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Much faster sorting when there are a large number of columns in the

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result set. (CVS 3141)

FossilOrigin-Name: 6b3717aeb4ac45a433f2a30bdd0264ed728676e1
This commit is contained in:
drh
2006-03-17 00:04:03 +00:00
parent 3752785f93
commit cdd536f0fd
5 changed files with 39 additions and 32 deletions
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26
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 1.307 2006/03/09 17:28:12 drh Exp $
** $Id: select.c,v 1.308 2006/03/17 00:04:03 drh Exp $
*/
#include "sqliteInt.h"
@@ -680,6 +680,7 @@ static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
** routine generates the code needed to do that.
*/
static void generateSortTail(
Parse *pParse, /* Parsing context */
Select *p, /* The SELECT statement */
Vdbe *v, /* Generate code into this VDBE */
int nColumn, /* Number of columns of data */
@@ -690,11 +691,20 @@ static void generateSortTail(
int cont = sqlite3VdbeMakeLabel(v);
int addr;
int iTab;
int pseudoTab;
ExprList *pOrderBy = p->pOrderBy;
iTab = pOrderBy->iECursor;
if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
pseudoTab = pParse->nTab++;
sqlite3VdbeAddOp(v, OP_OpenPseudo, pseudoTab, 0);
sqlite3VdbeAddOp(v, OP_SetNumColumns, pseudoTab, nColumn);
}
addr = 1 + sqlite3VdbeAddOp(v, OP_Sort, iTab, brk);
codeOffset(v, p, cont, 0);
if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
}
sqlite3VdbeAddOp(v, OP_Column, iTab, pOrderBy->nExpr + 1);
switch( eDest ){
case SRT_Table:
@@ -724,17 +734,15 @@ static void generateSortTail(
case SRT_Callback:
case SRT_Subroutine: {
int i;
sqlite3VdbeAddOp(v, OP_Integer, p->pEList->nExpr, 0);
sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
sqlite3VdbeAddOp(v, OP_Insert, pseudoTab, 0);
for(i=0; i<nColumn; i++){
sqlite3VdbeAddOp(v, OP_Column, -1-i, i);
sqlite3VdbeAddOp(v, OP_Column, pseudoTab, i);
}
if( eDest==SRT_Callback ){
sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
}else{
sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
}
sqlite3VdbeAddOp(v, OP_Pop, 2, 0);
break;
}
default: {
@@ -755,6 +763,10 @@ static void generateSortTail(
sqlite3VdbeResolveLabel(v, cont);
sqlite3VdbeAddOp(v, OP_Next, iTab, addr);
sqlite3VdbeResolveLabel(v, brk);
if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
sqlite3VdbeAddOp(v, OP_Close, pseudoTab, 0);
}
}
/*
@@ -1964,7 +1976,7 @@ static int multiSelect(
pKeyInfo->nField = nOrderByExpr;
sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
pKeyInfo = 0;
generateSortTail(p, v, p->pEList->nExpr, eDest, iParm);
generateSortTail(pParse, p, v, p->pEList->nExpr, eDest, iParm);
}
sqliteFree(pKeyInfo);
@@ -3253,7 +3265,7 @@ int sqlite3Select(
** and send them to the callback one by one.
*/
if( pOrderBy ){
generateSortTail(p, v, pEList->nExpr, eDest, iParm);
generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);
}
#ifndef SQLITE_OMIT_SUBQUERY