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Take the LIMIT clause into account when estimating the cost of sorting.

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FossilOrigin-Name: d491745cab951e0de70f1f79b7640ea8aff6e8bb
This commit is contained in:
drh 2016-02-25 16:04:59 +00:00
parent d8c22ac655
commit c3489bbf77
7 changed files with 93 additions and 59 deletions
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23
manifest
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@ -1,5 +1,5 @@
C In\sthe\scommand-line\sshell:\s\sWhen\sthe\s".import"\scommand\sis\screating\sa\snew\ntable\susing\scolumn\snames\sfrom\sthe\sfirst\srow\sof\sCSV\sinput,\smake\ssure\s\ndouble-quotes\sin\sthe\sname\sare\sproperly\sescaped.
D 2016-02-25T13:33:02.701
C Take\sthe\sLIMIT\sclause\sinto\saccount\swhen\sestimating\sthe\scost\sof\ssorting.
D 2016-02-25T16:04:59.636
F Makefile.in 4e90dc1521879022aa9479268a4cd141d1771142
F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
F Makefile.msc 28fc4ee02333996d31b3602b39eeb8e609a89ce4
@ -349,12 +349,12 @@ F src/printf.c 63e6fb12bbe702dd664dc3703776c090383a5a26
F src/random.c ba2679f80ec82c4190062d756f22d0c358180696
F src/resolve.c b8f7174e5f8c33c44ded3a25a973d0bb89228c20
F src/rowset.c 9fe4b3ad7cc00944386bb600233d8f523de07a6e
F src/select.c 1a7e23a3bb2edb9cdc46ab0cf7c1500109cf2531
F src/select.c dbc73a63bee99bf7cfac6052477ffc21e899bb08
F src/shell.c 89b73e894e737cc2f21e4bce0feb3ea21cc61124
F src/sqlite.h.in a7caa805a345d6a14136c11ccfa6f4c1a6ef6e7b
F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
F src/sqlite3ext.h dfbe62ffd95b99afe2140d8c35b180d11924072d
F src/sqliteInt.h 5200682fc1050f00fba07128c0facc37462c4411
F src/sqliteInt.h 5a87bccd05996f4c3facd8f831cf92a05b818b6f
F src/sqliteLimit.h 216557999cb45f2e3578ed53ebefe228d779cb46
F src/status.c 70912d7be68e9e2dbc4010c93d344af61d4c59ba
F src/table.c 5226df15ab9179b9ed558d89575ea0ce37b03fc9
@ -408,7 +408,7 @@ F src/test_windirent.h b12055cab6227f7be10f5c19296f67c60cc5e2a5
F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
F src/tokenize.c 3d338cdd00d916ce8a05c397001d64ed58e6fe1c
F src/treeview.c dc39ccf04e9331237388b9cb73289c9d87ea050b
F src/treeview.c c525282442111b3f61eb176784567cd6654db5dc
F src/trigger.c e14840ee0c3e549e758ec9bf3e4146e166002280
F src/update.c a7eeeaffad59c6506f01303a071dac11de8269ca
F src/utf.c 699001c79f28e48e9bcdf8a463da029ea660540c
@ -428,8 +428,8 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
F src/wal.c 10deb6b43887662691e5f53d10b3c171c401169b
F src/wal.h 2f7c831cf3b071fa548bf2d5cac640846a7ff19c
F src/walker.c 0f142b5bd3ed2041fc52d773880748b212e63354
F src/where.c 5b67fb8035ae4697cf721db095f800ef8dff5f56
F src/whereInt.h 78b6b4de94db84aecbdc07fe3e38f648eb391e9a
F src/where.c ba8f2cd97e5125d2423b3dffad9f77b888b9b1a8
F src/whereInt.h 93297d56edd137b7ea004490690fb6e2ce028a34
F src/wherecode.c 39c1ef4598bedf1d66249334c74efd23ddd182ac
F src/whereexpr.c fb87944b1254234e5bba671aaf6dee476241506a
F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
@ -1429,7 +1429,10 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh a98af506df552f3b3c0d904f94e4cdc4e1a6d598
F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
P e721975faa0925be4029330550ff2a9666041ff7
R c8d6b90bca6c11dea1a586d1afdb957c
P 2e67a1c823c7003e7d2619c7d8b6db6ce046c527
R 537d9f6aec4a86824de8d982730a8e8f
T *branch * planner-improvements
T *sym-planner-improvements *
T -sym-trunk *
U drh
Z 8dad8d5c86c3c0b275d53a26a0713023
Z 54aed3c7f721cc8ad2041b056394372f

2
manifest.uuid
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@ -1 +1 @@
2e67a1c823c7003e7d2619c7d8b6db6ce046c527
d491745cab951e0de70f1f79b7640ea8aff6e8bb

35
src/select.c
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@ -105,7 +105,7 @@ Select *sqlite3SelectNew(
ExprList *pGroupBy, /* the GROUP BY clause */
Expr *pHaving, /* the HAVING clause */
ExprList *pOrderBy, /* the ORDER BY clause */
u16 selFlags, /* Flag parameters, such as SF_Distinct */
u32 selFlags, /* Flag parameters, such as SF_Distinct */
Expr *pLimit, /* LIMIT value. NULL means not used */
Expr *pOffset /* OFFSET value. NULL means no offset */
){
@ -1845,8 +1845,9 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
VdbeComment((v, "LIMIT counter"));
if( n==0 ){
sqlite3VdbeGoto(v, iBreak);
}else if( n>=0 && p->nSelectRow>(u64)n ){
p->nSelectRow = n;
}else if( n>=0 && p->nSelectRow>sqlite3LogEst((u64)n) ){
p->nSelectRow = sqlite3LogEst((u64)n);
p->selFlags |= SF_FixedLimit;
}
}else{
sqlite3ExprCode(pParse, p->pLimit, iLimit);
@ -2287,12 +2288,12 @@ static int multiSelect(
testcase( rc!=SQLITE_OK );
pDelete = p->pPrior;
p->pPrior = pPrior;
p->nSelectRow += pPrior->nSelectRow;
p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
if( pPrior->pLimit
&& sqlite3ExprIsInteger(pPrior->pLimit, &nLimit)
&& nLimit>0 && p->nSelectRow > (u64)nLimit
&& nLimit>0 && p->nSelectRow > sqlite3LogEst((u64)nLimit)
){
p->nSelectRow = nLimit;
p->nSelectRow = sqlite3LogEst((u64)nLimit);
}
if( addr ){
sqlite3VdbeJumpHere(v, addr);
@ -2364,7 +2365,9 @@ static int multiSelect(
pDelete = p->pPrior;
p->pPrior = pPrior;
p->pOrderBy = 0;
if( p->op==TK_UNION ) p->nSelectRow += pPrior->nSelectRow;
if( p->op==TK_UNION ){
p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
}
sqlite3ExprDelete(db, p->pLimit);
p->pLimit = pLimit;
p->pOffset = pOffset;
@ -3001,7 +3004,7 @@ static int multiSelectOrderBy(
addrEofA_noB = sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, labelEnd);
VdbeCoverage(v);
sqlite3VdbeGoto(v, addrEofA);
p->nSelectRow += pPrior->nSelectRow;
p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
}
/* Generate a subroutine to run when the results from select B
@ -4987,7 +4990,7 @@ int sqlite3Select(
sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
sqlite3Select(pParse, pSub, &dest);
pItem->pTab->nRowLogEst = sqlite3LogEst(pSub->nSelectRow);
pItem->pTab->nRowLogEst = pSub->nSelectRow;
pItem->fg.viaCoroutine = 1;
pItem->regResult = dest.iSdst;
sqlite3VdbeEndCoroutine(v, pItem->regReturn);
@ -5018,7 +5021,7 @@ int sqlite3Select(
sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
sqlite3Select(pParse, pSub, &dest);
pItem->pTab->nRowLogEst = sqlite3LogEst(pSub->nSelectRow);
pItem->pTab->nRowLogEst = pSub->nSelectRow;
if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
VdbeComment((v, "end %s", pItem->pTab->zName));
@ -5101,7 +5104,7 @@ int sqlite3Select(
/* Set the limiter.
*/
iEnd = sqlite3VdbeMakeLabel(v);
p->nSelectRow = LARGEST_INT64;
p->nSelectRow = 320; /* 4 billion rows */
computeLimitRegisters(pParse, p, iEnd);
if( p->iLimit==0 && sSort.addrSortIndex>=0 ){
sqlite3VdbeChangeOpcode(v, sSort.addrSortIndex, OP_SorterOpen);
@ -5125,10 +5128,12 @@ int sqlite3Select(
if( !isAgg && pGroupBy==0 ){
/* No aggregate functions and no GROUP BY clause */
u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0);
assert( WHERE_USE_LIMIT==SF_FixedLimit );
wctrlFlags |= p->selFlags & SF_FixedLimit;
/* Begin the database scan. */
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, sSort.pOrderBy,
p->pEList, wctrlFlags, 0);
p->pEList, wctrlFlags, p->nSelectRow);
if( pWInfo==0 ) goto select_end;
if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){
p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo);
@ -5188,9 +5193,11 @@ int sqlite3Select(
for(k=pGroupBy->nExpr, pItem=pGroupBy->a; k>0; k--, pItem++){
pItem->u.x.iAlias = 0;
}
if( p->nSelectRow>100 ) p->nSelectRow = 100;
assert( 66==sqlite3LogEst(100) );
if( p->nSelectRow>66 ) p->nSelectRow = 66;
}else{
p->nSelectRow = 1;
assert( 0==sqlite3LogEst(1) );
p->nSelectRow = 0;
}
/* If there is both a GROUP BY and an ORDER BY clause and they are

42
src/sqliteInt.h
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@ -2442,6 +2442,7 @@ struct SrcList {
#define WHERE_SORTBYGROUP 0x0800 /* Support sqlite3WhereIsSorted() */
#define WHERE_REOPEN_IDX 0x1000 /* Try to use OP_ReopenIdx */
#define WHERE_ONEPASS_MULTIROW 0x2000 /* ONEPASS is ok with multiple rows */
#define WHERE_USE_LIMIT 0x4000 /* There is a constant LIMIT clause */
/* Allowed return values from sqlite3WhereIsDistinct()
*/
@ -2520,13 +2521,13 @@ struct NameContext {
struct Select {
ExprList *pEList; /* The fields of the result */
u8 op; /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
u16 selFlags; /* Various SF_* values */
LogEst nSelectRow; /* Estimated number of result rows */
u32 selFlags; /* Various SF_* values */
int iLimit, iOffset; /* Memory registers holding LIMIT & OFFSET counters */
#if SELECTTRACE_ENABLED
char zSelName[12]; /* Symbolic name of this SELECT use for debugging */
#endif
int addrOpenEphm[2]; /* OP_OpenEphem opcodes related to this select */
u64 nSelectRow; /* Estimated number of result rows */
SrcList *pSrc; /* The FROM clause */
Expr *pWhere; /* The WHERE clause */
ExprList *pGroupBy; /* The GROUP BY clause */
@ -2543,22 +2544,23 @@ struct Select {
** Allowed values for Select.selFlags. The "SF" prefix stands for
** "Select Flag".
*/
#define SF_Distinct 0x0001 /* Output should be DISTINCT */
#define SF_All 0x0002 /* Includes the ALL keyword */
#define SF_Resolved 0x0004 /* Identifiers have been resolved */
#define SF_Aggregate 0x0008 /* Contains aggregate functions */
#define SF_UsesEphemeral 0x0010 /* Uses the OpenEphemeral opcode */
#define SF_Expanded 0x0020 /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo 0x0040 /* FROM subqueries have Table metadata */
#define SF_Compound 0x0080 /* Part of a compound query */
#define SF_Values 0x0100 /* Synthesized from VALUES clause */
#define SF_MultiValue 0x0200 /* Single VALUES term with multiple rows */
#define SF_NestedFrom 0x0400 /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert 0x0800 /* Need convertCompoundSelectToSubquery() */
#define SF_MinMaxAgg 0x1000 /* Aggregate containing min() or max() */
#define SF_Recursive 0x2000 /* The recursive part of a recursive CTE */
#define SF_Converted 0x4000 /* By convertCompoundSelectToSubquery() */
#define SF_IncludeHidden 0x8000 /* Include hidden columns in output */
#define SF_Distinct 0x00001 /* Output should be DISTINCT */
#define SF_All 0x00002 /* Includes the ALL keyword */
#define SF_Resolved 0x00004 /* Identifiers have been resolved */
#define SF_Aggregate 0x00008 /* Contains aggregate functions */
#define SF_UsesEphemeral 0x00010 /* Uses the OpenEphemeral opcode */
#define SF_Expanded 0x00020 /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo 0x00040 /* FROM subqueries have Table metadata */
#define SF_Compound 0x00080 /* Part of a compound query */
#define SF_Values 0x00100 /* Synthesized from VALUES clause */
#define SF_MultiValue 0x00200 /* Single VALUES term with multiple rows */
#define SF_NestedFrom 0x00400 /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert 0x00800 /* Need convertCompoundSelectToSubquery() */
#define SF_MinMaxAgg 0x01000 /* Aggregate containing min() or max() */
#define SF_Recursive 0x02000 /* The recursive part of a recursive CTE */
#define SF_FixedLimit 0x04000 /* nSelectRow set by a constant LIMIT */
#define SF_Converted 0x08000 /* By convertCompoundSelectToSubquery() */
#define SF_IncludeHidden 0x10000 /* Include hidden columns in output */
/*
@ -3489,7 +3491,7 @@ Index *sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
void sqlite3DropIndex(Parse*, SrcList*, int);
int sqlite3Select(Parse*, Select*, SelectDest*);
Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
Expr*,ExprList*,u16,Expr*,Expr*);
Expr*,ExprList*,u32,Expr*,Expr*);
void sqlite3SelectDelete(sqlite3*, Select*);
Table *sqlite3SrcListLookup(Parse*, SrcList*);
int sqlite3IsReadOnly(Parse*, Table*, int);
@ -3501,7 +3503,7 @@ void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*,SrcList*,Expr*,ExprList*,ExprList*,u16,int);
void sqlite3WhereEnd(WhereInfo*);
u64 sqlite3WhereOutputRowCount(WhereInfo*);
LogEst sqlite3WhereOutputRowCount(WhereInfo*);
int sqlite3WhereIsDistinct(WhereInfo*);
int sqlite3WhereIsOrdered(WhereInfo*);
int sqlite3WhereIsSorted(WhereInfo*);

5
src/treeview.c
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@ -132,9 +132,10 @@ void sqlite3TreeViewSelect(TreeView *pView, const Select *p, u8 moreToFollow){
sqlite3TreeViewPush(pView, 1);
}
do{
sqlite3TreeViewLine(pView, "SELECT%s%s (0x%p) selFlags=0x%x",
sqlite3TreeViewLine(pView, "SELECT%s%s (0x%p) selFlags=0x%x nSelectRow=%d",
((p->selFlags & SF_Distinct) ? " DISTINCT" : ""),
((p->selFlags & SF_Aggregate) ? " agg_flag" : ""), p, p->selFlags
((p->selFlags & SF_Aggregate) ? " agg_flag" : ""), p, p->selFlags,
(int)p->nSelectRow
);
if( cnt++ ) sqlite3TreeViewPop(pView);
if( p->pPrior ){

44
src/where.c
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@ -31,8 +31,8 @@ static int whereLoopResize(sqlite3*, WhereLoop*, int);
/*
** Return the estimated number of output rows from a WHERE clause
*/
u64 sqlite3WhereOutputRowCount(WhereInfo *pWInfo){
return sqlite3LogEstToInt(pWInfo->nRowOut);
LogEst sqlite3WhereOutputRowCount(WhereInfo *pWInfo){
return pWInfo->nRowOut;
}
/*
@ -3438,6 +3438,7 @@ static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){
** order.
*/
static LogEst whereSortingCost(
WhereInfo *pWInfo,
LogEst nRow,
int nOrderBy,
int nSorted
@ -3458,7 +3459,15 @@ static LogEst whereSortingCost(
LogEst rScale, rSortCost;
assert( nOrderBy>0 && 66==sqlite3LogEst(100) );
rScale = sqlite3LogEst((nOrderBy-nSorted)*100/nOrderBy) - 66;
rSortCost = nRow + estLog(nRow) + rScale + 16;
rSortCost = nRow + rScale + 16;
/* Multiple by log(M) where M is the number of output rows.
** Use the LIMIT for M if it is smaller */
if( (pWInfo->wctrlFlags & WHERE_USE_LIMIT)!=0 ){
LogEst m = sqlite3LogEst(pWInfo->iLimit);
if( m<nRow ) nRow = m;
}
rSortCost += estLog(nRow);
return rSortCost;
}
@ -3592,7 +3601,7 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
if( isOrdered>=0 && isOrdered<nOrderBy ){
if( aSortCost[isOrdered]==0 ){
aSortCost[isOrdered] = whereSortingCost(
nRowEst, nOrderBy, isOrdered
pWInfo, nRowEst, nOrderBy, isOrdered
);
}
rCost = sqlite3LogEstAdd(rUnsorted, aSortCost[isOrdered]);
@ -3991,7 +4000,8 @@ WhereInfo *sqlite3WhereBegin(
ExprList *pOrderBy, /* An ORDER BY (or GROUP BY) clause, or NULL */
ExprList *pResultSet, /* Result set of the query */
u16 wctrlFlags, /* One of the WHERE_* flags defined in sqliteInt.h */
int iIdxCur /* If WHERE_ONETABLE_ONLY is set, index cursor number */
int iAuxArg /* If WHERE_ONETABLE_ONLY is set, index cursor number,
** If WHERE_USE_LIMIT, then the limit amount */
){
int nByteWInfo; /* Num. bytes allocated for WhereInfo struct */
int nTabList; /* Number of elements in pTabList */
@ -4012,6 +4022,10 @@ WhereInfo *sqlite3WhereBegin(
&& (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
));
/* Only one of WHERE_ONETABLE_ONLY or WHERE_USE_LIMIT */
assert( (wctrlFlags & WHERE_ONETABLE_ONLY)==0
|| (wctrlFlags & WHERE_USE_LIMIT)==0 );
/* Variable initialization */
db = pParse->db;
memset(&sWLB, 0, sizeof(sWLB));
@ -4065,6 +4079,7 @@ WhereInfo *sqlite3WhereBegin(
pWInfo->pResultSet = pResultSet;
pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(v);
pWInfo->wctrlFlags = wctrlFlags;
pWInfo->iLimit = iAuxArg;
pWInfo->savedNQueryLoop = pParse->nQueryLoop;
assert( pWInfo->eOnePass==ONEPASS_OFF ); /* ONEPASS defaults to OFF */
pMaskSet = &pWInfo->sMaskSet;
@ -4145,9 +4160,14 @@ WhereInfo *sqlite3WhereBegin(
}
/* Construct the WhereLoop objects */
WHERETRACE(0xffff,("*** Optimizer Start *** (wctrlFlags: 0x%x)\n",
wctrlFlags));
#if defined(WHERETRACE_ENABLED)
if( sqlite3WhereTrace & 0xffff ){
sqlite3DebugPrintf("*** Optimizer Start *** (wctrlFlags: 0x%x",wctrlFlags);
if( wctrlFlags & WHERE_USE_LIMIT ){
sqlite3DebugPrintf(", limit: %d", iAuxArg);
}
sqlite3DebugPrintf(")\n");
}
if( sqlite3WhereTrace & 0x100 ){ /* Display all terms of the WHERE clause */
int i;
for(i=0; i<sWLB.pWC->nTerm; i++){
@ -4330,8 +4350,8 @@ WhereInfo *sqlite3WhereBegin(
Index *pIx = pLoop->u.btree.pIndex;
int iIndexCur;
int op = OP_OpenRead;
/* iIdxCur is always set if to a positive value if ONEPASS is possible */
assert( iIdxCur!=0 || (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 );
/* iAuxArg is always set if to a positive value if ONEPASS is possible */
assert( iAuxArg!=0 || (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 );
if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIx)
&& (wctrlFlags & WHERE_ONETABLE_ONLY)!=0
){
@ -4341,7 +4361,7 @@ WhereInfo *sqlite3WhereBegin(
op = 0;
}else if( pWInfo->eOnePass!=ONEPASS_OFF ){
Index *pJ = pTabItem->pTab->pIndex;
iIndexCur = iIdxCur;
iIndexCur = iAuxArg;
assert( wctrlFlags & WHERE_ONEPASS_DESIRED );
while( ALWAYS(pJ) && pJ!=pIx ){
iIndexCur++;
@ -4349,8 +4369,8 @@ WhereInfo *sqlite3WhereBegin(
}
op = OP_OpenWrite;
pWInfo->aiCurOnePass[1] = iIndexCur;
}else if( iIdxCur && (wctrlFlags & WHERE_ONETABLE_ONLY)!=0 ){
iIndexCur = iIdxCur;
}else if( iAuxArg && (wctrlFlags & WHERE_ONETABLE_ONLY)!=0 ){
iIndexCur = iAuxArg;
if( wctrlFlags & WHERE_REOPEN_IDX ) op = OP_ReopenIdx;
}else{
iIndexCur = pParse->nTab++;

1
src/whereInt.h
View File

@ -412,6 +412,7 @@ struct WhereInfo {
WhereLoop *pLoops; /* List of all WhereLoop objects */
Bitmask revMask; /* Mask of ORDER BY terms that need reversing */
LogEst nRowOut; /* Estimated number of output rows */
LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */
u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */
i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */
u8 sorted; /* True if really sorted (not just grouped) */