diff options
Diffstat (limited to 'src/backend/parser/parse_expr.c')
| -rw-r--r-- | src/backend/parser/parse_expr.c | 119 |
1 files changed, 34 insertions, 85 deletions
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 234a15b6afb..2a48741b3a2 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.200 2006/12/21 16:05:14 petere Exp $ + * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.201 2006/12/23 00:43:11 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -2014,10 +2014,10 @@ make_row_comparison_op(ParseState *pstate, List *opname, RowCompareType rctype; List *opexprs; List *opnos; - List *opclasses; + List *opfamilies; ListCell *l, *r; - List **opclass_lists; + List **opfamily_lists; List **opstrat_lists; Bitmapset *strats; int nopers; @@ -2057,7 +2057,7 @@ make_row_comparison_op(ParseState *pstate, List *opname, /* * We don't use coerce_to_boolean here because we insist on the * operator yielding boolean directly, not via coercion. If it - * doesn't yield bool it won't be in any index opclasses... + * doesn't yield bool it won't be in any index opfamilies... */ if (cmp->opresulttype != BOOLOID) ereport(ERROR, @@ -2084,21 +2084,22 @@ make_row_comparison_op(ParseState *pstate, List *opname, /* * Now we must determine which row comparison semantics (= <> < <= > >=) - * apply to this set of operators. We look for btree opclasses containing + * apply to this set of operators. We look for btree opfamilies containing * the operators, and see which interpretations (strategy numbers) exist * for each operator. */ - opclass_lists = (List **) palloc(nopers * sizeof(List *)); + opfamily_lists = (List **) palloc(nopers * sizeof(List *)); opstrat_lists = (List **) palloc(nopers * sizeof(List *)); strats = NULL; i = 0; foreach(l, opexprs) { + Oid opno = ((OpExpr *) lfirst(l))->opno; Bitmapset *this_strats; ListCell *j; - get_op_btree_interpretation(((OpExpr *) lfirst(l))->opno, - &opclass_lists[i], &opstrat_lists[i]); + get_op_btree_interpretation(opno, + &opfamily_lists[i], &opstrat_lists[i]); /* * convert strategy number list to a Bitmapset to make the @@ -2116,68 +2117,23 @@ make_row_comparison_op(ParseState *pstate, List *opname, i++; } - switch (bms_membership(strats)) + /* + * If there are multiple common interpretations, we may use any one of + * them ... this coding arbitrarily picks the lowest btree strategy + * number. + */ + i = bms_first_member(strats); + if (i < 0) { - case BMS_EMPTY_SET: - /* No common interpretation, so fail */ - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("could not determine interpretation of row comparison operator %s", - strVal(llast(opname))), - errhint("Row comparison operators must be associated with btree operator classes."), - parser_errposition(pstate, location))); - rctype = 0; /* keep compiler quiet */ - break; - case BMS_SINGLETON: - /* Simple case: just one possible interpretation */ - rctype = bms_singleton_member(strats); - break; - case BMS_MULTIPLE: - default: /* keep compiler quiet */ - { - /* - * Prefer the interpretation with the most default opclasses. - */ - int best_defaults = 0; - bool multiple_best = false; - int this_rctype; - - rctype = 0; /* keep compiler quiet */ - while ((this_rctype = bms_first_member(strats)) >= 0) - { - int ndefaults = 0; - - for (i = 0; i < nopers; i++) - { - forboth(l, opclass_lists[i], r, opstrat_lists[i]) - { - Oid opclass = lfirst_oid(l); - int opstrat = lfirst_int(r); - - if (opstrat == this_rctype && - opclass_is_default(opclass)) - ndefaults++; - } - } - if (ndefaults > best_defaults) - { - best_defaults = ndefaults; - rctype = this_rctype; - multiple_best = false; - } - else if (ndefaults == best_defaults) - multiple_best = true; - } - if (best_defaults == 0 || multiple_best) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("could not determine interpretation of row comparison operator %s", - strVal(llast(opname))), - errdetail("There are multiple equally-plausible candidates."), - parser_errposition(pstate, location))); - break; - } + /* No common interpretation, so fail */ + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("could not determine interpretation of row comparison operator %s", + strVal(llast(opname))), + errhint("Row comparison operators must be associated with btree operator families."), + parser_errposition(pstate, location))); } + rctype = (RowCompareType) i; /* * For = and <> cases, we just combine the pairwise operators with AND or @@ -2193,34 +2149,27 @@ make_row_comparison_op(ParseState *pstate, List *opname, return (Node *) makeBoolExpr(OR_EXPR, opexprs); /* - * Otherwise we need to determine exactly which opclass to associate with + * Otherwise we need to choose exactly which opfamily to associate with * each operator. */ - opclasses = NIL; + opfamilies = NIL; for (i = 0; i < nopers; i++) { - Oid best_opclass = 0; - int ndefault = 0; - int nmatch = 0; + Oid opfamily = InvalidOid; - forboth(l, opclass_lists[i], r, opstrat_lists[i]) + forboth(l, opfamily_lists[i], r, opstrat_lists[i]) { - Oid opclass = lfirst_oid(l); int opstrat = lfirst_int(r); if (opstrat == rctype) { - if (ndefault == 0) - best_opclass = opclass; - if (opclass_is_default(opclass)) - ndefault++; - else - nmatch++; + opfamily = lfirst_oid(l); + break; } } - if (ndefault == 1 || (ndefault == 0 && nmatch == 1)) - opclasses = lappend_oid(opclasses, best_opclass); - else + if (OidIsValid(opfamily)) + opfamilies = lappend_oid(opfamilies, opfamily); + else /* should not happen */ ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("could not determine interpretation of row comparison operator %s", @@ -2250,7 +2199,7 @@ make_row_comparison_op(ParseState *pstate, List *opname, rcexpr = makeNode(RowCompareExpr); rcexpr->rctype = rctype; rcexpr->opnos = opnos; - rcexpr->opclasses = opclasses; + rcexpr->opfamilies = opfamilies; rcexpr->largs = largs; rcexpr->rargs = rargs; |