Re: Re: [COMMITTERS] pgsql: Make CheckRequiredParameterValues() depend upon correct

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Aidan Van Dyk <aidan@highrise.ca>, Simon Riggs <simon@2ndquadrant.com>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Fujii Masao <masao.fujii@gmail.com>, Alvaro Herrera <alvherre@commandprompt.com>, pgsql-hackers@postgresql.org
Date: 2010-04-29T17:20:03Z
Lists: pgsql-hackers
On Thu, Apr 29, 2010 at 1:03 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> That said, I'ld probalby be happy with PG 9 having a "default" config
>>> of:
>>>        wal_mode = hot_standby
>>>        recovery_connections = on
>
>> That would be a bad idea - there's a significant performance penalty
>> from setting wal_level to anything other than minimal (just as there
>> is for turning on archive_mode in 8.4).
>
> There is not only a performance penalty, but a reliability penalty.
> Enabling these switches turns on a whole lot of code that, with all
> due respect to those who have worked on it, is absolutely positively
> guaranteed to be full of bugs.  Not all of which are going to be flushed
> out during beta.  If we ship 9.0 with these things on by default, it
> will result in an immediate reliability downgrade for installations that
> are simply doing what they did before and not even interested in HS/SR.

This is a pretty good argument, and Heikki's argument just upthread
that a mismatched max_connections setting could bollix things is an
even better one.  So I'm now changing my mind and thinking this should
be off by default, also.

...Robert