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Add new Compare and Jump codes to the virtual machine. Use them in the

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implementation of aggregate queries. (CVS 5257)

FossilOrigin-Name: 083113652ff8f69b18cf1611710fdbbe5fbd9fef
This commit is contained in:
drh
2008-06-20 18:13:25 +00:00
parent 9324c8f280
commit 16ee60fff9
7 changed files with 100 additions and 40 deletions
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33
src/select.c
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@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.431 2008/06/20 15:24:02 drh Exp $
** $Id: select.c,v 1.432 2008/06/20 18:13:25 drh Exp $
*/
#include "sqliteInt.h"
@@ -1875,8 +1875,9 @@ static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** This routine is called to process a query that is really the union
** or intersection of two or more separate queries.
** This routine is called to process a compound query form from
** two or more separate queries using UNION, UNION ALL, EXCEPT, or
** INTERSECT
**
** "p" points to the right-most of the two queries. the query on the
** left is p->pPrior. The left query could also be a compound query
@@ -3291,12 +3292,10 @@ int sqlite3Select(
/* The following variables hold addresses or labels for parts of the
** virtual machine program we are putting together */
int addrOutputRow; /* Start of subroutine that outputs a result row */
int regOutputRow; /* Return address register for outputrow subroutine */
int regOutputRow; /* Return address register for output subroutine */
int addrSetAbort; /* Set the abort flag and return */
int addrInitializeLoop; /* Start of code that initializes the input loop */
int addrTopOfLoop; /* Top of the input loop */
int addrGroupByChange; /* Code that runs when any GROUP BY term changes */
int addrProcessRow; /* Code to process a single input row */
int addrEnd; /* End of all processing */
int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
int addrReset; /* Subroutine for resetting the accumulator */
@@ -3330,13 +3329,11 @@ int sqlite3Select(
*/
if( pGroupBy ){
KeyInfo *pKeyInfo; /* Keying information for the group by clause */
int j1;
/* Create labels that we will be needing
*/
addrInitializeLoop = sqlite3VdbeMakeLabel(v);
addrGroupByChange = sqlite3VdbeMakeLabel(v);
addrProcessRow = sqlite3VdbeMakeLabel(v);
/* If there is a GROUP BY clause we might need a sorting index to
** implement it. Allocate that sorting index now. If it turns out
@@ -3474,15 +3471,10 @@ int sqlite3Select(
sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
}
}
for(j=pGroupBy->nExpr-1; j>=0; j--){
if( j==0 ){
sqlite3VdbeAddOp3(v, OP_Eq, iAMem+j, addrProcessRow, iBMem+j);
}else{
sqlite3VdbeAddOp3(v, OP_Ne, iAMem+j, addrGroupByChange, iBMem+j);
}
sqlite3VdbeChangeP4(v, -1, (void*)pKeyInfo->aColl[j], P4_COLLSEQ);
sqlite3VdbeChangeP5(v, SQLITE_NULLEQUAL);
}
sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
(char*)pKeyInfo, P4_KEYINFO_STATIC);
j1 = sqlite3VdbeCurrentAddr(v);
sqlite3VdbeAddOp3(v, OP_Jump, j1+1, 0, j1+1);
/* Generate code that runs whenever the GROUP BY changes.
** Changes in the GROUP BY are detected by the previous code
@@ -3493,7 +3485,6 @@ int sqlite3Select(
** and resets the aggregate accumulator registers in preparation
** for the next GROUP BY batch.
*/
sqlite3VdbeResolveLabel(v, addrGroupByChange);
for(j=0; j<pGroupBy->nExpr; j++){
sqlite3ExprCodeMove(pParse, iBMem+j, iAMem+j);
}
@@ -3507,7 +3498,7 @@ int sqlite3Select(
/* Update the aggregate accumulators based on the content of
** the current row
*/
sqlite3VdbeResolveLabel(v, addrProcessRow);
sqlite3VdbeJumpHere(v, j1);
updateAccumulator(pParse, &sAggInfo);
sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
VdbeComment((v, "indicate data in accumulator"));
@@ -3579,7 +3570,7 @@ int sqlite3Select(
updateAccumulator(pParse, &sAggInfo);
if( !pMinMax && flag ){
sqlite3VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
VdbeComment((v, "%s() by index", (flag==WHERE_ORDERBY_MIN?"min":"max")));
VdbeComment((v, "%s() by index",(flag==WHERE_ORDERBY_MIN?"min":"max")));
}
sqlite3WhereEnd(pWInfo);
finalizeAggFunctions(pParse, &sAggInfo);