From 957d08c81f9cc277725c83b9381c5154b6318a5e Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Mon, 30 Apr 2007 03:23:49 +0000
Subject: Implement rate-limiting logic on how often backends will attempt to
 send messages to the stats collector.  This avoids the problem that enabling
 stats_row_level for autovacuum has a significant overhead for short read-only
 transactions, as noted by Arjen van der Meijden.  We can avoid an extra
 gettimeofday call by piggybacking on the one done for WAL-logging xact commit
 or abort (although that doesn't help read-only transactions, since they don't
 WAL-log anything).

In my proposal for this, I noted that we could change the WAL log entries
for commit/abort to record full TimestampTz precision, instead of only
time_t as at present.  That's not done in this patch, but will be committed
separately.
---
 src/include/utils/timestamp.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'src/include/utils')

diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index 0d31cc02940..594cd61e884 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.67 2007/02/16 03:39:45 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.68 2007/04/30 03:23:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -311,6 +311,9 @@ extern TimestampTz GetCurrentTimestamp(void);
 
 extern void TimestampDifference(TimestampTz start_time, TimestampTz stop_time,
 					long *secs, int *microsecs);
+extern bool TimestampDifferenceExceeds(TimestampTz start_time,
+									   TimestampTz stop_time,
+									   int msec);
 
 extern TimestampTz time_t_to_timestamptz(time_t tm);
 extern time_t timestamptz_to_time_t(TimestampTz t);
-- 
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