Index: vacuum.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/commands/vacuum.c,v
retrieving revision 1.363
diff -c -r1.363 vacuum.c
*** vacuum.c	3 Jan 2008 21:23:15 -0000	1.363
--- vacuum.c	10 Feb 2008 21:07:25 -0000
***************
*** 1659,1670 ****
  		free_space += vacpage->free;
  
  		/*
! 		 * Add the page to fraged_pages if it has a useful amount of free
! 		 * space.  "Useful" means enough for a minimal-sized tuple. But we
! 		 * don't know that accurately near the start of the relation, so add
! 		 * pages unconditionally if they have >= BLCKSZ/10 free space.
  		 */
! 		do_frag = (vacpage->free >= min_tlen || vacpage->free >= BLCKSZ / 10);
  
  		if (do_reap || do_frag)
  		{
--- 1659,1676 ----
  		free_space += vacpage->free;
  
  		/*
! 		 * Add the page to vacuum_pages if it requires reaping, and add it to
! 		 * fraged_pages if it has a useful amount of free space.  "Useful"
! 		 * means enough for a minimal-sized tuple.  But we don't know that
! 		 * accurately near the start of the relation, so add pages
! 		 * unconditionally if they have >= BLCKSZ/10 free space.  Also
! 		 * forcibly add pages with no live tuples, to avoid confusing the
! 		 * empty_end_pages logic.  (In the presence of unreasonably small
! 		 * fillfactor, it seems possible that such pages might not pass
! 		 * the free-space test, but they had better be in the list anyway.)
  		 */
! 		do_frag = (vacpage->free >= min_tlen || vacpage->free >= BLCKSZ / 10 ||
! 				   notup);
  
  		if (do_reap || do_frag)
  		{
***************
*** 1679,1684 ****
--- 1685,1691 ----
  		/*
  		 * Include the page in empty_end_pages if it will be empty after
  		 * vacuuming; this is to keep us from using it as a move destination.
+ 		 * Note that such pages are guaranteed to be in fraged_pages.
  		 */
  		if (notup)
  		{
***************
*** 3725,3731 ****
  static Size
  PageGetFreeSpaceWithFillFactor(Relation relation, Page page)
  {
! 	Size		freespace = PageGetHeapFreeSpace(page);
  	Size		targetfree;
  
  	targetfree = RelationGetTargetPageFreeSpace(relation,
--- 3732,3750 ----
  static Size
  PageGetFreeSpaceWithFillFactor(Relation relation, Page page)
  {
! 	/*
! 	 * It is correct to use PageGetExactFreeSpace() here, *not*
! 	 * PageGetHeapFreeSpace().  This is because (a) we do our own, exact
! 	 * accounting for whether line pointers must be added, and (b) we will
! 	 * recycle any LP_DEAD line pointers before starting to add rows to a
! 	 * page, but that may not have happened yet at the time this function is
! 	 * applied to a page, which means PageGetHeapFreeSpace()'s protection
! 	 * against too many line pointers on a page could fire incorrectly.  We do
! 	 * not need that protection here: since VACUUM FULL always recycles all
! 	 * dead line pointers first, it'd be physically impossible to insert more
! 	 * than MaxHeapTuplesPerPage tuples anyway.
! 	 */
! 	Size		freespace = PageGetExactFreeSpace(page);
  	Size		targetfree;
  
  	targetfree = RelationGetTargetPageFreeSpace(relation,