Re: patch to allow disable of WAL recycling - Mailing list pgsql-hackers

From Jerry Jelinek
Subject Re: patch to allow disable of WAL recycling
Date
Msg-id CACPQ5FoYw6Tz7dQMjWSKndA9iRnHg38RzWTh8QKJ=DyzmHARww@mail.gmail.com
Whole thread Raw
In response to Re: patch to allow disable of WAL recycling  (Alvaro Herrera <alvherre@2ndquadrant.com>)
List pgsql-hackers
Alvaro,

I'll perform several test runs with various combinations and post the results.

Thanks,
Jerry


On Tue, Jul 10, 2018 at 2:34 PM, Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
On 2018-Jul-10, Jerry Jelinek wrote:

> 2) Disabling WAL recycling reduces reliability, even on COW filesystems.

I think the problem here is that WAL recycling in normal filesystems
helps protect the case where filesystem gets full.  If you remove it,
that protection goes out the window.  You can claim that people needs to
make sure to have available disk space, but this does become a problem
in practice.  I think the thing to do is verify what happens with
recycling off when the disk gets full; is it possible to recover
afterwards?  Is there any corrupt data?  What happens if the disk gets
full just as the new WAL file is being created -- is there a Postgres
PANIC or something?  As I understand, with recycling on it is easy (?)
to recover, there is no PANIC crash, and no data corruption results.

--
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

pgsql-hackers by date:

Previous
From: amul sul
Date:
Subject: Re: partition pruning doesn't work with IS NULL clause in multikeyrange partition case
Next
From: Tomas Vondra
Date:
Subject: Re: Preferring index-only-scan when the cost is equal