Re: per backend WAL statistics

On Tue, Feb 25, 2025 at 03:00:35PM +0000, Bertrand Drouvot wrote:
> That makes fully sense. Done in 0004 attached. Somehow related to that, I've
> a patch in progress to address some of Rahila's comments ([1]) (the one related
> to the AuxiliaryPidGetProc() call is relevant specially since a051e71e28a where
> pgstat_tracks_backend_bktype() has been modified for B_WAL_RECEIVER, B_WAL_SUMMARIZER
> and B_WAL_WRITER). I'll wait for 0004 to go in before sharing the patch.

Applied v9-0001 and v9-0003 as these were fine, with more
documentation added in pgstat.h for the new WAL structure, and the
reason why it exists. I've noticed the difference with bktype in
v9-0004 as the WAL part does not need this information when generating
its tuple, OK here.

Doing v9-0003 after v9-0002 felt a bit odd, changing twice the
signature of pg_stat_wal_build_tuple() to adapt with the split for the
reset timestamp.

- values[4] = TimestampTzGetDatum(wal_stats->stat_reset_timestamp);
+ if (wal_stats.stat_reset_timestamp != 0)
+ values[4] = TimestampTzGetDatum(wal_stats.stat_reset_timestamp);
+ else
+ nulls[4] = true;

In patch v9-0002, is this nulls[4] required for the backend part?
--
Michael