| From: | Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
| Cc: | Kiriakos Georgiou <kg(dot)postgresql(at)olympiakos(dot)com>, Forums postgresql <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: pg_multixact issues |
| Date: | 2016-02-10 22:27:13 |
| Message-ID: | CAEepm=3m2Ej5FkU2B-Rgjpb_U=VM0t+e9WvPXwyqO7Bt8-24cQ@mail.gmail.com |
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| Lists: | pgsql-general |
On Thu, Feb 11, 2016 at 11:05 AM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> Thomas Munro wrote:
>
>> 4. You could look into whether all those multixacts with many member
>> are really expected. (Large numbers of concurrent FK checks or
>> explicit share locks on the same rows perhaps? A good proportion of
>> this happened on one day this week I see.)
>
> I think maybe this patch
> https://www.postgresql.org/message-id/20150620043650.GX133018%40postgresql.org
> should help with this. I expect to come back to this and get it pushed
> to 9.3 and 9.4 sometime ...
Ah, so the OP might get some improvement today by moving to 9.5, which
has the optimization already.
BTW in my message above I said vacuum_multixact_freeze_table_age when
I meant to say autovacuum_multixact_freeze_max_age (and its default is
400 million).
--
Thomas Munro
http://www.enterprisedb.com
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