From: Bruce Momjian <bruce@momjian.us>
To: Noah Misch <noah@leadboat.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: PG 13 release notes, first draft
Date: Mon, 11 May 2020 20:12:04 -0400
Message-ID: <20200512001204.GF4666@momjian.us> (raw)
In-Reply-To: <20200508042202.GA563018@rfd.leadboat.com>
References: <20200505031600.GB21752@momjian.us>
<20200506063910.GA515983@rfd.leadboat.com>
<20200506234025.GC3649@momjian.us>
<20200507052057.GB541283@rfd.leadboat.com>
<20200507133834.GJ3649@momjian.us>
<20200508042202.GA563018@rfd.leadboat.com>
On Thu, May 7, 2020 at 09:22:02PM -0700, Noah Misch wrote:
> On Thu, May 07, 2020 at 09:38:34AM -0400, Bruce Momjian wrote:
> > > > > - Crash recovery was losing tuples written via COPY TO. This fixes the bug.
> > > >
> > > > This was not backpatched?
> > >
> > > Right.
> >
> > Oh. So you are saying we could lose COPY data on a crash, even after a
> > commit. That seems bad. Can you show me the commit info? I can't find
> > it.
>
> commit c6b9204
> Author: Noah Misch <noah@leadboat.com>
> AuthorDate: Sat Apr 4 12:25:34 2020 -0700
> Commit: Noah Misch <noah@leadboat.com>
> CommitDate: Sat Apr 4 12:25:34 2020 -0700
>
> Skip WAL for new relfilenodes, under wal_level=minimal.
>
> Until now, only selected bulk operations (e.g. COPY) did this. If a
> given relfilenode received both a WAL-skipping COPY and a WAL-logged
> operation (e.g. INSERT), recovery could lose tuples from the COPY. See
> src/backend/access/transam/README section "Skipping WAL for New
> RelFileNode" for the new coding rules. Maintainers of table access
> methods should examine that section.
OK, so how do we want to document this? Do I mention in the text below
the WAL skipping item that this fixes a bug where a mix of simultaneous
COPY and INSERT into a table could lose rows during crash recovery, or
create a new item?
--
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. +
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To: pgsql-hackers@postgresql.org
Cc: bruce@momjian.us, noah@leadboat.com
Subject: Re: PG 13 release notes, first draft
In-Reply-To: <20200512001204.GF4666@momjian.us>
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