diff options
| author | Simon Riggs <simon@2ndQuadrant.com> | 2012-06-07 19:26:03 +0100 |
|---|---|---|
| committer | Simon Riggs <simon@2ndQuadrant.com> | 2012-06-07 19:26:03 +0100 |
| commit | 090e8a984cf1a8a3ef7f6db6dc919f843902d80c (patch) | |
| tree | 87eebd8c0642708688fa98188fcc6a90c74255d5 /src | |
| parent | 110ebff20972101236b27c876c14e6df2833b571 (diff) | |
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, allowing
significantly reduced data loss at failover.
Andres Freund and Simon Riggs
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 3902c583134..64d7660b38b 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -2115,6 +2115,7 @@ XLogBackgroundFlush(void) { XLogRecPtr WriteRqstPtr; bool flexible = true; + bool wrote_something = false; /* XLOG doesn't need flushing during recovery */ if (RecoveryInProgress()) @@ -2183,10 +2184,18 @@ XLogBackgroundFlush(void) WriteRqst.Write = WriteRqstPtr; WriteRqst.Flush = WriteRqstPtr; XLogWrite(WriteRqst, flexible, false); + wrote_something = true; } LWLockRelease(WALWriteLock); 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(); } /* |