From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 7 Apr 2009 18:10:56 +0000 (+0000)
Subject: Fix contrib/pg_freespacemap's underestimate of the number of pages it
X-Git-Tag: REL8_3_8~63
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=03baf4dd81e4688b3813466e540f9b524d982950;p=postgresql

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 cfe5cb0268..63d7d0ccf2 100644
--- 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 1.9.4.1 2009/04/07 18:10:56 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();