER
|
|
){
|
|
/* This is a candidate for bloom-filter pull-down (early evaluation).
|
|
** The test that WHERE_COLUMN_IN is omitted is important, as we are
|
|
** not able to do early evaluation of bloom filters that make use of
|
|
** the IN operator */
|
|
break;
|
|
}
|
|
}
|
|
}while( iLevel < pWInfo->nLevel );
|
|
sqlite3VdbeJumpHere(v, addrOnce);
|
|
}
|
|
|
|
|
|
#ifndef SQLITE_OMIT_VIRTUALTABLE
|
|
/*
|
|
** Allocate and populate an sqlite3_index_info structure. It is the
|
|
** responsibility of the caller to eventually release the structure
|
|
** by passing the pointer returned by this function to freeIndexInfo().
|
|
*/
|
|
static sqlite3_index_info *allocateIndexInfo(
|
|
WhereInfo *pWInfo, /* The WHERE clause */
|
|
WhereClause *pWC, /* The WHERE clause being analyzed */
|
|
Bitmask mUnusable, /* Ignore terms with these prereqs */
|
|
SrcItem *pSrc, /* The FROM clause term that is the vtab */
|
|
u16 *pmNoOmit /* Mask of terms not to omit */
|
|
){
|
|
int i, j;
|
|
int nTerm;
|
|
Parse *pParse = pWInfo->pParse;
|
|
struct sqlite3_index_constraint *pIdxCons;
|
|
struct sqlite3_index_orderby *pIdxOrderBy;
|
|
struct sqlite3_index_constraint_usage *pUsage;
|
|
struct HiddenIndexInfo *pHidden;
|
|
WhereTerm *pTerm;
|
|
int nOrderBy;
|
|
sqlite3_index_info *pIdxInfo;
|
|
u16 mNoOmit = 0;
|
|
const Table *pTab;
|
|
int eDistinct = 0;
|
|
ExprList *pOrderBy = pWInfo->pOrderBy;
|
|
|
|
assert( pSrc!=0 );
|
|
pTab = pSrc->pTab;
|
|
assert( pTab!=0 );
|
|
assert( IsVirtual(pTab) );
|
|
|
|
/* Find all WHERE clause constraints referring to this virtual table.
|
|
** Mark each term with the TERM_OK flag. Set nTerm to the number of
|
|
** terms found.
|
|
*/
|
|
for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
|
|
pTerm->wtFlags &= ~TERM_OK;
|
|
if( pTerm->leftCursor != pSrc->iCursor ) continue;
|
|
if( pTerm->prereqRight & mUnusable ) continue;
|
|
assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
|
|
testcase( pTerm->eOperator & WO_IN );
|
|
testcase( pTerm->eOperator & WO_ISNULL );
|
|
testcase( pTerm->eOperator & WO_IS );
|
|
testcase( pTerm->eOperator & WO_ALL );
|
|
if( (pTerm->eOperator & ~(WO_EQUIV))==0 ) continue;
|
|
if( pTerm->wtFlags & TERM_VNULL ) continue;
|
|
|
|
assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
|
|
assert( pTerm->u.x.leftColumn>=XN_ROWID );
|
|
assert( pTerm->u.x.leftColumn<pTab->nCol );
|
|
|
|
/* tag-20191211-002: WHERE-clause constraints are not useful to the
|
|
** right-hand table of a LEFT JOIN nor to the either table of a
|
|
** RIGHT JOIN. See tag-20191211-001 for the
|
|
** equivalent restriction for ordinary tables. */
|
|
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0 ){
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LEFT );
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_RIGHT );
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LTORJ );
|
|
testcase( ExprHasProperty(pTerm->pExpr, EP_OuterON) );
|
|
testcase( ExprHasProperty(pTerm->pExpr, EP_InnerON) );
|
|
if( !ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON)
|
|
|| pTerm->pExpr->w.iJoin != pSrc->iCursor
|
|
){
|
|
continue;
|
|
}
|
|
}
|
|
nTerm++;
|
|
pTerm->wtFlags |= TERM_OK;
|
|
}
|
|
|
|
/* If the ORDER BY clause contains only columns in the current
|
|
** virtual table then allocate space for the aOrderBy part of
|
|
** the sqlite3_index_info structure.
|
|
*/
|
|
nOrderBy = 0;
|
|
if( pOrderBy ){
|
|
int n = pOrderBy->nExpr;
|
|
for(i=0; i<n; i++){
|
|
Expr *pExpr = pOrderBy->a[i].pExpr;
|
|
Expr *pE2;
|
|
|
|
/* Skip over constant terms in the ORDER BY clause */
|
|
if( sqlite3ExprIsConstant(pExpr) ){
|
|
continue;
|
|
}
|
|
|
|
/* Virtual tables are unable to deal with NULLS FIRST */
|
|
if( pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_BIGNULL ) break;
|
|
|
|
/* First case - a direct column references without a COLLATE operator */
|
|
if( pExpr->op==TK_COLUMN && pExpr->iTable==pSrc->iCursor ){
|
|
assert( pExpr->iColumn>=XN_ROWID && pExpr->iColumn<pTab->nCol );
|
|
continue;
|
|
}
|
|
|
|
/* 2nd case - a column reference with a COLLATE operator. Only match
|
|
** of the COLLATE operator matches the collation of the column. */
|
|
if( pExpr->op==TK_COLLATE
|
|
&& (pE2 = pExpr->pLeft)->op==TK_COLUMN
|
|
&& pE2->iTable==pSrc->iCursor
|
|
){
|
|
const char *zColl; /* The collating sequence name */
|
|
assert( !ExprHasProperty(pExpr, EP_IntValue) );
|
|
assert( pExpr->u.zToken!=0 );
|
|
assert( pE2->iColumn>=XN_ROWID && pE2->iColumn<pTab->nCol );
|
|
pExpr->iColumn = pE2->iColumn;
|
|
if( pE2->iColumn<0 ) continue; /* Collseq does not matter for rowid */
|
|
zColl = sqlite3ColumnColl(&pTab->aCol[pE2->iColumn]);
|
|
if( zColl==0 ) zColl = sqlite3StrBINARY;
|
|
if( sqlite3_stricmp(pExpr->u.zToken, zColl)==0 ) continue;
|
|
}
|
|
|
|
/* No matches cause a break out of the loop */
|
|
break;
|
|
}
|
|
if( i==n ){
|
|
nOrderBy = n;
|
|
if( (pWInfo->wctrlFlags & WHERE_DISTINCTBY) ){
|
|
eDistinct = 2 + ((pWInfo->wctrlFlags & WHERE_SORTBYGROUP)!=0);
|
|
}else if( pWInfo->wctrlFlags & WHERE_GROUPBY ){
|
|
eDistinct = 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Allocate the sqlite3_index_info structure
|
|
*/
|
|
pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
|
|
+ (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
|
|
+ sizeof(*pIdxOrderBy)*nOrderBy + sizeof(*pHidden)
|
|
+ sizeof(sqlite3_value*)*nTerm );
|
|
if( pIdxInfo==0 ){
|
|
sqlite3ErrorMsg(pParse, "out of memory");
|
|
return 0;
|
|
}
|
|
pHidden = (struct HiddenIndexInfo*)&pIdxInfo[1];
|
|
pIdxCons = (struct sqlite3_index_constraint*)&pHidden->aRhs[nTerm];
|
|
pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
|
|
pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
|
|
pIdxInfo->aConstraint = pIdxCons;
|
|
pIdxInfo->aOrderBy = pIdxOrderBy;
|
|
pIdxInfo->aConstraintUsage = pUsage;
|
|
pHidden->pWC = pWC;
|
|
pHidden->pParse = pParse;
|
|
pHidden->eDistinct = eDistinct;
|
|
pHidden->mIn = 0;
|
|
for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
|
|
u16 op;
|
|
if( (pTerm->wtFlags & TERM_OK)==0 ) continue;
|
|
pIdxCons[j].iColumn = pTerm->u.x.leftColumn;
|
|
pIdxCons[j].iTermOffset = i;
|
|
op = pTerm->eOperator & WO_ALL;
|
|
if( op==WO_IN ){
|
|
if( (pTerm->wtFlags & TERM_SLICE)==0 ){
|
|
pHidden->mIn |= SMASKBIT32(j);
|
|
}
|
|
op = WO_EQ;
|
|
}
|
|
if( op==WO_AUX ){
|
|
pIdxCons[j].op = pTerm->eMatchOp;
|
|
}else if( op & (WO_ISNULL|WO_IS) ){
|
|
if( op==WO_ISNULL ){
|
|
pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_ISNULL;
|
|
}else{
|
|
pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_IS;
|
|
}
|
|
}else{
|
|
pIdxCons[j].op = (u8)op;
|
|
/* The direct assignment in the previous line is possible only because
|
|
** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical. The
|
|
** following asserts verify this fact. */
|
|
assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
|
|
assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
|
|
assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
|
|
assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
|
|
assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
|
|
assert( pTerm->eOperator&(WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_AUX) );
|
|
|
|
if( op & (WO_LT|WO_LE|WO_GT|WO_GE)
|
|
&& sqlite3ExprIsVector(pTerm->pExpr->pRight)
|
|
){
|
|
testcase( j!=i );
|
|
if( j<16 ) mNoOmit |= (1 << j);
|
|
if( op==WO_LT ) pIdxCons[j].op = WO_LE;
|
|
if( op==WO_GT ) pIdxCons[j].op = WO_GE;
|
|
}
|
|
}
|
|
|
|
j++;
|
|
}
|
|
assert( j==nTerm );
|
|
pIdxInfo->nConstraint = j;
|
|
for(i=j=0; i<nOrderBy; i++){
|
|
Expr *pExpr = pOrderBy->a[i].pExpr;
|
|
if( sqlite3ExprIsConstant(pExpr) ) continue;
|
|
assert( pExpr->op==TK_COLUMN
|
|
|| (pExpr->op==TK_COLLATE && pExpr->pLeft->op==TK_COLUMN
|
|
&& pExpr->iColumn==pExpr->pLeft->iColumn) );
|
|
pIdxOrderBy[j].iColumn = pExpr->iColumn;
|
|
pIdxOrderBy[j].desc = pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_DESC;
|
|
j++;
|
|
}
|
|
pIdxInfo->nOrderBy = j;
|
|
|
|
*pmNoOmit = mNoOmit;
|
|
return pIdxInfo;
|
|
}
|
|
|
|
/*
|
|
** Free an sqlite3_index_info structure allocated by allocateIndexInfo()
|
|
** and possibly modified by xBestIndex methods.
|
|
*/
|
|
static void freeIndexInfo(sqlite3 *db, sqlite3_index_info *pIdxInfo){
|
|
HiddenIndexInfo *pHidden;
|
|
int i;
|
|
assert( pIdxInfo!=0 );
|
|
pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
|
|
assert( pHidden->pParse!=0 );
|
|
assert( pHidden->pParse->db==db );
|
|
for(i=0; i<pIdxInfo->nConstraint; i++){
|
|
sqlite3ValueFree(pHidden->aRhs[i]); /* IMP: R-14553-25174 */
|
|
pHidden->aRhs[i] = 0;
|
|
}
|
|
sqlite3DbFree(db, pIdxInfo);
|
|
}
|
|
|
|
/*
|
|
** The table object reference passed as the second argument to this function
|
|
** must represent a virtual table. This function invokes the xBestIndex()
|
|
** method of the virtual table with the sqlite3_index_info object that
|
|
** comes in as the 3rd argument to this function.
|
|
**
|
|
** If an error occurs, pParse is populated with an error message and an
|
|
** appropriate error code is returned. A return of SQLITE_CONSTRAINT from
|
|
** xBestIndex is not considered an error. SQLITE_CONSTRAINT indicates that
|
|
** the current configuration of "unusable" flags in sqlite3_index_info can
|
|
** not result in a valid plan.
|
|
**
|
|
** Whether or not an error is returned, it is the responsibility of the
|
|
** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
|
|
** that this is required.
|
|
*/
|
|
static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){
|
|
sqlite3_vtab *pVtab = sqlite3GetVTable(pParse->db, pTab)->pVtab;
|
|
int rc;
|
|
|
|
whereTraceIndexInfoInputs(p);
|
|
pParse->db->nSchemaLock++;
|
|
rc = pVtab->pModule->xBestIndex(pVtab, p);
|
|
pParse->db->nSchemaLock--;
|
|
whereTraceIndexInfoOutputs(p);
|
|
|
|
if( rc!=SQLITE_OK && rc!=SQLITE_CONSTRAINT ){
|
|
if( rc==SQLITE_NOMEM ){
|
|
sqlite3OomFault(pParse->db);
|
|
}else if( !pVtab->zErrMsg ){
|
|
sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
|
|
}else{
|
|
sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg);
|
|
}
|
|
}
|
|
sqlite3_free(pVtab->zErrMsg);
|
|
pVtab->zErrMsg = 0;
|
|
return rc;
|
|
}
|
|
#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) */
|
|
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
/*
|
|
** Estimate the location of a particular key among all keys in an
|
|
** index. Store the results in aStat as follows:
|
|
**
|
|
** aStat[0] Est. number of rows less than pRec
|
|
** aStat[1] Est. number of rows equal to pRec
|
|
**
|
|
** Return the index of the sample that is the smallest sample that
|
|
** is greater than or equal to pRec. Note that this index is not an index
|
|
** into the aSample[] array - it is an index into a virtual set of samples
|
|
** based on the contents of aSample[] and the number of fields in record
|
|
** pRec.
|
|
*/
|
|
static int whereKeyStats(
|
|
Parse *pParse, /* Database connection */
|
|
Index *pIdx, /* Index to consider domain of */
|
|
UnpackedRecord *pRec, /* Vector of values to consider */
|
|
int roundUp, /* Round up if true. Round down if false */
|
|
tRowcnt *aStat /* OUT: stats written here */
|
|
){
|
|
IndexSample *aSample = pIdx->aSample;
|
|
int iCol; /* Index of required stats in anEq[] etc. */
|
|
int i; /* Index of first sample >= pRec */
|
|
int iSample; /* Smallest sample larger than or equal to pRec */
|
|
int iMin = 0; /* Smallest sample not yet tested */
|
|
int iTest; /* Next sample to test */
|
|
int res; /* Result of comparison operation */
|
|
int nField; /* Number of fields in pRec */
|
|
tRowcnt iLower = 0; /* anLt[] + anEq[] of largest sample pRec is > */
|
|
|
|
#ifndef SQLITE_DEBUG
|
|
UNUSED_PARAMETER( pParse );
|
|
#endif
|
|
assert( pRec!=0 );
|
|
assert( pIdx->nSample>0 );
|
|
assert( pRec->nField>0 );
|
|
|
|
/* Do a binary search to find the first sample greater than or equal
|
|
** to pRec. If pRec contains a single field, the set of samples to search
|
|
** is simply the aSample[] array. If the samples in aSample[] contain more
|
|
** than one fields, all fields following the first are ignored.
|
|
**
|
|
** If pRec contains N fields, where N is more than one, then as well as the
|
|
** samples in aSample[] (truncated to N fields), the search also has to
|
|
** consider prefixes of those samples. For example, if the set of samples
|
|
** in aSample is:
|
|
**
|
|
** aSample[0] = (a, 5)
|
|
** aSample[1] = (a, 10)
|
|
** aSample[2] = (b, 5)
|
|
** aSample[3] = (c, 100)
|
|
** aSample[4] = (c, 105)
|
|
**
|
|
** Then the search space should ideally be the samples above and the
|
|
** unique prefixes [a], [b] and [c]. But since that is hard to organize,
|
|
** the code actually searches this set:
|
|
**
|
|
** 0: (a)
|
|
** 1: (a, 5)
|
|
** 2: (a, 10)
|
|
** 3: (a, 10)
|
|
** 4: (b)
|
|
** 5: (b, 5)
|
|
** 6: (c)
|
|
** 7: (c, 100)
|
|
** 8: (c, 105)
|
|
** 9: (c, 105)
|
|
**
|
|
** For each sample in the aSample[] array, N samples are present in the
|
|
** effective sample array. In the above, samples 0 and 1 are based on
|
|
** sample aSample[0]. Samples 2 and 3 on aSample[1] etc.
|
|
**
|
|
** Often, sample i of each block of N effective samples has (i+1) fields.
|
|
** Except, each sample may be extended to ensure that it is greater than or
|
|
** equal to the previous sample in the array. For example, in the above,
|
|
** sample 2 is the first sample of a block of N samples, so at first it
|
|
** appears that it should be 1 field in size. However, that would make it
|
|
** smaller than sample 1, so the binary search would not work. As a result,
|
|
** it is extended to two fields. The duplicates that this creates do not
|
|
** cause any problems.
|
|
*/
|
|
nField = MIN(pRec->nField, pIdx->nSample);
|
|
iCol = 0;
|
|
iSample = pIdx->nSample * nField;
|
|
do{
|
|
int iSamp; /* Index in aSample[] of test sample */
|
|
int n; /* Number of fields in test sample */
|
|
|
|
iTest = (iMin+iSample)/2;
|
|
iSamp = iTest / nField;
|
|
if( iSamp>0 ){
|
|
/* The proposed effective sample is a prefix of sample aSample[iSamp].
|
|
** Specifically, the shortest prefix of at least (1 + iTest%nField)
|
|
** fields that is greater than the previous effective sample. */
|
|
for(n=(iTest % nField) + 1; n<nField; n++){
|
|
if( aSample[iSamp-1].anLt[n-1]!=aSample[iSamp].anLt[n-1] ) break;
|
|
}
|
|
}else{
|
|
n = iTest + 1;
|
|
}
|
|
|
|
pRec->nField = n;
|
|
res = sqlite3VdbeRecordCompare(aSample[iSamp].n, aSample[iSamp].p, pRec);
|
|
if( res<0 ){
|
|
iLower = aSample[iSamp].anLt[n-1] + aSample[iSamp].anEq[n-1];
|
|
iMin = iTest+1;
|
|
}else if( res==0 && n<nField ){
|
|
iLower = aSample[iSamp].anLt[n-1];
|
|
iMin = iTest+1;
|
|
res = -1;
|
|
}else{
|
|
iSample = iTest;
|
|
iCol = n-1;
|
|
}
|
|
}while( res && iMin<iSample );
|
|
i = iSample / nField;
|
|
|
|
#ifdef SQLITE_DEBUG
|
|
/* The following assert statements check that the binary search code
|
|
** above found the right answer. This block serves no purpose other
|
|
** than to invoke the asserts. */
|
|
if( pParse->db->mallocFailed==0 ){
|
|
if( res==0 ){
|
|
/* If (res==0) is true, then pRec must be equal to sample i. */
|
|
assert( i<pIdx->nSample );
|
|
assert( iCol==nField-1 );
|
|
pRec->nField = nField;
|
|
assert( 0==sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)
|
|
|| pParse->db->mallocFailed
|
|
);
|
|
}else{
|
|
/* Unless i==pIdx->nSample, indicating that pRec is larger than
|
|
** all samples in the aSample[] array, pRec must be smaller than the
|
|
** (iCol+1) field prefix of sample i. */
|
|
assert( i<=pIdx->nSample && i>=0 );
|
|
pRec->nField = iCol+1;
|
|
assert( i==pIdx->nSample
|
|
|| sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)>0
|
|
|| pParse->db->mallocFailed );
|
|
|
|
/* if i==0 and iCol==0, then record pRec is smaller than all samples
|
|
** in the aSample[] array. Otherwise, if (iCol>0) then pRec must
|
|
** be greater than or equal to the (iCol) field prefix of sample i.
|
|
** If (i>0), then pRec must also be greater than sample (i-1). */
|
|
if( iCol>0 ){
|
|
pRec->nField = iCol;
|
|
assert( sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)<=0
|
|
|| pParse->db->mallocFailed );
|
|
}
|
|
if( i>0 ){
|
|
pRec->nField = nField;
|
|
assert( sqlite3VdbeRecordCompare(aSample[i-1].n, aSample[i-1].p, pRec)<0
|
|
|| pParse->db->mallocFailed );
|
|
}
|
|
}
|
|
}
|
|
#endif /* ifdef SQLITE_DEBUG */
|
|
|
|
if( res==0 ){
|
|
/* Record pRec is equal to sample i */
|
|
assert( iCol==nField-1 );
|
|
aStat[0] = aSample[i].anLt[iCol];
|
|
aStat[1] = aSample[i].anEq[iCol];
|
|
}else{
|
|
/* At this point, the (iCol+1) field prefix of aSample[i] is the first
|
|
** sample that is greater than pRec. Or, if i==pIdx->nSample then pRec
|
|
** is larger than all samples in the array. */
|
|
tRowcnt iUpper, iGap;
|
|
if( i>=pIdx->nSample ){
|
|
iUpper = sqlite3LogEstToInt(pIdx->aiRowLogEst[0]);
|
|
}else{
|
|
iUpper = aSample[i].anLt[iCol];
|
|
}
|
|
|
|
if( iLower>=iUpper ){
|
|
iGap = 0;
|
|
}else{
|
|
iGap = iUpper - iLower;
|
|
}
|
|
if( roundUp ){
|
|
iGap = (iGap*2)/3;
|
|
}else{
|
|
iGap = iGap/3;
|
|
}
|
|
aStat[0] = iLower + iGap;
|
|
aStat[1] = pIdx->aAvgEq[nField-1];
|
|
}
|
|
|
|
/* Restore the pRec->nField value before returning. */
|
|
pRec->nField = nField;
|
|
return i;
|
|
}
|
|
#endif /* SQLITE_ENABLE_STAT4 */
|
|
|
|
/*
|
|
** If it is not NULL, pTerm is a term that provides an upper or lower
|
|
** bound on a range scan. Without considering pTerm, it is estimated
|
|
** that the scan will visit nNew rows. This function returns the number
|
|
** estimated to be visited after taking pTerm into account.
|
|
**
|
|
** If the user explicitly specified a likelihood() value for this term,
|
|
** then the return value is the likelihood multiplied by the number of
|
|
** input rows. Otherwise, this function assumes that an "IS NOT NULL" term
|
|
** has a likelihood of 0.50, and any other term a likelihood of 0.25.
|
|
*/
|
|
static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){
|
|
LogEst nRet = nNew;
|
|
if( pTerm ){
|
|
if( pTerm->truthProb<=0 ){
|
|
nRet += pTerm->truthProb;
|
|
}else if( (pTerm->wtFlags & TERM_VNULL)==0 ){
|
|
nRet -= 20; assert( 20==sqlite3LogEst(4) );
|
|
}
|
|
}
|
|
return nRet;
|
|
}
|
|
|
|
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
/*
|
|
** Return the affinity for a single column of an index.
|
|
*/
|
|
char sqlite3IndexColumnAffinity(sqlite3 *db, Index *pIdx, int iCol){
|
|
assert( iCol>=0 && iCol<pIdx->nColumn );
|
|
if( !pIdx->zColAff ){
|
|
if( sqlite3IndexAffinityStr(db, pIdx)==0 ) return SQLITE_AFF_BLOB;
|
|
}
|
|
assert( pIdx->zColAff[iCol]!=0 );
|
|
return pIdx->zColAff[iCol];
|
|
}
|
|
#endif
|
|
|
|
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
/*
|
|
** This function is called to estimate the number of rows visited by a
|
|
** range-scan on a skip-scan index. For example:
|
|
**
|
|
** CREATE INDEX i1 ON t1(a, b, c);
|
|
** SELECT * FROM t1 WHERE a=? AND c BETWEEN ? AND ?;
|
|
**
|
|
** Value pLoop->nOut is currently set to the estimated number of rows
|
|
** visited for scanning (a=? AND b=?). This function reduces that estimate
|
|
** by some factor to account for the (c BETWEEN ? AND ?) expression based
|
|
** on the stat4 data for the index. this scan will be peformed multiple
|
|
** times (once for each (a,b) combination that matches a=?) is dealt with
|
|
** by the caller.
|
|
**
|
|
** It does this by scanning through all stat4 samples, comparing values
|
|
** extracted from pLower and pUpper with the corresponding column in each
|
|
** sample. If L and U are the number of samples found to be less than or
|
|
** equal to the values extracted from pLower and pUpper respectively, and
|
|
** N is the total number of samples, the pLoop->nOut value is adjusted
|
|
** as follows:
|
|
**
|
|
** nOut = nOut * ( min(U - L, 1) / N )
|
|
**
|
|
** If pLower is NULL, or a value cannot be extracted from the term, L is
|
|
** set to zero. If pUpper is NULL, or a value cannot be extracted from it,
|
|
** U is set to N.
|
|
**
|
|
** Normally, this function sets *pbDone to 1 before returning. However,
|
|
** if no value can be extracted from either pLower or pUpper (and so the
|
|
** estimate of the number of rows delivered remains unchanged), *pbDone
|
|
** is left as is.
|
|
**
|
|
** If an error occurs, an SQLite error code is returned. Otherwise,
|
|
** SQLITE_OK.
|
|
*/
|
|
static int whereRangeSkipScanEst(
|
|
Parse *pParse, /* Parsing & code generating context */
|
|
WhereTerm *pLower, /* Lower bound on the range. ex: "x>123" Might be NULL */
|
|
WhereTerm *pUpper, /* Upper bound on the range. ex: "x<455" Might be NULL */
|
|
WhereLoop *pLoop, /* Update the .nOut value of this loop */
|
|
int *pbDone /* Set to true if at least one expr. value extracted */
|
|
){
|
|
Index *p = pLoop->u.btree.pIndex;
|
|
int nEq = pLoop->u.btree.nEq;
|
|
sqlite3 *db = pParse->db;
|
|
int nLower = -1;
|
|
int nUpper = p->nSample+1;
|
|
int rc = SQLITE_OK;
|
|
u8 aff = sqlite3IndexColumnAffinity(db, p, nEq);
|
|
CollSeq *pColl;
|
|
|
|
sqlite3_value *p1 = 0; /* Value extracted from pLower */
|
|
sqlite3_value *p2 = 0; /* Value extracted from pUpper */
|
|
sqlite3_value *pVal = 0; /* Value extracted from record */
|
|
|
|
pColl = sqlite3LocateCollSeq(pParse, p->azColl[nEq]);
|
|
if( pLower ){
|
|
rc = sqlite3Stat4ValueFromExpr(pParse, pLower->pExpr->pRight, aff, &p1);
|
|
nLower = 0;
|
|
}
|
|
if( pUpper && rc==SQLITE_OK ){
|
|
rc = sqlite3Stat4ValueFromExpr(pParse, pUpper->pExpr->pRight, aff, &p2);
|
|
nUpper = p2 ? 0 : p->nSample;
|
|
}
|
|
|
|
if( p1 || p2 ){
|
|
int i;
|
|
int nDiff;
|
|
for(i=0; rc==SQLITE_OK && i<p->nSample; i++){
|
|
rc = sqlite3Stat4Column(db, p->aSample[i].p, p->aSample[i].n, nEq, &pVal);
|
|
if( rc==SQLITE_OK && p1 ){
|
|
int res = sqlite3MemCompare(p1, pVal, pColl);
|
|
if( res>=0 ) nLower++;
|
|
}
|
|
if( rc==SQLITE_OK && p2 ){
|
|
int res = sqlite3MemCompare(p2, pVal, pColl);
|
|
if( res>=0 ) nUpper++;
|
|
}
|
|
}
|
|
nDiff = (nUpper - nLower);
|
|
if( nDiff<=0 ) nDiff = 1;
|
|
|
|
/* If there is both an upper and lower bound specified, and the
|
|
** comparisons indicate that they are close together, use the fallback
|
|
** method (assume that the scan visits 1/64 of the rows) for estimating
|
|
** the number of rows visited. Otherwise, estimate the number of rows
|
|
** using the method described in the header comment for this function. */
|
|
if( nDiff!=1 || pUpper==0 || pLower==0 ){
|
|
int nAdjust = (sqlite3LogEst(p->nSample) - sqlite3LogEst(nDiff));
|
|
pLoop->nOut -= nAdjust;
|
|
*pbDone = 1;
|
|
WHERETRACE(0x10, ("range skip-scan regions: %u..%u adjust=%d est=%d\n",
|
|
nLower, nUpper, nAdjust*-1, pLoop->nOut));
|
|
}
|
|
|
|
}else{
|
|
assert( *pbDone==0 );
|
|
}
|
|
|
|
sqlite3ValueFree(p1);
|
|
sqlite3ValueFree(p2);
|
|
sqlite3ValueFree(pVal);
|
|
|
|
return rc;
|
|
}
|
|
#endif /* SQLITE_ENABLE_STAT4 */
|
|
|
|
/*
|
|
** This function is used to estimate the number of rows that will be visited
|
|
** by scanning an index for a range of values. The range may have an upper
|
|
** bound, a lower bound, or both. The WHERE clause terms that set the upper
|
|
** and lower bounds are represented by pLower and pUpper respectively. For
|
|
** example, assuming that index p is on t1(a):
|
|
**
|
|
** ... FROM t1 WHERE a > ? AND a < ? ...
|
|
** |_____| |_____|
|
|
** | |
|
|
** pLower pUpper
|
|
**
|
|
** If either of the upper or lower bound is not present, then NULL is passed in
|
|
** place of the corresponding WhereTerm.
|
|
**
|
|
** The value in (pBuilder->pNew->u.btree.nEq) is the number of the index
|
|
** column subject to the range constraint. Or, equivalently, the number of
|
|
** equality constraints optimized by the proposed index scan. For example,
|
|
** assuming index p is on t1(a, b), and the SQL query is:
|
|
**
|
|
** ... FROM t1 WHERE a = ? AND b > ? AND b < ? ...
|
|
**
|
|
** then nEq is set to 1 (as the range restricted column, b, is the second
|
|
** left-most column of the index). Or, if the query is:
|
|
**
|
|
** ... FROM t1 WHERE a > ? AND a < ? ...
|
|
**
|
|
** then nEq is set to 0.
|
|
**
|
|
** When this function is called, *pnOut is set to the sqlite3LogEst() of the
|
|
** number of rows that the index scan is expected to visit without
|
|
** considering the range constraints. If nEq is 0, then *pnOut is the number of
|
|
** rows in the index. Assuming no error occurs, *pnOut is adjusted (reduced)
|
|
** to account for the range constraints pLower and pUpper.
|
|
**
|
|
** In the absence of sqlite_stat4 ANALYZE data, or if such data cannot be
|
|
** used, a single range inequality reduces the search space by a factor of 4.
|
|
** and a pair of constraints (x>? AND x<?) reduces the expected number of
|
|
** rows visited by a factor of 64.
|
|
*/
|
|
static int whereRangeScanEst(
|
|
Parse *pParse, /* Parsing & code generating context */
|
|
WhereLoopBuilder *pBuilder,
|
|
WhereTerm *pLower, /* Lower bound on the range. ex: "x>123" Might be NULL */
|
|
WhereTerm *pUpper, /* Upper bound on the range. ex: "x<455" Might be NULL */
|
|
WhereLoop *pLoop /* Modify the .nOut and maybe .rRun fields */
|
|
){
|
|
int rc = SQLITE_OK;
|
|
int nOut = pLoop->nOut;
|
|
LogEst nNew;
|
|
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
Index *p = pLoop->u.btree.pIndex;
|
|
int nEq = pLoop->u.btree.nEq;
|
|
|
|
if( p->nSample>0 && ALWAYS(nEq<p->nSampleCol)
|
|
&& OptimizationEnabled(pParse->db, SQLITE_Stat4)
|
|
){
|
|
if( nEq==pBuilder->nRecValid ){
|
|
UnpackedRecord *pRec = pBuilder->pRec;
|
|
tRowcnt a[2];
|
|
int nBtm = pLoop->u.btree.nBtm;
|
|
int nTop = pLoop->u.btree.nTop;
|
|
|
|
/* Variable iLower will be set to the estimate of the number of rows in
|
|
** the index that are less than the lower bound of the range query. The
|
|
** lower bound being the concatenation of $P and $L, where $P is the
|
|
** key-prefix formed by the nEq values matched against the nEq left-most
|
|
** columns of the index, and $L is the value in pLower.
|
|
**
|
|
** Or, if pLower is NULL or $L cannot be extracted from it (because it
|
|
** is not a simple variable or literal value), the lower bound of the
|
|
** range is $P. Due to a quirk in the way whereKeyStats() works, even
|
|
** if $L is available, whereKeyStats() is called for both ($P) and
|
|
** ($P:$L) and the larger of the two returned values is used.
|
|
**
|
|
** Similarly, iUpper is to be set to the estimate of the number of rows
|
|
** less than the upper bound of the range query. Where the upper bound
|
|
** is either ($P) or ($P:$U). Again, even if $U is available, both values
|
|
** of iUpper are requested of whereKeyStats() and the smaller used.
|
|
**
|
|
** The number of rows between the two bounds is then just iUpper-iLower.
|
|
*/
|
|
tRowcnt iLower; /* Rows less than the lower bound */
|
|
tRowcnt iUpper; /* Rows less than the upper bound */
|
|
int iLwrIdx = -2; /* aSample[] for the lower bound */
|
|
int iUprIdx = -1; /* aSample[] for the upper bound */
|
|
|
|
if( pRec ){
|
|
testcase( pRec->nField!=pBuilder->nRecValid );
|
|
pRec->nField = pBuilder->nRecValid;
|
|
}
|
|
/* Determine iLower and iUpper using ($P) only. */
|
|
if( nEq==0 ){
|
|
iLower = 0;
|
|
iUpper = p->nRowEst0;
|
|
}else{
|
|
/* Note: this call could be optimized away - since the same values must
|
|
** have been requested when testing key $P in whereEqualScanEst(). */
|
|
whereKeyStats(pParse, p, pRec, 0, a);
|
|
iLower = a[0];
|
|
iUpper = a[0] + a[1];
|
|
}
|
|
|
|
assert( pLower==0 || (pLower->eOperator & (WO_GT|WO_GE))!=0 );
|
|
assert( pUpper==0 || (pUpper->eOperator & (WO_LT|WO_LE))!=0 );
|
|
assert( p->aSortOrder!=0 );
|
|
if( p->aSortOrder[nEq] ){
|
|
/* The roles of pLower and pUpper are swapped for a DESC index */
|
|
SWAP(WhereTerm*, pLower, pUpper);
|
|
SWAP(int, nBtm, nTop);
|
|
}
|
|
|
|
/* If possible, improve on the iLower estimate using ($P:$L). */
|
|
if( pLower ){
|
|
int n; /* Values extracted from pExpr */
|
|
Expr *pExpr = pLower->pExpr->pRight;
|
|
rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, nBtm, nEq, &n);
|
|
if( rc==SQLITE_OK && n ){
|
|
tRowcnt iNew;
|
|
u16 mask = WO_GT|WO_LE;
|
|
if( sqlite3ExprVectorSize(pExpr)>n ) mask = (WO_LE|WO_LT);
|
|
iLwrIdx = whereKeyStats(pParse, p, pRec, 0, a);
|
|
iNew = a[0] + ((pLower->eOperator & mask) ? a[1] : 0);
|
|
if( iNew>iLower ) iLower = iNew;
|
|
nOut--;
|
|
pLower = 0;
|
|
}
|
|
}
|
|
|
|
/* If possible, improve on the iUpper estimate using ($P:$U). */
|
|
if( pUpper ){
|
|
int n; /* Values extracted from pExpr */
|
|
Expr *pExpr = pUpper->pExpr->pRight;
|
|
rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, nTop, nEq, &n);
|
|
if( rc==SQLITE_OK && n ){
|
|
tRowcnt iNew;
|
|
u16 mask = WO_GT|WO_LE;
|
|
if( sqlite3ExprVectorSize(pExpr)>n ) mask = (WO_LE|WO_LT);
|
|
iUprIdx = whereKeyStats(pParse, p, pRec, 1, a);
|
|
iNew = a[0] + ((pUpper->eOperator & mask) ? a[1] : 0);
|
|
if( iNew<iUpper ) iUpper = iNew;
|
|
nOut--;
|
|
pUpper = 0;
|
|
}
|
|
}
|
|
|
|
pBuilder->pRec = pRec;
|
|
if( rc==SQLITE_OK ){
|
|
if( iUpper>iLower ){
|
|
nNew = sqlite3LogEst(iUpper - iLower);
|
|
/* TUNING: If both iUpper and iLower are derived from the same
|
|
** sample, then assume they are 4x more selective. This brings
|
|
** the estimated selectivity more in line with what it would be
|
|
** if estimated without the use of STAT4 tables. */
|
|
if( iLwrIdx==iUprIdx ) nNew -= 20; assert( 20==sqlite3LogEst(4) );
|
|
}else{
|
|
nNew = 10; assert( 10==sqlite3LogEst(2) );
|
|
}
|
|
if( nNew<nOut ){
|
|
nOut = nNew;
|
|
}
|
|
WHERETRACE(0x10, ("STAT4 range scan: %u..%u est=%d\n",
|
|
(u32)iLower, (u32)iUpper, nOut));
|
|
}
|
|
}else{
|
|
int bDone = 0;
|
|
rc = whereRangeSkipScanEst(pParse, pLower, pUpper, pLoop, &bDone);
|
|
if( bDone ) return rc;
|
|
}
|
|
}
|
|
#else
|
|
UNUSED_PARAMETER(pParse);
|
|
UNUSED_PARAMETER(pBuilder);
|
|
assert( pLower || pUpper );
|
|
#endif
|
|
assert( pUpper==0 || (pUpper->wtFlags & TERM_VNULL)==0 );
|
|
nNew = whereRangeAdjust(pLower, nOut);
|
|
nNew = whereRangeAdjust(pUpper, nNew);
|
|
|
|
/* TUNING: If there is both an upper and lower limit and neither limit
|
|
** has an application-defined likelihood(), assume the range is
|
|
** reduced by an additional 75%. This means that, by default, an open-ended
|
|
** range query (e.g. col > ?) is assumed to match 1/4 of the rows in the
|
|
** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to
|
|
** match 1/64 of the index. */
|
|
if( pLower && pLower->truthProb>0 && pUpper && pUpper->truthProb>0 ){
|
|
nNew -= 20;
|
|
}
|
|
|
|
nOut -= (pLower!=0) + (pUpper!=0);
|
|
if( nNew<10 ) nNew = 10;
|
|
if( nNew<nOut ) nOut = nNew;
|
|
#if defined(WHERETRACE_ENABLED)
|
|
if( pLoop->nOut>nOut ){
|
|
WHERETRACE(0x10,("Range scan lowers nOut from %d to %d\n",
|
|
pLoop->nOut, nOut));
|
|
}
|
|
#endif
|
|
pLoop->nOut = (LogEst)nOut;
|
|
return rc;
|
|
}
|
|
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
/*
|
|
** Estimate the number of rows that will be returned based on
|
|
** an equality constraint x=VALUE and where that VALUE occurs in
|
|
** the histogram data. This only works when x is the left-most
|
|
** column of an index and sqlite_stat4 histogram data is available
|
|
** for that index. When pExpr==NULL that means the constraint is
|
|
** "x IS NULL" instead of "x=VALUE".
|
|
**
|
|
** Write the estimated row count into *pnRow and return SQLITE_OK.
|
|
** If unable to make an estimate, leave *pnRow unchanged and return
|
|
** non-zero.
|
|
**
|
|
** This routine can fail if it is unable to load a collating sequence
|
|
** required for string comparison, or if unable to allocate memory
|
|
** for a UTF conversion required for comparison. The error is stored
|
|
** in the pParse structure.
|
|
*/
|
|
static int whereEqualScanEst(
|
|
Parse *pParse, /* Parsing & code generating context */
|
|
WhereLoopBuilder *pBuilder,
|
|
Expr *pExpr, /* Expression for VALUE in the x=VALUE constraint */
|
|
tRowcnt *pnRow /* Write the revised row estimate here */
|
|
){
|
|
Index *p = pBuilder->pNew->u.btree.pIndex;
|
|
int nEq = pBuilder->pNew->u.btree.nEq;
|
|
UnpackedRecord *pRec = pBuilder->pRec;
|
|
int rc; /* Subfunction return code */
|
|
tRowcnt a[2]; /* Statistics */
|
|
int bOk;
|
|
|
|
assert( nEq>=1 );
|
|
assert( nEq<=p->nColumn );
|
|
assert( p->aSample!=0 );
|
|
assert( p->nSample>0 );
|
|
assert( pBuilder->nRecValid<nEq );
|
|
|
|
/* If values are not available for all fields of the index to the left
|
|
** of this one, no estimate can be made. Return SQLITE_NOTFOUND. */
|
|
if( pBuilder->nRecValid<(nEq-1) ){
|
|
return SQLITE_NOTFOUND;
|
|
}
|
|
|
|
/* This is an optimization only. The call to sqlite3Stat4ProbeSetValue()
|
|
** below would return the same value. */
|
|
if( nEq>=p->nColumn ){
|
|
*pnRow = 1;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, 1, nEq-1, &bOk);
|
|
pBuilder->pRec = pRec;
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
if( bOk==0 ) return SQLITE_NOTFOUND;
|
|
pBuilder->nRecValid = nEq;
|
|
|
|
whereKeyStats(pParse, p, pRec, 0, a);
|
|
WHERETRACE(0x10,("equality scan regions %s(%d): %d\n",
|
|
p->zName, nEq-1, (int)a[1]));
|
|
*pnRow = a[1];
|
|
|
|
return rc;
|
|
}
|
|
#endif /* SQLITE_ENABLE_STAT4 */
|
|
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
/*
|
|
** Estimate the number of rows that will be returned based on
|
|
** an IN constraint where the right-hand side of the IN operator
|
|
** is a list of values. Example:
|
|
**
|
|
** WHERE x IN (1,2,3,4)
|
|
**
|
|
** Write the estimated row count into *pnRow and return SQLITE_OK.
|
|
** If unable to make an estimate, leave *pnRow unchanged and return
|
|
** non-zero.
|
|
**
|
|
** This routine can fail if it is unable to load a collating sequence
|
|
** required for string comparison, or if unable to allocate memory
|
|
** for a UTF conversion required for comparison. The error is stored
|
|
** in the pParse structure.
|
|
*/
|
|
static int whereInScanEst(
|
|
Parse *pParse, /* Parsing & code generating context */
|
|
WhereLoopBuilder *pBuilder,
|
|
ExprList *pList, /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
|
|
tRowcnt *pnRow /* Write the revised row estimate here */
|
|
){
|
|
Index *p = pBuilder->pNew->u.btree.pIndex;
|
|
i64 nRow0 = sqlite3LogEstToInt(p->aiRowLogEst[0]);
|
|
int nRecValid = pBuilder->nRecValid;
|
|
int rc = SQLITE_OK; /* Subfunction return code */
|
|
tRowcnt nEst; /* Number of rows for a single term */
|
|
tRowcnt nRowEst = 0; /* New estimate of the number of rows */
|
|
int i; /* Loop counter */
|
|
|
|
assert( p->aSample!=0 );
|
|
for(i=0; rc==SQLITE_OK && i<pList->nExpr; i++){
|
|
nEst = nRow0;
|
|
rc = whereEqualScanEst(pParse, pBuilder, pList->a[i].pExpr, &nEst);
|
|
nRowEst += nEst;
|
|
pBuilder->nRecValid = nRecValid;
|
|
}
|
|
|
|
if( rc==SQLITE_OK ){
|
|
if( nRowEst > nRow0 ) nRowEst = nRow0;
|
|
*pnRow = nRowEst;
|
|
WHERETRACE(0x10,("IN row estimate: est=%d\n", nRowEst));
|
|
}
|
|
assert( pBuilder->nRecValid==nRecValid );
|
|
return rc;
|
|
}
|
|
#endif /* SQLITE_ENABLE_STAT4 */
|
|
|
|
|
|
#ifdef WHERETRACE_ENABLED
|
|
/*
|
|
** Print the content of a WhereTerm object
|
|
*/
|
|
void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm){
|
|
if( pTerm==0 ){
|
|
sqlite3DebugPrintf("TERM-%-3d NULL\n", iTerm);
|
|
}else{
|
|
char zType[8];
|
|
char zLeft[50];
|
|
memcpy(zType, "....", 5);
|
|
if( pTerm->wtFlags & TERM_VIRTUAL ) zType[0] = 'V';
|
|
if( pTerm->eOperator & WO_EQUIV ) zType[1] = 'E';
|
|
if( ExprHasProperty(pTerm->pExpr, EP_OuterON) ) zType[2] = 'L';
|
|
if( pTerm->wtFlags & TERM_CODED ) zType[3] = 'C';
|
|
if( pTerm->eOperator & WO_SINGLE ){
|
|
assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
|
|
sqlite3_snprintf(sizeof(zLeft),zLeft,"left={%d:%d}",
|
|
pTerm->leftCursor, pTerm->u.x.leftColumn);
|
|
}else if( (pTerm->eOperator & WO_OR)!=0 && pTerm->u.pOrInfo!=0 ){
|
|
sqlite3_snprintf(sizeof(zLeft),zLeft,"indexable=0x%llx",
|
|
pTerm->u.pOrInfo->indexable);
|
|
}else{
|
|
sqlite3_snprintf(sizeof(zLeft),zLeft,"left=%d", pTerm->leftCursor);
|
|
}
|
|
sqlite3DebugPrintf(
|
|
"TERM-%-3d %p %s %-12s op=%03x wtFlags=%04x",
|
|
iTerm, pTerm, zType, zLeft, pTerm->eOperator, pTerm->wtFlags);
|
|
/* The 0x10000 .wheretrace flag causes extra information to be
|
|
** shown about each Term */
|
|
if( sqlite3WhereTrace & 0x10000 ){
|
|
sqlite3DebugPrintf(" prob=%-3d prereq=%llx,%llx",
|
|
pTerm->truthProb, (u64)pTerm->prereqAll, (u64)pTerm->prereqRight);
|
|
}
|
|
if( (pTerm->eOperator & (WO_OR|WO_AND))==0 && pTerm->u.x.iField ){
|
|
sqlite3DebugPrintf(" iField=%d", pTerm->u.x.iField);
|
|
}
|
|
if( pTerm->iParent>=0 ){
|
|
sqlite3DebugPrintf(" iParent=%d", pTerm->iParent);
|
|
}
|
|
sqlite3DebugPrintf("\n");
|
|
sqlite3TreeViewExpr(0, pTerm->pExpr, 0);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#ifdef WHERETRACE_ENABLED
|
|
/*
|
|
** Show the complete content of a WhereClause
|
|
*/
|
|
void sqlite3WhereClausePrint(WhereClause *pWC){
|
|
int i;
|
|
for(i=0; i<pWC->nTerm; i++){
|
|
sqlite3WhereTermPrint(&pWC->a[i], i);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#ifdef WHERETRACE_ENABLED
|
|
/*
|
|
** Print a WhereLoop object for debugging purposes
|
|
*/
|
|
void sqlite3WhereLoopPrint(WhereLoop *p, WhereClause *pWC){
|
|
WhereInfo *pWInfo = pWC->pWInfo;
|
|
int nb = 1+(pWInfo->pTabList->nSrc+3)/4;
|
|
SrcItem *pItem = pWInfo->pTabList->a + p->iTab;
|
|
Table *pTab = pItem->pTab;
|
|
Bitmask mAll = (((Bitmask)1)<<(nb*4)) - 1;
|
|
sqlite3DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId,
|
|
p->iTab, nb, p->maskSelf, nb, p->prereq & mAll);
|
|
sqlite3DebugPrintf(" %12s",
|
|
pItem->zAlias ? pItem->zAlias : pTab->zName);
|
|
if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
|
|
const char *zName;
|
|
if( p->u.btree.pIndex && (zName = p->u.btree.pIndex->zName)!=0 ){
|
|
if( strncmp(zName, "sqlite_autoindex_", 17)==0 ){
|
|
int i = sqlite3Strlen30(zName) - 1;
|
|
while( zName[i]!='_' ) i--;
|
|
zName += i;
|
|
}
|
|
sqlite3DebugPrintf(".%-16s %2d", zName, p->u.btree.nEq);
|
|
}else{
|
|
sqlite3DebugPrintf("%20s","");
|
|
}
|
|
}else{
|
|
char *z;
|
|
if( p->u.vtab.idxStr ){
|
|
z = sqlite3_mprintf("(%d,\"%s\",%#x)",
|
|
p->u.vtab.idxNum, p->u.vtab.idxStr, p->u.vtab.omitMask);
|
|
}else{
|
|
z = sqlite3_mprintf("(%d,%x)", p->u.vtab.idxNum, p->u.vtab.omitMask);
|
|
}
|
|
sqlite3DebugPrintf(" %-19s", z);
|
|
sqlite3_free(z);
|
|
}
|
|
if( p->wsFlags & WHERE_SKIPSCAN ){
|
|
sqlite3DebugPrintf(" f %06x %d-%d", p->wsFlags, p->nLTerm,p->nSkip);
|
|
}else{
|
|
sqlite3DebugPrintf(" f %06x N %d", p->wsFlags, p->nLTerm);
|
|
}
|
|
sqlite3DebugPrintf(" cost %d,%d,%d\n", p->rSetup, p->rRun, p->nOut);
|
|
if( p->nLTerm && (sqlite3WhereTrace & 0x100)!=0 ){
|
|
int i;
|
|
for(i=0; i<p->nLTerm; i++){
|
|
sqlite3WhereTermPrint(p->aLTerm[i], i);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Convert bulk memory into a valid WhereLoop that can be passed
|
|
** to whereLoopClear harmlessly.
|
|
*/
|
|
static void whereLoopInit(WhereLoop *p){
|
|
p->aLTerm = p->aLTermSpace;
|
|
p->nLTerm = 0;
|
|
p->nLSlot = ArraySize(p->aLTermSpace);
|
|
p->wsFlags = 0;
|
|
}
|
|
|
|
/*
|
|
** Clear the WhereLoop.u union. Leave WhereLoop.pLTerm intact.
|
|
*/
|
|
static void whereLoopClearUnion(sqlite3 *db, WhereLoop *p){
|
|
if( p->wsFlags & (WHERE_VIRTUALTABLE|WHERE_AUTO_INDEX) ){
|
|
if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 && p->u.vtab.needFree ){
|
|
sqlite3_free(p->u.vtab.idxStr);
|
|
p->u.vtab.needFree = 0;
|
|
p->u.vtab.idxStr = 0;
|
|
}else if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 && p->u.btree.pIndex!=0 ){
|
|
sqlite3DbFree(db, p->u.btree.pIndex->zColAff);
|
|
sqlite3DbFreeNN(db, p->u.btree.pIndex);
|
|
p->u.btree.pIndex = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Deallocate internal memory used by a WhereLoop object. Leave the
|
|
** object in an initialized state, as if it had been newly allocated.
|
|
*/
|
|
static void whereLoopClear(sqlite3 *db, WhereLoop *p){
|
|
if( p->aLTerm!=p->aLTermSpace ){
|
|
sqlite3DbFreeNN(db, p->aLTerm);
|
|
p->aLTerm = p->aLTermSpace;
|
|
p->nLSlot = ArraySize(p->aLTermSpace);
|
|
}
|
|
whereLoopClearUnion(db, p);
|
|
p->nLTerm = 0;
|
|
p->wsFlags = 0;
|
|
}
|
|
|
|
/*
|
|
** Increase the memory allocation for pLoop->aLTerm[] to be at least n.
|
|
*/
|
|
static int whereLoopResize(sqlite3 *db, WhereLoop *p, int n){
|
|
WhereTerm **paNew;
|
|
if( p->nLSlot>=n ) return SQLITE_OK;
|
|
n = (n+7)&~7;
|
|
paNew = sqlite3DbMallocRawNN(db, sizeof(p->aLTerm[0])*n);
|
|
if( paNew==0 ) return SQLITE_NOMEM_BKPT;
|
|
memcpy(paNew, p->aLTerm, sizeof(p->aLTerm[0])*p->nLSlot);
|
|
if( p->aLTerm!=p->aLTermSpace ) sqlite3DbFreeNN(db, p->aLTerm);
|
|
p->aLTerm = paNew;
|
|
p->nLSlot = n;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Transfer content from the second pLoop into the first.
|
|
*/
|
|
static int whereLoopXfer(sqlite3 *db, WhereLoop *pTo, WhereLoop *pFrom){
|
|
whereLoopClearUnion(db, pTo);
|
|
if( pFrom->nLTerm > pTo->nLSlot
|
|
&& whereLoopResize(db, pTo, pFrom->nLTerm)
|
|
){
|
|
memset(pTo, 0, WHERE_LOOP_XFER_SZ);
|
|
return SQLITE_NOMEM_BKPT;
|
|
}
|
|
memcpy(pTo, pFrom, WHERE_LOOP_XFER_SZ);
|
|
memcpy(pTo->aLTerm, pFrom->aLTerm, pTo->nLTerm*sizeof(pTo->aLTerm[0]));
|
|
if( pFrom->wsFlags & WHERE_VIRTUALTABLE ){
|
|
pFrom->u.vtab.needFree = 0;
|
|
}else if( (pFrom->wsFlags & WHERE_AUTO_INDEX)!=0 ){
|
|
pFrom->u.btree.pIndex = 0;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Delete a WhereLoop object
|
|
*/
|
|
static void whereLoopDelete(sqlite3 *db, WhereLoop *p){
|
|
whereLoopClear(db, p);
|
|
sqlite3DbFreeNN(db, p);
|
|
}
|
|
|
|
/*
|
|
** Free a WhereInfo structure
|
|
*/
|
|
static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
|
|
assert( pWInfo!=0 );
|
|
sqlite3WhereClauseClear(&pWInfo->sWC);
|
|
while( pWInfo->pLoops ){
|
|
WhereLoop *p = pWInfo->pLoops;
|
|
pWInfo->pLoops = p->pNextLoop;
|
|
whereLoopDelete(db, p);
|
|
}
|
|
assert( pWInfo->pExprMods==0 );
|
|
while( pWInfo->pMemToFree ){
|
|
WhereMemBlock *pNext = pWInfo->pMemToFree->pNext;
|
|
sqlite3DbFreeNN(db, pWInfo->pMemToFree);
|
|
pWInfo->pMemToFree = pNext;
|
|
}
|
|
sqlite3DbFreeNN(db, pWInfo);
|
|
}
|
|
|
|
/* Undo all Expr node modifications
|
|
*/
|
|
static void whereUndoExprMods(WhereInfo *pWInfo){
|
|
while( pWInfo->pExprMods ){
|
|
WhereExprMod *p = pWInfo->pExprMods;
|
|
pWInfo->pExprMods = p->pNext;
|
|
memcpy(p->pExpr, &p->orig, sizeof(p->orig));
|
|
sqlite3DbFree(pWInfo->pParse->db, p);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Return TRUE if all of the following are true:
|
|
**
|
|
** (1) X has the same or lower cost, or returns the same or fewer rows,
|
|
** than Y.
|
|
** (2) X uses fewer WHERE clause terms than Y
|
|
** (3) Every WHERE clause term used by X is also used by Y
|
|
** (4) X skips at least as many columns as Y
|
|
** (5) If X is a covering index, than Y is too
|
|
**
|
|
** Conditions (2) and (3) mean that X is a "proper subset" of Y.
|
|
** If X is a proper subset of Y then Y is a better choice and ought
|
|
** to have a lower cost. This routine returns TRUE when that cost
|
|
** relationship is inverted and needs to be adjusted. Constraint (4)
|
|
** was added because if X uses skip-scan less than Y it still might
|
|
** deserve a lower cost even if it is a proper subset of Y. Constraint (5)
|
|
** was added because a covering index probably deserves to have a lower cost
|
|
** than a non-covering index even if it is a proper subset.
|
|
*/
|
|
static int whereLoopCheaperProperSubset(
|
|
const WhereLoop *pX, /* First WhereLoop to compare */
|
|
const WhereLoop *pY /* Compare against this WhereLoop */
|
|
){
|
|
int i, j;
|
|
if( pX->nLTerm-pX->nSkip >= pY->nLTerm-pY->nSkip ){
|
|
return 0; /* X is not a subset of Y */
|
|
}
|
|
if( pX->rRun>pY->rRun && pX->nOut>pY->nOut ) return 0;
|
|
if( pY->nSkip > pX->nSkip ) return 0;
|
|
for(i=pX->nLTerm-1; i>=0; i--){
|
|
if( pX->aLTerm[i]==0 ) continue;
|
|
for(j=pY->nLTerm-1; j>=0; j--){
|
|
if( pY->aLTerm[j]==pX->aLTerm[i] ) break;
|
|
}
|
|
if( j<0 ) return 0; /* X not a subset of Y since term X[i] not used by Y */
|
|
}
|
|
if( (pX->wsFlags&WHERE_IDX_ONLY)!=0
|
|
&& (pY->wsFlags&WHERE_IDX_ONLY)==0 ){
|
|
return 0; /* Constraint (5) */
|
|
}
|
|
return 1; /* All conditions meet */
|
|
}
|
|
|
|
/*
|
|
** Try to adjust the cost and number of output rows of WhereLoop pTemplate
|
|
** upwards or downwards so that:
|
|
**
|
|
** (1) pTemplate costs less than any other WhereLoops that are a proper
|
|
** subset of pTemplate
|
|
**
|
|
** (2) pTemplate costs more than any other WhereLoops for which pTemplate
|
|
** is a proper subset.
|
|
**
|
|
** To say "WhereLoop X is a proper subset of Y" means that X uses fewer
|
|
** WHERE clause terms than Y and that every WHERE clause term used by X is
|
|
** also used by Y.
|
|
*/
|
|
static void whereLoopAdjustCost(const WhereLoop *p, WhereLoop *pTemplate){
|
|
if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return;
|
|
for(; p; p=p->pNextLoop){
|
|
if( p->iTab!=pTemplate->iTab ) continue;
|
|
if( (p->wsFlags & WHERE_INDEXED)==0 ) continue;
|
|
if( whereLoopCheaperProperSubset(p, pTemplate) ){
|
|
/* Adjust pTemplate cost downward so that it is cheaper than its
|
|
** subset p. */
|
|
WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n",
|
|
pTemplate->rRun, pTemplate->nOut,
|
|
MIN(p->rRun, pTemplate->rRun),
|
|
MIN(p->nOut - 1, pTemplate->nOut)));
|
|
pTemplate->rRun = MIN(p->rRun, pTemplate->rRun);
|
|
pTemplate->nOut = MIN(p->nOut - 1, pTemplate->nOut);
|
|
}else if( whereLoopCheaperProperSubset(pTemplate, p) ){
|
|
/* Adjust pTemplate cost upward so that it is costlier than p since
|
|
** pTemplate is a proper subset of p */
|
|
WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n",
|
|
pTemplate->rRun, pTemplate->nOut,
|
|
MAX(p->rRun, pTemplate->rRun),
|
|
MAX(p->nOut + 1, pTemplate->nOut)));
|
|
pTemplate->rRun = MAX(p->rRun, pTemplate->rRun);
|
|
pTemplate->nOut = MAX(p->nOut + 1, pTemplate->nOut);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Search the list of WhereLoops in *ppPrev looking for one that can be
|
|
** replaced by pTemplate.
|
|
**
|
|
** Return NULL if pTemplate does not belong on the WhereLoop list.
|
|
** In other words if pTemplate ought to be dropped from further consideration.
|
|
**
|
|
** If pX is a WhereLoop that pTemplate can replace, then return the
|
|
** link that points to pX.
|
|
**
|
|
** If pTemplate cannot replace any existing element of the list but needs
|
|
** to be added to the list as a new entry, then return a pointer to the
|
|
** tail of the list.
|
|
*/
|
|
static WhereLoop **whereLoopFindLesser(
|
|
WhereLoop **ppPrev,
|
|
const WhereLoop *pTemplate
|
|
){
|
|
WhereLoop *p;
|
|
for(p=(*ppPrev); p; ppPrev=&p->pNextLoop, p=*ppPrev){
|
|
if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){
|
|
/* If either the iTab or iSortIdx values for two WhereLoop are different
|
|
** then those WhereLoops need to be considered separately. Neither is
|
|
** a candidate to replace the other. */
|
|
continue;
|
|
}
|
|
/* In the current implementation, the rSetup value is either zero
|
|
** or the cost of building an automatic index (NlogN) and the NlogN
|
|
** is the same for compatible WhereLoops. */
|
|
assert( p->rSetup==0 || pTemplate->rSetup==0
|
|
|| p->rSetup==pTemplate->rSetup );
|
|
|
|
/* whereLoopAddBtree() always generates and inserts the automatic index
|
|
** case first. Hence compatible candidate WhereLoops never have a larger
|
|
** rSetup. Call this SETUP-INVARIANT */
|
|
assert( p->rSetup>=pTemplate->rSetup );
|
|
|
|
/* Any loop using an appliation-defined index (or PRIMARY KEY or
|
|
** UNIQUE constraint) with one or more == constraints is better
|
|
** than an automatic index. Unless it is a skip-scan. */
|
|
if( (p->wsFlags & WHERE_AUTO_INDEX)!=0
|
|
&& (pTemplate->nSkip)==0
|
|
&& (pTemplate->wsFlags & WHERE_INDEXED)!=0
|
|
&& (pTemplate->wsFlags & WHERE_COLUMN_EQ)!=0
|
|
&& (p->prereq & pTemplate->prereq)==pTemplate->prereq
|
|
){
|
|
break;
|
|
}
|
|
|
|
/* If existing WhereLoop p is better than pTemplate, pTemplate can be
|
|
** discarded. WhereLoop p is better if:
|
|
** (1) p has no more dependencies than pTemplate, and
|
|
** (2) p has an equal or lower cost than pTemplate
|
|
*/
|
|
if( (p->prereq & pTemplate->prereq)==p->prereq /* (1) */
|
|
&& p->rSetup<=pTemplate->rSetup /* (2a) */
|
|
&& p->rRun<=pTemplate->rRun /* (2b) */
|
|
&& p->nOut<=pTemplate->nOut /* (2c) */
|
|
){
|
|
return 0; /* Discard pTemplate */
|
|
}
|
|
|
|
/* If pTemplate is always better than p, then cause p to be overwritten
|
|
** with pTemplate. pTemplate is better than p if:
|
|
** (1) pTemplate has no more dependences than p, and
|
|
** (2) pTemplate has an equal or lower cost than p.
|
|
*/
|
|
if( (p->prereq & pTemplate->prereq)==pTemplate->prereq /* (1) */
|
|
&& p->rRun>=pTemplate->rRun /* (2a) */
|
|
&& p->nOut>=pTemplate->nOut /* (2b) */
|
|
){
|
|
assert( p->rSetup>=pTemplate->rSetup ); /* SETUP-INVARIANT above */
|
|
break; /* Cause p to be overwritten by pTemplate */
|
|
}
|
|
}
|
|
return ppPrev;
|
|
}
|
|
|
|
/*
|
|
** Insert or replace a WhereLoop entry using the template supplied.
|
|
**
|
|
** An existing WhereLoop entry might be overwritten if the new template
|
|
** is better and has fewer dependencies. Or the template will be ignored
|
|
** and no insert will occur if an existing WhereLoop is faster and has
|
|
** fewer dependencies than the template. Otherwise a new WhereLoop is
|
|
** added based on the template.
|
|
**
|
|
** If pBuilder->pOrSet is not NULL then we care about only the
|
|
** prerequisites and rRun and nOut costs of the N best loops. That
|
|
** information is gathered in the pBuilder->pOrSet object. This special
|
|
** processing mode is used only for OR clause processing.
|
|
**
|
|
** When accumulating multiple loops (when pBuilder->pOrSet is NULL) we
|
|
** still might overwrite similar loops with the new template if the
|
|
** new template is better. Loops may be overwritten if the following
|
|
** conditions are met:
|
|
**
|
|
** (1) They have the same iTab.
|
|
** (2) They have the same iSortIdx.
|
|
** (3) The template has same or fewer dependencies than the current loop
|
|
** (4) The template has the same or lower cost than the current loop
|
|
*/
|
|
static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
|
|
WhereLoop **ppPrev, *p;
|
|
WhereInfo *pWInfo = pBuilder->pWInfo;
|
|
sqlite3 *db = pWInfo->pParse->db;
|
|
int rc;
|
|
|
|
/* Stop the search once we hit the query planner search limit */
|
|
if( pBuilder->iPlanLimit==0 ){
|
|
WHERETRACE(0xffffffff,("=== query planner search limit reached ===\n"));
|
|
if( pBuilder->pOrSet ) pBuilder->pOrSet->n = 0;
|
|
return SQLITE_DONE;
|
|
}
|
|
pBuilder->iPlanLimit--;
|
|
|
|
whereLoopAdjustCost(pWInfo->pLoops, pTemplate);
|
|
|
|
/* If pBuilder->pOrSet is defined, then only keep track of the costs
|
|
** and prereqs.
|
|
*/
|
|
if( pBuilder->pOrSet!=0 ){
|
|
if( pTemplate->nLTerm ){
|
|
#if WHERETRACE_ENABLED
|
|
u16 n = pBuilder->pOrSet->n;
|
|
int x =
|
|
#endif
|
|
whereOrInsert(pBuilder->pOrSet, pTemplate->prereq, pTemplate->rRun,
|
|
pTemplate->nOut);
|
|
#if WHERETRACE_ENABLED /* 0x8 */
|
|
if( sqlite3WhereTrace & 0x8 ){
|
|
sqlite3DebugPrintf(x?" or-%d: ":" or-X: ", n);
|
|
sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
|
|
}
|
|
#endif
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/* Look for an existing WhereLoop to replace with pTemplate
|
|
*/
|
|
ppPrev = whereLoopFindLesser(&pWInfo->pLoops, pTemplate);
|
|
|
|
if( ppPrev==0 ){
|
|
/* There already exists a WhereLoop on the list that is better
|
|
** than pTemplate, so just ignore pTemplate */
|
|
#if WHERETRACE_ENABLED /* 0x8 */
|
|
if( sqlite3WhereTrace & 0x8 ){
|
|
sqlite3DebugPrintf(" skip: ");
|
|
sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
|
|
}
|
|
#endif
|
|
return SQLITE_OK;
|
|
}else{
|
|
p = *ppPrev;
|
|
}
|
|
|
|
/* If we reach this point it means that either p[] should be overwritten
|
|
** with pTemplate[] if p[] exists, or if p==NULL then allocate a new
|
|
** WhereLoop and insert it.
|
|
*/
|
|
#if WHERETRACE_ENABLED /* 0x8 */
|
|
if( sqlite3WhereTrace & 0x8 ){
|
|
if( p!=0 ){
|
|
sqlite3DebugPrintf("replace: ");
|
|
sqlite3WhereLoopPrint(p, pBuilder->pWC);
|
|
sqlite3DebugPrintf(" with: ");
|
|
}else{
|
|
sqlite3DebugPrintf(" add: ");
|
|
}
|
|
sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
|
|
}
|
|
#endif
|
|
if( p==0 ){
|
|
/* Allocate a new WhereLoop to add to the end of the list */
|
|
*ppPrev = p = sqlite3DbMallocRawNN(db, sizeof(WhereLoop));
|
|
if( p==0 ) return SQLITE_NOMEM_BKPT;
|
|
whereLoopInit(p);
|
|
p->pNextLoop = 0;
|
|
}else{
|
|
/* We will be overwriting WhereLoop p[]. But before we do, first
|
|
** go through the rest of the list and delete any other entries besides
|
|
** p[] that are also supplated by pTemplate */
|
|
WhereLoop **ppTail = &p->pNextLoop;
|
|
WhereLoop *pToDel;
|
|
while( *ppTail ){
|
|
ppTail = whereLoopFindLesser(ppTail, pTemplate);
|
|
if( ppTail==0 ) break;
|
|
pToDel = *ppTail;
|
|
if( pToDel==0 ) break;
|
|
*ppTail = pToDel->pNextLoop;
|
|
#if WHERETRACE_ENABLED /* 0x8 */
|
|
if( sqlite3WhereTrace & 0x8 ){
|
|
sqlite3DebugPrintf(" delete: ");
|
|
sqlite3WhereLoopPrint(pToDel, pBuilder->pWC);
|
|
}
|
|
#endif
|
|
whereLoopDelete(db, pToDel);
|
|
}
|
|
}
|
|
rc = whereLoopXfer(db, p, pTemplate);
|
|
if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
|
|
Index *pIndex = p->u.btree.pIndex;
|
|
if( pIndex && pIndex->idxType==SQLITE_IDXTYPE_IPK ){
|
|
p->u.btree.pIndex = 0;
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Adjust the WhereLoop.nOut value downward to account for terms of the
|
|
** WHERE clause that reference the loop but which are not used by an
|
|
** index.
|
|
*
|
|
** For every WHERE clause term that is not used by the index
|
|
** and which has a truth probability assigned by one of the likelihood(),
|
|
** likely(), or unlikely() SQL functions, reduce the estimated number
|
|
** of output rows by the probability specified.
|
|
**
|
|
** TUNING: For every WHERE clause term that is not used by the index
|
|
** and which does not have an assigned truth probability, heuristics
|
|
** described below are used to try to estimate the truth probability.
|
|
** TODO --> Perhaps this is something that could be improved by better
|
|
** table statistics.
|
|
**
|
|
** Heuristic 1: Estimate the truth probability as 93.75%. The 93.75%
|
|
** value corresponds to -1 in LogEst notation, so this means decrement
|
|
** the WhereLoop.nOut field for every such WHERE clause term.
|
|
**
|
|
** Heuristic 2: If there exists one or more WHERE clause terms of the
|
|
** form "x==EXPR" and EXPR is not a constant 0 or 1, then make sure the
|
|
** final output row estimate is no greater than 1/4 of the total number
|
|
** of rows in the table. In other words, assume that x==EXPR will filter
|
|
** out at least 3 out of 4 rows. If EXPR is -1 or 0 or 1, then maybe the
|
|
** "x" column is boolean or else -1 or 0 or 1 is a common default value
|
|
** on the "x" column and so in that case only cap the output row estimate
|
|
** at 1/2 instead of 1/4.
|
|
*/
|
|
static void whereLoopOutputAdjust(
|
|
WhereClause *pWC, /* The WHERE clause */
|
|
WhereLoop *pLoop, /* The loop to adjust downward */
|
|
LogEst nRow /* Number of rows in the entire table */
|
|
){
|
|
WhereTerm *pTerm, *pX;
|
|
Bitmask notAllowed = ~(pLoop->prereq|pLoop->maskSelf);
|
|
int i, j;
|
|
LogEst iReduce = 0; /* pLoop->nOut should not exceed nRow-iReduce */
|
|
|
|
assert( (pLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
|
|
for(i=pWC->nBase, pTerm=pWC->a; i>0; i--, pTerm++){
|
|
assert( pTerm!=0 );
|
|
if( (pTerm->prereqAll & notAllowed)!=0 ) continue;
|
|
if( (pTerm->prereqAll & pLoop->maskSelf)==0 ) continue;
|
|
if( (pTerm->wtFlags & TERM_VIRTUAL)!=0 ) continue;
|
|
for(j=pLoop->nLTerm-1; j>=0; j--){
|
|
pX = pLoop->aLTerm[j];
|
|
if( pX==0 ) continue;
|
|
if( pX==pTerm ) break;
|
|
if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break;
|
|
}
|
|
if( j<0 ){
|
|
if( pLoop->maskSelf==pTerm->prereqAll ){
|
|
/* If there are extra terms in the WHERE clause not used by an index
|
|
** that depend only on the table being scanned, and that will tend to
|
|
** cause many rows to be omitted, then mark that table as
|
|
** "self-culling".
|
|
**
|
|
** 2022-03-24: Self-culling only applies if either the extra terms
|
|
** are straight comparison operators that are non-true with NULL
|
|
** operand, or if the loop is not an OUTER JOIN.
|
|
*/
|
|
if( (pTerm->eOperator & 0x3f)!=0
|
|
|| (pWC->pWInfo->pTabList->a[pLoop->iTab].fg.jointype
|
|
& (JT_LEFT|JT_LTORJ))==0
|
|
){
|
|
pLoop->wsFlags |= WHERE_SELFCULL;
|
|
}
|
|
}
|
|
if( pTerm->truthProb<=0 ){
|
|
/* If a truth probability is specified using the likelihood() hints,
|
|
** then use the probability provided by the application. */
|
|
pLoop->nOut += pTerm->truthProb;
|
|
}else{
|
|
/* In the absence of explicit truth probabilities, use heuristics to
|
|
** guess a reasonable truth probability. */
|
|
pLoop->nOut--;
|
|
if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0
|
|
&& (pTerm->wtFlags & TERM_HIGHTRUTH)==0 /* tag-20200224-1 */
|
|
){
|
|
Expr *pRight = pTerm->pExpr->pRight;
|
|
int k = 0;
|
|
testcase( pTerm->pExpr->op==TK_IS );
|
|
if( sqlite3ExprIsInteger(pRight, &k) && k>=(-1) && k<=1 ){
|
|
k = 10;
|
|
}else{
|
|
k = 20;
|
|
}
|
|
if( iReduce<k ){
|
|
pTerm->wtFlags |= TERM_HEURTRUTH;
|
|
iReduce = k;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if( pLoop->nOut > nRow-iReduce ){
|
|
pLoop->nOut = nRow - iReduce;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Term pTerm is a vector range comparison operation. The first comparison
|
|
** in the vector can be optimized using column nEq of the index. This
|
|
** function returns the total number of vector elements that can be used
|
|
** as part of the range comparison.
|
|
**
|
|
** For example, if the query is:
|
|
**
|
|
** WHERE a = ? AND (b, c, d) > (?, ?, ?)
|
|
**
|
|
** and the index:
|
|
**
|
|
** CREATE INDEX ... ON (a, b, c, d, e)
|
|
**
|
|
** then this function would be invoked with nEq=1. The value returned in
|
|
** this case is 3.
|
|
*/
|
|
static int whereRangeVectorLen(
|
|
Parse *pParse, /* Parsing context */
|
|
int iCur, /* Cursor open on pIdx */
|
|
Index *pIdx, /* The index to be used for a inequality constraint */
|
|
int nEq, /* Number of prior equality constraints on same index */
|
|
WhereTerm *pTerm /* The vector inequality constraint */
|
|
){
|
|
int nCmp = sqlite3ExprVectorSize(pTerm->pExpr->pLeft);
|
|
int i;
|
|
|
|
nCmp = MIN(nCmp, (pIdx->nColumn - nEq));
|
|
for(i=1; i<nCmp; i++){
|
|
/* Test if comparison i of pTerm is compatible with column (i+nEq)
|
|
** of the index. If not, exit the loop. */
|
|
char aff; /* Comparison affinity */
|
|
char idxaff = 0; /* Indexed columns affinity */
|
|
CollSeq *pColl; /* Comparison collation sequence */
|
|
Expr *pLhs, *pRhs;
|
|
|
|
assert( ExprUseXList(pTerm->pExpr->pLeft) );
|
|
pLhs = pTerm->pExpr->pLeft->x.pList->a[i].pExpr;
|
|
pRhs = pTerm->pExpr->pRight;
|
|
if( ExprUseXSelect(pRhs) ){
|
|
pRhs = pRhs->x.pSelect->pEList->a[i].pExpr;
|
|
}else{
|
|
pRhs = pRhs->x.pList->a[i].pExpr;
|
|
}
|
|
|
|
/* Check that the LHS of the comparison is a column reference to
|
|
** the right column of the right source table. And that the sort
|
|
** order of the index column is the same as the sort order of the
|
|
** leftmost index column. */
|
|
if( pLhs->op!=TK_COLUMN
|
|
|| pLhs->iTable!=iCur
|
|
|| pLhs->iColumn!=pIdx->aiColumn[i+nEq]
|
|
|| pIdx->aSortOrder[i+nEq]!=pIdx->aSortOrder[nEq]
|
|
){
|
|
break;
|
|
}
|
|
|
|
testcase( pLhs->iColumn==XN_ROWID );
|
|
aff = sqlite3CompareAffinity(pRhs, sqlite3ExprAffinity(pLhs));
|
|
idxaff = sqlite3TableColumnAffinity(pIdx->pTable, pLhs->iColumn);
|
|
if( aff!=idxaff ) break;
|
|
|
|
pColl = sqlite3BinaryCompareCollSeq(pParse, pLhs, pRhs);
|
|
if( pColl==0 ) break;
|
|
if( sqlite3StrICmp(pColl->zName, pIdx->azColl[i+nEq]) ) break;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
/*
|
|
** Adjust the cost C by the costMult facter T. This only occurs if
|
|
** compiled with -DSQLITE_ENABLE_COSTMULT
|
|
*/
|
|
#ifdef SQLITE_ENABLE_COSTMULT
|
|
# define ApplyCostMultiplier(C,T) C += T
|
|
#else
|
|
# define ApplyCostMultiplier(C,T)
|
|
#endif
|
|
|
|
/*
|
|
** We have so far matched pBuilder->pNew->u.btree.nEq terms of the
|
|
** index pIndex. Try to match one more.
|
|
**
|
|
** When this function is called, pBuilder->pNew->nOut contains the
|
|
** number of rows expected to be visited by filtering using the nEq
|
|
** terms only. If it is modified, this value is restored before this
|
|
** function returns.
|
|
**
|
|
** If pProbe->idxType==SQLITE_IDXTYPE_IPK, that means pIndex is
|
|
** a fake index used for the INTEGER PRIMARY KEY.
|
|
*/
|
|
static int whereLoopAddBtreeIndex(
|
|
WhereLoopBuilder *pBuilder, /* The WhereLoop factory */
|
|
SrcItem *pSrc, /* FROM clause term being analyzed */
|
|
Index *pProbe, /* An index on pSrc */
|
|
LogEst nInMul /* log(Number of iterations due to IN) */
|
|
){
|
|
WhereInfo *pWInfo = pBuilder->pWInfo; /* WHERE analyse context */
|
|
Parse *pParse = pWInfo->pParse; /* Parsing context */
|
|
sqlite3 *db = pParse->db; /* Database connection malloc context */
|
|
WhereLoop *pNew; /* Template WhereLoop under construction */
|
|
WhereTerm *pTerm; /* A WhereTerm under consideration */
|
|
int opMask; /* Valid operators for constraints */
|
|
WhereScan scan; /* Iterator for WHERE terms */
|
|
Bitmask saved_prereq; /* Original value of pNew->prereq */
|
|
u16 saved_nLTerm; /* Original value of pNew->nLTerm */
|
|
u16 saved_nEq; /* Original value of pNew->u.btree.nEq */
|
|
u16 saved_nBtm; /* Original value of pNew->u.btree.nBtm */
|
|
u16 saved_nTop; /* Original value of pNew->u.btree.nTop */
|
|
u16 saved_nSkip; /* Original value of pNew->nSkip */
|
|
u32 saved_wsFlags; /* Original value of pNew->wsFlags */
|
|
LogEst saved_nOut; /* Original value of pNew->nOut */
|
|
int rc = SQLITE_OK; /* Return code */
|
|
LogEst rSize; /* Number of rows in the table */
|
|
LogEst rLogSize; /* Logarithm of table size */
|
|
WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */
|
|
|
|
pNew = pBuilder->pNew;
|
|
if( db->mallocFailed ) return SQLITE_NOMEM_BKPT;
|
|
WHERETRACE(0x800, ("BEGIN %s.addBtreeIdx(%s), nEq=%d, nSkip=%d, rRun=%d\n",
|
|
pProbe->pTable->zName,pProbe->zName,
|
|
pNew->u.btree.nEq, pNew->nSkip, pNew->rRun));
|
|
|
|
assert( (pNew->wsFlags & WHERE_VIRTUALTABLE)==0 );
|
|
assert( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 );
|
|
if( pNew->wsFlags & WHERE_BTM_LIMIT ){
|
|
opMask = WO_LT|WO_LE;
|
|
}else{
|
|
assert( pNew->u.btree.nBtm==0 );
|
|
opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE|WO_ISNULL|WO_IS;
|
|
}
|
|
if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);
|
|
|
|
assert( pNew->u.btree.nEq<pProbe->nColumn );
|
|
assert( pNew->u.btree.nEq<pProbe->nKeyCol
|
|
|| pProbe->idxType!=SQLITE_IDXTYPE_PRIMARYKEY );
|
|
|
|
saved_nEq = pNew->u.btree.nEq;
|
|
saved_nBtm = pNew->u.btree.nBtm;
|
|
saved_nTop = pNew->u.btree.nTop;
|
|
saved_nSkip = pNew->nSkip;
|
|
saved_nLTerm = pNew->nLTerm;
|
|
saved_wsFlags = pNew->wsFlags;
|
|
saved_prereq = pNew->prereq;
|
|
saved_nOut = pNew->nOut;
|
|
pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, saved_nEq,
|
|
opMask, pProbe);
|
|
pNew->rSetup = 0;
|
|
rSize = pProbe->aiRowLogEst[0];
|
|
rLogSize = estLog(rSize);
|
|
for(; rc==SQLITE_OK && pTerm!=0; pTerm = whereScanNext(&scan)){
|
|
u16 eOp = pTerm->eOperator; /* Shorthand for pTerm->eOperator */
|
|
LogEst rCostIdx;
|
|
LogEst nOutUnadjusted; /* nOut before IN() and WHERE adjustments */
|
|
int nIn = 0;
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
int nRecValid = pBuilder->nRecValid;
|
|
#endif
|
|
if( (eOp==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0)
|
|
&& indexColumnNotNull(pProbe, saved_nEq)
|
|
){
|
|
continue; /* ignore IS [NOT] NULL constraints on NOT NULL columns */
|
|
}
|
|
if( pTerm->prereqRight & pNew->maskSelf ) continue;
|
|
|
|
/* Do not allow the upper bound of a LIKE optimization range constraint
|
|
** to mix with a lower range bound from some other source */
|
|
if( pTerm->wtFlags & TERM_LIKEOPT && pTerm->eOperator==WO_LT ) continue;
|
|
|
|
/* tag-20191211-001: Do not allow constraints from the WHERE clause to
|
|
** be used by the right table of a LEFT JOIN nor by the left table of a
|
|
** RIGHT JOIN. Only constraints in the ON clause are allowed.
|
|
** See tag-20191211-002 for the vtab equivalent.
|
|
**
|
|
** 2022-06-06: See https://sqlite.org/forum/forumpost/206d99a16dd9212f
|
|
** for an example of a WHERE clause constraints that may not be used on
|
|
** the right table of a RIGHT JOIN because the constraint implies a
|
|
** not-NULL condition on the left table of the RIGHT JOIN.
|
|
**
|
|
** 2022-06-10: The same condition applies to termCanDriveIndex() above.
|
|
** https://sqlite.org/forum/forumpost/51e6959f61
|
|
*/
|
|
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0 ){
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LEFT );
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_RIGHT );
|
|
testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LTORJ );
|
|
testcase( ExprHasProperty(pTerm->pExpr, EP_OuterON) )
|
|
testcase( ExprHasProperty(pTerm->pExpr, EP_InnerON) );
|
|
if( !ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON)
|
|
|| pTerm->pExpr->w.iJoin != pSrc->iCursor
|
|
){
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if( IsUniqueIndex(pProbe) && saved_nEq==pProbe->nKeyCol-1 ){
|
|
pBuilder->bldFlags1 |= SQLITE_BLDF1_UNIQUE;
|
|
}else{
|
|
pBuilder->bldFlags1 |= SQLITE_BLDF1_INDEXED;
|
|
}
|
|
pNew->wsFlags = saved_wsFlags;
|
|
pNew->u.btree.nEq = saved_nEq;
|
|
pNew->u.btree.nBtm = saved_nBtm;
|
|
pNew->u.btree.nTop = saved_nTop;
|
|
pNew->nLTerm = saved_nLTerm;
|
|
if( pNew->nLTerm>=pNew->nLSlot
|
|
&& whereLoopResize(db, pNew, pNew->nLTerm+1)
|
|
){
|
|
break; /* OOM while trying to enlarge the pNew->aLTerm array */
|
|
}
|
|
pNew->aLTerm[pNew->nLTerm++] = pTerm;
|
|
pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf;
|
|
|
|
assert( nInMul==0
|
|
|| (pNew->wsFlags & WHERE_COLUMN_NULL)!=0
|
|
|| (pNew->wsFlags & WHERE_COLUMN_IN)!=0
|
|
|| (pNew->wsFlags & WHERE_SKIPSCAN)!=0
|
|
);
|
|
|
|
if( eOp & WO_IN ){
|
|
Expr *pExpr = pTerm->pExpr;
|
|
if( ExprUseXSelect(pExpr) ){
|
|
/* "x IN (SELECT ...)": TUNING: the SELECT returns 25 rows */
|
|
int i;
|
|
nIn = 46; assert( 46==sqlite3LogEst(25) );
|
|
|
|
/* The expression may actually be of the form (x, y) IN (SELECT...).
|
|
** In this case there is a separate term for each of (x) and (y).
|
|
** However, the nIn multiplier should only be applied once, not once
|
|
** for each such term. The following loop checks that pTerm is the
|
|
** first such term in use, and sets nIn back to 0 if it is not. */
|
|
for(i=0; i<pNew->nLTerm-1; i++){
|
|
if( pNew->aLTerm[i] && pNew->aLTerm[i]->pExpr==pExpr ) nIn = 0;
|
|
}
|
|
}else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
|
|
/* "x IN (value, value, ...)" */
|
|
nIn = sqlite3LogEst(pExpr->x.pList->nExpr);
|
|
}
|
|
if( pProbe->hasStat1 && rLogSize>=10 ){
|
|
LogEst M, logK, x;
|
|
/* Let:
|
|
** N = the total number of rows in the table
|
|
** K = the number of entries on the RHS of the IN operator
|
|
** M = the number of rows in the table that match terms to the
|
|
** to the left in the same index. If the IN operator is on
|
|
** the left-most index column, M==N.
|
|
**
|
|
** Given the definitions above, it is better to omit the IN operator
|
|
** from the index lookup and instead do a scan of the M elements,
|
|
** testing each scanned row against the IN operator separately, if:
|
|
**
|
|
** M*log(K) < K*log(N)
|
|
**
|
|
** Our estimates for M, K, and N might be inaccurate, so we build in
|
|
** a safety margin of 2 (LogEst: 10) that favors using the IN operator
|
|
** with the index, as using an index has better worst-case behavior.
|
|
** If we do not have real sqlite_stat1 data, always prefer to use
|
|
** the index. Do not bother with this optimization on very small
|
|
** tables (less than 2 rows) as it is pointless in that case.
|
|
*/
|
|
M = pProbe->aiRowLogEst[saved_nEq];
|
|
logK = estLog(nIn);
|
|
/* TUNING v----- 10 to bias toward indexed IN */
|
|
x = M + logK + 10 - (nIn + rLogSize);
|
|
if( x>=0 ){
|
|
WHERETRACE(0x40,
|
|
("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d) "
|
|
"prefers indexed lookup\n",
|
|
saved_nEq, M, logK, nIn, rLogSize, x));
|
|
}else if( nInMul<2 && OptimizationEnabled(db, SQLITE_SeekScan) ){
|
|
WHERETRACE(0x40,
|
|
("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d"
|
|
" nInMul=%d) prefers skip-scan\n",
|
|
saved_nEq, M, logK, nIn, rLogSize, x, nInMul));
|
|
pNew->wsFlags |= WHERE_IN_SEEKSCAN;
|
|
}else{
|
|
WHERETRACE(0x40,
|
|
("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d"
|
|
" nInMul=%d) prefers normal scan\n",
|
|
saved_nEq, M, logK, nIn, rLogSize, x, nInMul));
|
|
continue;
|
|
}
|
|
}
|
|
pNew->wsFlags |= WHERE_COLUMN_IN;
|
|
}else if( eOp & (WO_EQ|WO_IS) ){
|
|
int iCol = pProbe->aiColumn[saved_nEq];
|
|
pNew->wsFlags |= WHERE_COLUMN_EQ;
|
|
assert( saved_nEq==pNew->u.btree.nEq );
|
|
if( iCol==XN_ROWID
|
|
|| (iCol>=0 && nInMul==0 && saved_nEq==pProbe->nKeyCol-1)
|
|
){
|
|
if( iCol==XN_ROWID || pProbe->uniqNotNull
|
|
|| (pProbe->nKeyCol==1 && pProbe->onError && eOp==WO_EQ)
|
|
){
|
|
pNew->wsFlags |= WHERE_ONEROW;
|
|
}else{
|
|
pNew->wsFlags |= WHERE_UNQ_WANTED;
|
|
}
|
|
}
|
|
if( scan.iEquiv>1 ) pNew->wsFlags |= WHERE_TRANSCONS;
|
|
}else if( eOp & WO_ISNULL ){
|
|
pNew->wsFlags |= WHERE_COLUMN_NULL;
|
|
}else{
|
|
int nVecLen = whereRangeVectorLen(
|
|
pParse, pSrc->iCursor, pProbe, saved_nEq, pTerm
|
|
);
|
|
if( eOp & (WO_GT|WO_GE) ){
|
|
testcase( eOp & WO_GT );
|
|
testcase( eOp & WO_GE );
|
|
pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT;
|
|
pNew->u.btree.nBtm = nVecLen;
|
|
pBtm = pTerm;
|
|
pTop = 0;
|
|
if( pTerm->wtFlags & TERM_LIKEOPT ){
|
|
/* Range constraints that come from the LIKE optimization are
|
|
** always used in pairs. */
|
|
pTop = &pTerm[1];
|
|
assert( (pTop-(pTerm->pWC->a))<pTerm->pWC->nTerm );
|
|
assert( pTop->wtFlags & TERM_LIKEOPT );
|
|
assert( pTop->eOperator==WO_LT );
|
|
if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
|
|
pNew->aLTerm[pNew->nLTerm++] = pTop;
|
|
pNew->wsFlags |= WHERE_TOP_LIMIT;
|
|
pNew->u.btree.nTop = 1;
|
|
}
|
|
}else{
|
|
assert( eOp & (WO_LT|WO_LE) );
|
|
testcase( eOp & WO_LT );
|
|
testcase( eOp & WO_LE );
|
|
pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_TOP_LIMIT;
|
|
pNew->u.btree.nTop = nVecLen;
|
|
pTop = pTerm;
|
|
pBtm = (pNew->wsFlags & WHERE_BTM_LIMIT)!=0 ?
|
|
pNew->aLTerm[pNew->nLTerm-2] : 0;
|
|
}
|
|
}
|
|
|
|
/* At this point pNew->nOut is set to the number of rows expected to
|
|
** be visited by the index scan before considering term pTerm, or the
|
|
** values of nIn and nInMul. In other words, assuming that all
|
|
** "x IN(...)" terms are replaced with "x = ?". This block updates
|
|
** the value of pNew->nOut to account for pTerm (but not nIn/nInMul). */
|
|
assert( pNew->nOut==saved_nOut );
|
|
if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
|
|
/* Adjust nOut using stat4 data. Or, if there is no stat4
|
|
** data, using some other estimate. */
|
|
whereRangeScanEst(pParse, pBuilder, pBtm, pTop, pNew);
|
|
}else{
|
|
int nEq = ++pNew->u.btree.nEq;
|
|
assert( eOp & (WO_ISNULL|WO_EQ|WO_IN|WO_IS) );
|
|
|
|
assert( pNew->nOut==saved_nOut );
|
|
if( pTerm->truthProb<=0 && pProbe->aiColumn[saved_nEq]>=0 ){
|
|
assert( (eOp & WO_IN) || nIn==0 );
|
|
testcase( eOp & WO_IN );
|
|
pNew->nOut += pTerm->truthProb;
|
|
pNew->nOut -= nIn;
|
|
}else{
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
tRowcnt nOut = 0;
|
|
if( nInMul==0
|
|
&& pProbe->nSample
|
|
&& ALWAYS(pNew->u.btree.nEq<=pProbe->nSampleCol)
|
|
&& ((eOp & WO_IN)==0 || ExprUseXList(pTerm->pExpr))
|
|
&& OptimizationEnabled(db, SQLITE_Stat4)
|
|
){
|
|
Expr *pExpr = pTerm->pExpr;
|
|
if( (eOp & (WO_EQ|WO_ISNULL|WO_IS))!=0 ){
|
|
testcase( eOp & WO_EQ );
|
|
testcase( eOp & WO_IS );
|
|
testcase( eOp & WO_ISNULL );
|
|
rc = whereEqualScanEst(pParse, pBuilder, pExpr->pRight, &nOut);
|
|
}else{
|
|
rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut);
|
|
}
|
|
if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
|
|
if( rc!=SQLITE_OK ) break; /* Jump out of the pTerm loop */
|
|
if( nOut ){
|
|
pNew->nOut = sqlite3LogEst(nOut);
|
|
if( nEq==1
|
|
/* TUNING: Mark terms as "low selectivity" if they seem likely
|
|
** to be true for half or more of the rows in the table.
|
|
** See tag-202002240-1 */
|
|
&& pNew->nOut+10 > pProbe->aiRowLogEst[0]
|
|
){
|
|
#if WHERETRACE_ENABLED /* 0x01 */
|
|
if( sqlite3WhereTrace & 0x01 ){
|
|
sqlite3DebugPrintf(
|
|
"STAT4 determines term has low selectivity:\n");
|
|
sqlite3WhereTermPrint(pTerm, 999);
|
|
}
|
|
#endif
|
|
pTerm->wtFlags |= TERM_HIGHTRUTH;
|
|
if( pTerm->wtFlags & TERM_HEURTRUTH ){
|
|
/* If the term has previously been used with an assumption of
|
|
** higher selectivity, then set the flag to rerun the
|
|
** loop computations. */
|
|
pBuilder->bldFlags2 |= SQLITE_BLDF2_2NDPASS;
|
|
}
|
|
}
|
|
if( pNew->nOut>saved_nOut ) pNew->nOut = saved_nOut;
|
|
pNew->nOut -= nIn;
|
|
}
|
|
}
|
|
if( nOut==0 )
|
|
#endif
|
|
{
|
|
pNew->nOut += (pProbe->aiRowLogEst[nEq] - pProbe->aiRowLogEst[nEq-1]);
|
|
if( eOp & WO_ISNULL ){
|
|
/* TUNING: If there is no likelihood() value, assume that a
|
|
** "col IS NULL" expression matches twice as many rows
|
|
** as (col=?). */
|
|
pNew->nOut += 10;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Set rCostIdx to the cost of visiting selected rows in index. Add
|
|
** it to pNew->rRun, which is currently set to the cost of the index
|
|
** seek only. Then, if this is a non-covering index, add the cost of
|
|
** visiting the rows in the main table. */
|
|
assert( pSrc->pTab->szTabRow>0 );
|
|
rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pTab->szTabRow;
|
|
pNew->rRun = sqlite3LogEstAdd(rLogSize, rCostIdx);
|
|
if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
|
|
pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16);
|
|
}
|
|
ApplyCostMultiplier(pNew->rRun, pProbe->pTable->costMult);
|
|
|
|
nOutUnadjusted = pNew->nOut;
|
|
pNew->rRun += nInMul + nIn;
|
|
pNew->nOut += nInMul + nIn;
|
|
whereLoopOutputAdjust(pBuilder->pWC, pNew, rSize);
|
|
rc = whereLoopInsert(pBuilder, pNew);
|
|
|
|
if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
|
|
pNew->nOut = saved_nOut;
|
|
}else{
|
|
pNew->nOut = nOutUnadjusted;
|
|
}
|
|
|
|
if( (pNew->wsFlags & WHERE_TOP_LIMIT)==0
|
|
&& pNew->u.btree.nEq<pProbe->nColumn
|
|
&& (pNew->u.btree.nEq<pProbe->nKeyCol ||
|
|
pProbe->idxType!=SQLITE_IDXTYPE_PRIMARYKEY)
|
|
){
|
|
whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nInMul+nIn);
|
|
}
|
|
pNew->nOut = saved_nOut;
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
pBuilder->nRecValid = nRecValid;
|
|
#endif
|
|
}
|
|
pNew->prereq = saved_prereq;
|
|
pNew->u.btree.nEq = saved_nEq;
|
|
pNew->u.btree.nBtm = saved_nBtm;
|
|
pNew->u.btree.nTop = saved_nTop;
|
|
pNew->nSkip = saved_nSkip;
|
|
pNew->wsFlags = saved_wsFlags;
|
|
pNew->nOut = saved_nOut;
|
|
pNew->nLTerm = saved_nLTerm;
|
|
|
|
/* Consider using a skip-scan if there are no WHERE clause constraints
|
|
** available for the left-most terms of the index, and if the average
|
|
** number of repeats in the left-most terms is at least 18.
|
|
**
|
|
** The magic number 18 is selected on the basis that scanning 17 rows
|
|
** is almost always quicker than an index seek (even though if the index
|
|
** contains fewer than 2^17 rows we assume otherwise in other parts of
|
|
** the code). And, even if it is not, it should not be too much slower.
|
|
** On the other hand, the extra seeks could end up being significantly
|
|
** more expensive. */
|
|
assert( 42==sqlite3LogEst(18) );
|
|
if( saved_nEq==saved_nSkip
|
|
&& saved_nEq+1<pProbe->nKeyCol
|
|
&& saved_nEq==pNew->nLTerm
|
|
&& pProbe->noSkipScan==0
|
|
&& pProbe->hasStat1!=0
|
|
&& OptimizationEnabled(db, SQLITE_SkipScan)
|
|
&& pProbe->aiRowLogEst[saved_nEq+1]>=42 /* TUNING: Minimum for skip-scan */
|
|
&& (rc = whereLoopResize(db, pNew, pNew->nLTerm+1))==SQLITE_OK
|
|
){
|
|
LogEst nIter;
|
|
pNew->u.btree.nEq++;
|
|
pNew->nSkip++;
|
|
pNew->aLTerm[pNew->nLTerm++] = 0;
|
|
pNew->wsFlags |= WHERE_SKIPSCAN;
|
|
nIter = pProbe->aiRowLogEst[saved_nEq] - pProbe->aiRowLogEst[saved_nEq+1];
|
|
pNew->nOut -= nIter;
|
|
/* TUNING: Because uncertainties in the estimates for skip-scan queries,
|
|
** add a 1.375 fudge factor to make skip-scan slightly less likely. */
|
|
nIter += 5;
|
|
whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter + nInMul);
|
|
pNew->nOut = saved_nOut;
|
|
pNew->u.btree.nEq = saved_nEq;
|
|
pNew->nSkip = saved_nSkip;
|
|
pNew->wsFlags = saved_wsFlags;
|
|
}
|
|
|
|
WHERETRACE(0x800, ("END %s.addBtreeIdx(%s), nEq=%d, rc=%d\n",
|
|
pProbe->pTable->zName, pProbe->zName, saved_nEq, rc));
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return True if it is possible that pIndex might be useful in
|
|
** implementing the ORDER BY clause in pBuilder.
|
|
**
|
|
** Return False if pBuilder does not contain an ORDER BY clause or
|
|
** if there is no way for pIndex to be useful in implementing that
|
|
** ORDER BY clause.
|
|
*/
|
|
static int indexMightHelpWithOrderBy(
|
|
WhereLoopBuilder *pBuilder,
|
|
Index *pIndex,
|
|
int iCursor
|
|
){
|
|
ExprList *pOB;
|
|
ExprList *aColExpr;
|
|
int ii, jj;
|
|
|
|
if( pIndex->bUnordered ) return 0;
|
|
if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
|
|
for(ii=0; ii<pOB->nExpr; ii++){
|
|
Expr *pExpr = sqlite3ExprSkipCollateAndLikely(pOB->a[ii].pExpr);
|
|
if( NEVER(pExpr==0) ) continue;
|
|
if( pExpr->op==TK_COLUMN && pExpr->iTable==iCursor ){
|
|
if( pExpr->iColumn<0 ) return 1;
|
|
for(jj=0; jj<pIndex->nKeyCol; jj++){
|
|
if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
|
|
}
|
|
}else if( (aColExpr = pIndex->aColExpr)!=0 ){
|
|
for(jj=0; jj<pIndex->nKeyCol; jj++){
|
|
if( pIndex->aiColumn[jj]!=XN_EXPR ) continue;
|
|
if( sqlite3ExprCompareSkip(pExpr,aColExpr->a[jj].pExpr,iCursor)==0 ){
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Check to see if a partial index with pPartIndexWhere can be used
|
|
** in the current query. Return true if it can be and false if not.
|
|
*/
|
|
static int whereUsablePartialIndex(
|
|
int iTab, /* The table for which we want an index */
|
|
u8 jointype, /* The JT_* flags on the join */
|
|
WhereClause *pWC, /* The WHERE clause of the query */
|
|
Expr *pWhere /* The WHERE clause from the partial index */
|
|
){
|
|
int i;
|
|
WhereTerm *pTerm;
|
|
Parse *pParse;
|
|
|
|
if( jointype & JT_LTORJ ) return 0;
|
|
pParse = pWC->pWInfo->pParse;
|
|
while( pWhere->op==TK_AND ){
|
|
if( !whereUsablePartialIndex(iTab,jointype,pWC,pWhere->pLeft) ) return 0;
|
|
pWhere = pWhere->pRight;
|
|
}
|
|
if( pParse->db->flags & SQLITE_EnableQPSG ) pParse = 0;
|
|
for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
|
|
Expr *pExpr;
|
|
pExpr = pTerm->pExpr;
|
|
if( (!ExprHasProperty(pExpr, EP_OuterON) || pExpr->w.iJoin==iTab)
|
|
&& ((jointype & JT_OUTER)==0 || ExprHasProperty(pExpr, EP_OuterON))
|
|
&& sqlite3ExprImpliesExpr(pParse, pExpr, pWhere, iTab)
|
|
&& (pTerm->wtFlags & TERM_VNULL)==0
|
|
){
|
|
return 1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Add all WhereLoop objects for a single table of the join where the table
|
|
** is identified by pBuilder->pNew->iTab. That table is guaranteed to be
|
|
** a b-tree table, not a virtual table.
|
|
**
|
|
** The costs (WhereLoop.rRun) of the b-tree loops added by this function
|
|
** are calculated as follows:
|
|
**
|
|
** For a full scan, assuming the table (or index) contains nRow rows:
|
|
**
|
|
** cost = nRow * 3.0 // full-table scan
|
|
** cost = nRow * K // scan of covering index
|
|
** cost = nRow * (K+3.0) // scan of non-covering index
|
|
**
|
|
** where K is a value between 1.1 and 3.0 set based on the relative
|
|
** estimated average size of the index and table records.
|
|
**
|
|
** For an index scan, where nVisit is the number of index rows visited
|
|
** by the scan, and nSeek is the number of seek operations required on
|
|
** the index b-tree:
|
|
**
|
|
** cost = nSeek * (log(nRow) + K * nVisit) // covering index
|
|
** cost = nSeek * (log(nRow) + (K+3.0) * nVisit) // non-covering index
|
|
**
|
|
** Normally, nSeek is 1. nSeek values greater than 1 come about if the
|
|
** WHERE clause includes "x IN (....)" terms used in place of "x=?". Or when
|
|
** implicit "x IN (SELECT x FROM tbl)" terms are added for skip-scans.
|
|
**
|
|
** The estimated values (nRow, nVisit, nSeek) often contain a large amount
|
|
** of uncertainty. For this reason, scoring is designed to pick plans that
|
|
** "do the least harm" if the estimates are inaccurate. For example, a
|
|
** log(nRow) factor is omitted from a non-covering index scan in order to
|
|
** bias the scoring in favor of using an index, since the worst-case
|
|
** performance of using an index is far better than the worst-case performance
|
|
** of a full table scan.
|
|
*/
|
|
static int whereLoopAddBtree(
|
|
WhereLoopBuilder *pBuilder, /* WHERE clause information */
|
|
Bitmask mPrereq /* Extra prerequesites for using this table */
|
|
){
|
|
WhereInfo *pWInfo; /* WHERE analysis context */
|
|
Index *pProbe; /* An index we are evaluating */
|
|
Index sPk; /* A fake index object for the primary key */
|
|
LogEst aiRowEstPk[2]; /* The aiRowLogEst[] value for the sPk index */
|
|
i16 aiColumnPk = -1; /* The aColumn[] value for the sPk index */
|
|
SrcList *pTabList; /* The FROM clause */
|
|
SrcItem *pSrc; /* The FROM clause btree term to add */
|
|
WhereLoop *pNew; /* Template WhereLoop object */
|
|
int rc = SQLITE_OK; /* Return code */
|
|
int iSortIdx = 1; /* Index number */
|
|
int b; /* A boolean value */
|
|
LogEst rSize; /* number of rows in the table */
|
|
WhereClause *pWC; /* The parsed WHERE clause */
|
|
Table *pTab; /* Table being queried */
|
|
|
|
pNew = pBuilder->pNew;
|
|
pWInfo = pBuilder->pWInfo;
|
|
pTabList = pWInfo->pTabList;
|
|
pSrc = pTabList->a + pNew->iTab;
|
|
pTab = pSrc->pTab;
|
|
pWC = pBuilder->pWC;
|
|
assert( !IsVirtual(pSrc->pTab) );
|
|
|
|
if( pSrc->fg.isIndexedBy ){
|
|
assert( pSrc->fg.isCte==0 );
|
|
/* An INDEXED BY clause specifies a particular index to use */
|
|
pProbe = pSrc->u2.pIBIndex;
|
|
}else if( !HasRowid(pTab) ){
|
|
pProbe = pTab->pIndex;
|
|
}else{
|
|
/* There is no INDEXED BY clause. Create a fake Index object in local
|
|
** variable sPk to represent the rowid primary key index. Make this
|
|
** fake index the first in a chain of Index objects with all of the real
|
|
** indices to follow */
|
|
Index *pFirst; /* First of real indices on the table */
|
|
memset(&sPk, 0, sizeof(Index));
|
|
sPk.nKeyCol = 1;
|
|
sPk.nColumn = 1;
|
|
sPk.aiColumn = &aiColumnPk;
|
|
sPk.aiRowLogEst = aiRowEstPk;
|
|
sPk.onError = OE_Replace;
|
|
sPk.pTable = pTab;
|
|
sPk.szIdxRow = pTab->szTabRow;
|
|
sPk.idxType = SQLITE_IDXTYPE_IPK;
|
|
aiRowEstPk[0] = pTab->nRowLogEst;
|
|
aiRowEstPk[1] = 0;
|
|
pFirst = pSrc->pTab->pIndex;
|
|
if( pSrc->fg.notIndexed==0 ){
|
|
/* The real indices of the table are only considered if the
|
|
** NOT INDEXED qualifier is omitted from the FROM clause */
|
|
sPk.pNext = pFirst;
|
|
}
|
|
pProbe = &sPk;
|
|
}
|
|
rSize = pTab->nRowLogEst;
|
|
|
|
#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
|
|
/* Automatic indexes */
|
|
if( !pBuilder->pOrSet /* Not part of an OR optimization */
|
|
&& (pWInfo->wctrlFlags & (WHERE_RIGHT_JOIN|WHERE_OR_SUBCLAUSE))==0
|
|
&& (pWInfo->pParse->db->flags & SQLITE_AutoIndex)!=0
|
|
&& !pSrc->fg.isIndexedBy /* Has no INDEXED BY clause */
|
|
&& !pSrc->fg.notIndexed /* Has no NOT INDEXED clause */
|
|
&& HasRowid(pTab) /* Not WITHOUT ROWID table. (FIXME: Why not?) */
|
|
&& !pSrc->fg.isCorrelated /* Not a correlated subquery */
|
|
&& !pSrc->fg.isRecursive /* Not a recursive common table expression. */
|
|
&& (pSrc->fg.jointype & JT_RIGHT)==0 /* Not the right tab of a RIGHT JOIN */
|
|
){
|
|
/* Generate auto-index WhereLoops */
|
|
LogEst rLogSize; /* Logarithm of the number of rows in the table */
|
|
WhereTerm *pTerm;
|
|
WhereTerm *pWCEnd = pWC->a + pWC->nTerm;
|
|
rLogSize = estLog(rSize);
|
|
for(pTerm=pWC->a; rc==SQLITE_OK && pTerm<pWCEnd; pTerm++){
|
|
if( pTerm->prereqRight & pNew->maskSelf ) continue;
|
|
if( termCanDriveIndex(pTerm, pSrc, 0) ){
|
|
pNew->u.btree.nEq = 1;
|
|
pNew->nSkip = 0;
|
|
pNew->u.btree.pIndex = 0;
|
|
pNew->nLTerm = 1;
|
|
pNew->aLTerm[0] = pTerm;
|
|
/* TUNING: One-time cost for computing the automatic index is
|
|
** estimated to be X*N*log2(N) where N is the number of rows in
|
|
** the table being indexed and where X is 7 (LogEst=28) for normal
|
|
** tables or 0.5 (LogEst=-10) for views and subqueries. The value
|
|
** of X is smaller for views and subqueries so that the query planner
|
|
** will be more aggressive about generating automatic indexes for
|
|
** those objects, since there is no opportunity to add schema
|
|
** indexes on subqueries and views. */
|
|
pNew->rSetup = rLogSize + rSize;
|
|
if( !IsView(pTab) && (pTab->tabFlags & TF_Ephemeral)==0 ){
|
|
pNew->rSetup += 28;
|
|
}else{
|
|
pNew->rSetup -= 10;
|
|
}
|
|
ApplyCostMultiplier(pNew->rSetup, pTab->costMult);
|
|
if( pNew->rSetup<0 ) pNew->rSetup = 0;
|
|
/* TUNING: Each index lookup yields 20 rows in the table. This
|
|
** is more than the usual guess of 10 rows, since we have no way
|
|
** of knowing how selective the index will ultimately be. It would
|
|
** not be unreasonable to make this value much larger. */
|
|
pNew->nOut = 43; assert( 43==sqlite3LogEst(20) );
|
|
pNew->rRun = sqlite3LogEstAdd(rLogSize,pNew->nOut);
|
|
pNew->wsFlags = WHERE_AUTO_INDEX;
|
|
pNew->prereq = mPrereq | pTerm->prereqRight;
|
|
rc = whereLoopInsert(pBuilder, pNew);
|
|
}
|
|
}
|
|
}
|
|
#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
|
|
|
|
/* Loop over all indices. If there was an INDEXED BY clause, then only
|
|
** consider index pProbe. */
|
|
for(; rc==SQLITE_OK && pProbe;
|
|
pProbe=(pSrc->fg.isIndexedBy ? 0 : pProbe->pNext), iSortIdx++
|
|
){
|
|
if( pProbe->pPartIdxWhere!=0
|
|
&& !whereUsablePartialIndex(pSrc->iCursor, pSrc->fg.jointype, pWC,
|
|
pProbe->pPartIdxWhere)
|
|
){
|
|
testcase( pNew->iTab!=pSrc->iCursor ); /* See ticket [98d973b8f5] */
|
|
continue; /* Partial index inappropriate for this query */
|
|
}
|
|
if( pProbe->bNoQuery ) continue;
|
|
rSize = pProbe->aiRowLogEst[0];
|
|
pNew->u.btree.nEq = 0;
|
|
pNew->u.btree.nBtm = 0;
|
|
pNew->u.btree.nTop = 0;
|
|
pNew->nSkip = 0;
|
|
pNew->nLTerm = 0;
|
|
pNew->iSortIdx = 0;
|
|
pNew->rSetup = 0;
|
|
pNew->prereq = mPrereq;
|
|
pNew->nOut = rSize;
|
|
pNew->u.btree.pIndex = pProbe;
|
|
b = indexMightHelpWithOrderBy(pBuilder, pProbe, pSrc->iCursor);
|
|
|
|
/* The ONEPASS_DESIRED flags never occurs together with ORDER BY */
|
|
assert( (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || b==0 );
|
|
if( pProbe->idxType==SQLITE_IDXTYPE_IPK ){
|
|
/* Integer primary key index */
|
|
pNew->wsFlags = WHERE_IPK;
|
|
|
|
/* Full table scan */
|
|
pNew->iSortIdx = b ? iSortIdx : 0;
|
|
/* TUNING: Cost of full table scan is 3.0*N. The 3.0 factor is an
|
|
** extra cost designed to discourage the use of full table scans,
|
|
** since index lookups have better worst-case performance if our
|
|
** stat guesses are wrong. Reduce the 3.0 penalty slightly
|
|
** (to 2.75) if we have valid STAT4 information for the table.
|
|
** At 2.75, a full table scan is preferred over using an index on
|
|
** a column with just two distinct values where each value has about
|
|
** an equal number of appearances. Without STAT4 data, we still want
|
|
** to use an index in that case, since the constraint might be for
|
|
** the scarcer of the two values, and in that case an index lookup is
|
|
** better.
|
|
*/
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
pNew->rRun = rSize + 16 - 2*((pTab->tabFlags & TF_HasStat4)!=0);
|
|
#else
|
|
pNew->rRun = rSize + 16;
|
|
#endif
|
|
ApplyCostMultiplier(pNew->rRun, pTab->costMult);
|
|
whereLoopOutputAdjust(pWC, pNew, rSize);
|
|
rc = whereLoopInsert(pBuilder, pNew);
|
|
pNew->nOut = rSize;
|
|
if( rc ) break;
|
|
}else{
|
|
Bitmask m;
|
|
if( pProbe->isCovering ){
|
|
pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED;
|
|
m = 0;
|
|
}else{
|
|
m = pSrc->colUsed & pProbe->colNotIdxed;
|
|
pNew->wsFlags = (m==0) ? (WHERE_IDX_ONLY|WHERE_INDEXED) : WHERE_INDEXED;
|
|
}
|
|
|
|
/* Full scan via index */
|
|
if( b
|
|
|| !HasRowid(pTab)
|
|
|| pProbe->pPartIdxWhere!=0
|
|
|| pSrc->fg.isIndexedBy
|
|
|| ( m==0
|
|
&& pProbe->bUnordered==0
|
|
&& (pProbe->szIdxRow<pTab->szTabRow)
|
|
&& (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0
|
|
&& sqlite3GlobalConfig.bUseCis
|
|
&& OptimizationEnabled(pWInfo->pParse->db, SQLITE_CoverIdxScan)
|
|
)
|
|
){
|
|
pNew->iSortIdx = b ? iSortIdx : 0;
|
|
|
|
/* The cost of visiting the index rows is N*K, where K is
|
|
** between 1.1 and 3.0, depending on the relative sizes of the
|
|
** index and table rows. */
|
|
pNew->rRun = rSize + 1 + (15*pProbe->szIdxRow)/pTab->szTabRow;
|
|
if( m!=0 ){
|
|
/* If this is a non-covering index scan, add in the cost of
|
|
** doing table lookups. The cost will be 3x the number of
|
|
** lookups. Take into account WHERE clause terms that can be
|
|
** satisfied using just the index, and that do not require a
|
|
** table lookup. */
|
|
LogEst nLookup = rSize + 16; /* Base cost: N*3 */
|
|
int ii;
|
|
int iCur = pSrc->iCursor;
|
|
WhereClause *pWC2 = &pWInfo->sWC;
|
|
for(ii=0; ii<pWC2->nTerm; ii++){
|
|
WhereTerm *pTerm = &pWC2->a[ii];
|
|
if( !sqlite3ExprCoveredByIndex(pTerm->pExpr, iCur, pProbe) ){
|
|
break;
|
|
}
|
|
/* pTerm can be evaluated using just the index. So reduce
|
|
** the expected number of table lookups accordingly */
|
|
if( pTerm->truthProb<=0 ){
|
|
nLookup += pTerm->truthProb;
|
|
}else{
|
|
nLookup--;
|
|
if( pTerm->eOperator & (WO_EQ|WO_IS) ) nLookup -= 19;
|
|
}
|
|
}
|
|
|
|
pNew->rRun = sqlite3LogEstAdd(pNew->rRun, nLookup);
|
|
}
|
|
ApplyCostMultiplier(pNew->rRun, pTab->costMult);
|
|
whereLoopOutputAdjust(pWC, pNew, rSize);
|
|
if( (pSrc->fg.jointype & JT_RIGHT)!=0 && pProbe->aColExpr ){
|
|
/* Do not do an SCAN of a index-on-expression in a RIGHT JOIN
|
|
** because the cursor used to access the index might not be
|
|
** positioned to the correct row during the right-join no-match
|
|
** loop. */
|
|
}else{
|
|
rc = whereLoopInsert(pBuilder, pNew);
|
|
}
|
|
pNew->nOut = rSize;
|
|
if( rc ) break;
|
|
}
|
|
}
|
|
|
|
pBuilder->bldFlags1 = 0;
|
|
rc = whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, 0);
|
|
if( pBuilder->bldFlags1==SQLITE_BLDF1_INDEXED ){
|
|
/* If a non-unique index is used, or if a prefix of the key for
|
|
** unique index is used (making the index functionally non-unique)
|
|
** then the sqlite_stat1 data becomes important for scoring the
|
|
** plan */
|
|
pTab->tabFlags |= TF_StatsUsed;
|
|
}
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
sqlite3Stat4ProbeFree(pBuilder->pRec);
|
|
pBuilder->nRecValid = 0;
|
|
pBuilder->pRec = 0;
|
|
#endif
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_VIRTUALTABLE
|
|
|
|
/*
|
|
** Return true if pTerm is a virtual table LIMIT or OFFSET term.
|
|
*/
|
|
static int isLimitTerm(WhereTerm *pTerm){
|
|
assert( pTerm->eOperator==WO_AUX || pTerm->eMatchOp==0 );
|
|
return pTerm->eMatchOp>=SQLITE_INDEX_CONSTRAINT_LIMIT
|
|
&& pTerm->eMatchOp<=SQLITE_INDEX_CONSTRAINT_OFFSET;
|
|
}
|
|
|
|
/*
|
|
** Argument pIdxInfo is already populated with all constraints that may
|
|
** be used by the virtual table identified by pBuilder->pNew->iTab. This
|
|
** function marks a subset of those constraints usable, invokes the
|
|
** xBestIndex method and adds the returned plan to pBuilder.
|
|
**
|
|
** A constraint is marked usable if:
|
|
**
|
|
** * Argument mUsable indicates that its prerequisites are available, and
|
|
**
|
|
** * It is not one of the operators specified in the mExclude mask passed
|
|
** as the fourth argument (which in practice is either WO_IN or 0).
|
|
**
|
|
** Argument mPrereq is a mask of tables that must be scanned before the
|
|
** virtual table in question. These are added to the plans prerequisites
|
|
** before it is added to pBuilder.
|
|
**
|
|
** Output parameter *pbIn is set to true if the plan added to pBuilder
|
|
** uses one or more WO_IN terms, or false otherwise.
|
|
*/
|
|
static int whereLoopAddVirtualOne(
|
|
WhereLoopBuilder *pBuilder,
|
|
Bitmask mPrereq, /* Mask of tables that must be used. */
|
|
Bitmask mUsable, /* Mask of usable tables */
|
|
u16 mExclude, /* Exclude terms using these operators */
|
|
sqlite3_index_info *pIdxInfo, /* Populated object for xBestIndex */
|
|
u16 mNoOmit, /* Do not omit these constraints */
|
|
int *pbIn, /* OUT: True if plan uses an IN(...) op */
|
|
int *pbRetryLimit /* OUT: Retry without LIMIT/OFFSET */
|
|
){
|
|
WhereClause *pWC = pBuilder->pWC;
|
|
HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
|
|
struct sqlite3_index_constraint *pIdxCons;
|
|
struct sqlite3_index_constraint_usage *pUsage = pIdxInfo->aConstraintUsage;
|
|
int i;
|
|
int mxTerm;
|
|
int rc = SQLITE_OK;
|
|
WhereLoop *pNew = pBuilder->pNew;
|
|
Parse *pParse = pBuilder->pWInfo->pParse;
|
|
SrcItem *pSrc = &pBuilder->pWInfo->pTabList->a[pNew->iTab];
|
|
int nConstraint = pIdxInfo->nConstraint;
|
|
|
|
assert( (mUsable & mPrereq)==mPrereq );
|
|
*pbIn = 0;
|
|
pNew->prereq = mPrereq;
|
|
|
|
/* Set the usable flag on the subset of constraints identified by
|
|
** arguments mUsable and mExclude. */
|
|
pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
|
|
for(i=0; i<nConstraint; i++, pIdxCons++){
|
|
WhereTerm *pTerm = &pWC->a[pIdxCons->iTermOffset];
|
|
pIdxCons->usable = 0;
|
|
if( (pTerm->prereqRight & mUsable)==pTerm->prereqRight
|
|
&& (pTerm->eOperator & mExclude)==0
|
|
&& (pbRetryLimit || !isLimitTerm(pTerm))
|
|
){
|
|
pIdxCons->usable = 1;
|
|
}
|
|
}
|
|
|
|
/* Initialize the output fields of the sqlite3_index_info structure */
|
|
memset(pUsage, 0, sizeof(pUsage[0])*nConstraint);
|
|
assert( pIdxInfo->needToFreeIdxStr==0 );
|
|
pIdxInfo->idxStr = 0;
|
|
pIdxInfo->idxNum = 0;
|
|
pIdxInfo->orderByConsumed = 0;
|
|
pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2;
|
|
pIdxInfo->estimatedRows = 25;
|
|
pIdxInfo->idxFlags = 0;
|
|
pIdxInfo->colUsed = (sqlite3_int64)pSrc->colUsed;
|
|
pHidden->mHandleIn = 0;
|
|
|
|
/* Invoke the virtual table xBestIndex() method */
|
|
rc = vtabBestIndex(pParse, pSrc->pTab, pIdxInfo);
|
|
if( rc ){
|
|
if( rc==SQLITE_CONSTRAINT ){
|
|
/* If the xBestIndex method returns SQLITE_CONSTRAINT, that means
|
|
** that the particular combination of parameters provided is unusable.
|
|
** Make no entries in the loop table.
|
|
*/
|
|
WHERETRACE(0xffff, (" ^^^^--- non-viable plan rejected!\n"));
|
|
return SQLITE_OK;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
mxTerm = -1;
|
|
assert( pNew->nLSlot>=nConstraint );
|
|
memset(pNew->aLTerm, 0, sizeof(pNew->aLTerm[0])*nConstraint );
|
|
memset(&pNew->u.vtab, 0, sizeof(pNew->u.vtab));
|
|
pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
|
|
for(i=0; i<nConstraint; i++, pIdxCons++){
|
|
int iTerm;
|
|
if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
|
|
WhereTerm *pTerm;
|
|
int j = pIdxCons->iTermOffset;
|
|
if( iTerm>=nConstraint
|
|
|| j<0
|
|
|| j>=pWC->nTerm
|
|
|| pNew->aLTerm[iTerm]!=0
|
|
|| pIdxCons->usable==0
|
|
){
|
|
sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pTab->zName);
|
|
testcase( pIdxInfo->needToFreeIdxStr );
|
|
return SQLITE_ERROR;
|
|
}
|
|
testcase( iTerm==nConstraint-1 );
|
|
testcase( j==0 );
|
|
testcase( j==pWC->nTerm-1 );
|
|
pTerm = &pWC->a[j];
|
|
pNew->prereq |= pTerm->prereqRight;
|
|
assert( iTerm<pNew->nLSlot );
|
|
pNew->aLTerm[iTerm] = pTerm;
|
|
if( iTerm>mxTerm ) mxTerm = iTerm;
|
|
testcase( iTerm==15 );
|
|
testcase( iTerm==16 );
|
|
if( pUsage[i].omit ){
|
|
if( i<16 && ((1<<i)&mNoOmit)==0 ){
|
|
testcase( i!=iTerm );
|
|
pNew->u.vtab.omitMask |= 1<<iTerm;
|
|
}else{
|
|
testcase( i!=iTerm );
|
|
}
|
|
if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET ){
|
|
pNew->u.vtab.bOmitOffset = 1;
|
|
}
|
|
}
|
|
if( SMASKBIT32(i) & pHidden->mHandleIn ){
|
|
pNew->u.vtab.mHandleIn |= MASKBIT32(iTerm);
|
|
}else if( (pTerm->eOperator & WO_IN)!=0 ){
|
|
/* A virtual table that is constrained by an IN clause may not
|
|
** consume the ORDER BY clause because (1) the order of IN terms
|
|
** is not necessarily related to the order of output terms and
|
|
** (2) Multiple outputs from a single IN value will not merge
|
|
** together. */
|
|
pIdxInfo->orderByConsumed = 0;
|
|
pIdxInfo->idxFlags &= ~SQLITE_INDEX_SCAN_UNIQUE;
|
|
*pbIn = 1; assert( (mExclude & WO_IN)==0 );
|
|
}
|
|
|
|
assert( pbRetryLimit || !isLimitTerm(pTerm) );
|
|
if( isLimitTerm(pTerm) && *pbIn ){
|
|
/* If there is an IN(...) term handled as an == (separate call to
|
|
** xFilter for each value on the RHS of the IN) and a LIMIT or
|
|
** OFFSET term handled as well, the plan is unusable. Set output
|
|
** variable *pbRetryLimit to true to tell the caller to retry with
|
|
** LIMIT and OFFSET disabled. */
|
|
if( pIdxInfo->needToFreeIdxStr ){
|
|
sqlite3_free(pIdxInfo->idxStr);
|
|
pIdxInfo->idxStr = 0;
|
|
pIdxInfo->needToFreeIdxStr = 0;
|
|
}
|
|
*pbRetryLimit = 1;
|
|
return SQLITE_OK;
|
|
}
|
|
}
|
|
}
|
|
|
|
pNew->nLTerm = mxTerm+1;
|
|
for(i=0; i<=mxTerm; i++){
|
|
if( pNew->aLTerm[i]==0 ){
|
|
/* The non-zero argvIdx values must be contiguous. Raise an
|
|
** error if they are not */
|
|
sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pTab->zName);
|
|
testcase( pIdxInfo->needToFreeIdxStr );
|
|
return SQLITE_ERROR;
|
|
}
|
|
}
|
|
assert( pNew->nLTerm<=pNew->nLSlot );
|
|
pNew->u.vtab.idxNum = pIdxInfo->idxNum;
|
|
pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
|
|
pIdxInfo->needToFreeIdxStr = 0;
|
|
pNew->u.vtab.idxStr = pIdxInfo->idxStr;
|
|
pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ?
|
|
pIdxInfo->nOrderBy : 0);
|
|
pNew->rSetup = 0;
|
|
pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
|
|
pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
|
|
|
|
/* Set the WHERE_ONEROW flag if the xBestIndex() method indicated
|
|
** that the scan will visit at most one row. Clear it otherwise. */
|
|
if( pIdxInfo->idxFlags & SQLITE_INDEX_SCAN_UNIQUE ){
|
|
pNew->wsFlags |= WHERE_ONEROW;
|
|
}else{
|
|
pNew->wsFlags &= ~WHERE_ONEROW;
|
|
}
|
|
rc = whereLoopInsert(pBuilder, pNew);
|
|
if( pNew->u.vtab.needFree ){
|
|
sqlite3_free(pNew->u.vtab.idxStr);
|
|
pNew->u.vtab.needFree = 0;
|
|
}
|
|
WHERETRACE(0xffff, (" bIn=%d prereqIn=%04llx prereqOut=%04llx\n",
|
|
*pbIn, (sqlite3_uint64)mPrereq,
|
|
(sqlite3_uint64)(pNew->prereq & ~mPrereq)));
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the collating sequence for a constraint passed into xBestIndex.
|
|
**
|
|
** pIdxInfo must be an sqlite3_index_info structure passed into xBestIndex.
|
|
** This routine depends on there being a HiddenIndexInfo structure immediately
|
|
** following the sqlite3_index_info structure.
|
|
**
|
|
** Return a pointer to the collation name:
|
|
**
|
|
** 1. If there is an explicit COLLATE operator on the constaint, return it.
|
|
**
|
|
** 2. Else, if the column has an alternative collation, return that.
|
|
**
|
|
** 3. Otherwise, return "BINARY".
|
|
*/
|
|
const char *sqlite3_vtab_collation(sqlite3_index_info *pIdxInfo, int iCons){
|
|
HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
|
|
const char *zRet = 0;
|
|
if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
|
|
CollSeq *pC = 0;
|
|
int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
|
|
Expr *pX = pHidden->pWC->a[iTerm].pExpr;
|
|
if( pX->pLeft ){
|
|
pC = sqlite3ExprCompareCollSeq(pHidden->pParse, pX);
|
|
}
|
|
zRet = (pC ? pC->zName : sqlite3StrBINARY);
|
|
}
|
|
return zRet;
|
|
}
|
|
|
|
/*
|
|
** Return true if constraint iCons is really an IN(...) constraint, or
|
|
** false otherwise. If iCons is an IN(...) constraint, set (if bHandle!=0)
|
|
** or clear (if bHandle==0) the flag to handle it using an iterator.
|
|
*/
|
|
int sqlite3_vtab_in(sqlite3_index_info *pIdxInfo, int iCons, int bHandle){
|
|
HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
|
|
u32 m = SMASKBIT32(iCons);
|
|
if( m & pHidden->mIn ){
|
|
if( bHandle==0 ){
|
|
pHidden->mHandleIn &= ~m;
|
|
}else if( bHandle>0 ){
|
|
pHidden->mHandleIn |= m;
|
|
}
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** This interface is callable from within the xBestIndex callback only.
|
|
**
|
|
** If possible, set (*ppVal) to point to an object containing the value
|
|
** on the right-hand-side of constraint iCons.
|
|
*/
|
|
int sqlite3_vtab_rhs_value(
|
|
sqlite3_index_info *pIdxInfo, /* Copy of first argument to xBestIndex */
|
|
int iCons, /* Constraint for which RHS is wanted */
|
|
sqlite3_value **ppVal /* Write value extracted here */
|
|
){
|
|
HiddenIndexInfo *pH = (HiddenIndexInfo*)&pIdxInfo[1];
|
|
sqlite3_value *pVal = 0;
|
|
int rc = SQLITE_OK;
|
|
if( iCons<0 || iCons>=pIdxInfo->nConstraint ){
|
|
rc = SQLITE_MISUSE; /* EV: R-30545-25046 */
|
|
}else{
|
|
if( pH->aRhs[iCons]==0 ){
|
|
WhereTerm *pTerm = &pH->pWC->a[pIdxInfo->aConstraint[iCons].iTermOffset];
|
|
rc = sqlite3ValueFromExpr(
|
|
pH->pParse->db, pTerm->pExpr->pRight, ENC(pH->pParse->db),
|
|
SQLITE_AFF_BLOB, &pH->aRhs[iCons]
|
|
);
|
|
testcase( rc!=SQLITE_OK );
|
|
}
|
|
pVal = pH->aRhs[iCons];
|
|
}
|
|
*ppVal = pVal;
|
|
|
|
if( rc==SQLITE_OK && pVal==0 ){ /* IMP: R-19933-32160 */
|
|
rc = SQLITE_NOTFOUND; /* IMP: R-36424-56542 */
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return true if ORDER BY clause may be handled as DISTINCT.
|
|
*/
|
|
int sqlite3_vtab_distinct(sqlite3_index_info *pIdxInfo){
|
|
HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
|
|
assert( pHidden->eDistinct>=0 && pHidden->eDistinct<=3 );
|
|
return pHidden->eDistinct;
|
|
}
|
|
|
|
#if (defined(SQLITE_ENABLE_DBPAGE_VTAB) || defined(SQLITE_TEST)) \
|
|
&& !defined(SQLITE_OMIT_VIRTUALTABLE)
|
|
/*
|
|
** Cause the prepared statement that is associated with a call to
|
|
** xBestIndex to potentiall use all schemas. If the statement being
|
|
** prepared is read-only, then just start read transactions on all
|
|
** schemas. But if this is a write operation, start writes on all
|
|
** schemas.
|
|
**
|
|
** This is used by the (built-in) sqlite_dbpage virtual table.
|
|
*/
|
|
void sqlite3VtabUsesAllSchemas(sqlite3_index_info *pIdxInfo){
|
|
HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
|
|
Parse *pParse = pHidden->pParse;
|
|
int nDb = pParse->db->nDb;
|
|
int i;
|
|
for(i=0; i<nDb; i++){
|
|
sqlite3CodeVerifySchema(pParse, i);
|
|
}
|
|
if( pParse->writeMask ){
|
|
for(i=0; i<nDb; i++){
|
|
sqlite3BeginWriteOperation(pParse, 0, i);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Add all WhereLoop objects for a table of the join identified by
|
|
** pBuilder->pNew->iTab. That table is guaranteed to be a virtual table.
|
|
**
|
|
** If there are no LEFT or CROSS JOIN joins in the query, both mPrereq and
|
|
** mUnusable are set to 0. Otherwise, mPrereq is a mask of all FROM clause
|
|
** entries that occur before the virtual table in the FROM clause and are
|
|
** separated from it by at least one LEFT or CROSS JOIN. Similarly, the
|
|
** mUnusable mask contains all FROM clause entries that occur after the
|
|
** virtual table and are separated from it by at least one LEFT or
|
|
** CROSS JOIN.
|
|
**
|
|
** For example, if the query were:
|
|
**
|
|
** ... FROM t1, t2 LEFT JOIN t3, t4, vt CROSS JOIN t5, t6;
|
|
**
|
|
** then mPrereq corresponds to (t1, t2) and mUnusable to (t5, t6).
|
|
**
|
|
** All the tables in mPrereq must be scanned before the current virtual
|
|
** table. So any terms for which all prerequisites are satisfied by
|
|
** mPrereq may be specified as "usable" in all calls to xBestIndex.
|
|
** Conversely, all tables in mUnusable must be scanned after the current
|
|
** virtual table, so any terms for which the prerequisites overlap with
|
|
** mUnusable should always be configured as "not-usable" for xBestIndex.
|
|
*/
|
|
static int whereLoopAddVirtual(
|
|
WhereLoopBuilder *pBuilder, /* WHERE clause information */
|
|
Bitmask mPrereq, /* Tables that must be scanned before this one */
|
|
Bitmask mUnusable /* Tables that must be scanned after this one */
|
|
){
|
|
int rc = SQLITE_OK; /* Return code */
|
|
WhereInfo *pWInfo; /* WHERE analysis context */
|
|
Parse *pParse; /* The parsing context */
|
|
WhereClause *pWC; /* The WHERE clause */
|
|
SrcItem *pSrc; /* The FROM clause term to search */
|
|
sqlite3_index_info *p; /* Object to pass to xBestIndex() */
|
|
int nConstraint; /* Number of constraints in p */
|
|
int bIn; /* True if plan uses IN(...) operator */
|
|
WhereLoop *pNew;
|
|
Bitmask mBest; /* Tables used by best possible plan */
|
|
u16 mNoOmit;
|
|
int bRetry = 0; /* True to retry with LIMIT/OFFSET disabled */
|
|
|
|
assert( (mPrereq & mUnusable)==0 );
|
|
pWInfo = pBuilder->pWInfo;
|
|
pParse = pWInfo->pParse;
|
|
pWC = pBuilder->pWC;
|
|
pNew = pBuilder->pNew;
|
|
pSrc = &pWInfo->pTabList->a[pNew->iTab];
|
|
assert( IsVirtual(pSrc->pTab) );
|
|
p = allocateIndexInfo(pWInfo, pWC, mUnusable, pSrc, &mNoOmit);
|
|
if( p==0 ) return SQLITE_NOMEM_BKPT;
|
|
pNew->rSetup = 0;
|
|
pNew->wsFlags = WHERE_VIRTUALTABLE;
|
|
pNew->nLTerm = 0;
|
|
pNew->u.vtab.needFree = 0;
|
|
nConstraint = p->nConstraint;
|
|
if( whereLoopResize(pParse->db, pNew, nConstraint) ){
|
|
freeIndexInfo(pParse->db, p);
|
|
return SQLITE_NOMEM_BKPT;
|
|
}
|
|
|
|
/* First call xBestIndex() with all constraints usable. */
|
|
WHERETRACE(0x800, ("BEGIN %s.addVirtual()\n", pSrc->pTab->zName));
|
|
WHERETRACE(0x40, (" VirtualOne: all usable\n"));
|
|
rc = whereLoopAddVirtualOne(
|
|
pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, &bRetry
|
|
);
|
|
if( bRetry ){
|
|
assert( rc==SQLITE_OK );
|
|
rc = whereLoopAddVirtualOne(
|
|
pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, 0
|
|
);
|
|
}
|
|
|
|
/* If the call to xBestIndex() with all terms enabled produced a plan
|
|
** that does not require any source tables (IOW: a plan with mBest==0)
|
|
** and does not use an IN(...) operator, then there is no point in making
|
|
** any further calls to xBestIndex() since they will all return the same
|
|
** result (if the xBestIndex() implementation is sane). */
|
|
if( rc==SQLITE_OK && ((mBest = (pNew->prereq & ~mPrereq))!=0 || bIn) ){
|
|
int seenZero = 0; /* True if a plan with no prereqs seen */
|
|
int seenZeroNoIN = 0; /* Plan with no prereqs and no IN(...) seen */
|
|
Bitmask mPrev = 0;
|
|
Bitmask mBestNoIn = 0;
|
|
|
|
/* If the plan produced by the earlier call uses an IN(...) term, call
|
|
** xBestIndex again, this time with IN(...) terms disabled. */
|
|
if( bIn ){
|
|
WHERETRACE(0x40, (" VirtualOne: all usable w/o IN\n"));
|
|
rc = whereLoopAddVirtualOne(
|
|
pBuilder, mPrereq, ALLBITS, WO_IN, p, mNoOmit, &bIn, 0);
|
|
assert( bIn==0 );
|
|
mBestNoIn = pNew->prereq & ~mPrereq;
|
|
if( mBestNoIn==0 ){
|
|
seenZero = 1;
|
|
seenZeroNoIN = 1;
|
|
}
|
|
}
|
|
|
|
/* Call xBestIndex once for each distinct value of (prereqRight & ~mPrereq)
|
|
** in the set of terms that apply to the current virtual table. */
|
|
while( rc==SQLITE_OK ){
|
|
int i;
|
|
Bitmask mNext = ALLBITS;
|
|
assert( mNext>0 );
|
|
for(i=0; i<nConstraint; i++){
|
|
Bitmask mThis = (
|
|
pWC->a[p->aConstraint[i].iTermOffset].prereqRight & ~mPrereq
|
|
);
|
|
if( mThis>mPrev && mThis<mNext ) mNext = mThis;
|
|
}
|
|
mPrev = mNext;
|
|
if( mNext==ALLBITS ) break;
|
|
if( mNext==mBest || mNext==mBestNoIn ) continue;
|
|
WHERETRACE(0x40, (" VirtualOne: mPrev=%04llx mNext=%04llx\n",
|
|
(sqlite3_uint64)mPrev, (sqlite3_uint64)mNext));
|
|
rc = whereLoopAddVirtualOne(
|
|
pBuilder, mPrereq, mNext|mPrereq, 0, p, mNoOmit, &bIn, 0);
|
|
if( pNew->prereq==mPrereq ){
|
|
seenZero = 1;
|
|
if( bIn==0 ) seenZeroNoIN = 1;
|
|
}
|
|
}
|
|
|
|
/* If the calls to xBestIndex() in the above loop did not find a plan
|
|
** that requires no source tables at all (i.e. one guaranteed to be
|
|
** usable), make a call here with all source tables disabled */
|
|
if( rc==SQLITE_OK && seenZero==0 ){
|
|
WHERETRACE(0x40, (" VirtualOne: all disabled\n"));
|
|
rc = whereLoopAddVirtualOne(
|
|
pBuilder, mPrereq, mPrereq, 0, p, mNoOmit, &bIn, 0);
|
|
if( bIn==0 ) seenZeroNoIN = 1;
|
|
}
|
|
|
|
/* If the calls to xBestIndex() have so far failed to find a plan
|
|
** that requires no source tables at all and does not use an IN(...)
|
|
** operator, make a final call to obtain one here. */
|
|
if( rc==SQLITE_OK && seenZeroNoIN==0 ){
|
|
WHERETRACE(0x40, (" VirtualOne: all disabled and w/o IN\n"));
|
|
rc = whereLoopAddVirtualOne(
|
|
pBuilder, mPrereq, mPrereq, WO_IN, p, mNoOmit, &bIn, 0);
|
|
}
|
|
}
|
|
|
|
if( p->needToFreeIdxStr ) sqlite3_free(p->idxStr);
|
|
freeIndexInfo(pParse->db, p);
|
|
WHERETRACE(0x800, ("END %s.addVirtual(), rc=%d\n", pSrc->pTab->zName, rc));
|
|
return rc;
|
|
}
|
|
#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
|
|
|
/*
|
|
** Add WhereLoop entries to handle OR terms. This works for either
|
|
** btrees or virtual tables.
|
|
*/
|
|
static int whereLoopAddOr(
|
|
WhereLoopBuilder *pBuilder,
|
|
Bitmask mPrereq,
|
|
Bitmask mUnusable
|
|
){
|
|
WhereInfo *pWInfo = pBuilder->pWInfo;
|
|
WhereClause *pWC;
|
|
WhereLoop *pNew;
|
|
WhereTerm *pTerm, *pWCEnd;
|
|
int rc = SQLITE_OK;
|
|
int iCur;
|
|
WhereClause tempWC;
|
|
WhereLoopBuilder sSubBuild;
|
|
WhereOrSet sSum, sCur;
|
|
SrcItem *pItem;
|
|
|
|
pWC = pBuilder->pWC;
|
|
pWCEnd = pWC->a + pWC->nTerm;
|
|
pNew = pBuilder->pNew;
|
|
memset(&sSum, 0, sizeof(sSum));
|
|
pItem = pWInfo->pTabList->a + pNew->iTab;
|
|
iCur = pItem->iCursor;
|
|
|
|
/* The multi-index OR optimization does not work for RIGHT and FULL JOIN */
|
|
if( pItem->fg.jointype & JT_RIGHT ) return SQLITE_OK;
|
|
|
|
for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){
|
|
if( (pTerm->eOperator & WO_OR)!=0
|
|
&& (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0
|
|
){
|
|
WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
|
|
WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
|
|
WhereTerm *pOrTerm;
|
|
int once = 1;
|
|
int i, j;
|
|
|
|
sSubBuild = *pBuilder;
|
|
sSubBuild.pOrSet = &sCur;
|
|
|
|
WHERETRACE(0x200, ("Begin processing OR-clause %p\n", pTerm));
|
|
for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
|
|
if( (pOrTerm->eOperator & WO_AND)!=0 ){
|
|
sSubBuild.pWC = &pOrTerm->u.pAndInfo->wc;
|
|
}else if( pOrTerm->leftCursor==iCur ){
|
|
tempWC.pWInfo = pWC->pWInfo;
|
|
tempWC.pOuter = pWC;
|
|
tempWC.op = TK_AND;
|
|
tempWC.nTerm = 1;
|
|
tempWC.nBase = 1;
|
|
tempWC.a = pOrTerm;
|
|
sSubBuild.pWC = &tempWC;
|
|
}else{
|
|
continue;
|
|
}
|
|
sCur.n = 0;
|
|
#ifdef WHERETRACE_ENABLED
|
|
WHERETRACE(0x200, ("OR-term %d of %p has %d subterms:\n",
|
|
(int)(pOrTerm-pOrWC->a), pTerm, sSubBuild.pWC->nTerm));
|
|
if( sqlite3WhereTrace & 0x400 ){
|
|
sqlite3WhereClausePrint(sSubBuild.pWC);
|
|
}
|
|
#endif
|
|
#ifndef SQLITE_OMIT_VIRTUALTABLE
|
|
if( IsVirtual(pItem->pTab) ){
|
|
rc = whereLoopAddVirtual(&sSubBuild, mPrereq, mUnusable);
|
|
}else
|
|
#endif
|
|
{
|
|
rc = whereLoopAddBtree(&sSubBuild, mPrereq);
|
|
}
|
|
if( rc==SQLITE_OK ){
|
|
rc = whereLoopAddOr(&sSubBuild, mPrereq, mUnusable);
|
|
}
|
|
assert( rc==SQLITE_OK || rc==SQLITE_DONE || sCur.n==0
|
|
|| rc==SQLITE_NOMEM );
|
|
testcase( rc==SQLITE_NOMEM && sCur.n>0 );
|
|
testcase( rc==SQLITE_DONE );
|
|
if( sCur.n==0 ){
|
|
sSum.n = 0;
|
|
break;
|
|
}else if( once ){
|
|
whereOrMove(&sSum, &sCur);
|
|
once = 0;
|
|
}else{
|
|
WhereOrSet sPrev;
|
|
whereOrMove(&sPrev, &sSum);
|
|
sSum.n = 0;
|
|
for(i=0; i<sPrev.n; i++){
|
|
for(j=0; j<sCur.n; j++){
|
|
whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq,
|
|
sqlite3LogEstAdd(sPrev.a[i].rRun, sCur.a[j].rRun),
|
|
sqlite3LogEstAdd(sPrev.a[i].nOut, sCur.a[j].nOut));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
pNew->nLTerm = 1;
|
|
pNew->aLTerm[0] = pTerm;
|
|
pNew->wsFlags = WHERE_MULTI_OR;
|
|
pNew->rSetup = 0;
|
|
pNew->iSortIdx = 0;
|
|
memset(&pNew->u, 0, sizeof(pNew->u));
|
|
for(i=0; rc==SQLITE_OK && i<sSum.n; i++){
|
|
/* TUNING: Currently sSum.a[i].rRun is set to the sum of the costs
|
|
** of all sub-scans required by the OR-scan. However, due to rounding
|
|
** errors, it may be that the cost of the OR-scan is equal to its
|
|
** most expensive sub-scan. Add the smallest possible penalty
|
|
** (equivalent to multiplying the cost by 1.07) to ensure that
|
|
** this does not happen. Otherwise, for WHERE clauses such as the
|
|
** following where there is an index on "y":
|
|
**
|
|
** WHERE likelihood(x=?, 0.99) OR y=?
|
|
**
|
|
** the planner may elect to "OR" together a full-table scan and an
|
|
** index lookup. And other similarly odd results. */
|
|
pNew->rRun = sSum.a[i].rRun + 1;
|
|
pNew->nOut = sSum.a[i].nOut;
|
|
pNew->prereq = sSum.a[i].prereq;
|
|
rc = whereLoopInsert(pBuilder, pNew);
|
|
}
|
|
WHERETRACE(0x200, ("End processing OR-clause %p\n", pTerm));
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Add all WhereLoop objects for all tables
|
|
*/
|
|
static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
|
|
WhereInfo *pWInfo = pBuilder->pWInfo;
|
|
Bitmask mPrereq = 0;
|
|
Bitmask mPrior = 0;
|
|
int iTab;
|
|
SrcList *pTabList = pWInfo->pTabList;
|
|
SrcItem *pItem;
|
|
SrcItem *pEnd = &pTabList->a[pWInfo->nLevel];
|
|
sqlite3 *db = pWInfo->pParse->db;
|
|
int rc = SQLITE_OK;
|
|
int bFirstPastRJ = 0;
|
|
int hasRightJoin = 0;
|
|
WhereLoop *pNew;
|
|
|
|
|
|
/* Loop over the tables in the join, from left to right */
|
|
pNew = pBuilder->pNew;
|
|
|
|
/* Verify that pNew has already been initialized */
|
|
assert( pNew->nLTerm==0 );
|
|
assert( pNew->wsFlags==0 );
|
|
assert( pNew->nLSlot>=ArraySize(pNew->aLTermSpace) );
|
|
assert( pNew->aLTerm!=0 );
|
|
|
|
pBuilder->iPlanLimit = SQLITE_QUERY_PLANNER_LIMIT;
|
|
for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){
|
|
Bitmask mUnusable = 0;
|
|
pNew->iTab = iTab;
|
|
pBuilder->iPlanLimit += SQLITE_QUERY_PLANNER_LIMIT_INCR;
|
|
pNew->maskSelf = sqlite3WhereGetMask(&pWInfo->sMaskSet, pItem->iCursor);
|
|
if( bFirstPastRJ
|
|
|| (pItem->fg.jointype & (JT_OUTER|JT_CROSS|JT_LTORJ))!=0
|
|
){
|
|
/* Add prerequisites to prevent reordering of FROM clause terms
|
|
** across CROSS joins and outer joins. The bFirstPastRJ boolean
|
|
** prevents the right operand of a RIGHT JOIN from being swapped with
|
|
** other elements even further to the right.
|
|
**
|
|
** The JT_LTORJ case and the hasRightJoin flag work together to
|
|
** prevent FROM-clause terms from moving from the right side of
|
|
** a LEFT JOIN over to the left side of that join if the LEFT JOIN
|
|
** is itself on the left side of a RIGHT JOIN.
|
|
*/
|
|
if( pItem->fg.jointype & JT_LTORJ ) hasRightJoin = 1;
|
|
mPrereq |= mPrior;
|
|
bFirstPastRJ = (pItem->fg.jointype & JT_RIGHT)!=0;
|
|
}else if( !hasRightJoin ){
|
|
mPrereq = 0;
|
|
}
|
|
#ifndef SQLITE_OMIT_VIRTUALTABLE
|
|
if( IsVirtual(pItem->pTab) ){
|
|
SrcItem *p;
|
|
for(p=&pItem[1]; p<pEnd; p++){
|
|
if( mUnusable || (p->fg.jointype & (JT_OUTER|JT_CROSS)) ){
|
|
mUnusable |= sqlite3WhereGetMask(&pWInfo->sMaskSet, p->iCursor);
|
|
}
|
|
}
|
|
rc = whereLoopAddVirtual(pBuilder, mPrereq, mUnusable);
|
|
}else
|
|
#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
|
{
|
|
rc = whereLoopAddBtree(pBuilder, mPrereq);
|
|
}
|
|
if( rc==SQLITE_OK && pBuilder->pWC->hasOr ){
|
|
rc = whereLoopAddOr(pBuilder, mPrereq, mUnusable);
|
|
}
|
|
mPrior |= pNew->maskSelf;
|
|
if( rc || db->mallocFailed ){
|
|
if( rc==SQLITE_DONE ){
|
|
/* We hit the query planner search limit set by iPlanLimit */
|
|
sqlite3_log(SQLITE_WARNING, "abbreviated query algorithm search");
|
|
rc = SQLITE_OK;
|
|
}else{
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
whereLoopClear(db, pNew);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Examine a WherePath (with the addition of the extra WhereLoop of the 6th
|
|
** parameters) to see if it outputs rows in the requested ORDER BY
|
|
** (or GROUP BY) without requiring a separate sort operation. Return N:
|
|
**
|
|
** N>0: N terms of the ORDER BY clause are satisfied
|
|
** N==0: No terms of the ORDER BY clause are satisfied
|
|
** N<0: Unknown yet how many terms of ORDER BY might be satisfied.
|
|
**
|
|
** Note that processing for WHERE_GROUPBY and WHERE_DISTINCTBY is not as
|
|
** strict. With GROUP BY and DISTINCT the only requirement is that
|
|
** equivalent rows appear immediately adjacent to one another. GROUP BY
|
|
** and DISTINCT do not require rows to appear in any particular order as long
|
|
** as equivalent rows are grouped together. Thus for GROUP BY and DISTINCT
|
|
** the pOrderBy terms can be matched in any order. With ORDER BY, the
|
|
** pOrderBy terms must be matched in strict left-to-right order.
|
|
*/
|
|
static i8 wherePathSatisfiesOrderBy(
|
|
WhereInfo *pWInfo, /* The WHERE clause */
|
|
ExprList *pOrderBy, /* ORDER BY or GROUP BY or DISTINCT clause to check */
|
|
WherePath *pPath, /* The WherePath to check */
|
|
u16 wctrlFlags, /* WHERE_GROUPBY or _DISTINCTBY or _ORDERBY_LIMIT */
|
|
u16 nLoop, /* Number of entries in pPath->aLoop[] */
|
|
WhereLoop *pLast, /* Add this WhereLoop to the end of pPath->aLoop[] */
|
|
Bitmask *pRevMask /* OUT: Mask of WhereLoops to run in reverse order */
|
|
){
|
|
u8 revSet; /* True if rev is known */
|
|
u8 rev; /* Composite sort order */
|
|
u8 revIdx; /* Index sort order */
|
|
u8 isOrderDistinct; /* All prior WhereLoops are order-distinct */
|
|
u8 distinctColumns; /* True if the loop has UNIQUE NOT NULL columns */
|
|
u8 isMatch; /* iColumn matches a term of the ORDER BY clause */
|
|
u16 eqOpMask; /* Allowed equality operators */
|
|
u16 nKeyCol; /* Number of key columns in pIndex */
|
|
u16 nColumn; /* Total number of ordered columns in the index */
|
|
u16 nOrderBy; /* Number terms in the ORDER BY clause */
|
|
int iLoop; /* Index of WhereLoop in pPath being processed */
|
|
int i, j; /* Loop counters */
|
|
int iCur; /* Cursor number for current WhereLoop */
|
|
int iColumn; /* A column number within table iCur */
|
|
WhereLoop *pLoop = 0; /* Current WhereLoop being processed. */
|
|
WhereTerm *pTerm; /* A single term of the WHERE clause */
|
|
Expr *pOBExpr; /* An expression from the ORDER BY clause */
|
|
CollSeq *pColl; /* COLLATE function from an ORDER BY clause term */
|
|
Index *pIndex; /* The index associated with pLoop */
|
|
sqlite3 *db = pWInfo->pParse->db; /* Database connection */
|
|
Bitmask obSat = 0; /* Mask of ORDER BY terms satisfied so far */
|
|
Bitmask obDone; /* Mask of all ORDER BY terms */
|
|
Bitmask orderDistinctMask; /* Mask of all well-ordered loops */
|
|
Bitmask ready; /* Mask of inner loops */
|
|
|
|
/*
|
|
** We say the WhereLoop is "one-row" if it generates no more than one
|
|
** row of output. A WhereLoop is one-row if all of the following are true:
|
|
** (a) All index columns match with WHERE_COLUMN_EQ.
|
|
** (b) The index is unique
|
|
** Any WhereLoop with an WHERE_COLUMN_EQ constraint on the rowid is one-row.
|
|
** Every one-row WhereLoop will have the WHERE_ONEROW bit set in wsFlags.
|
|
**
|
|
** We say the WhereLoop is "order-distinct" if the set of columns from
|
|
** that WhereLoop that are in the ORDER BY clause are different for every
|
|
** row of the WhereLoop. Every one-row WhereLoop is automatically
|
|
** order-distinct. A WhereLoop that has no columns in the ORDER BY clause
|
|
** is not order-distinct. To be order-distinct is not quite the same as being
|
|
** UNIQUE since a UNIQUE column or index can have multiple rows that
|
|
** are NULL and NULL values are equivalent for the purpose of order-distinct.
|
|
** To be order-distinct, the columns must be UNIQUE and NOT NULL.
|
|
**
|
|
** The rowid for a table is always UNIQUE and NOT NULL so whenever the
|
|
** rowid appears in the ORDER BY clause, the corresponding WhereLoop is
|
|
** automatically order-distinct.
|
|
*/
|
|
|
|
assert( pOrderBy!=0 );
|
|
if( nLoop && OptimizationDisabled(db, SQLITE_OrderByIdxJoin) ) return 0;
|
|
|
|
nOrderBy = pOrderBy->nExpr;
|
|
testcase( nOrderBy==BMS-1 );
|
|
if( nOrderBy>BMS-1 ) return 0; /* Cannot optimize overly large ORDER BYs */
|
|
isOrderDistinct = 1;
|
|
obDone = MASKBIT(nOrderBy)-1;
|
|
orderDistinctMask = 0;
|
|
ready = 0;
|
|
eqOpMask = WO_EQ | WO_IS | WO_ISNULL;
|
|
if( wctrlFlags & (WHERE_ORDERBY_LIMIT|WHERE_ORDERBY_MAX|WHERE_ORDERBY_MIN) ){
|
|
eqOpMask |= WO_IN;
|
|
}
|
|
for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){
|
|
if( iLoop>0 ) ready |= pLoop->maskSelf;
|
|
if( iLoop<nLoop ){
|
|
pLoop = pPath->aLoop[iLoop];
|
|
if( wctrlFlags & WHERE_ORDERBY_LIMIT ) continue;
|
|
}else{
|
|
pLoop = pLast;
|
|
}
|
|
if( pLoop->wsFlags & WHERE_VIRTUALTABLE ){
|
|
if( pLoop->u.vtab.isOrdered
|
|
&& ((wctrlFlags&(WHERE_DISTINCTBY|WHERE_SORTBYGROUP))!=WHERE_DISTINCTBY)
|
|
){
|
|
obSat = obDone;
|
|
}
|
|
break;
|
|
}else if( wctrlFlags & WHERE_DISTINCTBY ){
|
|
pLoop->u.btree.nDistinctCol = 0;
|
|
}
|
|
iCur = pWInfo->pTabList->a[pLoop->iTab].iCursor;
|
|
|
|
/* Mark off any ORDER BY term X that is a column in the table of
|
|
** the current loop for which there is term in the WHERE
|
|
** clause of the form X IS NULL or X=? that reference only outer
|
|
** loops.
|
|
*/
|
|
for(i=0; i<nOrderBy; i++){
|
|
if( MASKBIT(i) & obSat ) continue;
|
|
pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
|
|
if( NEVER(pOBExpr==0) ) continue;
|
|
if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) continue;
|
|
if( pOBExpr->iTable!=iCur ) continue;
|
|
pTerm = sqlite3WhereFindTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn,
|
|
~ready, eqOpMask, 0);
|
|
if( pTerm==0 ) continue;
|
|
if( pTerm->eOperator==WO_IN ){
|
|
/* IN terms are only valid for sorting in the ORDER BY LIMIT
|
|
** optimization, and then only if they are actually used
|
|
** by the query plan */
|
|
assert( wctrlFlags &
|
|
(WHERE_ORDERBY_LIMIT|WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX) );
|
|
for(j=0; j<pLoop->nLTerm && pTerm!=pLoop->aLTerm[j]; j++){}
|
|
if( j>=pLoop->nLTerm ) continue;
|
|
}
|
|
if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0 && pOBExpr->iColumn>=0 ){
|
|
Parse *pParse = pWInfo->pParse;
|
|
CollSeq *pColl1 = sqlite3ExprNNCollSeq(pParse, pOrderBy->a[i].pExpr);
|
|
CollSeq *pColl2 = sqlite3ExprCompareCollSeq(pParse, pTerm->pExpr);
|
|
assert( pColl1 );
|
|
if( pColl2==0 || sqlite3StrICmp(pColl1->zName, pColl2->zName) ){
|
|
continue;
|
|
}
|
|
testcase( pTerm->pExpr->op==TK_IS );
|
|
}
|
|
obSat |= MASKBIT(i);
|
|
}
|
|
|
|
if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){
|
|
if( pLoop->wsFlags & WHERE_IPK ){
|
|
pIndex = 0;
|
|
nKeyCol = 0;
|
|
nColumn = 1;
|
|
}else if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
|
|
return 0;
|
|
}else{
|
|
nKeyCol = pIndex->nKeyCol;
|
|
nColumn = pIndex->nColumn;
|
|
assert( nColumn==nKeyCol+1 || !HasRowid(pIndex->pTable) );
|
|
assert( pIndex->aiColumn[nColumn-1]==XN_ROWID
|
|
|| !HasRowid(pIndex->pTable));
|
|
/* All relevant terms of the index must also be non-NULL in order
|
|
** for isOrderDistinct to be true. So the isOrderDistint value
|
|
** computed here might be a false positive. Corrections will be
|
|
** made at tag-20210426-1 below */
|
|
isOrderDistinct = IsUniqueIndex(pIndex)
|
|
&& (pLoop->wsFlags & WHERE_SKIPSCAN)==0;
|
|
}
|
|
|
|
/* Loop through all columns of the index and deal with the ones
|
|
** that are not constrained by == or IN.
|
|
*/
|
|
rev = revSet = 0;
|
|
distinctColumns = 0;
|
|
for(j=0; j<nColumn; j++){
|
|
u8 bOnce = 1; /* True to run the ORDER BY search loop */
|
|
|
|
assert( j>=pLoop->u.btree.nEq
|
|
|| (pLoop->aLTerm[j]==0)==(j<pLoop->nSkip)
|
|
);
|
|
if( j<pLoop->u.btree.nEq && j>=pLoop->nSkip ){
|
|
u16 eOp = pLoop->aLTerm[j]->eOperator;
|
|
|
|
/* Skip over == and IS and ISNULL terms. (Also skip IN terms when
|
|
** doing WHERE_ORDERBY_LIMIT processing). Except, IS and ISNULL
|
|
** terms imply that the index is not UNIQUE NOT NULL in which case
|
|
** the loop need to be marked as not order-distinct because it can
|
|
** have repeated NULL rows.
|
|
**
|
|
** If the current term is a column of an ((?,?) IN (SELECT...))
|
|
** expression for which the SELECT returns more than one column,
|
|
** check that it is the only column used by this loop. Otherwise,
|
|
** if it is one of two or more, none of the columns can be
|
|
** considered to match an ORDER BY term.
|
|
*/
|
|
if( (eOp & eqOpMask)!=0 ){
|
|
if( eOp & (WO_ISNULL|WO_IS) ){
|
|
testcase( eOp & WO_ISNULL );
|
|
testcase( eOp & WO_IS );
|
|
testcase( isOrderDistinct );
|
|
isOrderDistinct = 0;
|
|
}
|
|
continue;
|
|
}else if( ALWAYS(eOp & WO_IN) ){
|
|
/* ALWAYS() justification: eOp is an equality operator due to the
|
|
** j<pLoop->u.btree.nEq constraint above. Any equality other
|
|
** than WO_IN is captured by the previous "if". So this one
|
|
** always has to be WO_IN. */
|
|
Expr *pX = pLoop->aLTerm[j]->pExpr;
|
|
for(i=j+1; i<pLoop->u.btree.nEq; i++){
|
|
if( pLoop->aLTerm[i]->pExpr==pX ){
|
|
assert( (pLoop->aLTerm[i]->eOperator & WO_IN) );
|
|
bOnce = 0;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Get the column number in the table (iColumn) and sort order
|
|
** (revIdx) for the j-th column of the index.
|
|
*/
|
|
if( pIndex ){
|
|
iColumn = pIndex->aiColumn[j];
|
|
revIdx = pIndex->aSortOrder[j] & KEYINFO_ORDER_DESC;
|
|
if( iColumn==pIndex->pTable->iPKey ) iColumn = XN_ROWID;
|
|
}else{
|
|
iColumn = XN_ROWID;
|
|
revIdx = 0;
|
|
}
|
|
|
|
/* An unconstrained column that might be NULL means that this
|
|
** WhereLoop is not well-ordered. tag-20210426-1
|
|
*/
|
|
if( isOrderDistinct ){
|
|
if( iColumn>=0
|
|
&& j>=pLoop->u.btree.nEq
|
|
&& pIndex->pTable->aCol[iColumn].notNull==0
|
|
){
|
|
isOrderDistinct = 0;
|
|
}
|
|
if( iColumn==XN_EXPR ){
|
|
isOrderDistinct = 0;
|
|
}
|
|
}
|
|
|
|
/* Find the ORDER BY term that corresponds to the j-th column
|
|
** of the index and mark that ORDER BY term off
|
|
*/
|
|
isMatch = 0;
|
|
for(i=0; bOnce && i<nOrderBy; i++){
|
|
if( MASKBIT(i) & obSat ) continue;
|
|
pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
|
|
testcase( wctrlFlags & WHERE_GROUPBY );
|
|
testcase( wctrlFlags & WHERE_DISTINCTBY );
|
|
if( NEVER(pOBExpr==0) ) continue;
|
|
if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
|
|
if( iColumn>=XN_ROWID ){
|
|
if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) continue;
|
|
if( pOBExpr->iTable!=iCur ) continue;
|
|
if( pOBExpr->iColumn!=iColumn ) continue;
|
|
}else{
|
|
Expr *pIdxExpr = pIndex->aColExpr->a[j].pExpr;
|
|
if( sqlite3ExprCompareSkip(pOBExpr, pIdxExpr, iCur) ){
|
|
continue;
|
|
}
|
|
}
|
|
if( iColumn!=XN_ROWID ){
|
|
pColl = sqlite3ExprNNCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
|
|
if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue;
|
|
}
|
|
if( wctrlFlags & WHERE_DISTINCTBY ){
|
|
pLoop->u.btree.nDistinctCol = j+1;
|
|
}
|
|
isMatch = 1;
|
|
break;
|
|
}
|
|
if( isMatch && (wctrlFlags & WHERE_GROUPBY)==0 ){
|
|
/* Make sure the sort order is compatible in an ORDER BY clause.
|
|
** Sort order is irrelevant for a GROUP BY clause. */
|
|
if( revSet ){
|
|
if( (rev ^ revIdx)
|
|
!= (pOrderBy->a[i].fg.sortFlags&KEYINFO_ORDER_DESC)
|
|
){
|
|
isMatch = 0;
|
|
}
|
|
}else{
|
|
rev = revIdx ^ (pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_DESC);
|
|
if( rev ) *pRevMask |= MASKBIT(iLoop);
|
|
revSet = 1;
|
|
}
|
|
}
|
|
if( isMatch && (pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_BIGNULL) ){
|
|
if( j==pLoop->u.btree.nEq ){
|
|
pLoop->wsFlags |= WHERE_BIGNULL_SORT;
|
|
}else{
|
|
isMatch = 0;
|
|
}
|
|
}
|
|
if( isMatch ){
|
|
if( iColumn==XN_ROWID ){
|
|
testcase( distinctColumns==0 );
|
|
distinctColumns = 1;
|
|
}
|
|
obSat |= MASKBIT(i);
|
|
}else{
|
|
/* No match found */
|
|
if( j==0 || j<nKeyCol ){
|
|
testcase( isOrderDistinct!=0 );
|
|
isOrderDistinct = 0;
|
|
}
|
|
break;
|
|
}
|
|
} /* end Loop over all index columns */
|
|
if( distinctColumns ){
|
|
testcase( isOrderDistinct==0 );
|
|
isOrderDistinct = 1;
|
|
}
|
|
} /* end-if not one-row */
|
|
|
|
/* Mark off any other ORDER BY terms that reference pLoop */
|
|
if( isOrderDistinct ){
|
|
orderDistinctMask |= pLoop->maskSelf;
|
|
for(i=0; i<nOrderBy; i++){
|
|
Expr *p;
|
|
Bitmask mTerm;
|
|
if( MASKBIT(i) & obSat ) continue;
|
|
p = pOrderBy->a[i].pExpr;
|
|
mTerm = sqlite3WhereExprUsage(&pWInfo->sMaskSet,p);
|
|
if( mTerm==0 && !sqlite3ExprIsConstant(p) ) continue;
|
|
if( (mTerm&~orderDistinctMask)==0 ){
|
|
obSat |= MASKBIT(i);
|
|
}
|
|
}
|
|
}
|
|
} /* End the loop over all WhereLoops from outer-most down to inner-most */
|
|
if( obSat==obDone ) return (i8)nOrderBy;
|
|
if( !isOrderDistinct ){
|
|
for(i=nOrderBy-1; i>0; i--){
|
|
Bitmask m = ALWAYS(i<BMS) ? MASKBIT(i) - 1 : 0;
|
|
if( (obSat&m)==m ) return i;
|
|
}
|
|
return 0;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
|
|
/*
|
|
** If the WHERE_GROUPBY flag is set in the mask passed to sqlite3WhereBegin(),
|
|
** the planner assumes that the specified pOrderBy list is actually a GROUP
|
|
** BY clause - and so any order that groups rows as required satisfies the
|
|
** request.
|
|
**
|
|
** Normally, in this case it is not possible for the caller to determine
|
|
** whether or not the rows are really being delivered in sorted order, or
|
|
** just in some other order that provides the required grouping. However,
|
|
** if the WHERE_SORTBYGROUP flag is also passed to sqlite3WhereBegin(), then
|
|
** this function may be called on the returned WhereInfo object. It returns
|
|
** true if the rows really will be sorted in the specified order, or false
|
|
** otherwise.
|
|
**
|
|
** For example, assuming:
|
|
**
|
|
** CREATE INDEX i1 ON t1(x, Y);
|
|
**
|
|
** then
|
|
**
|
|
** SELECT * FROM t1 GROUP BY x,y ORDER BY x,y; -- IsSorted()==1
|
|
** SELECT * FROM t1 GROUP BY y,x ORDER BY y,x; -- IsSorted()==0
|
|
*/
|
|
int sqlite3WhereIsSorted(WhereInfo *pWInfo){
|
|
assert( pWInfo->wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY) );
|
|
assert( pWInfo->wctrlFlags & WHERE_SORTBYGROUP );
|
|
return pWInfo->sorted;
|
|
}
|
|
|
|
#ifdef WHERETRACE_ENABLED
|
|
/* For debugging use only: */
|
|
static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){
|
|
static char zName[65];
|
|
int i;
|
|
for(i=0; i<nLoop; i++){ zName[i] = pPath->aLoop[i]->cId; }
|
|
if( pLast ) zName[i++] = pLast->cId;
|
|
zName[i] = 0;
|
|
return zName;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Return the cost of sorting nRow rows, assuming that the keys have
|
|
** nOrderby columns and that the first nSorted columns are already in
|
|
** order.
|
|
*/
|
|
static LogEst whereSortingCost(
|
|
WhereInfo *pWInfo,
|
|
LogEst nRow,
|
|
int nOrderBy,
|
|
int nSorted
|
|
){
|
|
/* TUNING: Estimated cost of a full external sort, where N is
|
|
** the number of rows to sort is:
|
|
**
|
|
** cost = (3.0 * N * log(N)).
|
|
**
|
|
** Or, if the order-by clause has X terms but only the last Y
|
|
** terms are out of order, then block-sorting will reduce the
|
|
** sorting cost to:
|
|
**
|
|
** cost = (3.0 * N * log(N)) * (Y/X)
|
|
**
|
|
** The (Y/X) term is implemented using stack variable rScale
|
|
** below.
|
|
*/
|
|
LogEst rScale, rSortCost;
|
|
assert( nOrderBy>0 && 66==sqlite3LogEst(100) );
|
|
rScale = sqlite3LogEst((nOrderBy-nSorted)*100/nOrderBy) - 66;
|
|
rSortCost = nRow + rScale + 16;
|
|
|
|
/* Multiple by log(M) where M is the number of output rows.
|
|
** Use the LIMIT for M if it is smaller. Or if this sort is for
|
|
** a DISTINCT operator, M will be the number of distinct output
|
|
** rows, so fudge it downwards a bit.
|
|
*/
|
|
if( (pWInfo->wctrlFlags & WHERE_USE_LIMIT)!=0 && pWInfo->iLimit<nRow ){
|
|
nRow = pWInfo->iLimit;
|
|
}else if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT) ){
|
|
/* TUNING: In the sort for a DISTINCT operator, assume that the DISTINCT
|
|
** reduces the number of output rows by a factor of 2 */
|
|
if( nRow>10 ){ nRow -= 10; assert( 10==sqlite3LogEst(2) ); }
|
|
}
|
|
rSortCost += estLog(nRow);
|
|
return rSortCost;
|
|
}
|
|
|
|
/*
|
|
** Given the list of WhereLoop objects at pWInfo->pLoops, this routine
|
|
** attempts to find the lowest cost path that visits each WhereLoop
|
|
** once. This path is then loaded into the pWInfo->a[].pWLoop fields.
|
|
**
|
|
** Assume that the total number of output rows that will need to be sorted
|
|
** will be nRowEst (in the 10*log2 representation). Or, ignore sorting
|
|
** costs if nRowEst==0.
|
|
**
|
|
** Return SQLITE_OK on success or SQLITE_NOMEM of a memory allocation
|
|
** error occurs.
|
|
*/
|
|
static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
|
|
int mxChoice; /* Maximum number of simultaneous paths tracked */
|
|
int nLoop; /* Number of terms in the join */
|
|
Parse *pParse; /* Parsing context */
|
|
sqlite3 *db; /* The database connection */
|
|
int iLoop; /* Loop counter over the terms of the join */
|
|
int ii, jj; /* Loop counters */
|
|
int mxI = 0; /* Index of next entry to replace */
|
|
int nOrderBy; /* Number of ORDER BY clause terms */
|
|
LogEst mxCost = 0; /* Maximum cost of a set of paths */
|
|
LogEst mxUnsorted = 0; /* Maximum unsorted cost of a set of path */
|
|
int nTo, nFrom; /* Number of valid entries in aTo[] and aFrom[] */
|
|
WherePath *aFrom; /* All nFrom paths at the previous level */
|
|
WherePath *aTo; /* The nTo best paths at the current level */
|
|
WherePath *pFrom; /* An element of aFrom[] that we are working on */
|
|
WherePath *pTo; /* An element of aTo[] that we are working on */
|
|
WhereLoop *pWLoop; /* One of the WhereLoop objects */
|
|
WhereLoop **pX; /* Used to divy up the pSpace memory */
|
|
LogEst *aSortCost = 0; /* Sorting and partial sorting costs */
|
|
char *pSpace; /* Temporary memory used by this routine */
|
|
int nSpace; /* Bytes of space allocated at pSpace */
|
|
|
|
pParse = pWInfo->pParse;
|
|
db = pParse->db;
|
|
nLoop = pWInfo->nLevel;
|
|
/* TUNING: For simple queries, only the best path is tracked.
|
|
** For 2-way joins, the 5 best paths are followed.
|
|
** For joins of 3 or more tables, track the 10 best paths */
|
|
mxChoice = (nLoop<=1) ? 1 : (nLoop==2 ? 5 : 10);
|
|
assert( nLoop<=pWInfo->pTabList->nSrc );
|
|
WHERETRACE(0x002, ("---- begin solver. (nRowEst=%d)\n", nRowEst));
|
|
|
|
/* If nRowEst is zero and there is an ORDER BY clause, ignore it. In this
|
|
** case the purpose of this call is to estimate the number of rows returned
|
|
** by the overall query. Once this estimate has been obtained, the caller
|
|
** will invoke this function a second time, passing the estimate as the
|
|
** nRowEst parameter. */
|
|
if( pWInfo->pOrderBy==0 || nRowEst==0 ){
|
|
nOrderBy = 0;
|
|
}else{
|
|
nOrderBy = pWInfo->pOrderBy->nExpr;
|
|
}
|
|
|
|
/* Allocate and initialize space for aTo, aFrom and aSortCost[] */
|
|
nSpace = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2;
|
|
nSpace += sizeof(LogEst) * nOrderBy;
|
|
pSpace = sqlite3DbMallocRawNN(db, nSpace);
|
|
if( pSpace==0 ) return SQLITE_NOMEM_BKPT;
|
|
aTo = (WherePath*)pSpace;
|
|
aFrom = aTo+mxChoice;
|
|
memset(aFrom, 0, sizeof(aFrom[0]));
|
|
pX = (WhereLoop**)(aFrom+mxChoice);
|
|
for(ii=mxChoice*2, pFrom=aTo; ii>0; ii--, pFrom++, pX += nLoop){
|
|
pFrom->aLoop = pX;
|
|
}
|
|
if( nOrderBy ){
|
|
/* If there is an ORDER BY clause and it is not being ignored, set up
|
|
** space for the aSortCost[] array. Each element of the aSortCost array
|
|
** is either zero - meaning it has not yet been initialized - or the
|
|
** cost of sorting nRowEst rows of data where the first X terms of
|
|
** the ORDER BY clause are already in order, where X is the array
|
|
** index. */
|
|
aSortCost = (LogEst*)pX;
|
|
memset(aSortCost, 0, sizeof(LogEst) * nOrderBy);
|
|
}
|
|
assert( aSortCost==0 || &pSpace[nSpace]==(char*)&aSortCost[nOrderBy] );
|
|
assert( aSortCost!=0 || &pSpace[nSpace]==(char*)pX );
|
|
|
|
/* Seed the search with a single WherePath containing zero WhereLoops.
|
|
**
|
|
** TUNING: Do not let the number of iterations go above 28. If the cost
|
|
** of computing an automatic index is not paid back within the first 28
|
|
** rows, then do not use the automatic index. */
|
|
aFrom[0].nRow = MIN(pParse->nQueryLoop, 48); assert( 48==sqlite3LogEst(28) );
|
|
nFrom = 1;
|
|
assert( aFrom[0].isOrdered==0 );
|
|
if( nOrderBy ){
|
|
/* If nLoop is zero, then there are no FROM terms in the query. Since
|
|
** in this case the query may return a maximum of one row, the results
|
|
** are already in the requested order. Set isOrdered to nOrderBy to
|
|
** indicate this. Or, if nLoop is greater than zero, set isOrdered to
|
|
** -1, indicating that the result set may or may not be ordered,
|
|
** depending on the loops added to the current plan. */
|
|
aFrom[0].isOrdered = nLoop>0 ? -1 : nOrderBy;
|
|
}
|
|
|
|
/* Compute successively longer WherePaths using the previous generation
|
|
** of WherePaths as the basis for the next. Keep track of the mxChoice
|
|
** best paths at each generation */
|
|
for(iLoop=0; iLoop<nLoop; iLoop++){
|
|
nTo = 0;
|
|
for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){
|
|
for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
|
|
LogEst nOut; /* Rows visited by (pFrom+pWLoop) */
|
|
LogEst rCost; /* Cost of path (pFrom+pWLoop) */
|
|
LogEst rUnsorted; /* Unsorted cost of (pFrom+pWLoop) */
|
|
i8 isOrdered; /* isOrdered for (pFrom+pWLoop) */
|
|
Bitmask maskNew; /* Mask of src visited by (..) */
|
|
Bitmask revMask; /* Mask of rev-order loops for (..) */
|
|
|
|
if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
|
|
if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
|
|
if( (pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0 && pFrom->nRow<3 ){
|
|
/* Do not use an automatic index if the this loop is expected
|
|
** to run less than 1.25 times. It is tempting to also exclude
|
|
** automatic index usage on an outer loop, but sometimes an automatic
|
|
** index is useful in the outer loop of a correlated subquery. */
|
|
assert( 10==sqlite3LogEst(2) );
|
|
continue;
|
|
}
|
|
|
|
/* At this point, pWLoop is a candidate to be the next loop.
|
|
** Compute its cost */
|
|
rUnsorted = sqlite3LogEstAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow);
|
|
rUnsorted = sqlite3LogEstAdd(rUnsorted, pFrom->rUnsorted);
|
|
nOut = pFrom->nRow + pWLoop->nOut;
|
|
maskNew = pFrom->maskLoop | pWLoop->maskSelf;
|
|
isOrdered = pFrom->isOrdered;
|
|
if( isOrdered<0 ){
|
|
revMask = 0;
|
|
isOrdered = wherePathSatisfiesOrderBy(pWInfo,
|
|
pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
|
|
iLoop, pWLoop, &revMask);
|
|
}else{
|
|
revMask = pFrom->revLoop;
|
|
}
|
|
if( isOrdered>=0 && isOrdered<nOrderBy ){
|
|
if( aSortCost[isOrdered]==0 ){
|
|
aSortCost[isOrdered] = whereSortingCost(
|
|
pWInfo, nRowEst, nOrderBy, isOrdered
|
|
);
|
|
}
|
|
/* TUNING: Add a small extra penalty (5) to sorting as an
|
|
** extra encouragment to the query planner to select a plan
|
|
** where the rows emerge in the correct order without any sorting
|
|
** required. */
|
|
rCost = sqlite3LogEstAdd(rUnsorted, aSortCost[isOrdered]) + 5;
|
|
|
|
WHERETRACE(0x002,
|
|
("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n",
|
|
aSortCost[isOrdered], (nOrderBy-isOrdered), nOrderBy,
|
|
rUnsorted, rCost));
|
|
}else{
|
|
rCost = rUnsorted;
|
|
rUnsorted -= 2; /* TUNING: Slight bias in favor of no-sort plans */
|
|
}
|
|
|
|
/* Check to see if pWLoop should be added to the set of
|
|
** mxChoice best-so-far paths.
|
|
**
|
|
** First look for an existing path among best-so-far paths
|
|
** that covers the same set of loops and has the same isOrdered
|
|
** setting as the current path candidate.
|
|
**
|
|
** The term "((pTo->isOrdered^isOrdered)&0x80)==0" is equivalent
|
|
** to (pTo->isOrdered==(-1))==(isOrdered==(-1))" for the range
|
|
** of legal values for isOrdered, -1..64.
|
|
*/
|
|
for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
|
|
if( pTo->maskLoop==maskNew
|
|
&& ((pTo->isOrdered^isOrdered)&0x80)==0
|
|
){
|
|
testcase( jj==nTo-1 );
|
|
break;
|
|
}
|
|
}
|
|
if( jj>=nTo ){
|
|
/* None of the existing best-so-far paths match the candidate. */
|
|
if( nTo>=mxChoice
|
|
&& (rCost>mxCost || (rCost==mxCost && rUnsorted>=mxUnsorted))
|
|
){
|
|
/* The current candidate is no better than any of the mxChoice
|
|
** paths currently in the best-so-far buffer. So discard
|
|
** this candidate as not viable. */
|
|
#ifdef WHERETRACE_ENABLED /* 0x4 */
|
|
if( sqlite3WhereTrace&0x4 ){
|
|
sqlite3DebugPrintf("Skip %s cost=%-3d,%3d,%3d order=%c\n",
|
|
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsorted,
|
|
isOrdered>=0 ? isOrdered+'0' : '?');
|
|
}
|
|
#endif
|
|
continue;
|
|
}
|
|
/* If we reach this points it means that the new candidate path
|
|
** needs to be added to the set of best-so-far paths. */
|
|
if( nTo<mxChoice ){
|
|
/* Increase the size of the aTo set by one */
|
|
jj = nTo++;
|
|
}else{
|
|
/* New path replaces the prior worst to keep count below mxChoice */
|
|
jj = mxI;
|
|
}
|
|
pTo = &aTo[jj];
|
|
#ifdef WHERETRACE_ENABLED /* 0x4 */
|
|
if( sqlite3WhereTrace&0x4 ){
|
|
sqlite3DebugPrintf("New %s cost=%-3d,%3d,%3d order=%c\n",
|
|
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsorted,
|
|
isOrdered>=0 ? isOrdered+'0' : '?');
|
|
}
|
|
#endif
|
|
}else{
|
|
/* Control reaches here if best-so-far path pTo=aTo[jj] covers the
|
|
** same set of loops and has the same isOrdered setting as the
|
|
** candidate path. Check to see if the candidate should replace
|
|
** pTo or if the candidate should be skipped.
|
|
**
|
|
** The conditional is an expanded vector comparison equivalent to:
|
|
** (pTo->rCost,pTo->nRow,pTo->rUnsorted) <= (rCost,nOut,rUnsorted)
|
|
*/
|
|
if( pTo->rCost<rCost
|
|
|| (pTo->rCost==rCost
|
|
&& (pTo->nRow<nOut
|
|
|| (pTo->nRow==nOut && pTo->rUnsorted<=rUnsorted)
|
|
)
|
|
)
|
|
){
|
|
#ifdef WHERETRACE_ENABLED /* 0x4 */
|
|
if( sqlite3WhereTrace&0x4 ){
|
|
sqlite3DebugPrintf(
|
|
"Skip %s cost=%-3d,%3d,%3d order=%c",
|
|
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsorted,
|
|
isOrdered>=0 ? isOrdered+'0' : '?');
|
|
sqlite3DebugPrintf(" vs %s cost=%-3d,%3d,%3d order=%c\n",
|
|
wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
|
|
pTo->rUnsorted, pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
|
|
}
|
|
#endif
|
|
/* Discard the candidate path from further consideration */
|
|
testcase( pTo->rCost==rCost );
|
|
continue;
|
|
}
|
|
testcase( pTo->rCost==rCost+1 );
|
|
/* Control reaches here if the candidate path is better than the
|
|
** pTo path. Replace pTo with the candidate. */
|
|
#ifdef WHERETRACE_ENABLED /* 0x4 */
|
|
if( sqlite3WhereTrace&0x4 ){
|
|
sqlite3DebugPrintf(
|
|
"Update %s cost=%-3d,%3d,%3d order=%c",
|
|
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsorted,
|
|
isOrdered>=0 ? isOrdered+'0' : '?');
|
|
sqlite3DebugPrintf(" was %s cost=%-3d,%3d,%3d order=%c\n",
|
|
wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
|
|
pTo->rUnsorted, pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
|
|
}
|
|
#endif
|
|
}
|
|
/* pWLoop is a winner. Add it to the set of best so far */
|
|
pTo->maskLoop = pFrom->maskLoop | pWLoop->maskSelf;
|
|
pTo->revLoop = revMask;
|
|
pTo->nRow = nOut;
|
|
pTo->rCost = rCost;
|
|
pTo->rUnsorted = rUnsorted;
|
|
pTo->isOrdered = isOrdered;
|
|
memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop);
|
|
pTo->aLoop[iLoop] = pWLoop;
|
|
if( nTo>=mxChoice ){
|
|
mxI = 0;
|
|
mxCost = aTo[0].rCost;
|
|
mxUnsorted = aTo[0].nRow;
|
|
for(jj=1, pTo=&aTo[1]; jj<mxChoice; jj++, pTo++){
|
|
if( pTo->rCost>mxCost
|
|
|| (pTo->rCost==mxCost && pTo->rUnsorted>mxUnsorted)
|
|
){
|
|
mxCost = pTo->rCost;
|
|
mxUnsorted = pTo->rUnsorted;
|
|
mxI = jj;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef WHERETRACE_ENABLED /* >=2 */
|
|
if( sqlite3WhereTrace & 0x02 ){
|
|
sqlite3DebugPrintf("---- after round %d ----\n", iLoop);
|
|
for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
|
|
sqlite3DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c",
|
|
wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
|
|
pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?');
|
|
if( pTo->isOrdered>0 ){
|
|
sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
|
|
}else{
|
|
sqlite3DebugPrintf("\n");
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* Swap the roles of aFrom and aTo for the next generation */
|
|
pFrom = aTo;
|
|
aTo = aFrom;
|
|
aFrom = pFrom;
|
|
nFrom = nTo;
|
|
}
|
|
|
|
if( nFrom==0 ){
|
|
sqlite3ErrorMsg(pParse, "no query solution");
|
|
sqlite3DbFreeNN(db, pSpace);
|
|
return SQLITE_ERROR;
|
|
}
|
|
|
|
/* Find the lowest cost path. pFrom will be left pointing to that path */
|
|
pFrom = aFrom;
|
|
for(ii=1; ii<nFrom; ii++){
|
|
if( pFrom->rCost>aFrom[ii].rCost ) pFrom = &aFrom[ii];
|
|
}
|
|
assert( pWInfo->nLevel==nLoop );
|
|
/* Load the lowest cost path into pWInfo */
|
|
for(iLoop=0; iLoop<nLoop; iLoop++){
|
|
WhereLevel *pLevel = pWInfo->a + iLoop;
|
|
pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop];
|
|
pLevel->iFrom = pWLoop->iTab;
|
|
pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor;
|
|
}
|
|
if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0
|
|
&& (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0
|
|
&& pWInfo->eDistinct==WHERE_DISTINCT_NOOP
|
|
&& nRowEst
|
|
){
|
|
Bitmask notUsed;
|
|
int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom,
|
|
WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], ¬Used);
|
|
if( rc==pWInfo->pResultSet->nExpr ){
|
|
pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
|
|
}
|
|
}
|
|
pWInfo->bOrderedInnerLoop = 0;
|
|
if( pWInfo->pOrderBy ){
|
|
pWInfo->nOBSat = pFrom->isOrdered;
|
|
if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){
|
|
if( pFrom->isOrdered==pWInfo->pOrderBy->nExpr ){
|
|
pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
|
|
}
|
|
}else{
|
|
pWInfo->revMask = pFrom->revLoop;
|
|
if( pWInfo->nOBSat<=0 ){
|
|
pWInfo->nOBSat = 0;
|
|
if( nLoop>0 ){
|
|
u32 wsFlags = pFrom->aLoop[nLoop-1]->wsFlags;
|
|
if( (wsFlags & WHERE_ONEROW)==0
|
|
&& (wsFlags&(WHERE_IPK|WHERE_COLUMN_IN))!=(WHERE_IPK|WHERE_COLUMN_IN)
|
|
){
|
|
Bitmask m = 0;
|
|
int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, pFrom,
|
|
WHERE_ORDERBY_LIMIT, nLoop-1, pFrom->aLoop[nLoop-1], &m);
|
|
testcase( wsFlags & WHERE_IPK );
|
|
testcase( wsFlags & WHERE_COLUMN_IN );
|
|
if( rc==pWInfo->pOrderBy->nExpr ){
|
|
pWInfo->bOrderedInnerLoop = 1;
|
|
pWInfo->revMask = m;
|
|
}
|
|
}
|
|
}
|
|
}else if( nLoop
|
|
&& pWInfo->nOBSat==1
|
|
&& (pWInfo->wctrlFlags & (WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX))!=0
|
|
){
|
|
pWInfo->bOrderedInnerLoop = 1;
|
|
}
|
|
}
|
|
if( (pWInfo->wctrlFlags & WHERE_SORTBYGROUP)
|
|
&& pWInfo->nOBSat==pWInfo->pOrderBy->nExpr && nLoop>0
|
|
){
|
|
Bitmask revMask = 0;
|
|
int nOrder = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy,
|
|
pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], &revMask
|
|
);
|
|
assert( pWInfo->sorted==0 );
|
|
if( nOrder==pWInfo->pOrderBy->nExpr ){
|
|
pWInfo->sorted = 1;
|
|
pWInfo->revMask = revMask;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
pWInfo->nRowOut = pFrom->nRow;
|
|
|
|
/* Free temporary memory and return success */
|
|
sqlite3DbFreeNN(db, pSpace);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Most queries use only a single table (they are not joins) and have
|
|
** simple == constraints against indexed fields. This routine attempts
|
|
** to plan those simple cases using much less ceremony than the
|
|
** general-purpose query planner, and thereby yield faster sqlite3_prepare()
|
|
** times for the common case.
|
|
**
|
|
** Return non-zero on success, if this query can be handled by this
|
|
** no-frills query planner. Return zero if this query needs the
|
|
** general-purpose query planner.
|
|
*/
|
|
static int whereShortCut(WhereLoopBuilder *pBuilder){
|
|
WhereInfo *pWInfo;
|
|
SrcItem *pItem;
|
|
WhereClause *pWC;
|
|
WhereTerm *pTerm;
|
|
WhereLoop *pLoop;
|
|
int iCur;
|
|
int j;
|
|
Table *pTab;
|
|
Index *pIdx;
|
|
WhereScan scan;
|
|
|
|
pWInfo = pBuilder->pWInfo;
|
|
if( pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE ) return 0;
|
|
assert( pWInfo->pTabList->nSrc>=1 );
|
|
pItem = pWInfo->pTabList->a;
|
|
pTab = pItem->pTab;
|
|
if( IsVirtual(pTab) ) return 0;
|
|
if( pItem->fg.isIndexedBy || pItem->fg.notIndexed ){
|
|
testcase( pItem->fg.isIndexedBy );
|
|
testcase( pItem->fg.notIndexed );
|
|
return 0;
|
|
}
|
|
iCur = pItem->iCursor;
|
|
pWC = &pWInfo->sWC;
|
|
pLoop = pBuilder->pNew;
|
|
pLoop->wsFlags = 0;
|
|
pLoop->nSkip = 0;
|
|
pTerm = whereScanInit(&scan, pWC, iCur, -1, WO_EQ|WO_IS, 0);
|
|
while( pTerm && pTerm->prereqRight ) pTerm = whereScanNext(&scan);
|
|
if( pTerm ){
|
|
testcase( pTerm->eOperator & WO_IS );
|
|
pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW;
|
|
pLoop->aLTerm[0] = pTerm;
|
|
pLoop->nLTerm = 1;
|
|
pLoop->u.btree.nEq = 1;
|
|
/* TUNING: Cost of a rowid lookup is 10 */
|
|
pLoop->rRun = 33; /* 33==sqlite3LogEst(10) */
|
|
}else{
|
|
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
|
int opMask;
|
|
assert( pLoop->aLTermSpace==pLoop->aLTerm );
|
|
if( !IsUniqueIndex(pIdx)
|
|
|| pIdx->pPartIdxWhere!=0
|
|
|| pIdx->nKeyCol>ArraySize(pLoop->aLTermSpace)
|
|
) continue;
|
|
opMask = pIdx->uniqNotNull ? (WO_EQ|WO_IS) : WO_EQ;
|
|
for(j=0; j<pIdx->nKeyCol; j++){
|
|
pTerm = whereScanInit(&scan, pWC, iCur, j, opMask, pIdx);
|
|
while( pTerm && pTerm->prereqRight ) pTerm = whereScanNext(&scan);
|
|
if( pTerm==0 ) break;
|
|
testcase( pTerm->eOperator & WO_IS );
|
|
pLoop->aLTerm[j] = pTerm;
|
|
}
|
|
if( j!=pIdx->nKeyCol ) continue;
|
|
pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED;
|
|
if( pIdx->isCovering || (pItem->colUsed & pIdx->colNotIdxed)==0 ){
|
|
pLoop->wsFlags |= WHERE_IDX_ONLY;
|
|
}
|
|
pLoop->nLTerm = j;
|
|
pLoop->u.btree.nEq = j;
|
|
pLoop->u.btree.pIndex = pIdx;
|
|
/* TUNING: Cost of a unique index lookup is 15 */
|
|
pLoop->rRun = 39; /* 39==sqlite3LogEst(15) */
|
|
break;
|
|
}
|
|
}
|
|
if( pLoop->wsFlags ){
|
|
pLoop->nOut = (LogEst)1;
|
|
pWInfo->a[0].pWLoop = pLoop;
|
|
assert( pWInfo->sMaskSet.n==1 && iCur==pWInfo->sMaskSet.ix[0] );
|
|
pLoop->maskSelf = 1; /* sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur); */
|
|
pWInfo->a[0].iTabCur = iCur;
|
|
pWInfo->nRowOut = 1;
|
|
if( pWInfo->pOrderBy ) pWInfo->nOBSat = pWInfo->pOrderBy->nExpr;
|
|
if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
|
|
pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
|
|
}
|
|
if( scan.iEquiv>1 ) pLoop->wsFlags |= WHERE_TRANSCONS;
|
|
#ifdef SQLITE_DEBUG
|
|
pLoop->cId = '0';
|
|
#endif
|
|
#ifdef WHERETRACE_ENABLED
|
|
if( sqlite3WhereTrace ){
|
|
sqlite3DebugPrintf("whereShortCut() used to compute solution\n");
|
|
}
|
|
#endif
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Helper function for exprIsDeterministic().
|
|
*/
|
|
static int exprNodeIsDeterministic(Walker *pWalker, Expr *pExpr){
|
|
if( pExpr->op==TK_FUNCTION && ExprHasProperty(pExpr, EP_ConstFunc)==0 ){
|
|
pWalker->eCode = 0;
|
|
return WRC_Abort;
|
|
}
|
|
return WRC_Continue;
|
|
}
|
|
|
|
/*
|
|
** Return true if the expression contains no non-deterministic SQL
|
|
** functions. Do not consider non-deterministic SQL functions that are
|
|
** part of sub-select statements.
|
|
*/
|
|
static int exprIsDeterministic(Expr *p){
|
|
Walker w;
|
|
memset(&w, 0, sizeof(w));
|
|
w.eCode = 1;
|
|
w.xExprCallback = exprNodeIsDeterministic;
|
|
w.xSelectCallback = sqlite3SelectWalkFail;
|
|
sqlite3WalkExpr(&w, p);
|
|
return w.eCode;
|
|
}
|
|
|
|
|
|
#ifdef WHERETRACE_ENABLED
|
|
/*
|
|
** Display all WhereLoops in pWInfo
|
|
*/
|
|
static void showAllWhereLoops(WhereInfo *pWInfo, WhereClause *pWC){
|
|
if( sqlite3WhereTrace ){ /* Display all of the WhereLoop objects */
|
|
WhereLoop *p;
|
|
int i;
|
|
static const char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
|
|
"ABCDEFGHIJKLMNOPQRSTUVWYXZ";
|
|
for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){
|
|
p->cId = zLabel[i%(sizeof(zLabel)-1)];
|
|
sqlite3WhereLoopPrint(p, pWC);
|
|
}
|
|
}
|
|
}
|
|
# define WHERETRACE_ALL_LOOPS(W,C) showAllWhereLoops(W,C)
|
|
#else
|
|
# define WHERETRACE_ALL_LOOPS(W,C)
|
|
#endif
|
|
|
|
/* Attempt to omit tables from a join that do not affect the result.
|
|
** For a table to not affect the result, the following must be true:
|
|
**
|
|
** 1) The query must not be an aggregate.
|
|
** 2) The table must be the RHS of a LEFT JOIN.
|
|
** 3) Either the query must be DISTINCT, or else the ON or USING clause
|
|
** must contain a constraint that limits the scan of the table to
|
|
** at most a single row.
|
|
** 4) The table must not be referenced by any part of the query apart
|
|
** from its own USING or ON clause.
|
|
**
|
|
** For example, given:
|
|
**
|
|
** CREATE TABLE t1(ipk INTEGER PRIMARY KEY, v1);
|
|
** CREATE TABLE t2(ipk INTEGER PRIMARY KEY, v2);
|
|
** CREATE TABLE t3(ipk INTEGER PRIMARY KEY, v3);
|
|
**
|
|
** then table t2 can be omitted from the following:
|
|
**
|
|
** SELECT v1, v3 FROM t1
|
|
** LEFT JOIN t2 ON (t1.ipk=t2.ipk)
|
|
** LEFT JOIN t3 ON (t1.ipk=t3.ipk)
|
|
**
|
|
** or from:
|
|
**
|
|
** SELECT DISTINCT v1, v3 FROM t1
|
|
** LEFT JOIN t2
|
|
** LEFT JOIN t3 ON (t1.ipk=t3.ipk)
|
|
*/
|
|
static SQLITE_NOINLINE Bitmask whereOmitNoopJoin(
|
|
WhereInfo *pWInfo,
|
|
Bitmask notReady
|
|
){
|
|
int i;
|
|
Bitmask tabUsed;
|
|
|
|
/* Preconditions checked by the caller */
|
|
assert( pWInfo->nLevel>=2 );
|
|
assert( OptimizationEnabled(pWInfo->pParse->db, SQLITE_OmitNoopJoin) );
|
|
|
|
/* These two preconditions checked by the caller combine to guarantee
|
|
** condition (1) of the header comment */
|
|
assert( pWInfo->pResultSet!=0 );
|
|
assert( 0==(pWInfo->wctrlFlags & WHERE_AGG_DISTINCT) );
|
|
|
|
tabUsed = sqlite3WhereExprListUsage(&pWInfo->sMaskSet, pWInfo->pResultSet);
|
|
if( pWInfo->pOrderBy ){
|
|
tabUsed |= sqlite3WhereExprListUsage(&pWInfo->sMaskSet, pWInfo->pOrderBy);
|
|
}
|
|
for(i=pWInfo->nLevel-1; i>=1; i--){
|
|
WhereTerm *pTerm, *pEnd;
|
|
SrcItem *pItem;
|
|
WhereLoop *pLoop;
|
|
pLoop = pWInfo->a[i].pWLoop;
|
|
pItem = &pWInfo->pTabList->a[pLoop->iTab];
|
|
if( (pItem->fg.jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ) continue;
|
|
if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)==0
|
|
&& (pLoop->wsFlags & WHERE_ONEROW)==0
|
|
){
|
|
continue;
|
|
}
|
|
if( (tabUsed & pLoop->maskSelf)!=0 ) continue;
|
|
pEnd = pWInfo->sWC.a + pWInfo->sWC.nTerm;
|
|
for(pTerm=pWInfo->sWC.a; pTerm<pEnd; pTerm++){
|
|
if( (pTerm->prereqAll & pLoop->maskSelf)!=0 ){
|
|
if( !ExprHasProperty(pTerm->pExpr, EP_OuterON)
|
|
|| pTerm->pExpr->w.iJoin!=pItem->iCursor
|
|
){
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if( pTerm<pEnd ) continue;
|
|
WHERETRACE(0xffff, ("-> drop loop %c not used\n", pLoop->cId));
|
|
notReady &= ~pLoop->maskSelf;
|
|
for(pTerm=pWInfo->sWC.a; pTerm<pEnd; pTerm++){
|
|
if( (pTerm->prereqAll & pLoop->maskSelf)!=0 ){
|
|
pTerm->wtFlags |= TERM_CODED;
|
|
}
|
|
}
|
|
if( i!=pWInfo->nLevel-1 ){
|
|
int nByte = (pWInfo->nLevel-1-i) * sizeof(WhereLevel);
|
|
memmove(&pWInfo->a[i], &pWInfo->a[i+1], nByte);
|
|
}
|
|
pWInfo->nLevel--;
|
|
assert( pWInfo->nLevel>0 );
|
|
}
|
|
return notReady;
|
|
}
|
|
|
|
/*
|
|
** Check to see if there are any SEARCH loops that might benefit from
|
|
** using a Bloom filter. Consider a Bloom filter if:
|
|
**
|
|
** (1) The SEARCH happens more than N times where N is the number
|
|
** of rows in the table that is being considered for the Bloom
|
|
** filter.
|
|
** (2) Some searches are expected to find zero rows. (This is determined
|
|
** by the WHERE_SELFCULL flag on the term.)
|
|
** (3) Bloom-filter processing is not disabled. (Checked by the
|
|
** caller.)
|
|
** (4) The size of the table being searched is known by ANALYZE.
|
|
**
|
|
** This block of code merely checks to see if a Bloom filter would be
|
|
** appropriate, and if so sets the WHERE_BLOOMFILTER flag on the
|
|
** WhereLoop. The implementation of the Bloom filter comes further
|
|
** down where the code for each WhereLoop is generated.
|
|
*/
|
|
static SQLITE_NOINLINE void whereCheckIfBloomFilterIsUseful(
|
|
const WhereInfo *pWInfo
|
|
){
|
|
int i;
|
|
LogEst nSearch;
|
|
|
|
assert( pWInfo->nLevel>=2 );
|
|
assert( OptimizationEnabled(pWInfo->pParse->db, SQLITE_BloomFilter) );
|
|
nSearch = pWInfo->a[0].pWLoop->nOut;
|
|
for(i=1; i<pWInfo->nLevel; i++){
|
|
WhereLoop *pLoop = pWInfo->a[i].pWLoop;
|
|
const unsigned int reqFlags = (WHERE_SELFCULL|WHERE_COLUMN_EQ);
|
|
if( (pLoop->wsFlags & reqFlags)==reqFlags
|
|
/* vvvvvv--- Always the case if WHERE_COLUMN_EQ is defined */
|
|
&& ALWAYS((pLoop->wsFlags & (WHERE_IPK|WHERE_INDEXED))!=0)
|
|
){
|
|
SrcItem *pItem = &pWInfo->pTabList->a[pLoop->iTab];
|
|
Table *pTab = pItem->pTab;
|
|
pTab->tabFlags |= TF_StatsUsed;
|
|
if( nSearch > pTab->nRowLogEst
|
|
&& (pTab->tabFlags & TF_HasStat1)!=0
|
|
){
|
|
testcase( pItem->fg.jointype & JT_LEFT );
|
|
pLoop->wsFlags |= WHERE_BLOOMFILTER;
|
|
pLoop->wsFlags &= ~WHERE_IDX_ONLY;
|
|
WHERETRACE(0xffff, (
|
|
"-> use Bloom-filter on loop %c because there are ~%.1e "
|
|
"lookups into %s which has only ~%.1e rows\n",
|
|
pLoop->cId, (double)sqlite3LogEstToInt(nSearch), pTab->zName,
|
|
(double)sqlite3LogEstToInt(pTab->nRowLogEst)));
|
|
}
|
|
}
|
|
nSearch += pLoop->nOut;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Generate the beginning of the loop used for WHERE clause processing.
|
|
** The return value is a pointer to an opaque structure that contains
|
|
** information needed to terminate the loop. Later, the calling routine
|
|
** should invoke sqlite3WhereEnd() with the return value of this function
|
|
** in order to complete the WHERE clause processing.
|
|
**
|
|
** If an error occurs, this routine returns NULL.
|
|
**
|
|
** The basic idea is to do a nested loop, one loop for each table in
|
|
** the FROM clause of a select. (INSERT and UPDATE statements are the
|
|
** same as a SELECT with only a single table in the FROM clause.) For
|
|
** example, if the SQL is this:
|
|
**
|
|
** SELECT * FROM t1, t2, t3 WHERE ...;
|
|
**
|
|
** Then the code generated is conceptually like the following:
|
|
**
|
|
** foreach row1 in t1 do \ Code generated
|
|
** foreach row2 in t2 do |-- by sqlite3WhereBegin()
|
|
** foreach row3 in t3 do /
|
|
** ...
|
|
** end \ Code generated
|
|
** end |-- by sqlite3WhereEnd()
|
|
** end /
|
|
**
|
|
** Note that the loops might not be nested in the order in which they
|
|
** appear in the FROM clause if a different order is better able to make
|
|
** use of indices. Note also that when the IN operator appears in
|
|
** the WHERE clause, it might result in additional nested loops for
|
|
** scanning through all values on the right-hand side of the IN.
|
|
**
|
|
** There are Btree cursors associated with each table. t1 uses cursor
|
|
** number pTabList->a[0].iCursor. t2 uses the cursor pTabList->a[1].iCursor.
|
|
** And so forth. This routine generates code to open those VDBE cursors
|
|
** and sqlite3WhereEnd() generates the code to close them.
|
|
**
|
|
** The code that sqlite3WhereBegin() generates leaves the cursors named
|
|
** in pTabList pointing at their appropriate entries. The [...] code
|
|
** can use OP_Column and OP_Rowid opcodes on these cursors to extract
|
|
** data from the various tables of the loop.
|
|
**
|
|
** If the WHERE clause is empty, the foreach loops must each scan their
|
|
** entire tables. Thus a three-way join is an O(N^3) operation. But if
|
|
** the tables have indices and there are terms in the WHERE clause that
|
|
** refer to those indices, a complete table scan can be avoided and the
|
|
** code will run much faster. Most of the work of this routine is checking
|
|
** to see if there are indices that can be used to speed up the loop.
|
|
**
|
|
** Terms of the WHERE clause are also used to limit which rows actually
|
|
** make it to the "..." in the middle of the loop. After each "foreach",
|
|
** terms of the WHERE clause that use only terms in that loop and outer
|
|
** loops are evaluated and if false a jump is made around all subsequent
|
|
** inner loops (or around the "..." if the test occurs within the inner-
|
|
** most loop)
|
|
**
|
|
** OUTER JOINS
|
|
**
|
|
** An outer join of tables t1 and t2 is conceptally coded as follows:
|
|
**
|
|
** foreach row1 in t1 do
|
|
** flag = 0
|
|
** foreach row2 in t2 do
|
|
** start:
|
|
** ...
|
|
** flag = 1
|
|
** end
|
|
** if flag==0 then
|
|
** move the row2 cursor to a null row
|
|
** goto start
|
|
** fi
|
|
** end
|
|
**
|
|
** ORDER BY CLAUSE PROCESSING
|
|
**
|
|
** pOrderBy is a pointer to the ORDER BY clause (or the GROUP BY clause
|
|
** if the WHERE_GROUPBY flag is set in wctrlFlags) of a SELECT statement
|
|
** if there is one. If there is no ORDER BY clause or if this routine
|
|
** is called from an UPDATE or DELETE statement, then pOrderBy is NULL.
|
|
**
|
|
** The iIdxCur parameter is the cursor number of an index. If
|
|
** WHERE_OR_SUBCLAUSE is set, iIdxCur is the cursor number of an index
|
|
** to use for OR clause processing. The WHERE clause should use this
|
|
** specific cursor. If WHERE_ONEPASS_DESIRED is set, then iIdxCur is
|
|
** the first cursor in an array of cursors for all indices. iIdxCur should
|
|
** be used to compute the appropriate cursor depending on which index is
|
|
** used.
|
|
*/
|
|
WhereInfo *sqlite3WhereBegin(
|
|
Parse *pParse, /* The parser context */
|
|
SrcList *pTabList, /* FROM clause: A list of all tables to be scanned */
|
|
Expr *pWhere, /* The WHERE clause */
|
|
ExprList *pOrderBy, /* An ORDER BY (or GROUP BY) clause, or NULL */
|
|
ExprList *pResultSet, /* Query result set. Req'd for DISTINCT */
|
|
Select *pLimit, /* Use this LIMIT/OFFSET clause, if any */
|
|
u16 wctrlFlags, /* The WHERE_* flags defined in sqliteInt.h */
|
|
int iAuxArg /* If WHERE_OR_SUBCLAUSE is set, index cursor number
|
|
** If WHERE_USE_LIMIT, then the limit amount */
|
|
){
|
|
int nByteWInfo; /* Num. bytes allocated for WhereInfo struct */
|
|
int nTabList; /* Number of elements in pTabList */
|
|
WhereInfo *pWInfo; /* Will become the return value of this function */
|
|
Vdbe *v = pParse->pVdbe; /* The virtual database engine */
|
|
Bitmask notReady; /* Cursors that are not yet positioned */
|
|
WhereLoopBuilder sWLB; /* The WhereLoop builder */
|
|
WhereMaskSet *pMaskSet; /* The expression mask set */
|
|
WhereLevel *pLevel; /* A single level in pWInfo->a[] */
|
|
WhereLoop *pLoop; /* Pointer to a single WhereLoop object */
|
|
int ii; /* Loop counter */
|
|
sqlite3 *db; /* Database connection */
|
|
int rc; /* Return code */
|
|
u8 bFordelete = 0; /* OPFLAG_FORDELETE or zero, as appropriate */
|
|
|
|
assert( (wctrlFlags & WHERE_ONEPASS_MULTIROW)==0 || (
|
|
(wctrlFlags & WHERE_ONEPASS_DESIRED)!=0
|
|
&& (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
|
|
));
|
|
|
|
/* Only one of WHERE_OR_SUBCLAUSE or WHERE_USE_LIMIT */
|
|
assert( (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
|
|
|| (wctrlFlags & WHERE_USE_LIMIT)==0 );
|
|
|
|
/* Variable initialization */
|
|
db = pParse->db;
|
|
memset(&sWLB, 0, sizeof(sWLB));
|
|
|
|
/* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */
|
|
testcase( pOrderBy && pOrderBy->nExpr==BMS-1 );
|
|
if( pOrderBy && pOrderBy->nExpr>=BMS ) pOrderBy = 0;
|
|
|
|
/* The number of tables in the FROM clause is limited by the number of
|
|
** bits in a Bitmask
|
|
*/
|
|
testcase( pTabList->nSrc==BMS );
|
|
if( pTabList->nSrc>BMS ){
|
|
sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);
|
|
return 0;
|
|
}
|
|
|
|
/* This function normally generates a nested loop for all tables in
|
|
** pTabList. But if the WHERE_OR_SUBCLAUSE flag is set, then we should
|
|
** only generate code for the first table in pTabList and assume that
|
|
** any cursors associated with subsequent tables are uninitialized.
|
|
*/
|
|
nTabList = (wctrlFlags & WHERE_OR_SUBCLAUSE) ? 1 : pTabList->nSrc;
|
|
|
|
/* Allocate and initialize the WhereInfo structure that will become the
|
|
** return value. A single allocation is used to store the WhereInfo
|
|
** struct, the contents of WhereInfo.a[], the WhereClause structure
|
|
** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
|
|
** field (type Bitmask) it must be aligned on an 8-byte boundary on
|
|
** some architectures. Hence the ROUND8() below.
|
|
*/
|
|
nByteWInfo = ROUND8P(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel));
|
|
pWInfo = sqlite3DbMallocRawNN(db, nByteWInfo + sizeof(WhereLoop));
|
|
if( db->mallocFailed ){
|
|
sqlite3DbFree(db, pWInfo);
|
|
pWInfo = 0;
|
|
goto whereBeginError;
|
|
}
|
|
pWInfo->pParse = pParse;
|
|
pWInfo->pTabList = pTabList;
|
|
pWInfo->pOrderBy = pOrderBy;
|
|
pWInfo->pWhere = pWhere;
|
|
pWInfo->pResultSet = pResultSet;
|
|
pWInfo->aiCurOnePass[0] = pWInfo->aiCurOnePass[1] = -1;
|
|
pWInfo->nLevel = nTabList;
|
|
pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(pParse);
|
|
pWInfo->wctrlFlags = wctrlFlags;
|
|
pWInfo->iLimit = iAuxArg;
|
|
pWInfo->savedNQueryLoop = pParse->nQueryLoop;
|
|
#ifndef SQLITE_OMIT_VIRTUALTABLE
|
|
pWInfo->pLimit = pLimit;
|
|
#endif
|
|
memset(&pWInfo->nOBSat, 0,
|
|
offsetof(WhereInfo,sWC) - offsetof(WhereInfo,nOBSat));
|
|
memset(&pWInfo->a[0], 0, sizeof(WhereLoop)+nTabList*sizeof(WhereLevel));
|
|
assert( pWInfo->eOnePass==ONEPASS_OFF ); /* ONEPASS defaults to OFF */
|
|
pMaskSet = &pWInfo->sMaskSet;
|
|
pMaskSet->n = 0;
|
|
pMaskSet->ix[0] = -99; /* Initialize ix[0] to a value that can never be
|
|
** a valid cursor number, to avoid an initial
|
|
** test for pMaskSet->n==0 in sqlite3WhereGetMask() */
|
|
sWLB.pWInfo = pWInfo;
|
|
sWLB.pWC = &pWInfo->sWC;
|
|
sWLB.pNew = (WhereLoop*)(((char*)pWInfo)+nByteWInfo);
|
|
assert( EIGHT_BYTE_ALIGNMENT(sWLB.pNew) );
|
|
whereLoopInit(sWLB.pNew);
|
|
#ifdef SQLITE_DEBUG
|
|
sWLB.pNew->cId = '*';
|
|
#endif
|
|
|
|
/* Split the WHERE clause into separate subexpressions where each
|
|
** subexpression is separated by an AND operator.
|
|
*/
|
|
sqlite3WhereClauseInit(&pWInfo->sWC, pWInfo);
|
|
sqlite3WhereSplit(&pWInfo->sWC, pWhere, TK_AND);
|
|
|
|
/* Special case: No FROM clause
|
|
*/
|
|
if( nTabList==0 ){
|
|
if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
|
|
if( (wctrlFlags & WHERE_WANT_DISTINCT)!=0
|
|
&& OptimizationEnabled(db, SQLITE_DistinctOpt)
|
|
){
|
|
pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
|
|
}
|
|
ExplainQueryPlan((pParse, 0, "SCAN CONSTANT ROW"));
|
|
}else{
|
|
/* Assign a bit from the bitmask to every term in the FROM clause.
|
|
**
|
|
** The N-th term of the FROM clause is assigned a bitmask of 1<<N.
|
|
**
|
|
** The rule of the previous sentence ensures thta if X is the bitmask for
|
|
** a table T, then X-1 is the bitmask for all other tables to the left of T.
|
|
** Knowing the bitmask for all tables to the left of a left join is
|
|
** important. Ticket #3015.
|
|
**
|
|
** Note that bitmasks are created for all pTabList->nSrc tables in
|
|
** pTabList, not just the first nTabList tables. nTabList is normally
|
|
** equal to pTabList->nSrc but might be shortened to 1 if the
|
|
** WHERE_OR_SUBCLAUSE flag is set.
|
|
*/
|
|
ii = 0;
|
|
do{
|
|
createMask(pMaskSet, pTabList->a[ii].iCursor);
|
|
sqlite3WhereTabFuncArgs(pParse, &pTabList->a[ii], &pWInfo->sWC);
|
|
}while( (++ii)<pTabList->nSrc );
|
|
#ifdef SQLITE_DEBUG
|
|
{
|
|
Bitmask mx = 0;
|
|
for(ii=0; ii<pTabList->nSrc; ii++){
|
|
Bitmask m = sqlite3WhereGetMask(pMaskSet, pTabList->a[ii].iCursor);
|
|
assert( m>=mx );
|
|
mx = m;
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* Analyze all of the subexpressions. */
|
|
sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
|
|
sqlite3WhereAddLimit(&pWInfo->sWC, pLimit);
|
|
if( pParse->nErr ) goto whereBeginError;
|
|
|
|
/* Special case: WHERE terms that do not refer to any tables in the join
|
|
** (constant expressions). Evaluate each such term, and jump over all the
|
|
** generated code if the result is not true.
|
|
**
|
|
** Do not do this if the expression contains non-deterministic functions
|
|
** that are not within a sub-select. This is not strictly required, but
|
|
** preserves SQLite's legacy behaviour in the following two cases:
|
|
**
|
|
** FROM ... WHERE random()>0; -- eval random() once per row
|
|
** FROM ... WHERE (SELECT random())>0; -- eval random() once overall
|
|
*/
|
|
for(ii=0; ii<sWLB.pWC->nBase; ii++){
|
|
WhereTerm *pT = &sWLB.pWC->a[ii];
|
|
if( pT->wtFlags & TERM_VIRTUAL ) continue;
|
|
if( pT->prereqAll==0 && (nTabList==0 || exprIsDeterministic(pT->pExpr)) ){
|
|
sqlite3ExprIfFalse(pParse, pT->pExpr, pWInfo->iBreak, SQLITE_JUMPIFNULL);
|
|
pT->wtFlags |= TERM_CODED;
|
|
}
|
|
}
|
|
|
|
if( wctrlFlags & WHERE_WANT_DISTINCT ){
|
|
if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){
|
|
/* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
|
|
** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
|
|
wctrlFlags &= ~WHERE_WANT_DISTINCT;
|
|
pWInfo->wctrlFlags &= ~WHERE_WANT_DISTINCT;
|
|
}else if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
|
|
/* The DISTINCT marking is pointless. Ignore it. */
|
|
pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
|
|
}else if( pOrderBy==0 ){
|
|
/* Try to ORDER BY the result set to make distinct processing easier */
|
|
pWInfo->wctrlFlags |= WHERE_DISTINCTBY;
|
|
pWInfo->pOrderBy = pResultSet;
|
|
}
|
|
}
|
|
|
|
/* Construct the WhereLoop objects */
|
|
#if defined(WHERETRACE_ENABLED)
|
|
if( sqlite3WhereTrace & 0xffff ){
|
|
sqlite3DebugPrintf("*** Optimizer Start *** (wctrlFlags: 0x%x",wctrlFlags);
|
|
if( wctrlFlags & WHERE_USE_LIMIT ){
|
|
sqlite3DebugPrintf(", limit: %d", iAuxArg);
|
|
}
|
|
sqlite3DebugPrintf(")\n");
|
|
if( sqlite3WhereTrace & 0x100 ){
|
|
Select sSelect;
|
|
memset(&sSelect, 0, sizeof(sSelect));
|
|
sSelect.selFlags = SF_WhereBegin;
|
|
sSelect.pSrc = pTabList;
|
|
sSelect.pWhere = pWhere;
|
|
sSelect.pOrderBy = pOrderBy;
|
|
sSelect.pEList = pResultSet;
|
|
sqlite3TreeViewSelect(0, &sSelect, 0);
|
|
}
|
|
}
|
|
if( sqlite3WhereTrace & 0x100 ){ /* Display all terms of the WHERE clause */
|
|
sqlite3DebugPrintf("---- WHERE clause at start of analysis:\n");
|
|
sqlite3WhereClausePrint(sWLB.pWC);
|
|
}
|
|
#endif
|
|
|
|
if( nTabList!=1 || whereShortCut(&sWLB)==0 ){
|
|
rc = whereLoopAddAll(&sWLB);
|
|
if( rc ) goto whereBeginError;
|
|
|
|
#ifdef SQLITE_ENABLE_STAT4
|
|
/* If one or more WhereTerm.truthProb values were used in estimating
|
|
** loop parameters, but then those truthProb values were subsequently
|
|
** changed based on STAT4 information while computing subsequent loops,
|
|
** then we need to rerun the whole loop building process so that all
|
|
** loops will be built using the revised truthProb values. */
|
|
if( sWLB.bldFlags2 & SQLITE_BLDF2_2NDPASS ){
|
|
WHERETRACE_ALL_LOOPS(pWInfo, sWLB.pWC);
|
|
WHERETRACE(0xffff,
|
|
("**** Redo all loop computations due to"
|
|
" TERM_HIGHTRUTH changes ****\n"));
|
|
while( pWInfo->pLoops ){
|
|
WhereLoop *p = pWInfo->pLoops;
|
|
pWInfo->pLoops = p->pNextLoop;
|
|
whereLoopDelete(db, p);
|
|
}
|
|
rc = whereLoopAddAll(&sWLB);
|
|
if( rc ) goto whereBeginError;
|
|
}
|
|
#endif
|
|
WHERETRACE_ALL_LOOPS(pWInfo, sWLB.pWC);
|
|
|
|
wherePathSolver(pWInfo, 0);
|
|
if( db->mallocFailed ) goto whereBeginError;
|
|
if( pWInfo->pOrderBy ){
|
|
wherePathSolver(pWInfo, pWInfo->nRowOut+1);
|
|
if( db->mallocFailed ) goto whereBeginError;
|
|
}
|
|
}
|
|
if( pWInfo->pOrderBy==0 && (db->flags & SQLITE_ReverseOrder)!=0 ){
|
|
pWInfo->revMask = ALLBITS;
|
|
}
|
|
if( pParse->nErr ){
|
|
goto whereBeginError;
|
|
}
|
|
assert( db->mallocFailed==0 );
|
|
#ifdef WHERETRACE_ENABLED
|
|
if( sqlite3WhereTrace ){
|
|
sqlite3DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut);
|
|
if( pWInfo->nOBSat>0 ){
|
|
sqlite3DebugPrintf(" ORDERBY=%d,0x%llx", pWInfo->nOBSat, pWInfo->revMask);
|
|
}
|
|
switch( pWInfo->eDistinct ){
|
|
case WHERE_DISTINCT_UNIQUE: {
|
|
sqlite3DebugPrintf(" DISTINCT=unique");
|
|
break;
|
|
}
|
|
case WHERE_DISTINCT_ORDERED: {
|
|
sqlite3DebugPrintf(" DISTINCT=ordered");
|
|
break;
|
|
}
|
|
case WHERE_DISTINCT_UNORDERED: {
|
|
sqlite3DebugPrintf(" DISTINCT=unordered");
|
|
break;
|
|
}
|
|
}
|
|
sqlite3DebugPrintf("\n");
|
|
for(ii=0; ii<pWInfo->nLevel; ii++){
|
|
sqlite3WhereLoopPrint(pWInfo->a[ii].pWLoop, sWLB.pWC);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* Attempt to omit tables from a join that do not affect the result.
|
|
** See the comment on whereOmitNoopJoin() for further information.
|
|
**
|
|
** This query optimization is factored out into a separate "no-inline"
|
|
** procedure to keep the sqlite3WhereBegin() procedure from becoming
|
|
** too large. If sqlite3WhereBegin() becomes too large, that prevents
|
|
** some C-compiler optimizers from in-lining the
|
|
** sqlite3WhereCodeOneLoopStart() procedure, and it is important to
|
|
** in-line sqlite3WhereCodeOneLoopStart() for performance reasons.
|
|
*/
|
|
notReady = ~(Bitmask)0;
|
|
if( pWInfo->nLevel>=2
|
|
&& pResultSet!=0 /* these two combine to guarantee */
|
|
&& 0==(wctrlFlags & WHERE_AGG_DISTINCT) /* condition (1) above */
|
|
&& OptimizationEnabled(db, SQLITE_OmitNoopJoin)
|
|
){
|
|
notReady = whereOmitNoopJoin(pWInfo, notReady);
|
|
nTabList = pWInfo->nLevel;
|
|
assert( nTabList>0 );
|
|
}
|
|
|
|
/* Check to see if there are any SEARCH loops that might benefit from
|
|
** using a Bloom filter.
|
|
*/
|
|
if( pWInfo->nLevel>=2
|
|
&& OptimizationEnabled(db, SQLITE_BloomFilter)
|
|
){
|
|
whereCheckIfBloomFilterIsUseful(pWInfo);
|
|
}
|
|
|
|
#if defined(WHERETRACE_ENABLED)
|
|
if( sqlite3WhereTrace & 0x100 ){ /* Display all terms of the WHERE clause */
|
|
sqlite3DebugPrintf("---- WHERE clause at end of analysis:\n");
|
|
sqlite3WhereClausePrint(sWLB.pWC);
|
|
}
|
|
WHERETRACE(0xffff,("*** Optimizer Finished ***\n"));
|
|
#endif
|
|
pWInfo->pParse->nQueryLoop += pWInfo->nRowOut;
|
|
|
|
/* If the caller is an UPDATE or DELETE statement that is requesting
|
|
** to use a one-pass algorithm, determine if this is appropriate.
|
|
**
|
|
** A one-pass approach can be used if the caller has requested one
|
|
** and either (a) the scan visits at most one row or (b) each
|
|
** of the following are true:
|
|
**
|
|
** * the caller has indicated that a one-pass approach can be used
|
|
** with multiple rows (by setting WHERE_ONEPASS_MULTIROW), and
|
|
** * the table is not a virtual table, and
|
|
** * either the scan does not use the OR optimization or the caller
|
|
** is a DELETE operation (WHERE_DUPLICATES_OK is only specified
|
|
** for DELETE).
|
|
**
|
|
** The last qualification is because an UPDATE statement uses
|
|
** WhereInfo.aiCurOnePass[1] to determine whether or not it really can
|
|
** use a one-pass approach, and this is not set accurately for scans
|
|
** that use the OR optimization.
|
|
*/
|
|
assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
|
|
if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 ){
|
|
int wsFlags = pWInfo->a[0].pWLoop->wsFlags;
|
|
int bOnerow = (wsFlags & WHERE_ONEROW)!=0;
|
|
assert( !(wsFlags & WHERE_VIRTUALTABLE) || IsVirtual(pTabList->a[0].pTab) );
|
|
if( bOnerow || (
|
|
0!=(wctrlFlags & WHERE_ONEPASS_MULTIROW)
|
|
&& !IsVirtual(pTabList->a[0].pTab)
|
|
&& (0==(wsFlags & WHERE_MULTI_OR) || (wctrlFlags & WHERE_DUPLICATES_OK))
|
|
)){
|
|
pWInfo->eOnePass = bOnerow ? ONEPASS_SINGLE : ONEPASS_MULTI;
|
|
if( HasRowid(pTabList->a[0].pTab) && (wsFlags & WHERE_IDX_ONLY) ){
|
|
if( wctrlFlags & WHERE_ONEPASS_MULTIROW ){
|
|
bFordelete = OPFLAG_FORDELETE;
|
|
}
|
|
pWInfo->a[0].pWLoop->wsFlags = (wsFlags & ~WHERE_IDX_ONLY);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Open all tables in the pTabList and any indices selected for
|
|
** searching those tables.
|
|
*/
|
|
for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){
|
|
Table *pTab; /* Table to open */
|
|
int iDb; /* Index of database containing table/index */
|
|
SrcItem *pTabItem;
|
|
|
|
pTabItem = &pTabList->a[pLevel->iFrom];
|
|
pTab = pTabItem->pTab;
|
|
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
|
|
pLoop = pLevel->pWLoop;
|
|
if( (pTab->tabFlags & TF_Ephemeral)!=0 || IsView(pTab) ){
|
|
/* Do nothing */
|
|
}else
|
|
#ifndef SQLITE_OMIT_VIRTUALTABLE
|
|
if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
|
|
const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
|
|
int iCur = pTabItem->iCursor;
|
|
sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);
|
|
}else if( IsVirtual(pTab) ){
|
|
/* noop */
|
|
}else
|
|
#endif
|
|
if( ((pLoop->wsFlags & WHERE_IDX_ONLY)==0
|
|
&& (wctrlFlags & WHERE_OR_SUBCLAUSE)==0)
|
|
|| (pTabItem->fg.jointype & (JT_LTORJ|JT_RIGHT))!=0
|
|
){
|
|
int op = OP_OpenRead;
|
|
if( pWInfo->eOnePass!=ONEPASS_OFF ){
|
|
op = OP_OpenWrite;
|
|
pWInfo->aiCurOnePass[0] = pTabItem->iCursor;
|
|
};
|
|
sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
|
|
assert( pTabItem->iCursor==pLevel->iTabCur );
|
|
testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS-1 );
|
|
testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS );
|
|
if( pWInfo->eOnePass==ONEPASS_OFF
|
|
&& pTab->nCol<BMS
|
|
&& (pTab->tabFlags & (TF_HasGenerated|TF_WithoutRowid))==0
|
|
&& (pLoop->wsFlags & (WHERE_AUTO_INDEX|WHERE_BLOOMFILTER))==0
|
|
){
|
|
/* If we know that only a prefix of the record will be used,
|
|
** it is advantageous to reduce the "column count" field in
|
|
** the P4 operand of the OP_OpenRead/Write opcode. */
|
|
Bitmask b = pTabItem->colUsed;
|
|
int n = 0;
|
|
for(; b; b=b>>1, n++){}
|
|
sqlite3VdbeChangeP4(v, -1, SQLITE_INT_TO_PTR(n), P4_INT32);
|
|
assert( n<=pTab->nCol );
|
|
}
|
|
#ifdef SQLITE_ENABLE_CURSOR_HINTS
|
|
if( pLoop->u.btree.pIndex!=0 ){
|
|
sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ|bFordelete);
|
|
}else
|
|
#endif
|
|
{
|
|
sqlite3VdbeChangeP5(v, bFordelete);
|
|
}
|
|
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
|
|
sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, pTabItem->iCursor, 0, 0,
|
|
(const u8*)&pTabItem->colUsed, P4_INT64);
|
|
#endif
|
|
}else{
|
|
sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
|
|
}
|
|
if( pLoop->wsFlags & WHERE_INDEXED ){
|
|
Index *pIx = pLoop->u.btree.pIndex;
|
|
int iIndexCur;
|
|
int op = OP_OpenRead;
|
|
/* iAuxArg is always set to a positive value if ONEPASS is possible */
|
|
assert( iAuxArg!=0 || (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 );
|
|
if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIx)
|
|
&& (wctrlFlags & WHERE_OR_SUBCLAUSE)!=0
|
|
){
|
|
/* This is one term of an OR-optimization using the PRIMARY KEY of a
|
|
** WITHOUT ROWID table. No need for a separate index */
|
|
iIndexCur = pLevel->iTabCur;
|
|
op = 0;
|
|
}else if( pWInfo->eOnePass!=ONEPASS_OFF ){
|
|
Index *pJ = pTabItem->pTab->pIndex;
|
|
iIndexCur = iAuxArg;
|
|
assert( wctrlFlags & WHERE_ONEPASS_DESIRED );
|
|
while( ALWAYS(pJ) && pJ!=pIx ){
|
|
iIndexCur++;
|
|
pJ = pJ->pNext;
|
|
}
|
|
op = OP_OpenWrite;
|
|
pWInfo->aiCurOnePass[1] = iIndexCur;
|
|
}else if( iAuxArg && (wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 ){
|
|
iIndexCur = iAuxArg;
|
|
op = OP_ReopenIdx;
|
|
}else{
|
|
iIndexCur = pParse->nTab++;
|
|
}
|
|
pLevel->iIdxCur = iIndexCur;
|
|
assert( pIx!=0 );
|
|
assert( pIx->pSchema==pTab->pSchema );
|
|
assert( iIndexCur>=0 );
|
|
if( op ){
|
|
sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb);
|
|
sqlite3VdbeSetP4KeyInfo(pParse, pIx);
|
|
if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0
|
|
&& (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0
|
|
&& (pLoop->wsFlags & WHERE_BIGNULL_SORT)==0
|
|
&& (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0
|
|
&& (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0
|
|
&& pWInfo->eDistinct!=WHERE_DISTINCT_ORDERED
|
|
){
|
|
sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ);
|
|
}
|
|
VdbeComment((v, "%s", pIx->zName));
|
|
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
|
|
{
|
|
u64 colUsed = 0;
|
|
int ii, jj;
|
|
for(ii=0; ii<pIx->nColumn; ii++){
|
|
jj = pIx->aiColumn[ii];
|
|
if( jj<0 ) continue;
|
|
if( jj>63 ) jj = 63;
|
|
if( (pTabItem->colUsed & MASKBIT(jj))==0 ) continue;
|
|
colUsed |= ((u64)1)<<(ii<63 ? ii : 63);
|
|
}
|
|
sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, iIndexCur, 0, 0,
|
|
(u8*)&colUsed, P4_INT64);
|
|
}
|
|
#endif /* SQLITE_ENABLE_COLUMN_USED_MASK */
|
|
}
|
|
}
|
|
if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
|
|
if( (pTabItem->fg.jointype & JT_RIGHT)!=0
|
|
&& (pLevel->pRJ = sqlite3WhereMalloc(pWInfo, sizeof(WhereRightJoin)))!=0
|
|
){
|
|
WhereRightJoin *pRJ = pLevel->pRJ;
|
|
pRJ->iMatch = pParse->nTab++;
|
|
pRJ->regBloom = ++pParse->nMem;
|
|
sqlite3VdbeAddOp2(v, OP_Blob, 65536, pRJ->regBloom);
|
|
pRJ->regReturn = ++pParse->nMem;
|
|
sqlite3VdbeAddOp2(v, OP_Null, 0, pRJ->regReturn);
|
|
assert( pTab==pTabItem->pTab );
|
|
if( HasRowid(pTab) ){
|
|
KeyInfo *pInfo;
|
|
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRJ->iMatch, 1);
|
|
pInfo = sqlite3KeyInfoAlloc(pParse->db, 1, 0);
|
|
if( pInfo ){
|
|
pInfo->aColl[0] = 0;
|
|
pInfo->aSortFlags[0] = 0;
|
|
sqlite3VdbeAppendP4(v, pInfo, P4_KEYINFO);
|
|
}
|
|
}else{
|
|
Index *pPk = sqlite3PrimaryKeyIndex(pTab);
|
|
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRJ->iMatch, pPk->nKeyCol);
|
|
sqlite3VdbeSetP4KeyInfo(pParse, pPk);
|
|
}
|
|
pLoop->wsFlags &= ~WHERE_IDX_ONLY;
|
|
/* The nature of RIGHT JOIN processing is such that it messes up
|
|
** the output order. So omit any ORDER BY/GROUP BY elimination
|
|
** optimizations. We need to do an actual sort for RIGHT JOIN. */
|
|
pWInfo->nOBSat = 0;
|
|
pWInfo->eDistinct = WHERE_DISTINCT_UNORDERED;
|
|
}
|
|
}
|
|
pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
|
|
if( db->mallocFailed ) goto whereBeginError;
|
|
|
|
/* Generate the code to do the search. Each iteration of the for
|
|
** loop below generates code for a single nested loop of the VM
|
|
** program.
|
|
*/
|
|
for(ii=0; ii<nTabList; ii++){
|
|
int addrExplain;
|
|
int wsFlags;
|
|
SrcItem *pSrc;
|
|
if( pParse->nErr ) goto whereBeginError;
|
|
pLevel = &pWInfo->a[ii];
|
|
wsFlags = pLevel->pWLoop->wsFlags;
|
|
pSrc = &pTabList->a[pLevel->iFrom];
|
|
if( pSrc->fg.isMaterialized ){
|
|
if( pSrc->fg.isCorrelated ){
|
|
sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->regReturn, pSrc->addrFillSub);
|
|
}else{
|
|
int iOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
|
|
sqlite3VdbeAddOp2(v, OP_Gosub, pSrc->regReturn, pSrc->addrFillSub);
|
|
sqlite3VdbeJumpHere(v, iOnce);
|
|
}
|
|
}
|
|
if( (wsFlags & (WHERE_AUTO_INDEX|WHERE_BLOOMFILTER))!=0 ){
|
|
if( (wsFlags & WHERE_AUTO_INDEX)!=0 ){
|
|
#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
|
|
constructAutomaticIndex(pParse, &pWInfo->sWC,
|
|
&pTabList->a[pLevel->iFrom], notReady, pLevel);
|
|
#endif
|
|
}else{
|
|
sqlite3ConstructBloomFilter(pWInfo, ii, pLevel, notReady);
|
|
}
|
|
if( db->mallocFailed ) goto whereBeginError;
|
|
}
|
|
addrExplain = sqlite3WhereExplainOneScan(
|
|
pParse, pTabList, pLevel, wctrlFlags
|
|
);
|
|
pLevel->addrBody = sqlite3VdbeCurrentAddr(v);
|
|
notReady = sqlite3WhereCodeOneLoopStart(pParse,v,pWInfo,ii,pLevel,notReady);
|
|
pWInfo->iContinue = pLevel->addrCont;
|
|
if( (wsFlags&WHERE_MULTI_OR)==0 && (wctrlFlags&WHERE_OR_SUBCLAUSE)==0 ){
|
|
sqlite3WhereAddScanStatus(v, pTabList, pLevel, addrExplain);
|
|
}
|
|
}
|
|
|
|
/* Done. */
|
|
VdbeModuleComment((v, "Begin WHERE-core"));
|
|
pWInfo->iEndWhere = sqlite3VdbeCurrentAddr(v);
|
|
return pWInfo;
|
|
|
|
/* Jump here if malloc fails */
|
|
whereBeginError:
|
|
if( pWInfo ){
|
|
testcase( pWInfo->pExprMods!=0 );
|
|
whereUndoExprMods(pWInfo);
|
|
pParse->nQueryLoop = pWInfo->savedNQueryLoop;
|
|
whereInfoFree(db, pWInfo);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Part of sqlite3WhereEnd() will rewrite opcodes to reference the
|
|
** index rather than the main table. In SQLITE_DEBUG mode, we want
|
|
** to trace those changes if PRAGMA vdbe_addoptrace=on. This routine
|
|
** does that.
|
|
*/
|
|
#ifndef SQLITE_DEBUG
|
|
# define OpcodeRewriteTrace(D,K,P) /* no-op */
|
|
#else
|
|
# define OpcodeRewriteTrace(D,K,P) sqlite3WhereOpcodeRewriteTrace(D,K,P)
|
|
static void sqlite3WhereOpcodeRewriteTrace(
|
|
sqlite3 *db,
|
|
int pc,
|
|
VdbeOp *pOp
|
|
){
|
|
if( (db->flags & SQLITE_VdbeAddopTrace)==0 ) return;
|
|
sqlite3VdbePrintOp(0, pc, pOp);
|
|
}
|
|
#endif
|
|
|
|
#ifdef SQLITE_DEBUG
|
|
/*
|
|
** Return true if cursor iCur is opened by instruction k of the
|
|
** bytecode. Used inside of assert() only.
|
|
*/
|
|
static int cursorIsOpen(Vdbe *v, int iCur, int k){
|
|
while( k>=0 ){
|
|
VdbeOp *pOp = sqlite3VdbeGetOp(v,k--);
|
|
if( pOp->p1!=iCur ) continue;
|
|
if( pOp->opcode==OP_Close ) return 0;
|
|
if( pOp->opcode==OP_OpenRead ) return 1;
|
|
if( pOp->opcode==OP_OpenWrite ) return 1;
|
|
if( pOp->opcode==OP_OpenDup ) return 1;
|
|
if( pOp->opcode==OP_OpenAutoindex ) return 1;
|
|
if( pOp->opcode==OP_OpenEphemeral ) return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
#endif /* SQLITE_DEBUG */
|
|
|
|
/*
|
|
** Generate the end of the WHERE loop. See comments on
|
|
** sqlite3WhereBegin() for additional information.
|
|
*/
|
|
void sqlite3WhereEnd(WhereInfo *pWInfo){
|
|
Parse *pParse = pWInfo->pParse;
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i;
|
|
WhereLevel *pLevel;
|
|
WhereLoop *pLoop;
|
|
SrcList *pTabList = pWInfo->pTabList;
|
|
sqlite3 *db = pParse->db;
|
|
int iEnd = sqlite3VdbeCurrentAddr(v);
|
|
int nRJ = 0;
|
|
|
|
/* Generate loop termination code.
|
|
*/
|
|
VdbeModuleComment((v, "End WHERE-core"));
|
|
for(i=pWInfo->nLevel-1; i>=0; i--){
|
|
int addr;
|
|
pLevel = &pWInfo->a[i];
|
|
if( pLevel->pRJ ){
|
|
/* Terminate the subroutine that forms the interior of the loop of
|
|
** the RIGHT JOIN table */
|
|
WhereRightJoin *pRJ = pLevel->pRJ;
|
|
sqlite3VdbeResolveLabel(v, pLevel->addrCont);
|
|
pLevel->addrCont = 0;
|
|
pRJ->endSubrtn = sqlite3VdbeCurrentAddr(v);
|
|
sqlite3VdbeAddOp3(v, OP_Return, pRJ->regReturn, pRJ->addrSubrtn, 1);
|
|
VdbeCoverage(v);
|
|
nRJ++;
|
|
}
|
|
pLoop = pLevel->pWLoop;
|
|
if( pLevel->op!=OP_Noop ){
|
|
#ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
|
|
int addrSeek = 0;
|
|
Index *pIdx;
|
|
int n;
|
|
if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED
|
|
&& i==pWInfo->nLevel-1 /* Ticket [ef9318757b152e3] 2017-10-21 */
|
|
&& (pLoop->wsFlags & WHERE_INDEXED)!=0
|
|
&& (pIdx = pLoop->u.btree.pIndex)->hasStat1
|
|
&& (n = pLoop->u.btree.nDistinctCol)>0
|
|
&& pIdx->aiRowLogEst[n]>=36
|
|
){
|
|
int r1 = pParse->nMem+1;
|
|
int j, op;
|
|
for(j=0; j<n; j++){
|
|
sqlite3VdbeAddOp3(v, OP_Column, pLevel->iIdxCur, j, r1+j);
|
|
}
|
|
pParse->nMem += n+1;
|
|
op = pLevel->op==OP_Prev ? OP_SeekLT : OP_SeekGT;
|
|
addrSeek = sqlite3VdbeAddOp4Int(v, op, pLevel->iIdxCur, 0, r1, n);
|
|
VdbeCoverageIf(v, op==OP_SeekLT);
|
|
VdbeCoverageIf(v, op==OP_SeekGT);
|
|
sqlite3VdbeAddOp2(v, OP_Goto, 1, pLevel->p2);
|
|
}
|
|
#endif /* SQLITE_DISABLE_SKIPAHEAD_DISTINCT */
|
|
/* The common case: Advance to the next row */
|
|
if( pLevel->addrCont ) sqlite3VdbeResolveLabel(v, pLevel->addrCont);
|
|
sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3);
|
|
sqlite3VdbeChangeP5(v, pLevel->p5);
|
|
VdbeCoverage(v);
|
|
VdbeCoverageIf(v, pLevel->op==OP_Next);
|
|
VdbeCoverageIf(v, pLevel->op==OP_Prev);
|
|
VdbeCoverageIf(v, pLevel->op==OP_VNext);
|
|
if( pLevel->regBignull ){
|
|
sqlite3VdbeResolveLabel(v, pLevel->addrBignull);
|
|
sqlite3VdbeAddOp2(v, OP_DecrJumpZero, pLevel->regBignull, pLevel->p2-1);
|
|
VdbeCoverage(v);
|
|
}
|
|
#ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
|
|
if( addrSeek ) sqlite3VdbeJumpHere(v, addrSeek);
|
|
#endif
|
|
}else if( pLevel->addrCont ){
|
|
sqlite3VdbeResolveLabel(v, pLevel->addrCont);
|
|
}
|
|
if( (pLoop->wsFlags & WHERE_IN_ABLE)!=0 && pLevel->u.in.nIn>0 ){
|
|
struct InLoop *pIn;
|
|
int j;
|
|
sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
|
|
for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
|
|
assert( sqlite3VdbeGetOp(v, pIn->addrInTop+1)->opcode==OP_IsNull
|
|
|| pParse->db->mallocFailed );
|
|
sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
|
|
if( pIn->eEndLoopOp!=OP_Noop ){
|
|
if( pIn->nPrefix ){
|
|
int bEarlyOut =
|
|
(pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
|
|
&& (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0;
|
|
if( pLevel->iLeftJoin ){
|
|
/* For LEFT JOIN queries, cursor pIn->iCur may not have been
|
|
** opened yet. This occurs for WHERE clauses such as
|
|
** "a = ? AND b IN (...)", where the index is on (a, b). If
|
|
** the RHS of the (a=?) is NULL, then the "b IN (...)" may
|
|
** never have been coded, but the body of the loop run to
|
|
** return the null-row. So, if the cursor is not open yet,
|
|
** jump over the OP_Next or OP_Prev instruction about to
|
|
** be coded. */
|
|
sqlite3VdbeAddOp2(v, OP_IfNotOpen, pIn->iCur,
|
|
sqlite3VdbeCurrentAddr(v) + 2 + bEarlyOut);
|
|
VdbeCoverage(v);
|
|
}
|
|
if( bEarlyOut ){
|
|
sqlite3VdbeAddOp4Int(v, OP_IfNoHope, pLevel->iIdxCur,
|
|
sqlite3VdbeCurrentAddr(v)+2,
|
|
pIn->iBase, pIn->nPrefix);
|
|
VdbeCoverage(v);
|
|
/* Retarget the OP_IsNull against the left operand of IN so
|
|
** it jumps past the OP_IfNoHope. This is because the
|
|
** OP_IsNull also bypasses the OP_Affinity opcode that is
|
|
** required by OP_IfNoHope. */
|
|
sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
|
|
}
|
|
}
|
|
sqlite3VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
|
|
VdbeCoverage(v);
|
|
VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Prev);
|
|
VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Next);
|
|
}
|
|
sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
|
|
}
|
|
}
|
|
sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
|
|
if( pLevel->pRJ ){
|
|
sqlite3VdbeAddOp3(v, OP_Return, pLevel->pRJ->regReturn, 0, 1);
|
|
VdbeCoverage(v);
|
|
}
|
|
if( pLevel->addrSkip ){
|
|
sqlite3VdbeGoto(v, pLevel->addrSkip);
|
|
VdbeComment((v, "next skip-scan on %s", pLoop->u.btree.pIndex->zName));
|
|
sqlite3VdbeJumpHere(v, pLevel->addrSkip);
|
|
sqlite3VdbeJumpHere(v, pLevel->addrSkip-2);
|
|
}
|
|
#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
|
|
if( pLevel->addrLikeRep ){
|
|
sqlite3VdbeAddOp2(v, OP_DecrJumpZero, (int)(pLevel->iLikeRepCntr>>1),
|
|
pLevel->addrLikeRep);
|
|
VdbeCoverage(v);
|
|
}
|
|
#endif
|
|
if( pLevel->iLeftJoin ){
|
|
int ws = pLoop->wsFlags;
|
|
addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin); VdbeCoverage(v);
|
|
assert( (ws & WHERE_IDX_ONLY)==0 || (ws & WHERE_INDEXED)!=0 );
|
|
if( (ws & WHERE_IDX_ONLY)==0 ){
|
|
assert( pLevel->iTabCur==pTabList->a[pLevel->iFrom].iCursor );
|
|
sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iTabCur);
|
|
}
|
|
if( (ws & WHERE_INDEXED)
|
|
|| ((ws & WHERE_MULTI_OR) && pLevel->u.pCoveringIdx)
|
|
){
|
|
if( ws & WHERE_MULTI_OR ){
|
|
Index *pIx = pLevel->u.pCoveringIdx;
|
|
int iDb = sqlite3SchemaToIndex(db, pIx->pSchema);
|
|
sqlite3VdbeAddOp3(v, OP_ReopenIdx, pLevel->iIdxCur, pIx->tnum, iDb);
|
|
sqlite3VdbeSetP4KeyInfo(pParse, pIx);
|
|
}
|
|
sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
|
|
}
|
|
if( pLevel->op==OP_Return ){
|
|
sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
|
|
}else{
|
|
sqlite3VdbeGoto(v, pLevel->addrFirst);
|
|
}
|
|
sqlite3VdbeJumpHere(v, addr);
|
|
}
|
|
VdbeModuleComment((v, "End WHERE-loop%d: %s", i,
|
|
pWInfo->pTabList->a[pLevel->iFrom].pTab->zName));
|
|
}
|
|
|
|
assert( pWInfo->nLevel<=pTabList->nSrc );
|
|
if( pWInfo->pExprMods ) whereUndoExprMods(pWInfo);
|
|
for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
|
|
int k, last;
|
|
VdbeOp *pOp, *pLastOp;
|
|
Index *pIdx = 0;
|
|
SrcItem *pTabItem = &pTabList->a[pLevel->iFrom];
|
|
Table *pTab = pTabItem->pTab;
|
|
assert( pTab!=0 );
|
|
pLoop = pLevel->pWLoop;
|
|
|
|
/* Do RIGHT JOIN processing. Generate code that will output the
|
|
** unmatched rows of the right operand of the RIGHT JOIN with
|
|
** all of the columns of the left operand set to NULL.
|
|
*/
|
|
if( pLevel->pRJ ){
|
|
sqlite3WhereRightJoinLoop(pWInfo, i, pLevel);
|
|
continue;
|
|
}
|
|
|
|
/* For a co-routine, change all OP_Column references to the table of
|
|
** the co-routine into OP_Copy of result contained in a register.
|
|
** OP_Rowid becomes OP_Null.
|
|
*/
|
|
if( pTabItem->fg.viaCoroutine ){
|
|
testcase( pParse->db->mallocFailed );
|
|
translateColumnToCopy(pParse, pLevel->addrBody, pLevel->iTabCur,
|
|
pTabItem->regResult, 0);
|
|
continue;
|
|
}
|
|
|
|
/* If this scan uses an index, make VDBE code substitutions to read data
|
|
** from the index instead of from the table where possible. In some cases
|
|
** this optimization prevents the table from ever being read, which can
|
|
** yield a significant performance boost.
|
|
**
|
|
** Calls to the code generator in between sqlite3WhereBegin and
|
|
** sqlite3WhereEnd will have created code that references the table
|
|
** directly. This loop scans all that code looking for opcodes
|
|
** that reference the table and converts them into opcodes that
|
|
** reference the index.
|
|
*/
|
|
if( pLoop->wsFlags & (WHERE_INDEXED|WHERE_IDX_ONLY) ){
|
|
pIdx = pLoop->u.btree.pIndex;
|
|
}else if( pLoop->wsFlags & WHERE_MULTI_OR ){
|
|
pIdx = pLevel->u.pCoveringIdx;
|
|
}
|
|
if( pIdx
|
|
&& !db->mallocFailed
|
|
){
|
|
if( pWInfo->eOnePass==ONEPASS_OFF || !HasRowid(pIdx->pTable) ){
|
|
last = iEnd;
|
|
}else{
|
|
last = pWInfo->iEndWhere;
|
|
}
|
|
k = pLevel->addrBody + 1;
|
|
#ifdef SQLITE_DEBUG
|
|
if( db->flags & SQLITE_VdbeAddopTrace ){
|
|
printf("TRANSLATE opcodes in range %d..%d\n", k, last-1);
|
|
}
|
|
/* Proof that the "+1" on the k value above is safe */
|
|
pOp = sqlite3VdbeGetOp(v, k - 1);
|
|
assert( pOp->opcode!=OP_Column || pOp->p1!=pLevel->iTabCur );
|
|
assert( pOp->opcode!=OP_Rowid || pOp->p1!=pLevel->iTabCur );
|
|
assert( pOp->opcode!=OP_IfNullRow || pOp->p1!=pLevel->iTabCur );
|
|
#endif
|
|
pOp = sqlite3VdbeGetOp(v, k);
|
|
pLastOp = pOp + (last - k);
|
|
assert( pOp<=pLastOp );
|
|
do{
|
|
if( pOp->p1!=pLevel->iTabCur ){
|
|
/* no-op */
|
|
}else if( pOp->opcode==OP_Column
|
|
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
|
|
|| pOp->opcode==OP_Offset
|
|
#endif
|
|
){
|
|
int x = pOp->p2;
|
|
assert( pIdx->pTable==pTab );
|
|
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
|
|
if( pOp->opcode==OP_Offset ){
|
|
/* Do not need to translate the column number */
|
|
}else
|
|
#endif
|
|
if( !HasRowid(pTab) ){
|
|
Index *pPk = sqlite3PrimaryKeyIndex(pTab);
|
|
x = pPk->aiColumn[x];
|
|
assert( x>=0 );
|
|
}else{
|
|
testcase( x!=sqlite3StorageColumnToTable(pTab,x) );
|
|
x = sqlite3StorageColumnToTable(pTab,x);
|
|
}
|
|
x = sqlite3TableColumnToIndex(pIdx, x);
|
|
if( x>=0 ){
|
|
pOp->p2 = x;
|
|
pOp->p1 = pLevel->iIdxCur;
|
|
OpcodeRewriteTrace(db, k, pOp);
|
|
}else{
|
|
/* Unable to translate the table reference into an index
|
|
** reference. Verify that this is harmless - that the
|
|
** table being referenced really is open.
|
|
*/
|
|
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
|
|
assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
|
|
|| cursorIsOpen(v,pOp->p1,k)
|
|
|| pOp->opcode==OP_Offset
|
|
);
|
|
#else
|
|
assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
|
|
|| cursorIsOpen(v,pOp->p1,k)
|
|
);
|
|
#endif
|
|
}
|
|
}else if( pOp->opcode==OP_Rowid ){
|
|
pOp->p1 = pLevel->iIdxCur;
|
|
pOp->opcode = OP_IdxRowid;
|
|
OpcodeRewriteTrace(db, k, pOp);
|
|
}else if( pOp->opcode==OP_IfNullRow ){
|
|
pOp->p1 = pLevel->iIdxCur;
|
|
OpcodeRewriteTrace(db, k, pOp);
|
|
}
|
|
#ifdef SQLITE_DEBUG
|
|
k++;
|
|
#endif
|
|
}while( (++pOp)<pLastOp );
|
|
#ifdef SQLITE_DEBUG
|
|
if( db->flags & SQLITE_VdbeAddopTrace ) printf("TRANSLATE complete\n");
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/* The "break" point is here, just past the end of the outer loop.
|
|
** Set it.
|
|
*/
|
|
sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
|
|
|
|
/* Final cleanup
|
|
*/
|
|
pParse->nQueryLoop = pWInfo->savedNQueryLoop;
|
|
whereInfoFree(db, pWInfo);
|
|
pParse->withinRJSubrtn -= nRJ;
|
|
return;
|
|
}
|