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Allow the "a=?1 OR a=?2" to "a IN (?1,?2)" transformation to work on virtual

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tables again.  This was formerly restricted because virtual tables could not
optimize IN terms.  (See check-in [fad88e71cf195e].)  But IN terms are now
used by virtual tables (as of check-in [3d65c70343]) so the restriction can
now be removed.

FossilOrigin-Name: a917c1f09254b54e03e31b119cc49c551269d82e
This commit is contained in:
drh
2013-02-08 16:04:19 +00:00
parent 1b8fc65b92
commit c3e552ff5c
3 changed files with 9 additions and 25 deletions
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17
src/where.c
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@@ -140,7 +140,6 @@ struct WhereTerm {
struct WhereClause {
Parse *pParse; /* The parser context */
WhereMaskSet *pMaskSet; /* Mapping of table cursor numbers to bitmasks */
Bitmask vmask; /* Bitmask identifying virtual table cursors */
WhereClause *pOuter; /* Outer conjunction */
u8 op; /* Split operator. TK_AND or TK_OR */
u16 wctrlFlags; /* Might include WHERE_AND_ONLY */
@@ -317,7 +316,6 @@ static void whereClauseInit(
pWC->nTerm = 0;
pWC->nSlot = ArraySize(pWC->aStatic);
pWC->a = pWC->aStatic;
pWC->vmask = 0;
pWC->wctrlFlags = wctrlFlags;
}
@@ -917,7 +915,7 @@ static void transferJoinMarkings(Expr *pDerived, Expr *pBase){
**
** CASE 1:
**
** If all subterms are of the form T.C=expr for some single column of C
** If all subterms are of the form T.C=expr for some single column of C and
** a single table T (as shown in example B above) then create a new virtual
** term that is an equivalent IN expression. In other words, if the term
** being analyzed is:
@@ -1005,7 +1003,7 @@ static void exprAnalyzeOrTerm(
** Compute the set of tables that might satisfy cases 1 or 2.
*/
indexable = ~(Bitmask)0;
chngToIN = ~(pWC->vmask);
chngToIN = ~(Bitmask)0;
for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
WhereAndInfo *pAndInfo;
@@ -5062,24 +5060,13 @@ WhereInfo *sqlite3WhereBegin(
** bitmask for all tables to the left of the join. Knowing the bitmask
** for all tables to the left of a left join is important. Ticket #3015.
**
** Configure the WhereClause.vmask variable so that bits that correspond
** to virtual table cursors are set. This is used to selectively disable
** the OR-to-IN transformation in exprAnalyzeOrTerm(). It is not helpful
** with virtual tables.
**
** Note that bitmasks are created for all pTabList->nSrc tables in
** pTabList, not just the first nTabList tables. nTabList is normally
** equal to pTabList->nSrc but might be shortened to 1 if the
** WHERE_ONETABLE_ONLY flag is set.
*/
assert( sWBI.pWC->vmask==0 && pMaskSet->n==0 );
for(ii=0; ii<pTabList->nSrc; ii++){
createMask(pMaskSet, pTabList->a[ii].iCursor);
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( ALWAYS(pTabList->a[ii].pTab) && IsVirtual(pTabList->a[ii].pTab) ){
sWBI.pWC->vmask |= ((Bitmask)1 << ii);
}
#endif
}
#ifndef NDEBUG
{