Re: pg_basebackup fails: could not receive data from WAL stream: server closed the connection unexpectedly

Hi,
Thank you very much for the response.

I reckon we can return to more conventional approach of postgres db
synchronization:
1) SELECT pg_start_backup('label', true);
2) rsync/cp $PGDATA directory;
3) SELECT pg_stop_backup();

In my opinion this approach looks better because it does not depend on
wal_sender_timeout value.

I have a question. What is your opinion about pg_basebackup utility and
its behaviour for this condition? Is it a bug? Should it be fixed?

Best regards,
Andrei

From: Shreeyansh Dba <shreeyansh2014(at)gmail(dot)com>
To: AYahorau(at)ibagroup(dot)eu,
Cc: pgsql-admin <pgsql-admin(at)postgresql(dot)org>, MikalaiKeida(at)ibagroup(dot)eu
Date: 03/12/2018 15:15
Subject: Re: pg_basebackup fails: could not receive data from WAL
stream: server closed the connection unexpectedly

Hi Andrei Yahorau,

As it is difficult to give an exact recommendation, however, We have
enabled and tested your exact error with the same parameters in our
testing environment, we received the same error and able to resolve this
problem by increasing 'wal_sender_timeout' parameter value.

I think you need to test and verify before implementing it on your server
according to your business, configuration requirements.

On Mon, Dec 3, 2018 at 2:17 PM <AYahorau(at)ibagroup(dot)eu> wrote:
Hello PostgreSQL Community!

Not so long ago I faced the problem of database synchronization using
pg_basebackup utility on linux SLES 12 machine using PostgreSQL 10.4:

pg_basebackup -h host01 -U dbuser -D /var/PostgresDb -w
LOG: standby "pg_basebackup" is now a synchronous standby with priority 1
pg_basebackup: could not receive data from WAL stream: server closed the
connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
pg_basebackup: child process exited with error 1
pg_basebackup: removing contents of data directory "/var/RtpPostgresDb"

PostgreSQL log of master server contain the following error entry:
terminating walsender process due to replication timeout

Currently my configuration is the following:
wal_sender_timeout = 1s
wal_receiver_timeout = 1s
wal_receiver_status_interval = 10s

I see that some people faced this situation:
https://www.postgresql.org/message-id/109968546.289.1460409481048.JavaMail.pbrunnen%40Station8.local

The suggestion was increasing wal_sender_timeout parameter.

On the one hand I understand that if my database gets bigger it will
require bigger value of wal_sender_timeout. On the other hand I use
wal_sender_timeout = 1s on purpose in order to detect if network bad.

Could you please suggest an appropriate configuration, sensible relations
between configuration parameters or any other approach of database
synchronization which overcomes this issue?

Thank you in advance,
Andrei Yahorau