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Get rid of the special RowSet processing in where.c and move that into

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clients.  Added the WHERE_DUPLICATES_OK option to eliminate an unnecessary
RowSet during DELETE with a WHERE clause containing ORs. (CVS 6546)

FossilOrigin-Name: 98606bee9e41b8969fb639fc43864e230185ca43
This commit is contained in:
drh
2009-04-24 15:46:21 +00:00
parent 46619d6787
commit 336a5300de
7 changed files with 58 additions and 94 deletions
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92
src/where.c
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@@ -16,7 +16,7 @@
** so is applicable. Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.389 2009/04/24 14:51:42 drh Exp $
** $Id: where.c,v 1.390 2009/04/24 15:46:22 drh Exp $
*/
#include "sqliteInt.h"
@@ -2395,7 +2395,7 @@ static int codeAllEqualityTerms(
static Bitmask codeOneLoopStart(
WhereInfo *pWInfo, /* Complete information about the WHERE clause */
int iLevel, /* Which level of pWInfo->a[] should be coded */
u8 wctrlFlags, /* One of the WHERE_* flags defined in sqliteInt.h */
u16 wctrlFlags, /* One of the WHERE_* flags defined in sqliteInt.h */
Bitmask notReady /* Which tables are currently available */
){
int j, k; /* Loop counters */
@@ -2411,21 +2411,6 @@ static Bitmask codeOneLoopStart(
struct SrcList_item *pTabItem; /* FROM clause term being coded */
int addrBrk; /* Jump here to break out of the loop */
int addrCont; /* Jump here to continue with next cycle */
int regRowSet; /* Write rowids to this RowSet if non-negative */
/* Sometimes, this function is required to generate code to do
** something with the rowid of each row scanned. Specifically,
** If pWInfo->regRowSet is non-zero, then the rowid must be inserted
** into the RowSet object stored in register pWInfo->regRowSet.
**
** Extracting a rowid value from a VDBE cursor is not always a cheap
** operation, especially if the rowid is being extracted from an index
** cursor. If the rowid value is available as a by-product of the code
** generated to create the top of the scan loop, then it can be reused
** without extracting it from a cursor. The following two variables are
** used to communicate the availability of the rowid value to the C-code
** at the end of this function that generates the rowid-handling VDBE code.
*/
int iRowidReg = 0; /* Rowid is stored in this register, if not zero */
int iReleaseReg = 0; /* Temp register to free before returning */
@@ -2437,8 +2422,7 @@ static Bitmask codeOneLoopStart(
iCur = pTabItem->iCursor;
bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;
omitTable = (pLevel->plan.wsFlags & WHERE_IDX_ONLY)!=0
&& (wctrlFlags & WHERE_FILL_ROWTEST)==0;
regRowSet = pWInfo->regRowSet;
&& (wctrlFlags & WHERE_FORCE_TABLE)==0;
/* Create labels for the "break" and "continue" instructions
** for the current loop. Jump to addrBrk to break out of a loop.
@@ -2836,14 +2820,13 @@ static Bitmask codeOneLoopStart(
** B: <after the loop>
**
*/
const int f = WHERE_OMIT_OPEN | WHERE_OMIT_CLOSE | WHERE_FILL_ROWTEST;
WhereClause *pOrWc; /* The OR-clause broken out into subterms */
WhereTerm *pFinal; /* Final subterm within the OR-clause. */
SrcList oneTab; /* Shortened table list */
int regReturn = ++pParse->nMem; /* Register used with OP_Gosub */
int regRowset = ++pParse->nMem; /* Register for RowSet object */
int regRowset; /* Register for RowSet object */
int regRowid; /* Register holding rowid */
int iLoopBody = sqlite3VdbeMakeLabel(v); /* Start of loop body */
int iRetInit; /* Address of regReturn init */
int ii;
@@ -2871,7 +2854,11 @@ static Bitmask codeOneLoopStart(
** fall through to the next instruction, just as an OP_Next does if
** called on an uninitialized cursor.
*/
sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
regRowset = ++pParse->nMem;
regRowid = ++pParse->nMem;
sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
}
iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn);
for(ii=0; ii<pOrWc->nTerm; ii++){
@@ -2880,20 +2867,18 @@ static Bitmask codeOneLoopStart(
WhereInfo *pSubWInfo; /* Info for single OR-term scan */
/* Loop through table entries that match term pOrTerm. */
pSubWInfo = sqlite3WhereBegin(
pParse, &oneTab, pOrTerm->pExpr, 0, f, regRowset);
pSubWInfo = sqlite3WhereBegin(pParse, &oneTab, pOrTerm->pExpr, 0,
WHERE_OMIT_OPEN | WHERE_OMIT_CLOSE | WHERE_FORCE_TABLE);
if( pSubWInfo ){
int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
/* The call to sqlite3WhereBegin has coded an OP_RowSetTest
** at instruction iRowSet. Set P2 (the jump target) of this
** instruction to jump past the OP_Gosub coded below. This way,
** if the rowid is already in the hash-table, the body of the
** loop is not executed.
*/
int iRowSet = pSubWInfo->iRowidHandler;
assert( iRowSet>0 || pWInfo->pParse->db->mallocFailed );
sqlite3VdbeChangeP2(v, iRowSet, sqlite3VdbeCurrentAddr(v) + 1);
sqlite3VdbeChangeP4(v, iRowSet, (char *)iSet, P4_INT32);
if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
int r;
r = sqlite3ExprCodeGetColumn(pParse, pTabItem->pTab, -1, iCur,
regRowid, 0);
sqlite3VdbeAddOp4(v, OP_RowSetTest, regRowset,
sqlite3VdbeCurrentAddr(v)+2,
r, (char*)iSet, P4_INT32);
}
sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);
/* Finish the loop through table entries that match term pOrTerm. */
@@ -2902,7 +2887,7 @@ static Bitmask codeOneLoopStart(
}
}
sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
/* sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset); */
sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
sqlite3VdbeResolveLabel(v, iLoopBody);
@@ -2965,28 +2950,6 @@ static Bitmask codeOneLoopStart(
pTerm->wtFlags |= TERM_CODED;
}
}
/* Do the special rowid handling now. */
if( regRowSet ){
assert( regRowSet>0 );
if( iRowidReg==0 ){
/* The rowid was not available as a side-effect of the code
** genenerated above. So extract it from the cursor now.
*/
assert( iReleaseReg==0 );
iReleaseReg = iRowidReg = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
}
if( pWInfo->wctrlFlags&WHERE_FILL_ROWSET ){
sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, iRowidReg);
VVA_ONLY( pWInfo->iRowidHandler = 0; )
}else{
assert( pWInfo->wctrlFlags&WHERE_FILL_ROWTEST );
pWInfo->iRowidHandler =
sqlite3VdbeAddOp3(v, OP_RowSetTest, regRowSet, 0, iRowidReg);
}
}
sqlite3ReleaseTempReg(pParse, iReleaseReg);
return notReady;
@@ -3120,8 +3083,7 @@ WhereInfo *sqlite3WhereBegin(
SrcList *pTabList, /* A list of all tables to be scanned */
Expr *pWhere, /* The WHERE clause */
ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
u8 wctrlFlags, /* One of the WHERE_* flags defined in sqliteInt.h */
int regRowSet /* Register hold RowSet if WHERE_FILL_ROWSET is set */
u16 wctrlFlags /* One of the WHERE_* flags defined in sqliteInt.h */
){
int i; /* Loop counter */
int nByteWInfo; /* Num. bytes allocated for WhereInfo struct */
@@ -3170,11 +3132,9 @@ WhereInfo *sqlite3WhereBegin(
pWInfo->pParse = pParse;
pWInfo->pTabList = pTabList;
pWInfo->iBreak = sqlite3VdbeMakeLabel(v);
pWInfo->regRowSet = regRowSet;
pWInfo->pWC = pWC = (WhereClause *)&((u8 *)pWInfo)[nByteWInfo];
pWInfo->wctrlFlags = wctrlFlags;
pMaskSet = (WhereMaskSet*)&pWC[1];
assert( regRowSet==0 || (wctrlFlags&(WHERE_FILL_ROWSET|WHERE_FILL_ROWTEST)) );
/* Split the WHERE clause into separate subexpressions where each
** subexpression is separated by an AND operator.
@@ -3534,7 +3494,11 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
if( pLevel->iIdxCur>=0 ){
sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
}
sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
if( pLevel->op==OP_Return ){
sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
}else{
sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
}
sqlite3VdbeJumpHere(v, addr);
}
}