diff options
| author | Tom Lane | 2016-08-17 00:33:01 +0000 |
|---|---|---|
| committer | Tom Lane | 2016-08-17 00:33:01 +0000 |
| commit | 0bb51aa96783e8a6c473c2b5e3725e23e95db834 (patch) | |
| tree | f4d4077257f5a4937fefafd0fe6f914f5e4027fd /src/backend/optimizer | |
| parent | 4bc4cfe3bd186b4a1d1b01279bfd0e6ab11268b2 (diff) | |
Improve parsetree representation of special functions such as CURRENT_DATE.
We implement a dozen or so parameterless functions that the SQL standard
defines special syntax for. Up to now, that was done by converting them
into more or less ad-hoc constructs such as "'now'::text::date". That's
messy for multiple reasons: it exposes what should be implementation
details to users, and performance is worse than it needs to be in several
cases. To improve matters, invent a new expression node type
SQLValueFunction that can represent any of these parameterless functions.
Bump catversion because this changes stored parsetrees for rules.
Discussion: <30058.1463091294@sss.pgh.pa.us>
Diffstat (limited to 'src/backend/optimizer')
| -rw-r--r-- | src/backend/optimizer/util/clauses.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 4e23898ff9..a40ad40606 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -962,6 +962,12 @@ contain_mutable_functions_walker(Node *node, void *context) context)) return true; + if (IsA(node, SQLValueFunction)) + { + /* all variants of SQLValueFunction are stable */ + return true; + } + /* * It should be safe to treat MinMaxExpr as immutable, because it will * depend on a non-cross-type btree comparison function, and those should @@ -1031,7 +1037,8 @@ contain_volatile_functions_walker(Node *node, void *context) /* * See notes in contain_mutable_functions_walker about why we treat - * MinMaxExpr, XmlExpr, and CoerceToDomain as immutable. + * MinMaxExpr, XmlExpr, and CoerceToDomain as immutable, while + * SQLValueFunction is stable. Hence, none of them are of interest here. */ /* Recurse to check arguments */ @@ -1076,7 +1083,8 @@ contain_volatile_functions_not_nextval_walker(Node *node, void *context) /* * See notes in contain_mutable_functions_walker about why we treat - * MinMaxExpr, XmlExpr, and CoerceToDomain as immutable. + * MinMaxExpr, XmlExpr, and CoerceToDomain as immutable, while + * SQLValueFunction is stable. Hence, none of them are of interest here. */ /* Recurse to check arguments */ @@ -1143,7 +1151,8 @@ has_parallel_hazard_walker(Node *node, has_parallel_hazard_arg *context) * (Note: in principle that's wrong because a domain constraint could * contain a parallel-unsafe function; but useful constraints probably * never would have such, and assuming they do would cripple use of - * parallel query in the presence of domain types.) + * parallel query in the presence of domain types.) SQLValueFunction + * should be safe in all cases. */ if (IsA(node, CoerceToDomain)) { @@ -1458,6 +1467,7 @@ contain_leaked_vars_walker(Node *node, void *context) case T_CaseTestExpr: case T_RowExpr: case T_MinMaxExpr: + case T_SQLValueFunction: case T_NullTest: case T_BooleanTest: case T_List: |