postgres.git / summary / log / commit / refs

commit    2c8a4e9be2730342cbca85150a2a9d876aa77ff6
Author:   Simon Riggs <simon@2ndQuadrant.com>
Date:     Thu Jun 07 18:22:47 2012 +0000
First released in: 9.2.0, REL9_0_STABLE (reverted before release), 9.1.5
Reverted by: da6bb58ed9da (in 9.0.9)

    Wake WALSender to reduce data loss at failover for async commit.
    WALSender now woken up after each background flush by WALwriter, avoiding
    multi-second replication delay for an all-async commit workload.
    Replication delay reduced from 7s with default settings to 200ms and often
    much less, allowing significantly reduced data loss at failover.
    
    Andres Freund and Simon Riggs


 src/backend/access/transam/xlog.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index d3650bdf051..0f2678cfda0 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -2271,6 +2271,13 @@ XLogBackgroundFlush(void)
 
 	END_CRIT_SECTION();
 
+	/*
+	 * If we wrote something then we have something to send to standbys also,
+	 * otherwise the replication delay become around 7s with just async commit.
+	 */
+	if (wrote_something)
+		WalSndWakeup();
+
 	return wrote_something;
 }
 


[parent: b50991eedb45]