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Preliminary code to support RIGHT JOIN. Everything seems to work, except that

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the code to compute the unmatched rows for the RIGHT JOIN has not yet been
added, so the result of a RIGHT JOIN is currently the same as an INNER JOIN.

FossilOrigin-Name: 415abd6731b8e8a605adabfa6066c8a852a8531c300df41325d5f7e75cae5a70
This commit is contained in:
drh
2022-04-08 19:20:12 +00:00
parent 7d0ae00361
commit a76ac88af8
12 changed files with 103 additions and 90 deletions
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79
src/where.c
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@@ -732,13 +732,13 @@ static int termCanDriveIndex(
char aff;
if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) return 0;
if( (pSrc->fg.jointype & JT_LEFT)
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ))!=0
&& !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
&& (pTerm->eOperator & WO_IS)
){
/* Cannot use an IS term from the WHERE clause as an index driver for
** the RHS of a LEFT JOIN. Such a term can only be used if it is from
** the ON clause. */
** the RHS of a LEFT JOIN or for the LHS of a RIGHT JOIN. Such a term
** can only be used if it is from the ON clause. */
return 0;
}
if( (pTerm->prereqRight & notReady)!=0 ) return 0;
@@ -808,7 +808,8 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
** WHERE clause (or the ON clause of a LEFT join) that constrain which
** rows of the target table (pSrc) that can be used. */
if( (pTerm->wtFlags & TERM_VIRTUAL)==0
&& ((pSrc->fg.jointype&JT_LEFT)==0 || ExprHasProperty(pExpr,EP_FromJoin))
&& ((pSrc->fg.jointype&(JT_LEFT|JT_LTORJ))==0
|| ExprHasProperty(pExpr,EP_FromJoin))
&& sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor)
){
pPartial = sqlite3ExprAnd(pParse, pPartial,
@@ -1081,7 +1082,7 @@ static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
const SrcItem *pTabItem;
pLevel = &pWInfo->a[iLevel];
pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
if( pTabItem->fg.jointype & JT_LEFT ) continue;
if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ) ) continue;
pLoop = pLevel->pWLoop;
if( NEVER(pLoop==0) ) continue;
if( pLoop->prereq & notReady ) continue;
@@ -1154,9 +1155,10 @@ static sqlite3_index_info *allocateIndexInfo(
assert( pTerm->u.x.leftColumn<pTab->nCol );
/* tag-20191211-002: WHERE-clause constraints are not useful to the
** right-hand table of a LEFT JOIN. See tag-20191211-001 for the
** right-hand table of a LEFT JOIN nor to the left-hand table of a
** RIGHT JOIN. See tag-20191211-001 for the
** equivalent restriction for ordinary tables. */
if( (pSrc->fg.jointype & JT_LEFT)!=0
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ))!=0
&& !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
){
continue;
@@ -2600,10 +2602,11 @@ static void whereLoopOutputAdjust(
**
** 2022-03-24: Self-culling only applies if either the extra terms
** are straight comparison operators that are non-true with NULL
** operand, or if the loop is not a LEFT JOIN.
** operand, or if the loop is not an OUTER JOIN.
*/
if( (pTerm->eOperator & 0x3f)!=0
|| (pWC->pWInfo->pTabList->a[pLoop->iTab].fg.jointype & JT_LEFT)==0
|| (pWC->pWInfo->pTabList->a[pLoop->iTab].fg.jointype
& (JT_LEFT|JT_LTORJ))==0
){
pLoop->wsFlags |= WHERE_SELFCULL;
}
@@ -2810,9 +2813,10 @@ static int whereLoopAddBtreeIndex(
if( pTerm->wtFlags & TERM_LIKEOPT && pTerm->eOperator==WO_LT ) continue;
/* tag-20191211-001: Do not allow constraints from the WHERE clause to
** be used by the right table of a LEFT JOIN. Only constraints in the
** be used by the right table of a LEFT JOIN nor by the left table of a
** RIGHT JOIN. Only constraints in the
** ON clause are allowed. See tag-20191211-002 for the vtab equivalent. */
if( (pSrc->fg.jointype & JT_LEFT)!=0
if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ))!=0
&& !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
){
continue;
@@ -4114,9 +4118,9 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
pNew->iTab = iTab;
pBuilder->iPlanLimit += SQLITE_QUERY_PLANNER_LIMIT_INCR;
pNew->maskSelf = sqlite3WhereGetMask(&pWInfo->sMaskSet, pItem->iCursor);
if( (pItem->fg.jointype & (JT_LEFT|JT_CROSS))!=0 ){
if( (pItem->fg.jointype & (JT_OUTER|JT_CROSS))!=0 ){
/* This condition is true when pItem is the FROM clause term on the
** right-hand-side of a LEFT or CROSS JOIN. */
** right-hand-side of a OUTER or CROSS JOIN. */
mPrereq = mPrior;
}else{
mPrereq = 0;
@@ -4125,7 +4129,7 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
if( IsVirtual(pItem->pTab) ){
SrcItem *p;
for(p=&pItem[1]; p<pEnd; p++){
if( mUnusable || (p->fg.jointype & (JT_LEFT|JT_CROSS)) ){
if( mUnusable || (p->fg.jointype & (JT_OUTER|JT_CROSS)) ){
mUnusable |= sqlite3WhereGetMask(&pWInfo->sMaskSet, p->iCursor);
}
}
@@ -5844,6 +5848,10 @@ WhereInfo *sqlite3WhereBegin(
}
}
if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
if( pTabItem->fg.jointype & JT_RIGHT ){
VdbeModuleComment((v, "TO-DO: Setup for the RIGHT JOIN of %s",
pTab->zName));
}
}
pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
if( db->mallocFailed ) goto whereBeginError;
@@ -6091,11 +6099,6 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
pWInfo->pTabList->a[pLevel->iFrom].pTab->zName));
}
/* The "break" point is here, just past the end of the outer loop.
** Set it.
*/
sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
assert( pWInfo->nLevel<=pTabList->nSrc );
for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
int k, last;
@@ -6106,6 +6109,16 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
assert( pTab!=0 );
pLoop = pLevel->pWLoop;
/* Do RIGHT JOIN processing. Generate code that will output the
** unmatched rows of the right operand of the RIGHT JOIN with
** all of the columns of the left operand set to NULL.
*/
if( pTabItem->fg.jointype & JT_RIGHT ){
VdbeModuleComment((v, "TO-DO: RIGHT JOIN post-processing for %s",
pTab->zName));
}
/* For a co-routine, change all OP_Column references to the table of
** the co-routine into OP_Copy of result contained in a register.
** OP_Rowid becomes OP_Null.
@@ -6117,29 +6130,6 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
continue;
}
#ifdef SQLITE_ENABLE_EARLY_CURSOR_CLOSE
/* Close all of the cursors that were opened by sqlite3WhereBegin.
** Except, do not close cursors that will be reused by the OR optimization
** (WHERE_OR_SUBCLAUSE). And do not close the OP_OpenWrite cursors
** created for the ONEPASS optimization.
*/
if( (pTab->tabFlags & TF_Ephemeral)==0
&& !IsView(pTab)
&& (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)==0
){
int ws = pLoop->wsFlags;
if( pWInfo->eOnePass==ONEPASS_OFF && (ws & WHERE_IDX_ONLY)==0 ){
sqlite3VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
}
if( (ws & WHERE_INDEXED)!=0
&& (ws & (WHERE_IPK|WHERE_AUTO_INDEX))==0
&& pLevel->iIdxCur!=pWInfo->aiCurOnePass[1]
){
sqlite3VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
}
}
#endif
/* If this scan uses an index, make VDBE code substitutions to read data
** from the index instead of from the table where possible. In some cases
** this optimization prevents the table from ever being read, which can
@@ -6240,6 +6230,11 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
}
}
/* The "break" point is here, just past the end of the outer loop.
** Set it.
*/
sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
/* Final cleanup
*/
if( pWInfo->pExprMods ) whereUndoExprMods(pWInfo);