Skip site navigation (1) Skip section navigation (2)

Re: Proposal for Allow postgresql.conf values to be changed via SQL

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Magnus Hagander <magnus(at)hagander(dot)net>, Amit Kapila <amit(dot)kapila(at)huawei(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Christopher Browne <cbbrowne(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Proposal for Allow postgresql.conf values to be changed via SQL
Date: 2012-11-07 18:47:54
Message-ID: CA+Tgmob-h1fUeBBP4jz96xBpXrAs5FUjHM8MYXMjGVYFn6UdAg@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On Wed, Nov 7, 2012 at 12:29 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Magnus Hagander <magnus(at)hagander(dot)net> writes:
>> On Wed, Nov 7, 2012 at 6:19 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> You could dig it out of the stack if it's there, but that doesn't fix
>>> the race-condition aspect.  Now a race is inevitable if two sessions try
>>> to set the *same* variable, but I think people will be unhappy if a SET
>>> on one variable makes a recent SET on some other variable disappear.
>
>> I think if we require an exclusive lock on a single global lock for
>> "set permanent", people are quite ok with that, really.
>
> That doesn't fix it either, at least not without a whole lot of other
> changes --- we don't normally read the config file within-commands,
> and there are both semantic and implementation problems to overcome
> if you want to do so.

Why would you need to?  It seems to me that we ought to be able to
rewrite a machine-generated configuration file without loading those
values into the current session.  If we can't, that seems like prima
facie evidence that the format is not sufficiently easy to
machine-parse.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


In response to

Responses

pgsql-hackers by date

Next:From: Tom LaneDate: 2012-11-07 18:58:13
Subject: Re: Proposal for Allow postgresql.conf values to be changed via SQL
Previous:From: Tom LaneDate: 2012-11-07 17:52:22
Subject: Re: Extend libpq to support mixed text and binary results

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group