Re: Server won't start with fallback setting by initdb.

From: Michael Paquier <michael(at)paquier(dot)xyz>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Server won't start with fallback setting by initdb.
Date: 2018-03-05 01:53:58
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

On Sun, Mar 04, 2018 at 03:31:31PM -0500, Tom Lane wrote:
> Then, seeing that the factory defaults are ReservedBackends = 3 and
> max_wal_senders = 10, something's got to give; there's no way that
> max_connections = 10 can work with those. But what I would argue is that
> of those three choices, the least defensible one is max_wal_senders = 10.
> Where did that come from? What fraction of real-world installations will
> need that? We don't choose defaults that overprovision small
> installations by 5X or 10X anywhere else, so why here?

Those numbers are coming from f6d6d29, which points to this thread at
its root:

The number of max_wal_senders came out as a consensus because those are
cheap to enable, now the number came out by itself. I am not seeing on
the thread any specific reason behind.

> My proposal is to default max_wal_senders to perhaps 3, and leave
> initdb's logic alone.

I agree with you here. That was actually my first counter proposal on
the matter, which is also conservative:

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Amit Langote 2018-03-05 01:59:37 Re: constraint exclusion and nulls in IN (..) clause
Previous Message Michael Paquier 2018-03-05 01:41:01 Re: [HACKERS] Support for Secure Transport SSL library on macOS as OpenSSL alternative