Index: src/backend/catalog/pg_enum.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/catalog/pg_enum.c,v
retrieving revision 1.11
diff -c -c -r1.11 pg_enum.c
*** src/backend/catalog/pg_enum.c	24 Dec 2009 22:17:58 -0000	1.11
--- src/backend/catalog/pg_enum.c	24 Dec 2009 22:29:17 -0000
***************
*** 25,30 ****
--- 25,32 ----
  
  static int	oid_cmp(const void *p1, const void *p2);
  
+ Oid binary_upgrade_next_pg_enum_oid = InvalidOid;
+ 
  
  /*
   * EnumValuesCreate
***************
*** 58,82 ****
  	tupDesc = pg_enum->rd_att;
  
  	/*
! 	 * Allocate oids.  While this method does not absolutely guarantee that we
! 	 * generate no duplicate oids (since we haven't entered each oid into the
! 	 * table before allocating the next), trouble could only occur if the oid
! 	 * counter wraps all the way around before we finish. Which seems
! 	 * unlikely.
  	 */
  	oids = (Oid *) palloc(num_elems * sizeof(Oid));
! 	for (elemno = 0; elemno < num_elems; elemno++)
  	{
  		/*
! 		 *	The pg_enum.oid is stored in user tables.  This oid must be
! 		 *	preserved by binary upgrades.
  		 */
! 		oids[elemno] = GetNewOid(pg_enum);
  	}
  
- 	/* sort them, just in case counter wrapped from high to low */
- 	qsort(oids, num_elems, sizeof(Oid), oid_cmp);
- 
  	/* and make the entries */
  	memset(nulls, false, sizeof(nulls));
  
--- 60,94 ----
  	tupDesc = pg_enum->rd_att;
  
  	/*
! 	 *	Allocate oids
  	 */
  	oids = (Oid *) palloc(num_elems * sizeof(Oid));
! 	if (num_elems == 1 && OidIsValid(binary_upgrade_next_pg_enum_oid))
! 	{
! 			oids[0] = binary_upgrade_next_pg_enum_oid;
! 			binary_upgrade_next_pg_enum_oid = InvalidOid;
! 	}	
! 	else
  	{
  		/*
! 		 * While this method does not absolutely guarantee that we generate
! 		 * no duplicate oids (since we haven't entered each oid into the
! 		 * table before allocating the next), trouble could only occur if
! 		 * the oid counter wraps all the way around before we finish. Which
! 		 * seems unlikely.
  		 */
! 		for (elemno = 0; elemno < num_elems; elemno++)
! 		{
! 			/*
! 			 *	The pg_enum.oid is stored in user tables.  This oid must be
! 			 *	preserved by binary upgrades.
! 			 */
! 			oids[elemno] = GetNewOid(pg_enum);
! 		}
! 		/* sort them, just in case counter wrapped from high to low */
! 		qsort(oids, num_elems, sizeof(Oid), oid_cmp);
  	}
  
  	/* and make the entries */
  	memset(nulls, false, sizeof(nulls));