Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit900429d

Browse files
committed
walsnd: Don't set waiting_for_ping_response spuriously
Ashutosh Bapat noticed that when logical walsender needs to wait forWAL, and it realizes that it must send a keepalive message towalreceiver to update the sent-LSN, which *does not* request a replyfrom walreceiver, it wrongly sets the flag that it's going to wait forthat reply. That means that any future would-be sender of feedbackmessages ends up not sending a feedback message, because they allbelieve that a reply is expected.With built-in logical replication there's not much harm in this, becauseWalReceiverMain will send a ping-back every wal_receiver_timeout/2anyway; but with other logical replication systems (e.g. pglogical) itcan cause significant pain.This problem was introduced in commit41d5f8a, where therequest-reply flag was changed from true to false to WalSndKeepalive,without at the same time removing the line that setswaiting_for_ping_response.Just removing that line would be a sufficient fix, but it seems betterto shift the responsibility of setting the flag to WalSndKeepaliveitself instead of requiring caller to do it; this is clearly lesserror-prone.Author: Álvaro Herrera <alvherre@alvh.no-ip.org>Reported-by: Ashutosh Bapat <ashutosh.bapat@2ndquadrant.com>Backpatch: 9.5 and upDiscussion:https://postgr.es/m/20200806225558.GA22401@alvherre.pgsql
1 parentf1c3a41 commit900429d

File tree

1 file changed

+12
-12
lines changed

1 file changed

+12
-12
lines changed

‎src/backend/replication/walsender.c‎

Lines changed: 12 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -151,7 +151,7 @@ static XLogRecPtr sendTimeLineValidUpto = InvalidXLogRecPtr;
151151
* How far have we sent WAL already? This is also advertised in
152152
* MyWalSnd->sentPtr. (Actually, this is the next WAL location to send.)
153153
*/
154-
staticXLogRecPtrsentPtr=0;
154+
staticXLogRecPtrsentPtr=InvalidXLogRecPtr;
155155

156156
/* Buffers for constructing outgoing messages and processing reply messages. */
157157
staticStringInfoDataoutput_message;
@@ -1451,10 +1451,7 @@ WalSndWaitForWal(XLogRecPtr loc)
14511451
if (MyWalSnd->flush<sentPtr&&
14521452
MyWalSnd->write<sentPtr&&
14531453
!waiting_for_ping_response)
1454-
{
14551454
WalSndKeepalive(false);
1456-
waiting_for_ping_response= true;
1457-
}
14581455

14591456
/* check whether we're done */
14601457
if (loc <=RecentFlushPtr)
@@ -2932,10 +2929,7 @@ WalSndDone(WalSndSendDataCallback send_data)
29322929
proc_exit(0);
29332930
}
29342931
if (!waiting_for_ping_response)
2935-
{
29362932
WalSndKeepalive(true);
2937-
waiting_for_ping_response= true;
2938-
}
29392933
}
29402934

29412935
/*
@@ -3432,10 +3426,13 @@ pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
34323426
}
34333427

34343428
/*
3435-
* This function is used to send a keepalive message to standby.
3436-
* If requestReply is set, sets a flag in the message requesting the standby
3437-
* to send a message back to us, for heartbeat purposes.
3438-
*/
3429+
* Send a keepalive message to standby.
3430+
*
3431+
* If requestReply is set, the message requests the other party to send
3432+
* a message back to us, for heartbeat purposes. We also set a flag to
3433+
* let nearby code that we're waiting for that response, to avoid
3434+
* repeated requests.
3435+
*/
34393436
staticvoid
34403437
WalSndKeepalive(boolrequestReply)
34413438
{
@@ -3450,6 +3447,10 @@ WalSndKeepalive(bool requestReply)
34503447

34513448
/* ... and send it wrapped in CopyData */
34523449
pq_putmessage_noblock('d',output_message.data,output_message.len);
3450+
3451+
/* Set local flag */
3452+
if (requestReply)
3453+
waiting_for_ping_response= true;
34533454
}
34543455

34553456
/*
@@ -3480,7 +3481,6 @@ WalSndKeepaliveIfNecessary(void)
34803481
if (last_processing >=ping_time)
34813482
{
34823483
WalSndKeepalive(true);
3483-
waiting_for_ping_response= true;
34843484

34853485
/* Try to flush pending output to the client */
34863486
if (pq_flush_if_writable()!=0)

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp