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author | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2020-08-08 12:31:55 -0400 |
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committer | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2020-08-08 12:31:55 -0400 |
commit | 470687b4a5bb3b9f2b5bf7c9235680b3c91bd050 (patch) | |
tree | 8032c324e99bf180e3d0f28b337cc117065bae01 /contrib/intarray/_int_gist.c | |
parent | 82a0ba7707e010a29f5fe1a0020d963c82b8f1cb (diff) | |
download | postgresql-470687b4a5bb3b9f2b5bf7c9235680b3c91bd050.tar.gz postgresql-470687b4a5bb3b9f2b5bf7c9235680b3c91bd050.zip |
walsnd: Don't set waiting_for_ping_response spuriously
Ashutosh Bapat noticed that when logical walsender needs to wait for
WAL, and it realizes that it must send a keepalive message to
walreceiver to update the sent-LSN, which *does not* request a reply
from walreceiver, it wrongly sets the flag that it's going to wait for
that reply. That means that any future would-be sender of feedback
messages ends up not sending a feedback message, because they all
believe that a reply is expected.
With built-in logical replication there's not much harm in this, because
WalReceiverMain will send a ping-back every wal_receiver_timeout/2
anyway; but with other logical replication systems (e.g. pglogical) it
can cause significant pain.
This problem was introduced in commit 41d5f8ad734, where the
request-reply flag was changed from true to false to WalSndKeepalive,
without at the same time removing the line that sets
waiting_for_ping_response.
Just removing that line would be a sufficient fix, but it seems better
to shift the responsibility of setting the flag to WalSndKeepalive
itself instead of requiring caller to do it; this is clearly less
error-prone.
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reported-by: Ashutosh Bapat <ashutosh.bapat@2ndquadrant.com>
Backpatch: 9.5 and up
Discussion: https://postgr.es/m/20200806225558.GA22401@alvherre.pgsql
Diffstat (limited to 'contrib/intarray/_int_gist.c')
0 files changed, 0 insertions, 0 deletions