On 2020-02-28 08:45, Michael Paquier wrote:
On Thu, Feb 27, 2020 at 02:37:24PM +0100, Peter Eisentraut wrote:
On 2020-02-27 11:13, Fujii Masao wrote:
Btw., I think the current setup is slightly buggy. The
MaxBackends value that is used to size shared memory is computed as
MaxConnections + autovacuum_max_workers + 1 + max_worker_processes +
max_wal_senders, but we don't track autovacuum_max_workers in WAL.
Maybe this is because autovacuum doesn't work during recovery?
Autovacuum on the primary can use locks or xids, and so it's possible that
the standby when processing WAL encounters more of those than it has locally
allocated shared memory to handle.
Putting aside your patch because that sounds like a separate issue..
Doesn't this mean that autovacuum_max_workers should be added to the
control file, that we need to record in WAL any updates done to it and
that CheckRequiredParameterValues() is wrong?
That would be a direct fix, yes.
Perhaps it might be better to track the combined MaxBackends instead,
however.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
