diff options
Diffstat (limited to 'src/backend/optimizer/util/clauses.c')
| -rw-r--r-- | src/backend/optimizer/util/clauses.c | 73 |
1 files changed, 70 insertions, 3 deletions
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 2b6583c1dad..5266ff85d82 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.205 2005/12/28 01:30:00 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.206 2006/01/25 20:29:23 tgl Exp $ * * HISTORY * AUTHOR DATE MAJOR EVENT @@ -1167,12 +1167,12 @@ NumRelids(Node *clause) } /* - * CommuteClause: commute a binary operator clause + * CommuteOpExpr: commute a binary operator clause * * XXX the clause is destructively modified! */ void -CommuteClause(OpExpr *clause) +CommuteOpExpr(OpExpr *clause) { Oid opoid; Node *temp; @@ -1201,6 +1201,73 @@ CommuteClause(OpExpr *clause) } /* + * CommuteRowCompareExpr: commute a RowCompareExpr clause + * + * XXX the clause is destructively modified! + */ +void +CommuteRowCompareExpr(RowCompareExpr *clause) +{ + List *newops; + List *temp; + ListCell *l; + + /* Sanity checks: caller is at fault if these fail */ + if (!IsA(clause, RowCompareExpr)) + elog(ERROR, "expected a RowCompareExpr"); + + /* Build list of commuted operators */ + newops = NIL; + foreach(l, clause->opnos) + { + Oid opoid = lfirst_oid(l); + + opoid = get_commutator(opoid); + if (!OidIsValid(opoid)) + elog(ERROR, "could not find commutator for operator %u", + lfirst_oid(l)); + newops = lappend_oid(newops, opoid); + } + + /* + * modify the clause in-place! + */ + switch (clause->rctype) + { + case ROWCOMPARE_LT: + clause->rctype = ROWCOMPARE_GT; + break; + case ROWCOMPARE_LE: + clause->rctype = ROWCOMPARE_GE; + break; + case ROWCOMPARE_GE: + clause->rctype = ROWCOMPARE_LE; + break; + case ROWCOMPARE_GT: + clause->rctype = ROWCOMPARE_LT; + break; + default: + elog(ERROR, "unexpected RowCompare type: %d", + (int) clause->rctype); + break; + } + + clause->opnos = newops; + /* + * Note: we don't bother to update the opclasses list, but just set + * it to empty. This is OK since this routine is currently only used + * for index quals, and the index machinery won't use the opclass + * information. The original opclass list is NOT valid if we have + * commuted any cross-type comparisons, so don't leave it in place. + */ + clause->opclasses = NIL; /* XXX */ + + temp = clause->largs; + clause->largs = clause->rargs; + clause->rargs = temp; +} + +/* * strip_implicit_coercions: remove implicit coercions at top level of tree * * Note: there isn't any useful thing we can do with a RowExpr here, so |