Re: Fwd: PostgreSQL 9.4.13 is facing issue in shutting down

On Tue, Aug 22, 2017 at 1:58 PM, Abhijit Gharami
<abhijitgharami(at)gmail(dot)com> wrote:
> Recently we have updated our PostgreSQL version from 9.4.12 to 9.4.13. With
> version 9.4.13 while trying to stop the PostgreSQL server, database is
> facing issues in shutting down. The problem probably occurs because of the
> WAL sender process not getting terminated on shutdown request.
> ps output:
> postgre+ 7915 0.0 1.9 589772 39528 ? S< 09:11 0:00
> /..../bin/postgres -D /.../postgresql -h 0.0.0.0 -p 5432
> postgre+ 8617 0.0 0.4 590760 8344 ? S<s 09:13 0:00 postgres:
> wal sender process replicator xx.xx.xx.xxx(45948) streaming 0/4000090

One change introduced between 9.4.12 and 9.4.13 is the way WAL senders
are stopped at shutdown. The checkpointer will first send a signal to
all the WAL senders after all the normal backends have exited before
beginning to issue the checkpoint shutdown. This will switch the WAL
senders to a stopping state where all new queries are blocked, and all
WAL senders exit after they have sent any remaining WAL to the
clients, including the checkpoint shutdown record. So, what is the
client behind this WAL sender? It seems that this WAL sender is
waiting for some confirmation activity.
--
Michael