Horton

Re: patch to allow disable of WAL recycling

Jerry Jelinek <jerry.jelinek@joyent.com>

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From: Jerry Jelinek <jerry.jelinek@joyent.com>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Michael Paquier <michael@paquier.xyz>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Thomas Munro <thomas.munro@enterprisedb.com>, Andres Freund <andres@anarazel.de>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-03-07T21:12:59Z
Lists: pgsql-hackers

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On Wed, Mar 6, 2019 at 4:14 PM Jerry Jelinek <jerry.jelinek@joyent.com>
wrote:

>
> It sounds like everyone is in agreement that I should get rid  of the
> single COW GUC tunable and provide two different tunables instead. I will
> update the patch to go back to the original name (wal_recycle) for the
> original WAL recycling behavior. The default value of that will be true to
> provide the existing behavior. This matches my original proposal from last
> year. I will add a new tunable (wal_init_zero) which will control the
> zero-fill behavior for the WAL file. Again, the default value will be true
> and provide the existing behavior. Both of these could (should) be set to
> false for a COW filesystem like ZFS.
>
> If anyone objects to this new approach, let me know, otherwise I'll start
> preparing an updated patch.
>

 I have attached a new version of the patch that implements the changes
we've discussed over the past couple of days. Let me know if there are any
comments or suggestions.

Thanks,
Jerry

Commits

  1. Add wal_recycle and wal_init_zero GUCs.

  2. Add GUC and storage parameter to set the maximum size of GIN pending list.