Hi, On Thu, Jan 23, 2025 at 09:57:50AM +0000, Bertrand Drouvot wrote: > On Thu, Jan 23, 2025 at 05:05:30PM +0900, Michael Paquier wrote: > > As far I got it from a code > > read, prevWalUsage, prevBackendWalUsage and their local trackings in > > pgstat_backend.c and pgstat_wal.c rely on instrument.c as the primary > > source, as pgWalUsage can never be reset. Is that right? > > yeah, IIUC pgWalUsage acts as the primary source that both prevWalUsage and > prevBackendWalUsage diff against to calculate incremental stats. >
Now that a051e71e28a is in, I think that we can reduce the scope of this patch (i.e reduce the number of stats provided by pg_stat_get_backend_wal()). I think we can keep: wal_records wal_fpi wal_bytes (because it differs from write_bytes in pg_stat_get_backend_io()) wal_buffers_full The first 3 are in the WalUsage struct. I think that: wal_write (and wal_write_time) wal_sync (and wal_sync_time) can be extracted from pg_stat_get_backend_io(), so there is no need to duplicate this information. The same comment could be done for pg_stat_wal and pg_stat_io though, but pg_stat_wal already exists so removing fields has not the same effect. What are you thoughts about keeping in pg_stat_get_backend_wal() only the 4 stats mentioned above? Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
