Hi,
On 11/17/22 1:51 PM, Bharath Rupireddy wrote:
> Hi,
>
> pg_stat_bgwriter view currently reports checkpointer stats as well. It
> is that way because historically checkpointer was part of bgwriter
> until the commits 806a2ae and bf405ba, that went into PG 9.2,
> separated them out. I think it is time for us to separate checkpointer
> stats to its own view. I discussed it in another thread [1] and it
> seems like there's an unequivocal agreement for the proposal.
>
> I'm attaching a patch introducing a new pg_stat_checkpointer view,
> with this change the pg_stat_bgwriter view only focuses on bgwriter
> related stats. The patch does mostly mechanical changes. I'll add it
> to CF in a bit.
>
> Thoughts?
+1 for the dedicated view.
+ <para>
+ The <structname>pg_stat_checkpointer</structname> view will always have a
+ single row, containing global data for the cluster.
+ </para>
what about "containing data about checkpointer activity of the cluster"? (to provide more "details" (even if that seems
obviousgiven the name of the view) and be consistent with the pg_stat_wal description too).
And if it makes sense to you, While at it, why not go for "containing data about bgwriter activity of the cluster" for
pg_stat_bgwritertoo?
+CREATE VIEW pg_stat_checkpointer AS
+ SELECT
+ pg_stat_get_timed_checkpoints() AS checkpoints_timed,
+ pg_stat_get_requested_checkpoints() AS checkpoints_req,
+ pg_stat_get_checkpoint_write_time() AS checkpoint_write_time,
+ pg_stat_get_checkpoint_sync_time() AS checkpoint_sync_time,
+ pg_stat_get_buf_written_checkpoints() AS buffers_checkpoint,
+ pg_stat_get_buf_written_backend() AS buffers_backend,
+ pg_stat_get_buf_fsync_backend() AS buffers_backend_fsync,
+ pg_stat_get_checkpointer_stat_reset_time() AS stats_reset;
I don't think we should keep the checkpoints_ prefix (or _checkpoint suffix) in the column names now that they belong
toa dedicated view (also the pg_stat_bgwriter view's columns don't have a
bgwriter prefix/suffix).
And while at it, I'm not sure the wal_ suffix in pg_stat_wal make sense too.
The idea is to have consistent naming between the views and their columns: I'd vote without prefix/suffix.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
