Re: Hooks for session start and end, take two

Michael Paquier-2 wrote
> On Thu, Sep 26, 2019 at 09:57:57AM -0700, legrand legrand wrote:
>> Does that mean that all processes seen in pg_stat_activity like
>> - autovacuum launcher
>> - logical replication launcher
>> - background writer
>> - checkpointer
>> - walwriter
>> ...
>> - Parallel worker
>> are available with that hook (it seems not) ?
>
> All processes using PostgresMain() for their startup take this code
> path like WAL senders and normal backend sessions, but not things
> going through StartChildProcess() (WAL receiver, bgwriter, etc.) or
> other processes like autovacuum processes which use a different start
> code path.

OK I confirm:
- "client backend" appears at session start and end hook,
- "autovacuum worker" and "pg_background" only appears at session end hook
(backend_start can be retreived from pg_stat_activity),
- "parallel workers" are not visible at all
(because extension cannot assign XIDs during a parallel operation)

All seems fine to me.

Regards
PAscal

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