diff -Ncr ../base/src/backend/optimizer/path/costsize.c src/backend/optimizer/path/costsize.c
*** ../base/src/backend/optimizer/path/costsize.c	Tue Jun  1 05:02:52 2004
--- src/backend/optimizer/path/costsize.c	Tue Jun  8 08:34:27 2004
***************
*** 189,199 ****
   * for now by assuming we are given an effective_cache_size parameter.
   *
   * Given a guesstimated cache size, we estimate the actual I/O cost per page
!  * with the entirely ad-hoc equations:
   *	if relpages >= effective_cache_size:
!  *		random_page_cost * (1 - (effective_cache_size/relpages)/2)
   *	if relpages < effective_cache_size:
!  *		1 + (random_page_cost/2-1) * (relpages/effective_cache_size) ** 2
   * These give the right asymptotic behavior (=> 1.0 as relpages becomes
   * small, => random_page_cost as it becomes large) and meet in the middle
   * with the estimate that the cache is about 50% effective for a relation
--- 189,200 ----
   * for now by assuming we are given an effective_cache_size parameter.
   *
   * Given a guesstimated cache size, we estimate the actual I/O cost per page
!  * with the entirely ad-hoc equations (writing rpc for random_page_cost and
!  * relsize for relpages/effective_cache_size):
   *	if relpages >= effective_cache_size:
!  *		rpc - (rpc-1)/2 * 1/relsize
   *	if relpages < effective_cache_size:
!  *		1 + (rpc-1)/2 * relsize
   * These give the right asymptotic behavior (=> 1.0 as relpages becomes
   * small, => random_page_cost as it becomes large) and meet in the middle
   * with the estimate that the cache is about 50% effective for a relation
***************
*** 213,221 ****
  	relsize = relpages / effective_cache_size;
  
  	if (relsize >= 1.0)
! 		return random_page_cost * (1.0 - 0.5 / relsize);
  	else
! 		return 1.0 + (random_page_cost * 0.5 - 1.0) * relsize * relsize;
  }
  
  /*
--- 214,222 ----
  	relsize = relpages / effective_cache_size;
  
  	if (relsize >= 1.0)
! 		return random_page_cost - (random_page_cost - 1.0) / 2.0 / relsize;
  	else
! 		return 1.0 + (random_page_cost - 1.0) / 2.0 * relsize;
  }
  
  /*