Remove a sanity check in the exclusion-constraint code that prevented users

from defining non-self-conflicting constraints.

Jeff Davis

Note: I (tgl) objected to removing this check in 9.0 on the grounds that it
was an important sanity check in new, poorly tested code.  However, it should
be all right to remove it for 9.1, since we'll get field testing from the
9.0 branch.

Author: tglsfdc

src/backend/executor/execUtils.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.173 2010/07/06 19:18:56 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.174 2010/07/16 00:45:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1309,16 +1309,12 @@ check_exclusion_constraint(Relation heap, Relation index, IndexInfo *indexInfo,
 	index_endscan(index_scan);
 
 	/*
-	 * We should have found our tuple in the index, unless we exited the loop
-	 * early because of conflict.  Complain if not.  If we ever implement '<>'
-	 * index opclasses, this check will fail and will have to be removed.
+	 * Ordinarily, at this point the search should have found the originally
+	 * inserted tuple, unless we exited the loop early because of conflict.
+	 * However, it is possible to define exclusion constraints for which
+	 * that wouldn't be true --- for instance, if the operator is <>.
+	 * So we no longer complain if found_self is still false.
 	 */
-	if (!found_self && !conflict)
-		ereport(ERROR,
-				(errcode(ERRCODE_INTERNAL_ERROR),
-				 errmsg("failed to re-find tuple within index \"%s\"",
-						RelationGetRelationName(index)),
-		errhint("This may be because of a non-immutable index expression.")));
 
 	econtext->ecxt_scantuple = save_scantuple;