Fix contrib/pg_freespacemap's underestimate of the number of pages it

could find in the FSM.  Per report from Dimitri Fontaine and Andrew Gierth.

(Affects only 8.2 and 8.3 since HEAD no longer has MaxFSMPages at all.)

diff --git a/contrib/pg_freespacemap/pg_freespacemap.c b/contrib/pg_freespacemap/pg_freespacemap.c
index cfe5cb0268c7909763008cd51f20c98cd5352e3b..e4475c1ffc1b60d9ee8eee3856483e714abe3256 100644 (file)
--- a/contrib/pg_freespacemap/pg_freespacemap.c
+++ b/contrib/pg_freespacemap/pg_freespacemap.c
@@ -3,7 +3,7 @@
  * pg_freespacemap.c
  *   display some contents of the free space relation and page maps.
  *
- *   $PostgreSQL: pgsql/contrib/pg_freespacemap/pg_freespacemap.c,v 1.9 2006/10/19 18:32:46 tgl Exp $
+ *   $PostgreSQL: pgsql/contrib/pg_freespacemap/pg_freespacemap.c,v 1.9.2.1 2009/04/07 18:11:04 tgl Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -94,6 +94,7 @@ pg_freespacemap_pages(PG_FUNCTION_ARGS)
    if (SRF_IS_FIRSTCALL())
    {
        int         i;
+       int         nchunks;    /* Size of freespace.c's arena. */
        int         numPages;   /* Max possible no. of pages in map. */
        int         nPages;     /* Mapped pages for a relation. */
 
@@ -102,7 +103,10 @@ pg_freespacemap_pages(PG_FUNCTION_ARGS)
         */
        FreeSpaceMap = GetFreeSpaceMap();
 
-       numPages = MaxFSMPages;
+       /* this must match calculation in InitFreeSpaceMap(): */
+       nchunks = (MaxFSMPages - 1) / CHUNKPAGES + 1;
+       /* Worst case (lots of indexes) could have this many pages: */
+       numPages = nchunks * INDEXCHUNKPAGES;
 
        funcctx = SRF_FIRSTCALL_INIT();