RE: New statistics for tuning WAL buffer size

tsunakawa.takay@fujitsu.com <tsunakawa.takay@fujitsu.com>

From: "tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>
To: 'Fujii Masao' <masao.fujii@oss.nttdata.com>, Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2020-08-21T03:08:44Z
Lists: pgsql-hackers
From: Fujii Masao <masao.fujii@oss.nttdata.com>
> Just idea; it may be worth exposing the number of when new WAL file is
> created and zero-filled. This initialization may have impact on
> the performance of write-heavy workload generating lots of WAL. If this
> number is reported high, to reduce the number of this initialization,
> we can tune WAL-related parameters so that more "recycled" WAL files
> can be hold.

Sounds good.  Actually, I want to know how much those zeroing affected the transaction response times, but it may be the target of the wait event statistics that Imai-san is addressing.

(I wonder how the fallocate() patch went that tries to minimize the zeroing time.)


Regards
Takayuki Tsunakawa

Commits

  1. Add pg_stat_wal statistics view.