Index: src/backend/commands/cluster.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/commands/cluster.c,v
retrieving revision 1.137
diff -c -c -r1.137 cluster.c
*** src/backend/commands/cluster.c	6 May 2005 17:24:53 -0000	1.137
--- src/backend/commands/cluster.c	10 May 2005 00:26:48 -0000
***************
*** 292,298 ****
  	OldHeap = heap_open(rvtc->tableOid, AccessExclusiveLock);
  
  	/* Check index is valid to cluster on */
! 	check_index_is_clusterable(OldHeap, rvtc->indexOid);
  
  	/* rebuild_relation does all the dirty work */
  	rebuild_relation(OldHeap, rvtc->indexOid);
--- 292,298 ----
  	OldHeap = heap_open(rvtc->tableOid, AccessExclusiveLock);
  
  	/* Check index is valid to cluster on */
! 	check_index_is_clusterable(OldHeap, rvtc->indexOid, recheck);
  
  	/* rebuild_relation does all the dirty work */
  	rebuild_relation(OldHeap, rvtc->indexOid);
***************
*** 309,315 ****
   * definition can't change under us.
   */
  void
! check_index_is_clusterable(Relation OldHeap, Oid indexOid)
  {
  	Relation	OldIndex;
  
--- 309,315 ----
   * definition can't change under us.
   */
  void
! check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck)
  {
  	Relation	OldIndex;
  
***************
*** 336,342 ****
  	if (!heap_attisnull(OldIndex->rd_indextuple, Anum_pg_index_indpred))
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 				 errmsg("cannot cluster on partial index")));
  	if (!OldIndex->rd_am->amindexnulls)
  	{
  		AttrNumber	colno;
--- 336,344 ----
  	if (!heap_attisnull(OldIndex->rd_indextuple, Anum_pg_index_indpred))
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 				 errmsg("cannot cluster on partial index \"%s\"",
! 						RelationGetRelationName(OldIndex))));
! 	
  	if (!OldIndex->rd_am->amindexnulls)
  	{
  		AttrNumber	colno;
***************
*** 354,374 ****
  			if (!OldHeap->rd_att->attrs[colno - 1]->attnotnull)
  				ereport(ERROR,
  						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 						 errmsg("cannot cluster when index access method does not handle null values"),
! 						 errhint("You may be able to work around this by marking column \"%s\" NOT NULL.",
! 				  NameStr(OldHeap->rd_att->attrs[colno - 1]->attname))));
  		}
  		else if (colno < 0)
  		{
  			/* system column --- okay, always non-null */
  		}
  		else
- 		{
  			/* index expression, lose... */
  			ereport(ERROR,
  					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 					 errmsg("cannot cluster on expressional index when index access method does not handle null values")));
! 		}
  	}
  
  	/*
--- 356,380 ----
  			if (!OldHeap->rd_att->attrs[colno - 1]->attnotnull)
  				ereport(ERROR,
  						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 						 errmsg("cannot cluster on index \"%s\" because access method\n"
! 								"does not handle null values",
! 							  RelationGetRelationName(OldIndex)),
! 						 errhint("You may be able to work around this by marking column \"%s\" NOT NULL%s",
! 							NameStr(OldHeap->rd_att->attrs[colno - 1]->attname),
! 							recheck ? ",\nor use ALTER TABLE ... SET WITHOUT CLUSTER to remove the cluster\n"
! 									"specification from the table." : ".")));
  		}
  		else if (colno < 0)
  		{
  			/* system column --- okay, always non-null */
  		}
  		else
  			/* index expression, lose... */
  			ereport(ERROR,
  					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 					 errmsg("cannot cluster on expressional index \"%s\" because its index access\n"
! 							"method does not handle null values",
! 						RelationGetRelationName(OldIndex))));
  	}
  
  	/*
Index: src/backend/commands/tablecmds.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v
retrieving revision 1.156
diff -c -c -r1.156 tablecmds.c
*** src/backend/commands/tablecmds.c	6 May 2005 17:24:53 -0000	1.156
--- src/backend/commands/tablecmds.c	10 May 2005 00:26:51 -0000
***************
*** 5464,5470 ****
  						indexName, RelationGetRelationName(rel))));
  
  	/* Check index is valid to cluster on */
! 	check_index_is_clusterable(rel, indexOid);
  
  	/* And do the work */
  	mark_index_clustered(rel, indexOid);
--- 5464,5470 ----
  						indexName, RelationGetRelationName(rel))));
  
  	/* Check index is valid to cluster on */
! 	check_index_is_clusterable(rel, indexOid, false);
  
  	/* And do the work */
  	mark_index_clustered(rel, indexOid);
Index: src/include/commands/cluster.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/commands/cluster.h,v
retrieving revision 1.27
diff -c -c -r1.27 cluster.h
*** src/include/commands/cluster.h	31 Dec 2004 22:03:28 -0000	1.27
--- src/include/commands/cluster.h	10 May 2005 00:26:53 -0000
***************
*** 19,25 ****
  
  extern void cluster(ClusterStmt *stmt);
  
! extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid);
  extern void mark_index_clustered(Relation rel, Oid indexOid);
  extern Oid make_new_heap(Oid OIDOldHeap, const char *NewName,
  			  Oid NewTableSpace);
--- 19,26 ----
  
  extern void cluster(ClusterStmt *stmt);
  
! extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
! 			  bool recheck);
  extern void mark_index_clustered(Relation rel, Oid indexOid);
  extern Oid make_new_heap(Oid OIDOldHeap, const char *NewName,
  			  Oid NewTableSpace);