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Reduce memory requirements for ORDER BY combined with LIMIT. Ticket #1586. (CVS 2887)

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FossilOrigin-Name: 55e703ecac6e03d7364c2d919ba18d7293d6b7f6
This commit is contained in:
drh
2006-01-08 05:02:54 +00:00
parent 76873ab240
commit d59ba6ce61
3 changed files with 42 additions and 17 deletions
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12
manifest
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@@ -1,5 +1,5 @@
C Invalidate\sall\sVDBE\scursor\srow\scaches\sin\sbetween\scalls\sto\ssqlite3_step()\nsince\sthe\semphemeral\scontent\sthat\sthose\scaches\spoint\sto\smight\schange\sif\nthe\sstatement\sis\sREAD\sUNCOMMITTED.\s(CVS\s2886) C Reduce\smemory\srequirements\sfor\sORDER\sBY\scombined\swith\sLIMIT.\s\sTicket\s#1586.\s(CVS\s2887)
D 2006-01-07T18:48:26 D 2006-01-08T05:02:55
F Makefile.in c79fbdaa264c6afcd435f2fb492551de5a8cf80d F Makefile.in c79fbdaa264c6afcd435f2fb492551de5a8cf80d
F Makefile.linux-gcc aee18d8a05546dcf1888bd4547e442008a49a092 F Makefile.linux-gcc aee18d8a05546dcf1888bd4547e442008a49a092
F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -66,7 +66,7 @@ F src/pragma.c ae8b135531e7a4d692c60bd909c819d0b3fc588a
F src/prepare.c fef89dc92703d345251142af966b60e44a66cfc5 F src/prepare.c fef89dc92703d345251142af966b60e44a66cfc5
F src/printf.c f47a2f4b5387cd2ebb12e9117a1a5d6bd9a2b812 F src/printf.c f47a2f4b5387cd2ebb12e9117a1a5d6bd9a2b812
F src/random.c d40f8d356cecbd351ccfab6eaedd7ec1b54f5261 F src/random.c d40f8d356cecbd351ccfab6eaedd7ec1b54f5261
F src/select.c 77bcb71f609ff95247a529acf7dfc1c1ec09154b F src/select.c ad632ffd92ac280d9f8565fe27256e0c4e94c2c9
F src/shell.c 66b073375efbdee19045e7e0cd38b85f9aff71da F src/shell.c 66b073375efbdee19045e7e0cd38b85f9aff71da
F src/sqlite.h.in ba3a29daa6a16e054191ccb384a981964e882a1d F src/sqlite.h.in ba3a29daa6a16e054191ccb384a981964e882a1d
F src/sqliteInt.h 40c3511c05df83c7c1c244d0432baa9497feee4d F src/sqliteInt.h 40c3511c05df83c7c1c244d0432baa9497feee4d
@@ -335,7 +335,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513 F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513
P 15fda14ee0c0524d3064d767f48edd689c090d95 P 0ae461313c1642a49a9f6cda608c42c7c0053ce4
R 8b6ba0a7cf083b8ec0fb5215eb91310f R 79c569a066edb0857c89ee545cff9b3e
U drh U drh
Z c1686b0c208bc7bdd63ff2b9442034c8 Z e2eb2297d27afb66b9b69713714cfa42

2
manifest.uuid
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@@ -1 +1 @@
0ae461313c1642a49a9f6cda608c42c7c0053ce4 55e703ecac6e03d7364c2d919ba18d7293d6b7f6

45
src/select.c
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@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser ** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite. ** to handle SELECT statements in SQLite.
** **
** $Id: select.c,v 1.286 2006/01/07 13:21:04 danielk1977 Exp $ ** $Id: select.c,v 1.287 2006/01/08 05:02:55 drh Exp $
*/ */
#include "sqliteInt.h" #include "sqliteInt.h"
@@ -351,12 +351,28 @@ void sqlite3SelectDelete(Select *p){
** Insert code into "v" that will push the record on the top of the ** Insert code into "v" that will push the record on the top of the
** stack into the sorter. ** stack into the sorter.
*/ */
static void pushOntoSorter(Parse *pParse, Vdbe *v, ExprList *pOrderBy){ static void pushOntoSorter(
Parse *pParse, /* Parser context */
ExprList *pOrderBy, /* The ORDER BY clause */
Select *pSelect /* The whole SELECT statement */
){
Vdbe *v = pParse->pVdbe;
sqlite3ExprCodeExprList(pParse, pOrderBy); sqlite3ExprCodeExprList(pParse, pOrderBy);
sqlite3VdbeAddOp(v, OP_Sequence, pOrderBy->iECursor, 0); sqlite3VdbeAddOp(v, OP_Sequence, pOrderBy->iECursor, 0);
sqlite3VdbeAddOp(v, OP_Pull, pOrderBy->nExpr + 1, 0); sqlite3VdbeAddOp(v, OP_Pull, pOrderBy->nExpr + 1, 0);
sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0); sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0); sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0);
if( pSelect->iLimit>=0 ){
int addr1;
sqlite3VdbeAddOp(v, OP_MemIncr, pSelect->iLimit+1, 0);
addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, pSelect->iLimit+1, 0);
sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
sqlite3VdbeJumpHere(v, addr1);
sqlite3VdbeAddOp(v, OP_Last, pOrderBy->iECursor, 0);
sqlite3VdbeAddOp(v, OP_Delete, pOrderBy->iECursor, 0);
sqlite3VdbeJumpHere(v, addr1+1);
pSelect->iLimit = -1;
}
} }
/* /*
@@ -504,7 +520,7 @@ static int selectInnerLoop(
case SRT_VirtualTab: { case SRT_VirtualTab: {
sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0); sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
if( pOrderBy ){ if( pOrderBy ){
pushOntoSorter(pParse, v, pOrderBy); pushOntoSorter(pParse, pOrderBy, p);
}else{ }else{
sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0); sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
sqlite3VdbeAddOp(v, OP_Pull, 1, 0); sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
@@ -531,7 +547,7 @@ static int selectInnerLoop(
** ORDER BY in this case since the order of entries in the set ** ORDER BY in this case since the order of entries in the set
** does not matter. But there might be a LIMIT clause, in which ** does not matter. But there might be a LIMIT clause, in which
** case the order does matter */ ** case the order does matter */
pushOntoSorter(pParse, v, pOrderBy); pushOntoSorter(pParse, pOrderBy, p);
}else{ }else{
char aff = (iParm>>16)&0xFF; char aff = (iParm>>16)&0xFF;
aff = sqlite3CompareAffinity(pEList->a[0].pExpr, aff); aff = sqlite3CompareAffinity(pEList->a[0].pExpr, aff);
@@ -558,7 +574,7 @@ static int selectInnerLoop(
case SRT_Mem: { case SRT_Mem: {
assert( nColumn==1 ); assert( nColumn==1 );
if( pOrderBy ){ if( pOrderBy ){
pushOntoSorter(pParse, v, pOrderBy); pushOntoSorter(pParse, pOrderBy, p);
}else{ }else{
sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1); sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
/* The LIMIT clause will jump out of the loop for us */ /* The LIMIT clause will jump out of the loop for us */
@@ -575,7 +591,7 @@ static int selectInnerLoop(
case SRT_Callback: { case SRT_Callback: {
if( pOrderBy ){ if( pOrderBy ){
sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0); sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
pushOntoSorter(pParse, v, pOrderBy); pushOntoSorter(pParse, pOrderBy, p);
}else if( eDest==SRT_Subroutine ){ }else if( eDest==SRT_Subroutine ){
sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm); sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
}else{ }else{
@@ -1358,7 +1374,7 @@ Vdbe *sqlite3GetVdbe(Parse *pParse){
** the limit and offset. If there is no limit and/or offset, then ** the limit and offset. If there is no limit and/or offset, then
** iLimit and iOffset are negative. ** iLimit and iOffset are negative.
** **
** This routine changes the values if iLimit and iOffset only if ** This routine changes the values of iLimit and iOffset only if
** a limit or offset is defined by pLimit and pOffset. iLimit and ** a limit or offset is defined by pLimit and pOffset. iLimit and
** iOffset should have been preset to appropriate default values ** iOffset should have been preset to appropriate default values
** (usually but not always -1) prior to calling this routine. ** (usually but not always -1) prior to calling this routine.
@@ -1375,13 +1391,14 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
** no rows. ** no rows.
*/ */
if( p->pLimit ){ if( p->pLimit ){
int iMem = pParse->nMem++; int iMem = pParse->nMem;
pParse->nMem += 2;
Vdbe *v = sqlite3GetVdbe(pParse); Vdbe *v = sqlite3GetVdbe(pParse);
if( v==0 ) return; if( v==0 ) return;
sqlite3ExprCode(pParse, p->pLimit); sqlite3ExprCode(pParse, p->pLimit);
sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0); sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
sqlite3VdbeAddOp(v, OP_Negative, 0, 0); sqlite3VdbeAddOp(v, OP_Negative, 0, 0);
sqlite3VdbeAddOp(v, OP_MemStore, iMem, 1); sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
VdbeComment((v, "# LIMIT counter")); VdbeComment((v, "# LIMIT counter"));
sqlite3VdbeAddOp(v, OP_IfMemZero, iMem, iBreak); sqlite3VdbeAddOp(v, OP_IfMemZero, iMem, iBreak);
p->iLimit = iMem; p->iLimit = iMem;
@@ -1393,10 +1410,18 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
sqlite3ExprCode(pParse, p->pOffset); sqlite3ExprCode(pParse, p->pOffset);
sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0); sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
sqlite3VdbeAddOp(v, OP_Negative, 0, 0); sqlite3VdbeAddOp(v, OP_Negative, 0, 0);
sqlite3VdbeAddOp(v, OP_MemStore, iMem, 1); sqlite3VdbeAddOp(v, OP_MemStore, iMem, p->pLimit==0);
VdbeComment((v, "# OFFSET counter")); VdbeComment((v, "# OFFSET counter"));
if( p->pLimit ){
sqlite3VdbeAddOp(v, OP_Add, 0, 0);
}
p->iOffset = iMem; p->iOffset = iMem;
} }
if( p->pLimit ){
Vdbe *v = pParse->pVdbe;
sqlite3VdbeAddOp(v, OP_MemStore, p->iLimit+1, 1);
VdbeComment((v, "# LIMIT+OFFSET"));
}
} }
/* /*