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Overview
Comment:Transitive equality constriants do not work on a RIGHT JOIN, since the right-hand side might be a non-matched row.
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SHA3-256: 0f96810b840dd6f209562635b21f55a7ed6210c01336fcfeb3b79e08a615a28d
User & Date: drh 2022-05-13 20:11:32
Context
2022-05-13
23:01
Change an unreachable branch into an assert(). (check-in: 778e57a5 user: drh tags: trunk)
20:11
Transitive equality constriants do not work on a RIGHT JOIN, since the right-hand side might be a non-matched row. (check-in: 0f96810b user: drh tags: trunk)
19:50
Walk back the optimization from check-in [cc458317bd77046c] that tries to reuse the same ephemeral cursor of a list subquery when that subquery is reused, as it does not work in cases where the list subquery is used both for lookups and for scans. (check-in: 12ee29d6 user: drh tags: trunk)
Changes
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Changes to src/wherecode.c.

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  for(pTerm=pWC->a, j=pWC->nBase; j>0; j--, pTerm++){
    Expr *pE, sEAlt;
    WhereTerm *pAlt;
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) continue;
    if( (pTerm->eOperator & WO_EQUIV)==0 ) continue;
    if( pTerm->leftCursor!=iCur ) continue;
    if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ) ) continue;
    pE = pTerm->pExpr;
#ifdef WHERETRACE_ENABLED /* 0x800 */
    if( sqlite3WhereTrace & 0x800 ){
      sqlite3DebugPrintf("Coding transitive constraint:\n");
      sqlite3WhereTermPrint(pTerm, pWC->nTerm-j);
    }
#endif








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  for(pTerm=pWC->a, j=pWC->nBase; j>0; j--, pTerm++){
    Expr *pE, sEAlt;
    WhereTerm *pAlt;
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) continue;
    if( (pTerm->eOperator & WO_EQUIV)==0 ) continue;
    if( pTerm->leftCursor!=iCur ) continue;
    if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ) continue;
    pE = pTerm->pExpr;
#ifdef WHERETRACE_ENABLED /* 0x800 */
    if( sqlite3WhereTrace & 0x800 ){
      sqlite3DebugPrintf("Coding transitive constraint:\n");
      sqlite3WhereTermPrint(pTerm, pWC->nTerm-j);
    }
#endif
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