GROUP BY can only infer functional dependency from non-deferrable primary keys.

tglsfdc · tglsfdc · commit a756f5ce1409 · 2010-09-05T15:45:42.000Z
Peter's original patch had this right, but I dropped the check while revising
the code to search pg_constraint instead of pg_index.  Spotted by Dean Rasheed.
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.55 2010/08/07 02:44:06 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.56 2010/09/05 15:45:42 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -836,6 +836,9 @@ check_functional_grouping(Oid relid,
 		/* Only PK constraints are of interest for now, see comment above */
 		if (con->contype != CONSTRAINT_PRIMARY)
 			continue;
+		/* Constraint must be non-deferrable */
+		if (con->condeferrable)
+			continue;
 
 		/* Extract the conkey array, ie, attnums of PK's columns */
 		adatum = heap_getattr(tuple, Anum_pg_constraint_conkey,

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.55 2010/08/07 02:44:06 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.56 2010/09/05 15:45:42 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -836,6 +836,9 @@ check_functional_grouping(Oid relid,`
`836`	`836`	`/* Only PK constraints are of interest for now, see comment above */`
`837`	`837`	`if (con->contype != CONSTRAINT_PRIMARY)`
`838`	`838`	`continue;`
	`839`	`+ /* Constraint must be non-deferrable */`
	`840`	`+ if (con->condeferrable)`
	`841`	`+ continue;`
`839`	`842`
`840`	`843`	`/* Extract the conkey array, ie, attnums of PK's columns */`
`841`	`844`	`adatum = heap_getattr(tuple, Anum_pg_constraint_conkey,`