aboutsummaryrefslogtreecommitdiff
path: root/src/where.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/where.c')
-rw-r--r--src/where.c96
1 files changed, 61 insertions, 35 deletions
diff --git a/src/where.c b/src/where.c
index cdc0e1683..e20f2b301 100644
--- a/src/where.c
+++ b/src/where.c
@@ -383,7 +383,7 @@ struct WhereInfo {
Parse *pParse; /* Parsing and code generating context */
SrcList *pTabList; /* List of tables in the join */
ExprList *pOrderBy; /* The ORDER BY clause or NULL */
- ExprList *pDistinct; /* DISTINCT ON values, or NULL */
+ ExprList *pResultSet; /* Result set. DISTINCT operates on these */
WhereLoop *pLoops; /* List of all WhereLoop objects */
Bitmask revMask; /* Mask of ORDER BY terms that need reversing */
WhereCost nRowOut; /* Estimated number of output rows */
@@ -392,10 +392,10 @@ struct WhereInfo {
u8 okOnePass; /* Ok to use one-pass algorithm for UPDATE/DELETE */
u8 untestedTerms; /* Not all WHERE terms resolved by outer loop */
u8 eDistinct; /* One of the WHERE_DISTINCT_* values below */
+ u8 nLevel; /* Number of nested loop */
int iTop; /* The very beginning of the WHERE loop */
int iContinue; /* Jump here to continue with next record */
int iBreak; /* Jump here to break out of the loop */
- int nLevel; /* Number of nested loop */
int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */
WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */
WhereClause sWC; /* Decomposition of the WHERE clause */
@@ -3928,9 +3928,9 @@ static void whereLoopPrint(WhereLoop *p, SrcList *pTabList){
int nb = 1+(pTabList->nSrc+7)/8;
struct SrcList_item *pItem = pTabList->a + p->iTab;
Table *pTab = pItem->pTab;
- sqlite3DebugPrintf("%c %2d.%0*llx.%0*llx", p->cId,
+ sqlite3DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId,
p->iTab, nb, p->maskSelf, nb, p->prereq);
- sqlite3DebugPrintf(" %8s",
+ sqlite3DebugPrintf(" %12s",
pItem->zAlias ? pItem->zAlias : pTab->zName);
if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
if( p->u.btree.pIndex ){
@@ -3941,9 +3941,9 @@ static void whereLoopPrint(WhereLoop *p, SrcList *pTabList){
while( zName[i]!='_' ) i--;
zName += i;
}
- sqlite3DebugPrintf(".%-12s %2d", zName, p->u.btree.nEq);
+ sqlite3DebugPrintf(".%-16s %2d", zName, p->u.btree.nEq);
}else{
- sqlite3DebugPrintf("%16s","");
+ sqlite3DebugPrintf("%20s","");
}
}else{
char *z;
@@ -3953,10 +3953,10 @@ static void whereLoopPrint(WhereLoop *p, SrcList *pTabList){
}else{
z = sqlite3_mprintf("(%d,%x)", p->u.vtab.idxNum, p->u.vtab.omitMask);
}
- sqlite3DebugPrintf(" %-15s", z);
+ sqlite3DebugPrintf(" %-19s", z);
sqlite3_free(z);
}
- sqlite3DebugPrintf(" fg %05x N %d", p->wsFlags, p->nLTerm);
+ sqlite3DebugPrintf(" f %04x N %d", p->wsFlags, p->nLTerm);
sqlite3DebugPrintf(" cost %d,%d,%d\n", p->rSetup, p->rRun, p->nOut);
}
#endif
@@ -5370,12 +5370,13 @@ static int wherePathSolver(WhereInfo *pWInfo, WhereCost nRowEst){
pLevel->iFrom = pWLoop->iTab;
pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor;
}
- if( (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0
- && pWInfo->pDistinct
+ if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0
+ && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0
+ && pWInfo->eDistinct==WHERE_DISTINCT_NOOP
&& nRowEst
){
Bitmask notUsed;
- int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pDistinct, pFrom,
+ int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom,
WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], &notUsed);
if( rc==1 ) pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
}
@@ -5464,7 +5465,9 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){
pWInfo->a[0].iTabCur = iCur;
pWInfo->nRowOut = 1;
if( pWInfo->pOrderBy ) pWInfo->bOBSat = 1;
- if( pWInfo->pDistinct ) pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+ if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
+ pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+ }
#ifdef SQLITE_DEBUG
pLoop->cId = '0';
#endif
@@ -5554,10 +5557,10 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){
*/
WhereInfo *sqlite3WhereBegin(
Parse *pParse, /* The parser context */
- SrcList *pTabList, /* A list of all tables to be scanned */
+ 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 *pDistinct, /* The select-list for DISTINCT queries - 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 */
){
@@ -5569,15 +5572,23 @@ WhereInfo *sqlite3WhereBegin(
WhereLoopBuilder sWLB; /* The WhereLoop builder */
WhereMaskSet *pMaskSet; /* The expression mask set */
WhereLevel *pLevel; /* A single level in pWInfo->a[] */
+ WhereLoop *pLoop; /* Pointer to a single WhereLoop object */
int ii; /* Loop counter */
sqlite3 *db; /* Database connection */
int rc; /* Return code */
/* Variable initialization */
+ db = pParse->db;
memset(&sWLB, 0, sizeof(sWLB));
sWLB.pOrderBy = pOrderBy;
+ /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
+ ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
+ if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){
+ wctrlFlags &= ~WHERE_WANT_DISTINCT;
+ }
+
/* The number of tables in the FROM clause is limited by the number of
** bits in a Bitmask
*/
@@ -5601,7 +5612,6 @@ WhereInfo *sqlite3WhereBegin(
** field (type Bitmask) it must be aligned on an 8-byte boundary on
** some architectures. Hence the ROUND8() below.
*/
- db = pParse->db;
nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel));
pWInfo = sqlite3DbMallocZero(db, nByteWInfo + sizeof(WhereLoop));
if( db->mallocFailed ){
@@ -5613,7 +5623,7 @@ WhereInfo *sqlite3WhereBegin(
pWInfo->pParse = pParse;
pWInfo->pTabList = pTabList;
pWInfo->pOrderBy = pOrderBy;
- pWInfo->pDistinct = pDistinct;
+ pWInfo->pResultSet = pResultSet;
pWInfo->iBreak = sqlite3VdbeMakeLabel(v);
pWInfo->wctrlFlags = wctrlFlags;
pWInfo->savedNQueryLoop = pParse->nQueryLoop;
@@ -5626,10 +5636,6 @@ WhereInfo *sqlite3WhereBegin(
sWLB.pNew->cId = '*';
#endif
- /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
- ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
- if( OptimizationDisabled(db, SQLITE_DistinctOpt) ) pDistinct = 0;
-
/* Split the WHERE clause into separate subexpressions where each
** subexpression is separated by an AND operator.
*/
@@ -5650,7 +5656,9 @@ WhereInfo *sqlite3WhereBegin(
*/
if( nTabList==0 ){
if( pOrderBy ) pWInfo->bOBSat = 1;
- if( pDistinct ) pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+ if( wctrlFlags & WHERE_WANT_DISTINCT ){
+ pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+ }
}
/* Assign a bit from the bitmask to every term in the FROM clause.
@@ -5697,7 +5705,7 @@ WhereInfo *sqlite3WhereBegin(
** expressions, then we won't be able to satisfy it using indices, so
** go ahead and disable it now.
*/
- if( pOrderBy && pDistinct ){
+ if( pOrderBy && (wctrlFlags & WHERE_WANT_DISTINCT)!=0 ){
for(ii=0; ii<pOrderBy->nExpr; ii++){
Expr *pExpr = sqlite3ExprSkipCollate(pOrderBy->a[ii].pExpr);
if( pExpr->op!=TK_COLUMN ){
@@ -5709,17 +5717,14 @@ WhereInfo *sqlite3WhereBegin(
}
}
- /* Check if the DISTINCT qualifier, if there is one, is redundant.
- ** If it is, then set pDistinct to NULL and WhereInfo.eDistinct to
- ** WHERE_DISTINCT_UNIQUE to tell the caller to ignore the DISTINCT.
- */
- if( pDistinct ){
- if( isDistinctRedundant(pParse,pTabList,&pWInfo->sWC,pDistinct) ){
- pDistinct = 0;
+ if( wctrlFlags & WHERE_WANT_DISTINCT ){
+ if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
+ /* The DISTINCT marking is pointless. Ignore it. */
pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
}else if( pOrderBy==0 ){
+ /* Try to ORDER BY the result set to make distinct processing easier */
pWInfo->wctrlFlags |= WHERE_DISTINCTBY;
- pWInfo->pOrderBy = pDistinct;
+ pWInfo->pOrderBy = pResultSet;
}
}
@@ -5733,11 +5738,11 @@ WhereInfo *sqlite3WhereBegin(
#ifdef WHERETRACE_ENABLED
if( sqlite3WhereTrace ){
WhereLoop *p;
- int i = 0;
+ int i;
static char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
"ABCDEFGHIJKLMNOPQRSTUVWYXZ";
- for(p=pWInfo->pLoops; p; p=p->pNextLoop){
- p->cId = zLabel[(i++)%sizeof(zLabel)];
+ for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){
+ p->cId = zLabel[i%sizeof(zLabel)];
whereLoopPrint(p, pTabList);
}
}
@@ -5778,11 +5783,32 @@ WhereInfo *sqlite3WhereBegin(
}
}
sqlite3DebugPrintf("\n");
- for(ii=0; ii<nTabList; ii++){
+ for(ii=0; ii<pWInfo->nLevel; ii++){
whereLoopPrint(pWInfo->a[ii].pWLoop, pTabList);
}
}
#endif
+ /* Attempt to omit tables from the join that do not effect the result */
+ if( pWInfo->nLevel>=2
+ && pResultSet!=0
+ && OptimizationEnabled(db, SQLITE_OmitNoopJoin)
+ ){
+ Bitmask tabUsed = exprListTableUsage(pMaskSet, pResultSet);
+ if( pOrderBy ) tabUsed |= exprListTableUsage(pMaskSet, pOrderBy);
+ while( pWInfo->nLevel>=2 ){
+ pLoop = pWInfo->a[pWInfo->nLevel-1].pWLoop;
+ if( (pWInfo->pTabList->a[pLoop->iTab].jointype & JT_LEFT)==0 ) break;
+ if( (wctrlFlags & WHERE_WANT_DISTINCT)==0
+ && (pLoop->wsFlags & WHERE_ONEROW)==0
+ ){
+ break;
+ }
+ if( (tabUsed & pLoop->maskSelf)!=0 ) break;
+ WHERETRACE(0xffff, ("-> drop loop %c not used\n", pLoop->cId));
+ pWInfo->nLevel--;
+ nTabList--;
+ }
+ }
WHERETRACE(0xffff,("*** Optimizer Finished ***\n"));
pWInfo->pParse->nQueryLoop += pWInfo->nRowOut;
@@ -5951,7 +5977,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
/* Close all of the cursors that were opened by sqlite3WhereBegin.
*/
- assert( pWInfo->nLevel==1 || pWInfo->nLevel==pTabList->nSrc );
+ assert( pWInfo->nLevel<=pTabList->nSrc );
for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
Index *pIdx = 0;
struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-22 10:50:18 +0000