From: Bruce Momjian <bruce@momjian.us>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: noah@leadboat.com
Cc: pgsql-hackers@postgresql.org
Subject: Re: PG 13 release notes, first draft
Date: Wed, 13 May 2020 11:15:18 -0400
Message-ID: <20200513151518.GA20111@momjian.us> (raw)
In-Reply-To: <20200513.115633.157251733478541458.horikyota.ntt@gmail.com>
References: <20200512001204.GF4666@momjian.us>
<20200512.130908.2082912530895654639.horikyota.ntt@gmail.com>
<20200512203809.GA4666@momjian.us>
<20200513.115633.157251733478541458.horikyota.ntt@gmail.com>
On Wed, May 13, 2020 at 11:56:33AM +0900, Kyotaro Horiguchi wrote:
> >
> > Allow skipping of WAL for new tables and indexes if wal_level is
> > 'minimal' (Kyotaro Horiguchi)
> >
> > Relations larger than wal_skip_threshold will have their files
> > fsync'ed rather than writing their WAL records. Previously this
> > was done only for COPY operations, but the implementation had a
> > bug that could cause data loss during crash recovery.
>
> I see it. It is giving weight on improvement. Looks good the overall
> structure of the description above. However, wal-skipping is always
> done regardless of table size. wal_skip_threshold is an optimization
> to choose which to use fsync or FPI records (that is, not WAL records
> in the common sense) at commit for speed.
Well, as far as users are concerned, everything wrtiten to WAL is a WAL
record.
> So how about the following?
>
> All kinds of bulk-insertion are not WAL-logged then fsync'ed at
> commit. Using FPI WAL records instead of fsync for relations smaller
> than wal_skip_threshold. Previously this was done only for COPY
> operations and always using fsync, but the implementation had a bug
> that could cause data loss during crash recovery.
That is too much detail for the release notes. We already will link to
the docs. Why put it here?
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: bruce@momjian.us, horikyota.ntt@gmail.com, noah@leadboat.com
Subject: Re: PG 13 release notes, first draft
In-Reply-To: <20200513151518.GA20111@momjian.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox