summaryrefslogtreecommitdiffstats
path: root/src/select.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/select.c')
-rw-r--r--src/select.c79
1 files changed, 54 insertions, 25 deletions
diff --git a/src/select.c b/src/select.c
index fdc7f5e..9278ea1 100644
--- a/src/select.c
+++ b/src/select.c
@@ -1673,9 +1673,16 @@ static void generateSortTail(
int addrExplain; /* Address of OP_Explain instruction */
#endif
- ExplainQueryPlan2(addrExplain, (pParse, 0,
- "USE TEMP B-TREE FOR %sORDER BY", pSort->nOBSat>0?"RIGHT PART OF ":"")
- );
+ nKey = pOrderBy->nExpr - pSort->nOBSat;
+ if( pSort->nOBSat==0 || nKey==1 ){
+ ExplainQueryPlan2(addrExplain, (pParse, 0,
+ "USE TEMP B-TREE FOR %sORDER BY", pSort->nOBSat?"LAST TERM OF ":""
+ ));
+ }else{
+ ExplainQueryPlan2(addrExplain, (pParse, 0,
+ "USE TEMP B-TREE FOR LAST %d TERMS OF ORDER BY", nKey
+ ));
+ }
sqlite3VdbeScanStatusRange(v, addrExplain,pSort->addrPush,pSort->addrPushEnd);
sqlite3VdbeScanStatusCounters(v, addrExplain, addrExplain, pSort->addrPush);
@@ -1713,7 +1720,6 @@ static void generateSortTail(
regRow = sqlite3GetTempRange(pParse, nColumn);
}
}
- nKey = pOrderBy->nExpr - pSort->nOBSat;
if( pSort->sortFlags & SORTFLAG_UseSorter ){
int regSortOut = ++pParse->nMem;
iSortTab = pParse->nTab++;
@@ -2318,8 +2324,7 @@ void sqlite3SubqueryColumnTypes(
NameContext sNC;
assert( pSelect!=0 );
- testcase( (pSelect->selFlags & SF_Resolved)==0 );
- assert( (pSelect->selFlags & SF_Resolved)!=0 || IN_RENAME_OBJECT );
+ assert( (pSelect->selFlags & SF_Resolved)!=0 );
assert( pTab->nCol==pSelect->pEList->nExpr || pParse->nErr>0 );
assert( aff==SQLITE_AFF_NONE || aff==SQLITE_AFF_BLOB );
if( db->mallocFailed || IN_RENAME_OBJECT ) return;
@@ -2330,17 +2335,22 @@ void sqlite3SubqueryColumnTypes(
for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
const char *zType;
i64 n;
+ int m = 0;
+ Select *pS2 = pSelect;
pTab->tabFlags |= (pCol->colFlags & COLFLAG_NOINSERT);
p = a[i].pExpr;
/* pCol->szEst = ... // Column size est for SELECT tables never used */
pCol->affinity = sqlite3ExprAffinity(p);
+ while( pCol->affinity<=SQLITE_AFF_NONE && pS2->pNext!=0 ){
+ m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
+ pS2 = pS2->pNext;
+ pCol->affinity = sqlite3ExprAffinity(pS2->pEList->a[i].pExpr);
+ }
if( pCol->affinity<=SQLITE_AFF_NONE ){
pCol->affinity = aff;
}
- if( pCol->affinity>=SQLITE_AFF_TEXT && pSelect->pNext ){
- int m = 0;
- Select *pS2;
- for(m=0, pS2=pSelect->pNext; pS2; pS2=pS2->pNext){
+ if( pCol->affinity>=SQLITE_AFF_TEXT && (pS2->pNext || pS2!=pSelect) ){
+ for(pS2=pS2->pNext; pS2; pS2=pS2->pNext){
m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
}
if( pCol->affinity==SQLITE_AFF_TEXT && (m&0x01)!=0 ){
@@ -2370,12 +2380,12 @@ void sqlite3SubqueryColumnTypes(
}
}
if( zType ){
- i64 m = sqlite3Strlen30(zType);
+ const i64 k = sqlite3Strlen30(zType);
n = sqlite3Strlen30(pCol->zCnName);
- pCol->zCnName = sqlite3DbReallocOrFree(db, pCol->zCnName, n+m+2);
+ pCol->zCnName = sqlite3DbReallocOrFree(db, pCol->zCnName, n+k+2);
pCol->colFlags &= ~(COLFLAG_HASTYPE|COLFLAG_HASCOLL);
if( pCol->zCnName ){
- memcpy(&pCol->zCnName[n+1], zType, m+1);
+ memcpy(&pCol->zCnName[n+1], zType, k+1);
pCol->colFlags |= COLFLAG_HASTYPE;
}
}
@@ -4772,7 +4782,7 @@ static void constInsert(
){
int i;
assert( pColumn->op==TK_COLUMN );
- assert( sqlite3ExprIsConstant(pValue) );
+ assert( sqlite3ExprIsConstant(pConst->pParse, pValue) );
if( ExprHasProperty(pColumn, EP_FixedCol) ) return;
if( sqlite3ExprAffinity(pValue)!=0 ) return;
@@ -4830,10 +4840,10 @@ static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
pLeft = pExpr->pLeft;
assert( pRight!=0 );
assert( pLeft!=0 );
- if( pRight->op==TK_COLUMN && sqlite3ExprIsConstant(pLeft) ){
+ if( pRight->op==TK_COLUMN && sqlite3ExprIsConstant(pConst->pParse, pLeft) ){
constInsert(pConst,pRight,pLeft,pExpr);
}
- if( pLeft->op==TK_COLUMN && sqlite3ExprIsConstant(pRight) ){
+ if( pLeft->op==TK_COLUMN && sqlite3ExprIsConstant(pConst->pParse, pRight) ){
constInsert(pConst,pLeft,pRight,pExpr);
}
}
@@ -5054,6 +5064,18 @@ static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){
** The hope is that the terms added to the inner query will make it more
** efficient.
**
+** NAME AMBIGUITY
+**
+** This optimization is called the "WHERE-clause push-down optimization".
+**
+** Do not confuse this optimization with another unrelated optimization
+** with a similar name: The "MySQL push-down optimization" causes WHERE
+** clause terms that can be evaluated using only the index and without
+** reference to the table are run first, so that if they are false,
+** unnecessary table seeks are avoided.
+**
+** RULES
+**
** Do not attempt this optimization if:
**
** (1) (** This restriction was removed on 2017-09-29. We used to
@@ -5119,10 +5141,10 @@ static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){
** (9c) There is a RIGHT JOIN (or FULL JOIN) in between the ON/USING
** clause and the subquery.
**
-** Without this restriction, the push-down optimization might move
-** the ON/USING filter expression from the left side of a RIGHT JOIN
-** over to the right side, which leads to incorrect answers. See
-** also restriction (6) in sqlite3ExprIsSingleTableConstraint().
+** Without this restriction, the WHERE-clause push-down optimization
+** might move the ON/USING filter expression from the left side of a
+** RIGHT JOIN over to the right side, which leads to incorrect answers.
+** See also restriction (6) in sqlite3ExprIsSingleTableConstraint().
**
** (10) The inner query is not the right-hand table of a RIGHT JOIN.
**
@@ -5254,7 +5276,7 @@ static int pushDownWhereTerms(
}
#endif
- if( sqlite3ExprIsSingleTableConstraint(pWhere, pSrcList, iSrc) ){
+ if( sqlite3ExprIsSingleTableConstraint(pWhere, pSrcList, iSrc, 1) ){
nChng++;
pSubq->selFlags |= SF_PushDown;
while( pSubq ){
@@ -6389,8 +6411,7 @@ static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
if( p->selFlags & SF_HasTypeInfo ) return;
p->selFlags |= SF_HasTypeInfo;
pParse = pWalker->pParse;
- testcase( (p->selFlags & SF_Resolved)==0 );
- assert( (p->selFlags & SF_Resolved) || IN_RENAME_OBJECT );
+ assert( (p->selFlags & SF_Resolved) );
pTabList = p->pSrc;
for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
Table *pTab = pFrom->pTab;
@@ -6460,6 +6481,8 @@ void sqlite3SelectPrep(
*/
static void printAggInfo(AggInfo *pAggInfo){
int ii;
+ sqlite3DebugPrintf("AggInfo %d/%p:\n",
+ pAggInfo->selId, pAggInfo);
for(ii=0; ii<pAggInfo->nColumn; ii++){
struct AggInfo_col *pCol = &pAggInfo->aCol[ii];
sqlite3DebugPrintf(
@@ -7650,7 +7673,7 @@ int sqlite3Select(
/* Generate code for all sub-queries in the FROM clause
*/
pSub = pItem->pSelect;
- if( pSub==0 ) continue;
+ if( pSub==0 || pItem->addrFillSub!=0 ) continue;
/* The code for a subquery should only be generated once. */
assert( pItem->addrFillSub==0 );
@@ -7681,7 +7704,7 @@ int sqlite3Select(
#endif
assert( pItem->pSelect && (pItem->pSelect->selFlags & SF_PushDown)!=0 );
}else{
- TREETRACE(0x4000,pParse,p,("Push-down not possible\n"));
+ TREETRACE(0x4000,pParse,p,("WHERE-lcause push-down not possible\n"));
}
/* Convert unused result columns of the subquery into simple NULL
@@ -8562,6 +8585,12 @@ select_end:
sqlite3ExprListDelete(db, pMinMaxOrderBy);
#ifdef SQLITE_DEBUG
if( pAggInfo && !db->mallocFailed ){
+#if TREETRACE_ENABLED
+ if( sqlite3TreeTrace & 0x20 ){
+ TREETRACE(0x20,pParse,p,("Finished with AggInfo\n"));
+ printAggInfo(pAggInfo);
+ }
+#endif
for(i=0; i<pAggInfo->nColumn; i++){
Expr *pExpr = pAggInfo->aCol[i].pCExpr;
if( pExpr==0 ) continue;
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-12 04:12:22 +0000