Delay write of pg_stats file to once every five minutes, during

shutdown, or when requested by a backend:

It changes so the file is only written once every 5 minutes (changeable
of course, I just picked something) instead of once every half second.
It's still written when the stats collector shuts down, just as before.
And it is now also written on backend request. A backend requests a
rewrite by simply sending a special stats message. It operates on the
assumption that the backends aren't actually going to read the
statistics file very often, compared to how frequent it's written today.

Magnus Hagander

1 files changed, 12 insertions, 2 deletions

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 00631b3e12..4497e4d1f5 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -5,7 +5,7 @@
  *
  *	Copyright (c) 2001-2006, PostgreSQL Global Development Group
  *
- *	$PostgreSQL: pgsql/src/include/pgstat.h,v 1.43 2006/04/06 20:38:00 tgl Exp $
+ *	$PostgreSQL: pgsql/src/include/pgstat.h,v 1.44 2006/04/27 00:06:59 momjian Exp $
  * ----------
  */
 #ifndef PGSTAT_H
@@ -32,7 +32,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_RESETCOUNTER,
 	PGSTAT_MTYPE_AUTOVAC_START,
 	PGSTAT_MTYPE_VACUUM,
-	PGSTAT_MTYPE_ANALYZE
+	PGSTAT_MTYPE_ANALYZE,
+	PGSTAT_MTYPE_REWRITE
 } StatMsgType;
 
 /* ----------
@@ -108,6 +109,15 @@ typedef struct PgStat_MsgDummy
 } PgStat_MsgDummy;
 
 /* ----------
+ * PgStat_MsgRewrite            Sent by backends to cause a rewrite of the stats file
+ * ----------
+ */
+typedef struct Pgstat_MsgRewrite
+{
+	PgStat_MsgHdr m_hdr;
+} PgStat_MsgRewrite;
+
+/* ----------
  * PgStat_MsgBestart			Sent by the backend on startup
  * ----------
  */