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-rw-r--r--src/where.c128
1 files changed, 73 insertions, 55 deletions
diff --git a/src/where.c b/src/where.c
index 6cd9c167a..ee608dd83 100644
--- a/src/where.c
+++ b/src/where.c
@@ -39,7 +39,7 @@ int sqlite3WhereIsDistinct(WhereInfo *pWInfo){
** Return FALSE if the output needs to be sorted.
*/
int sqlite3WhereIsOrdered(WhereInfo *pWInfo){
- return pWInfo->bOBSat!=0;
+ return pWInfo->nOBSat;
}
/*
@@ -3036,8 +3036,11 @@ static Bitmask codeOneLoopStart(
** the first one after the nEq equality constraints in the index,
** this requires some special handling.
*/
+ assert( pWInfo->pOrderBy==0
+ || pWInfo->pOrderBy->nExpr==1
+ || (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0 );
if( (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)!=0
- && (pWInfo->bOBSat!=0)
+ && pWInfo->nOBSat>0
&& (pIdx->nKeyCol>nEq)
){
assert( pLoop->u.btree.nSkip==0 );
@@ -4506,8 +4509,8 @@ static int whereLoopAddVirtual(
pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
pIdxInfo->needToFreeIdxStr = 0;
pNew->u.vtab.idxStr = pIdxInfo->idxStr;
- pNew->u.vtab.isOrdered = (u8)((pIdxInfo->nOrderBy!=0)
- && pIdxInfo->orderByConsumed);
+ pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ?
+ pIdxInfo->nOrderBy : 0);
pNew->rSetup = 0;
pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
@@ -4668,11 +4671,11 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
/*
** Examine a WherePath (with the addition of the extra WhereLoop of the 5th
** parameters) to see if it outputs rows in the requested ORDER BY
-** (or GROUP BY) without requiring a separate sort operation. Return:
+** (or GROUP BY) without requiring a separate sort operation. Return N:
**
-** 0: ORDER BY is not satisfied. Sorting required
-** 1: ORDER BY is satisfied. Omit sorting
-** -1: Unknown at this time
+** N>0: N terms of the ORDER BY clause are satisfied
+** N==0: No terms of the ORDER BY clause are satisfied
+** N<0: Unknown yet how many terms of ORDER BY might be satisfied.
**
** Note that processing for WHERE_GROUPBY and WHERE_DISTINCTBY is not as
** strict. With GROUP BY and DISTINCT the only requirement is that
@@ -4682,7 +4685,7 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
** the pOrderBy terms can be matched in any order. With ORDER BY, the
** pOrderBy terms must be matched in strict left-to-right order.
*/
-static int wherePathSatisfiesOrderBy(
+static i8 wherePathSatisfiesOrderBy(
WhereInfo *pWInfo, /* The WHERE clause */
ExprList *pOrderBy, /* ORDER BY or GROUP BY or DISTINCT clause to check */
WherePath *pPath, /* The WherePath to check */
@@ -4915,8 +4918,14 @@ static int wherePathSatisfiesOrderBy(
}
}
} /* End the loop over all WhereLoops from outer-most down to inner-most */
- if( obSat==obDone ) return 1;
- if( !isOrderDistinct ) return 0;
+ if( obSat==obDone ) return nOrderBy;
+ if( !isOrderDistinct ){
+ for(i=nOrderBy-1; i>0; i--){
+ Bitmask m = MASKBIT(i) - 1;
+ if( (obSat&m)==m ) return i;
+ }
+ return 0;
+ }
return -1;
}
@@ -4953,11 +4962,11 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
int iLoop; /* Loop counter over the terms of the join */
int ii, jj; /* Loop counters */
int mxI = 0; /* Index of next entry to replace */
+ int nOrderBy; /* Number of ORDER BY clause terms */
LogEst rCost; /* Cost of a path */
LogEst nOut; /* Number of outputs */
LogEst mxCost = 0; /* Maximum cost of a set of paths */
LogEst mxOut = 0; /* Maximum nOut value on the set of paths */
- LogEst rSortCost; /* Cost to do a sort */
int nTo, nFrom; /* Number of valid entries in aTo[] and aFrom[] */
WherePath *aFrom; /* All nFrom paths at the previous level */
WherePath *aTo; /* The nTo best paths at the current level */
@@ -4999,16 +5008,12 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
/* Precompute the cost of sorting the final result set, if the caller
** to sqlite3WhereBegin() was concerned about sorting */
- rSortCost = 0;
if( pWInfo->pOrderBy==0 || nRowEst==0 ){
- aFrom[0].isOrderedValid = 1;
+ aFrom[0].isOrdered = 0;
+ nOrderBy = 0;
}else{
- /* TUNING: Estimated cost of sorting is 48*N*log2(N) where N is the
- ** number of output rows. The 48 is the expected size of a row to sort.
- ** FIXME: compute a better estimate of the 48 multiplier based on the
- ** result set expressions. */
- rSortCost = nRowEst + estLog(nRowEst);
- WHERETRACE(0x002,("---- sort cost=%-3d\n", rSortCost));
+ aFrom[0].isOrdered = -1;
+ nOrderBy = pWInfo->pOrderBy->nExpr;
}
/* Compute successively longer WherePaths using the previous generation
@@ -5020,8 +5025,7 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
Bitmask maskNew;
Bitmask revMask = 0;
- u8 isOrderedValid = pFrom->isOrderedValid;
- u8 isOrdered = pFrom->isOrdered;
+ i8 isOrdered = pFrom->isOrdered;
if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
/* At this point, pWLoop is a candidate to be the next loop.
@@ -5030,21 +5034,27 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
rCost = sqlite3LogEstAdd(rCost, pFrom->rCost);
nOut = pFrom->nRow + pWLoop->nOut;
maskNew = pFrom->maskLoop | pWLoop->maskSelf;
- if( !isOrderedValid ){
- switch( wherePathSatisfiesOrderBy(pWInfo,
+ if( isOrdered<0 ){
+ isOrdered = wherePathSatisfiesOrderBy(pWInfo,
pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
- iLoop, pWLoop, &revMask) ){
- case 1: /* Yes. pFrom+pWLoop does satisfy the ORDER BY clause */
- isOrdered = 1;
- isOrderedValid = 1;
- break;
- case 0: /* No. pFrom+pWLoop will require a separate sort */
- isOrdered = 0;
- isOrderedValid = 1;
- rCost = sqlite3LogEstAdd(rCost, rSortCost);
- break;
- default: /* Cannot tell yet. Try again on the next iteration */
- break;
+ iLoop, pWLoop, &revMask);
+ if( isOrdered>=0 && isOrdered<nOrderBy ){
+ /* TUNING: Estimated cost of sorting cost as roughly N*log(N).
+ ** If some but not all of the columns are in sorted order, then
+ ** scale down the log(N) term. */
+ LogEst rScale = sqlite3LogEst((nOrderBy-isOrdered)*100/nOrderBy);
+ LogEst rSortCost = nRowEst + estLog(nRowEst) + rScale - 66;
+ /* TUNING: The cost of implementing DISTINCT using a B-TREE is
+ ** also N*log(N) but it has a larger constant of proportionality.
+ ** Multiply by 3.0. */
+ if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
+ rSortCost += 16;
+ }
+ WHERETRACE(0x002,
+ ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n",
+ rSortCost, (nOrderBy-isOrdered), nOrderBy, rCost,
+ sqlite3LogEstAdd(rCost,rSortCost)));
+ rCost = sqlite3LogEstAdd(rCost, rSortCost);
}
}else{
revMask = pFrom->revLoop;
@@ -5052,7 +5062,7 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
/* Check to see if pWLoop should be added to the mxChoice best so far */
for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
if( pTo->maskLoop==maskNew
- && pTo->isOrderedValid==isOrderedValid
+ && ((pTo->isOrdered^isOrdered)&80)==0
&& ((pTo->rCost<=rCost && pTo->nRow<=nOut) ||
(pTo->rCost>=rCost && pTo->nRow>=nOut))
){
@@ -5066,7 +5076,7 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
if( sqlite3WhereTrace&0x4 ){
sqlite3DebugPrintf("Skip %s cost=%-3d,%3d order=%c\n",
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
- isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
+ isOrdered>=0 ? isOrdered+'0' : '?');
}
#endif
continue;
@@ -5084,7 +5094,7 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
if( sqlite3WhereTrace&0x4 ){
sqlite3DebugPrintf("New %s cost=%-3d,%3d order=%c\n",
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
- isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
+ isOrdered>=0 ? isOrdered+'0' : '?');
}
#endif
}else{
@@ -5094,10 +5104,10 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
sqlite3DebugPrintf(
"Skip %s cost=%-3d,%3d order=%c",
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
- isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
+ isOrdered>=0 ? isOrdered+'0' : '?');
sqlite3DebugPrintf(" vs %s cost=%-3d,%d order=%c\n",
wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
- pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
+ pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
}
#endif
testcase( pTo->rCost==rCost );
@@ -5110,10 +5120,10 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
sqlite3DebugPrintf(
"Update %s cost=%-3d,%3d order=%c",
wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
- isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
+ isOrdered>=0 ? isOrdered+'0' : '?');
sqlite3DebugPrintf(" was %s cost=%-3d,%3d order=%c\n",
wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
- pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
+ pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
}
#endif
}
@@ -5122,7 +5132,6 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
pTo->revLoop = revMask;
pTo->nRow = nOut;
pTo->rCost = rCost;
- pTo->isOrderedValid = isOrderedValid;
pTo->isOrdered = isOrdered;
memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop);
pTo->aLoop[iLoop] = pWLoop;
@@ -5147,8 +5156,8 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
sqlite3DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c",
wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
- pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
- if( pTo->isOrderedValid && pTo->isOrdered ){
+ pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?');
+ if( pTo->isOrdered>0 ){
sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
}else{
sqlite3DebugPrintf("\n");
@@ -5191,13 +5200,18 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
Bitmask notUsed;
int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom,
WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], &notUsed);
- if( rc==1 ) pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+ if( rc==pWInfo->pResultSet->nExpr ){
+ pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+ }
}
- if( pFrom->isOrdered ){
+ if( pWInfo->pOrderBy ){
if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){
- pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+ if( pFrom->isOrdered==pWInfo->pOrderBy->nExpr ){
+ pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+ }
}else{
- pWInfo->bOBSat = 1;
+ pWInfo->nOBSat = pFrom->isOrdered;
+ if( pWInfo->nOBSat<0 ) pWInfo->nOBSat = 0;
pWInfo->revMask = pFrom->revLoop;
}
}
@@ -5282,7 +5296,7 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){
pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur);
pWInfo->a[0].iTabCur = iCur;
pWInfo->nRowOut = 1;
- if( pWInfo->pOrderBy ) pWInfo->bOBSat = 1;
+ if( pWInfo->pOrderBy ) pWInfo->nOBSat = pWInfo->pOrderBy->nExpr;
if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
}
@@ -5386,7 +5400,7 @@ WhereInfo *sqlite3WhereBegin(
Parse *pParse, /* The parser context */
SrcList *pTabList, /* FROM clause: A list of all tables to be scanned */
Expr *pWhere, /* The WHERE clause */
- ExprList *pOrderBy, /* An ORDER BY clause, or NULL */
+ 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 */
@@ -5408,6 +5422,10 @@ WhereInfo *sqlite3WhereBegin(
/* Variable initialization */
db = pParse->db;
memset(&sWLB, 0, sizeof(sWLB));
+
+ /* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */
+ testcase( pOrderBy && pOrderBy->nExpr==BMS-1 );
+ if( pOrderBy && pOrderBy->nExpr>=BMS ) pOrderBy = 0;
sWLB.pOrderBy = pOrderBy;
/* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
@@ -5486,7 +5504,7 @@ WhereInfo *sqlite3WhereBegin(
/* Special case: No FROM clause
*/
if( nTabList==0 ){
- if( pOrderBy ) pWInfo->bOBSat = 1;
+ if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
if( wctrlFlags & WHERE_WANT_DISTINCT ){
pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
}
@@ -5597,8 +5615,8 @@ WhereInfo *sqlite3WhereBegin(
if( sqlite3WhereTrace ){
int ii;
sqlite3DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut);
- if( pWInfo->bOBSat ){
- sqlite3DebugPrintf(" ORDERBY=0x%llx", pWInfo->revMask);
+ if( pWInfo->nOBSat>0 ){
+ sqlite3DebugPrintf(" ORDERBY=%d,0x%llx", pWInfo->nOBSat, pWInfo->revMask);
}
switch( pWInfo->eDistinct ){
case WHERE_DISTINCT_UNIQUE: {
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-21 22:29:16 +0000