Reconsider old decision to try to constant-fold default and constraint

expressions before they are stored.  This seems like not such a hot idea,
particularly now that the constant-folder will try to inline SQL functions.

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 3d671e92f3d422c1d286bb73f6dd548fe8b7f424..8d176c12cde6707326115f0e91d03c15cb3ab47e 100644 (file)
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.238 2002/12/16 18:39:22 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.239 2003/01/08 22:06:20 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1604,11 +1604,6 @@ AddRelationRawConstraints(Relation rel,
        if (contain_agg_clause(expr))
            elog(ERROR, "cannot use aggregate function in CHECK constraint expression");
 
-       /*
-        * Might as well try to reduce any constant expressions.
-        */
-       expr = eval_const_expressions(expr);
-
        /*
         * Constraints are evaluated with execQual, which expects an
         * implicit-AND list, so convert expression to implicit-AND form.
@@ -1733,7 +1728,7 @@ cookDefault(ParseState *pstate,
     * column's type.  We store the expression without coercion, however,
     * to avoid premature coercion in cases like
     *
-    * CREATE TABLE tbl (fld timestamp DEFAULT 'now'::text);
+    * CREATE TABLE tbl (fld timestamp DEFAULT 'now');
     *
     * NB: this should match the code in rewrite/rewriteHandler.c that will
     * actually do the coercion, to ensure we don't accept an unusable
@@ -1755,11 +1750,6 @@ cookDefault(ParseState *pstate,
                 format_type_be(type_id));
    }
 
-   /*
-    * Might as well try to reduce any constant expressions.
-    */
-   expr = eval_const_expressions(expr);
-
    return (expr);
 }
 

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3f9cad16ce4ce139560414de9bfc81372e585c44..84ea31885d67efb59de90bfd2197c79940257ff4 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.64 2002/12/30 19:45:17 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.65 2003/01/08 22:06:23 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2756,7 +2756,10 @@ AlterTableAddCheckConstraint(Relation rel, Constraint *constr)
        elog(ERROR, "cannot use aggregate function in CHECK constraint expression");
 
    /*
-    * Might as well try to reduce any constant expressions.
+    * Might as well try to reduce any constant expressions, so as to
+    * minimize overhead while testing the constraint at each row.
+    *
+    * Note that the stored form of the constraint will NOT be const-folded.
     */
    expr = eval_const_expressions(expr);
 

diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 7d4ff1f0b649368d49f71f79fbde5e9cb9b356b9..379e4bb9b45eee930b245fc097c17a92a730b8b6 100644 (file)
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/commands/typecmds.c,v 1.28 2003/01/08 21:40:39 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/commands/typecmds.c,v 1.29 2003/01/08 22:06:23 tgl Exp $
  *
  * DESCRIPTION
  *   The "DefineFoo" routines take the parse tree and pick out the
@@ -1623,11 +1623,6 @@ domainAddConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
    if (contain_agg_clause(expr))
        elog(ERROR, "cannot use aggregate function in CHECK constraint expression");
 
-   /*
-    * Might as well try to reduce any constant expressions.
-    */
-   expr = eval_const_expressions(expr);
-
    /*
     * Convert to string form for storage.
     */