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Tweak planner so that index expressions and predicates are matched to

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queries without regard to whether coercions are stated explicitly or
implicitly.  Per suggestion from Stephan Szabo.
This commit is contained in:
Tom Lane
2004-03-14 23:41:27 +00:00
parent e1d08faf04
commit 04226b6404
5 changed files with 58 additions and 10 deletions
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38
src/backend/optimizer/util/clauses.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.163 2004/01/28 00:05:04 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.164 2004/03/14 23:41:27 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -60,6 +60,7 @@ static bool contain_subplans_walker(Node *node, void *context);
static bool contain_mutable_functions_walker(Node *node, void *context);
static bool contain_volatile_functions_walker(Node *node, void *context);
static bool contain_nonstrict_functions_walker(Node *node, void *context);
static bool set_coercionform_dontcare_walker(Node *node, void *context);
static Node *eval_const_expressions_mutator(Node *node, List *active_fns);
static List *simplify_or_arguments(List *args,
bool *haveNull, bool *forceTrue);
@@ -1002,6 +1003,39 @@ CommuteClause(OpExpr *clause)
lsecond(clause->args) = temp;
}
/*
* set_coercionform_dontcare: set all CoercionForm fields to COERCE_DONTCARE
*
* This is used to make index expressions and index predicates more easily
* comparable to clauses of queries. CoercionForm is not semantically
* significant (for cases where it does matter, the significant info is
* coded into the coercion function arguments) so we can ignore it during
* comparisons. Thus, for example, an index on "foo::int4" can match an
* implicit coercion to int4.
*
* Caution: the passed expression tree is modified in-place.
*/
void
set_coercionform_dontcare(Node *node)
{
(void) set_coercionform_dontcare_walker(node, NULL);
}
static bool
set_coercionform_dontcare_walker(Node *node, void *context)
{
if (node == NULL)
return false;
if (IsA(node, FuncExpr))
((FuncExpr *) node)->funcformat = COERCE_DONTCARE;
if (IsA(node, RelabelType))
((RelabelType *) node)->relabelformat = COERCE_DONTCARE;
if (IsA(node, CoerceToDomain))
((CoerceToDomain *) node)->coercionformat = COERCE_DONTCARE;
return expression_tree_walker(node, set_coercionform_dontcare_walker,
context);
}
/*--------------------
* eval_const_expressions
@@ -1766,7 +1800,7 @@ evaluate_function(Oid funcid, Oid result_type, List *args,
newexpr->funcid = funcid;
newexpr->funcresulttype = result_type;
newexpr->funcretset = false;
newexpr->funcformat = COERCE_EXPLICIT_CALL; /* doesn't matter */
newexpr->funcformat = COERCE_DONTCARE; /* doesn't matter */
newexpr->args = args;
return evaluate_expr((Expr *) newexpr, result_type);