Re: patch to allow disable of WAL recycling

Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>

From: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
To: robertmhaas@gmail.com
Cc: peter.eisentraut@2ndquadrant.com, jerry.jelinek@joyent.com, andres@anarazel.de, pgsql-hackers@postgresql.org
Date: 2018-07-19T04:04:12Z
Lists: pgsql-hackers
At Thu, 19 Jul 2018 12:59:26 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote in <20180719.125926.257896670.horiguchi.kyotaro@lab.ntt.co.jp>
> At Thu, 19 Jul 2018 12:37:26 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote in <20180719.123726.00899102.horiguchi.kyotaro@lab.ntt.co.jp>
> > At Tue, 17 Jul 2018 21:01:03 -0400, Robert Haas <robertmhaas@gmail.com> wrote in <CA+Tgmob0hs=eZ7RquTLzYUwAuHtgORvPxjNXgifZ04he-JK7Rw@mail.gmail.com>
> > > On Tue, Jul 17, 2018 at 3:12 PM, Peter Eisentraut
> > > <peter.eisentraut@2ndquadrant.com> wrote:
> > > > The actual implementation could use another round of consideration.  I
> > > > wonder how this should interact with min_wal_size.  Wouldn't
> > > > min_wal_size = 0 already do what we need (if you could set it to 0,
> > > > which is currently not possible)?
> > > 
> > > Hmm, would that actually disable recycling, or just make it happen only rarely?
> > 
> > It doens't. Instead setting max_wal_size smaller than checkpoint
> > interval should do that.
> 
> And that's wrong. It makes checkpoint unreasonably frequent.
> 
> My result is that we cannot disable recycling perfectly just by
> setting min/max_wal_size.

s/result/conclusion/;

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center



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.