On 2020/09/30 20:21, Amit Kapila wrote:
On Tue, Sep 29, 2020 at 9:23 PM Fujii Masao <masao.fu...@oss.nttdata.com> wrote:
On 2020/09/29 11:51, Masahiro Ikeda wrote:
On 2020-09-29 11:43, Amit Kapila wrote:
On Tue, Sep 29, 2020 at 7:39 AM Masahiro Ikeda <ikeda...@oss.nttdata.com> wrote:
On 2020-09-28 12:43, Amit Kapila wrote:
On Mon, Sep 28, 2020 at 8:24 AM Kyotaro Horiguchi
<horikyota....@gmail.com> wrote:
At Mon, 28 Sep 2020 08:11:23 +0530, Amit Kapila
<amit.kapil...@gmail.com> wrote in
One other thing that occurred to me today is can't we keep this as
part of PgStat_GlobalStats? We can use pg_stat_reset_shared('wal'); to
reset it. It seems to me this is a cluster-wide stats and somewhat
similar to some of the other stats we maintain there.
I like that direction, but PgStat_GlobalStats is actually
PgStat_BgWriterStats and cleard by a RESET_BGWRITER message.
Yeah, I think if we want to pursue this direction then we probably
need to have a separate message to set/reset WAL-related stuff. I
guess we probably need to have a separate reset timestamp for WAL. I
think the difference would be that we can have one structure to refer
to global_stats instead of referring to multiple structures and we
don't need to issue separate read/write calls but OTOH I don't see
many disadvantages of the current approach as well.
IIUC, if we keep wal stats as part of PgStat_GlobalStats,
don't we need to add PgStat_ArchiverStats and PgStat_SLRUStats
to PgStat_GlobalStats too?
I have given the idea for wal_stats because there is just one counter
in that. I think you can just try to evaluate the merits of each
approach and choose whichever you feel is good. This is just a
suggestion, if you don't like it feel free to proceed with the current
approach.
Thanks for your suggestion.
I understood that the point is that WAL-related stats have just one counter now.
Since we may add some WAL-related stats like pgWalUsage.(bytes, records, fpi),
I think that the current approach is good.
+1
Okay, it makes sense to keep it in the current form if we have a plan
to extend this view with additional stats. However, why don't we
expose it with a function similar to pg_stat_get_archiver() instead of
providing individual functions like pg_stat_get_wal_buffers_full() and
pg_stat_get_wal_stat_reset_time?
We can adopt either of those approaches for pg_stat_wal. I think that
the former is a bit more flexible because we can collect only one of
WAL information even when pg_stat_wal will contain many information
in the future, by using the function. But you thought there are some
reasons that the latter is better for pg_stat_wal?
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
