Remove the pgstat_drop_relation() call from smgr_internal_unlink(), because

we don't know at that point which relation OID to tell pgstat to forget.
The code was passing the relfilenode, which is incorrect, and could possibly
cause some other relation's stats to be zeroed out.  While we could try to
clean this up, it seems much simpler and more reliable to let the next
invocation of pgstat_vacuum_tabstat() fix things; which indeed is how it
worked before I introduced the buggy code into 8.1.3 and later :-(.
Problem noticed by Itagaki Takahiro, fix is per subsequent discussion.

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 23dd081ae990b4cf31d97bbce316ecf3d32bac3b..db309c7e14d2d64f8c7505a6fce9f397b45ad4a7 100644 (file)
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -13,7 +13,7 @@
  *
  *     Copyright (c) 2001-2005, PostgreSQL Global Development Group
  *
- *     $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.111.2.8 2007/06/07 19:07:11 alvherre Exp $
+ *     $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.111.2.9 2007/07/08 22:23:32 tgl Exp $
  * ----------
  */
 #include "postgres.h"
@@ -1070,8 +1070,12 @@ pgstat_drop_database(Oid databaseid)
  *     Tell the collector that we just dropped a relation.
  *     (If the message gets lost, we will still clean the dead entry eventually
  *     via future invocations of pgstat_vacuum_tabstat().)
+ *
+ *     Currently not used for lack of any good place to call it; we rely
+ *     entirely on pgstat_vacuum_tabstat() to clean out stats for dead rels.
  * ----------
  */
+#ifdef NOT_USED
 void
 pgstat_drop_relation(Oid relid)
 {
@@ -1090,6 +1094,7 @@ pgstat_drop_relation(Oid relid)
        msg.m_databaseid = MyDatabaseId;
        pgstat_send(&msg, len);
 }
+#endif /* NOT_USED */
 
 
 /* ----------

diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index ea5075e12df66525ddddd7940ed303afda4e42ba..a21c3089e683459d0c17576fe8eb3f6da5189a4d 100644 (file)
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.93.2.3 2006/03/30 22:11:59 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.93.2.4 2007/07/08 22:23:32 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -19,7 +19,6 @@
 
 #include "access/xact.h"
 #include "commands/tablespace.h"
-#include "pgstat.h"
 #include "storage/bufmgr.h"
 #include "storage/freespace.h"
 #include "storage/ipc.h"
@@ -471,13 +470,11 @@ smgr_internal_unlink(RelFileNode rnode, int which, bool isTemp, bool isRedo)
        FreeSpaceMapForgetRel(&rnode);
 
        /*
-        * Tell the stats collector to forget it immediately, too.  Skip this
-        * in recovery mode, since the stats collector likely isn't running
-        * (and if it is, pgstats.c will get confused because we aren't a real
-        * backend process).
+        * It'd be nice to tell the stats collector to forget it immediately, too.
+        * But we can't because we don't know the OID (and in cases involving
+        * relfilenode swaps, it's not always clear which table OID to forget,
+        * anyway).
         */
-       if (!InRecovery)
-               pgstat_drop_relation(rnode.relNode);
 
        /*
         * And delete the physical files.

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index d49e30b098bcc9c502e5ed797218ddad1ade82f6..083977797910f72d81f3316decd308c585f2f275 100644 (file)
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -5,7 +5,7 @@
  *
  *     Copyright (c) 2001-2005, PostgreSQL Global Development Group
  *
- *     $PostgreSQL: pgsql/src/include/pgstat.h,v 1.38.2.1 2006/01/18 20:35:16 tgl Exp $
+ *     $PostgreSQL: pgsql/src/include/pgstat.h,v 1.38.2.2 2007/07/08 22:23:32 tgl Exp $
  * ----------
  */
 #ifndef PGSTAT_H
@@ -412,7 +412,6 @@ extern void pgstat_report_analyze(Oid tableoid, bool shared,
                                          PgStat_Counter livetuples,
                                          PgStat_Counter deadtuples);
 extern void pgstat_vacuum_tabstat(void);
-extern void pgstat_drop_relation(Oid relid);
 
 extern void pgstat_reset_counters(void);