Remove overspecification of precision of CURRENT_TIMESTAMP, LOCALTIMESTAMP,

CURRENT_TIME, and LOCALTIME: now they just produce "timestamptz" not
"timestamptz(6)", etc.  This makes the behavior more consistent with our
choice to not assign a specific default precision to column datatypes.
It should also save a few cycles at runtime due to not having to invoke
the round-to-given-precision functions.
I also took the opportunity to translate CURRENT_TIMESTAMP into "now()"
instead of an invocation of the timestamptz input converter --- this should
save a few cycles too.

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 2603a652922a9f2208f47536c792ab84adb7987f..4ad61ab409a3c068c68c52c08dfaa50b8197d1f5 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.496 2005/06/22 21:14:29 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.497 2005/06/24 14:28:06 tgl Exp $
  *
  * HISTORY
  *       AUTHOR                        DATE                    MAJOR EVENT
@@ -6002,14 +6002,6 @@ ConstDatetime:
                                         * - thomas 2001-09-06
                                         */
                                        $$->timezone = $2;
-                                       /* SQL99 specified a default precision of six
-                                        * for schema definitions. But for timestamp
-                                        * literals we don't want to throw away precision
-                                        * so leave this as unspecified for now.
-                                        * Later, we may want a different production
-                                        * for schemas. - thomas 2001-12-07
-                                        */
-                                       $$->typmod = -1;
                                }
                        | TIME '(' Iconst ')' opt_timezone
                                {
@@ -6039,11 +6031,6 @@ ConstDatetime:
                                                $$ = SystemTypeName("timetz");
                                        else
                                                $$ = SystemTypeName("time");
-                                       /* SQL99 specified a default precision of zero.
-                                        * See comments for timestamp above on why we will
-                                        * leave this unspecified for now. - thomas 2001-12-07
-                                        */
-                                       $$->typmod = -1;
                                }
                ;
 
@@ -6715,7 +6702,9 @@ func_expr:        func_name '(' ')'
                                         *
                                         * This could be simplified if we had a way to generate
                                         * an expression tree representing runtime application
-                                        * of type-input conversion functions...
+                                        * of type-input conversion functions.  (As of PG 7.3
+                                        * that is actually possible, but not clear that we want
+                                        * to rely on it.)
                                         */
                                        A_Const *s = makeNode(A_Const);
                                        TypeName *d;
@@ -6742,12 +6731,6 @@ func_expr:       func_name '(' ')'
                                        s->typename = SystemTypeName("text");
 
                                        d = SystemTypeName("timetz");
-                                       /* SQL99 mandates a default precision of zero for TIME
-                                        * fields in schemas. However, for CURRENT_TIME
-                                        * let's preserve the microsecond precision we
-                                        * might see from the system clock. - thomas 2001-12-07
-                                        */
-                                       d->typmod = 6;
 
                                        $$ = (Node *)makeTypeCast((Node *)s, d);
                                }
@@ -6784,25 +6767,15 @@ func_expr:      func_name '(' ')'
                        | CURRENT_TIMESTAMP
                                {
                                        /*
-                                        * Translate as "'now'::text::timestamptz".
-                                        * See comments for CURRENT_DATE.
-                                        */
-                                       A_Const *s = makeNode(A_Const);
-                                       TypeName *d;
-
-                                       s->val.type = T_String;
-                                       s->val.val.str = "now";
-                                       s->typename = SystemTypeName("text");
-
-                                       d = SystemTypeName("timestamptz");
-                                       /* SQL99 mandates a default precision of 6 for timestamp.
-                                        * Also, that is about as precise as we will get since
-                                        * we are using a microsecond time interface.
-                                        * - thomas 2001-12-07
+                                        * Translate as "now()", since we have a function that
+                                        * does exactly what is needed.
                                         */
-                                       d->typmod = 6;
-
-                                       $$ = (Node *)makeTypeCast((Node *)s, d);
+                                       FuncCall *n = makeNode(FuncCall);
+                                       n->funcname = SystemFuncName("now");
+                                       n->args = NIL;
+                                       n->agg_star = FALSE;
+                                       n->agg_distinct = FALSE;
+                                       $$ = (Node *)n;
                                }
                        | CURRENT_TIMESTAMP '(' Iconst ')'
                                {
@@ -6849,12 +6822,6 @@ func_expr:       func_name '(' ')'
                                        s->typename = SystemTypeName("text");
 
                                        d = SystemTypeName("time");
-                                       /* SQL99 mandates a default precision of zero for TIME
-                                        * fields in schemas. However, for LOCALTIME
-                                        * let's preserve the microsecond precision we
-                                        * might see from the system clock. - thomas 2001-12-07
-                                        */
-                                       d->typmod = 6;
 
                                        $$ = (Node *)makeTypeCast((Node *)s, d);
                                }
@@ -6902,12 +6869,6 @@ func_expr:       func_name '(' ')'
                                        s->typename = SystemTypeName("text");
 
                                        d = SystemTypeName("timestamp");
-                                       /* SQL99 mandates a default precision of 6 for timestamp.
-                                        * Also, that is about as precise as we will get since
-                                        * we are using a microsecond time interface.
-                                        * - thomas 2001-12-07
-                                        */
-                                       d->typmod = 6;
 
                                        $$ = (Node *)makeTypeCast((Node *)s, d);
                                }