Re: Active connections are terminated because of small wal_sender_timeout

Hello Everyone!

Sorry for being persistent.

> I do not think anybody thinks this is a bug. Setting wal_sender_timeout
> too small is a configuration mistake.

Why is it a configuration mistake? This value is allowed to be set. There
is no any restriction about it.
I would like to ask a question regarding wal_sender_timeout description
and its real behaviour.
Description:
Terminate replication connections that are inactive longer than the
specified number of milliseconds.
Real behaviour:
A standby server can be busy and does not send "keepalive" packets to the
master.
(By the way wal_sender_timeot cannot be not so small as in my tests. This
situation can happen when wal_sender_timeout=10seconds and so on and and
so forth).

Does it work properly according to the description? Don't you see the
contradiction between the description and real behaviour? As I mentioned
before the connection between master and standby is good. There is no any
problem.
So where is a bug: in the description or in the implementation?

> Yeah. I don't see any bug here. Please note that it can be also a
> problem to set up a too high value in some configuration setups. The
> lack of flexibility in this area is why wal_sender_timeout has been
> switch to be user-settable in v12. In short you can configure it in
> the connection string to enforce a custom value per standby.

Will a small value of wal_sender_timeout in PostgreSQL v12 lead to the
same failure "terminating walsender process due to replication timeout" as
we observe in v11 ?

Best regards,
Andrei Yahorau