Reduce memory requirements for ORDER BY combined with LIMIT. Ticket #1586. (CVS 2887)
FossilOrigin-Name: 55e703ecac6e03d7364c2d919ba18d7293d6b7f6
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drh
parent
76873ab240
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12
manifest
12
manifest
@ -1,5 +1,5 @@
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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)
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D 2006-01-07T18:48:26
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C Reduce\smemory\srequirements\sfor\sORDER\sBY\scombined\swith\sLIMIT.\s\sTicket\s#1586.\s(CVS\s2887)
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D 2006-01-08T05:02:55
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F Makefile.in c79fbdaa264c6afcd435f2fb492551de5a8cf80d
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F Makefile.linux-gcc aee18d8a05546dcf1888bd4547e442008a49a092
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F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
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@ -66,7 +66,7 @@ F src/pragma.c ae8b135531e7a4d692c60bd909c819d0b3fc588a
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F src/prepare.c fef89dc92703d345251142af966b60e44a66cfc5
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F src/printf.c f47a2f4b5387cd2ebb12e9117a1a5d6bd9a2b812
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F src/random.c d40f8d356cecbd351ccfab6eaedd7ec1b54f5261
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F src/select.c 77bcb71f609ff95247a529acf7dfc1c1ec09154b
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F src/select.c ad632ffd92ac280d9f8565fe27256e0c4e94c2c9
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F src/shell.c 66b073375efbdee19045e7e0cd38b85f9aff71da
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F src/sqlite.h.in ba3a29daa6a16e054191ccb384a981964e882a1d
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F src/sqliteInt.h 40c3511c05df83c7c1c244d0432baa9497feee4d
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@ -335,7 +335,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
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F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
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F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
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F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513
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P 15fda14ee0c0524d3064d767f48edd689c090d95
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R 8b6ba0a7cf083b8ec0fb5215eb91310f
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P 0ae461313c1642a49a9f6cda608c42c7c0053ce4
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R 79c569a066edb0857c89ee545cff9b3e
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U drh
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Z c1686b0c208bc7bdd63ff2b9442034c8
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Z e2eb2297d27afb66b9b69713714cfa42
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@ -1 +1 @@
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0ae461313c1642a49a9f6cda608c42c7c0053ce4
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55e703ecac6e03d7364c2d919ba18d7293d6b7f6
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45
src/select.c
45
src/select.c
@ -12,7 +12,7 @@
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** This file contains C code routines that are called by the parser
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** to handle SELECT statements in SQLite.
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**
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** $Id: select.c,v 1.286 2006/01/07 13:21:04 danielk1977 Exp $
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** $Id: select.c,v 1.287 2006/01/08 05:02:55 drh Exp $
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*/
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#include "sqliteInt.h"
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@ -351,12 +351,28 @@ void sqlite3SelectDelete(Select *p){
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** Insert code into "v" that will push the record on the top of the
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** stack into the sorter.
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*/
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static void pushOntoSorter(Parse *pParse, Vdbe *v, ExprList *pOrderBy){
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static void pushOntoSorter(
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Parse *pParse, /* Parser context */
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ExprList *pOrderBy, /* The ORDER BY clause */
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Select *pSelect /* The whole SELECT statement */
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){
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Vdbe *v = pParse->pVdbe;
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sqlite3ExprCodeExprList(pParse, pOrderBy);
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sqlite3VdbeAddOp(v, OP_Sequence, pOrderBy->iECursor, 0);
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sqlite3VdbeAddOp(v, OP_Pull, pOrderBy->nExpr + 1, 0);
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sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
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sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0);
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if( pSelect->iLimit>=0 ){
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int addr1;
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sqlite3VdbeAddOp(v, OP_MemIncr, pSelect->iLimit+1, 0);
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addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, pSelect->iLimit+1, 0);
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sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
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sqlite3VdbeJumpHere(v, addr1);
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sqlite3VdbeAddOp(v, OP_Last, pOrderBy->iECursor, 0);
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sqlite3VdbeAddOp(v, OP_Delete, pOrderBy->iECursor, 0);
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sqlite3VdbeJumpHere(v, addr1+1);
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pSelect->iLimit = -1;
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}
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}
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/*
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@ -504,7 +520,7 @@ static int selectInnerLoop(
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case SRT_VirtualTab: {
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sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
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if( pOrderBy ){
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pushOntoSorter(pParse, v, pOrderBy);
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pushOntoSorter(pParse, pOrderBy, p);
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}else{
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sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
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sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
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@ -531,7 +547,7 @@ static int selectInnerLoop(
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** ORDER BY in this case since the order of entries in the set
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** does not matter. But there might be a LIMIT clause, in which
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** case the order does matter */
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pushOntoSorter(pParse, v, pOrderBy);
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pushOntoSorter(pParse, pOrderBy, p);
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}else{
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char aff = (iParm>>16)&0xFF;
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aff = sqlite3CompareAffinity(pEList->a[0].pExpr, aff);
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@ -558,7 +574,7 @@ static int selectInnerLoop(
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case SRT_Mem: {
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assert( nColumn==1 );
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if( pOrderBy ){
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pushOntoSorter(pParse, v, pOrderBy);
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pushOntoSorter(pParse, pOrderBy, p);
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}else{
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sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
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/* The LIMIT clause will jump out of the loop for us */
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@ -575,7 +591,7 @@ static int selectInnerLoop(
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case SRT_Callback: {
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if( pOrderBy ){
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sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
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pushOntoSorter(pParse, v, pOrderBy);
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pushOntoSorter(pParse, pOrderBy, p);
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}else if( eDest==SRT_Subroutine ){
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sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
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}else{
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@ -1358,7 +1374,7 @@ Vdbe *sqlite3GetVdbe(Parse *pParse){
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** the limit and offset. If there is no limit and/or offset, then
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** iLimit and iOffset are negative.
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**
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** This routine changes the values if iLimit and iOffset only if
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** This routine changes the values of iLimit and iOffset only if
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** a limit or offset is defined by pLimit and pOffset. iLimit and
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** iOffset should have been preset to appropriate default values
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** (usually but not always -1) prior to calling this routine.
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@ -1375,13 +1391,14 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
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** no rows.
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*/
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if( p->pLimit ){
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int iMem = pParse->nMem++;
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int iMem = pParse->nMem;
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pParse->nMem += 2;
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Vdbe *v = sqlite3GetVdbe(pParse);
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if( v==0 ) return;
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sqlite3ExprCode(pParse, p->pLimit);
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sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
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sqlite3VdbeAddOp(v, OP_Negative, 0, 0);
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sqlite3VdbeAddOp(v, OP_MemStore, iMem, 1);
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sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
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VdbeComment((v, "# LIMIT counter"));
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sqlite3VdbeAddOp(v, OP_IfMemZero, iMem, iBreak);
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p->iLimit = iMem;
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@ -1393,10 +1410,18 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
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sqlite3ExprCode(pParse, p->pOffset);
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sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
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sqlite3VdbeAddOp(v, OP_Negative, 0, 0);
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sqlite3VdbeAddOp(v, OP_MemStore, iMem, 1);
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sqlite3VdbeAddOp(v, OP_MemStore, iMem, p->pLimit==0);
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VdbeComment((v, "# OFFSET counter"));
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if( p->pLimit ){
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sqlite3VdbeAddOp(v, OP_Add, 0, 0);
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}
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p->iOffset = iMem;
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}
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if( p->pLimit ){
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Vdbe *v = pParse->pVdbe;
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sqlite3VdbeAddOp(v, OP_MemStore, p->iLimit+1, 1);
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VdbeComment((v, "# LIMIT+OFFSET"));
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}
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}
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/*
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