| From: | "tsunakawa(dot)takay(at)fujitsu(dot)com" <tsunakawa(dot)takay(at)fujitsu(dot)com> |
|---|---|
| To: | "ikedamsh(at)oss(dot)nttdata(dot)com" <ikedamsh(at)oss(dot)nttdata(dot)com>, 'Kyotaro Horiguchi' <horikyota(dot)ntt(at)gmail(dot)com>, "masao(dot)fujii(at)oss(dot)nttdata(dot)com" <masao(dot)fujii(at)oss(dot)nttdata(dot)com> |
| Cc: | "amit(dot)kapila16(at)gmail(dot)com" <amit(dot)kapila16(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, "magnus(at)hagander(dot)net" <magnus(at)hagander(dot)net> |
| Subject: | RE: New statistics for tuning WAL buffer size |
| Date: | 2020-10-01 01:50:56 |
| Message-ID: | TYAPR01MB2990CB908A18CFD0970EE4AFFE300@TYAPR01MB2990.jpnprd01.prod.outlook.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
From: Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>
> Another reason that I mildly want to object to subdivided functions is
> I was annoyed that a stats view makes many individual calls to
> functions that internally share the same statistics entry. That
> behavior required me to provide an entry-caching feature to my
> shared-memory statistics patch.
+1
The views for troubleshooting performance problems should be as light as possible. IIRC, we saw frequently searching pg_stat_replication consume unexpectedly high CPU power, because it calls pg_stat_get_activity(null) to get all sessions and join them with the walsenders. At that time, we had hundreds of client sessions. We expected pg_stat_replication to be very lightweight because it provides information about a few walsenders.
Regards
Takayuki Tsunakawa
| From | Date | Subject | |
|---|---|---|---|
| Next Message | k.jamison@fujitsu.com | 2020-10-01 01:55:10 | RE: [Patch] Optimize dropping of relation buffers using dlist |
| Previous Message | Michael Paquier | 2020-10-01 01:40:44 | Re: __pg_log_level in anonynous enum should be initialized? (Was: pgsql: Change SHA2 implementation based on OpenSSL to use EVP digest ro) |