Message-ID: <4C07E137.1070400@2ndquadrant.com>
Date: Thu, 03 Jun 2010 13:07:03 -0400
From: Greg Smith <greg@2ndquadrant.com>
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To: v.tolstov@selfip.ru
CC: Shoaib Mir <shoaibmir@gmail.com>, Anh Ky Huynh <xkyanh@gmail.com>,
	PostgreSQL Admin <pgsql-admin@postgresql.org>
Subject: Re: graceful reload
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	<AANLkTimZnrPMgeo_Wdy8lLnH5PmWiZnbuu7bIwKqefx2@mail.gmail.com>
	<1275552074.23110.7.camel@work.selfip.ru>
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Vasiliy G Tolstov wrote:
> In config file some in of this settings exists comment line like
> "changes require restart". This is mean exactly restart or reload can do
> this?
>   

Run this:

$ psql -c "select name,context from pg_settings"

This will sort out which settings are in which category definitively, 
rather than relying on the sometimes ambiguous comments in the file.  
Settings that say "postmaster" require a full database restart.  Ones 
labeled "sighup" can be changed in the postgresql.conf and then the 
server signaled to use them, most easily with:

pg_ctl reload
-OR-
psql -c "select pg_reload_conf()"

Ones labeled "user" you can actually change for any user at any time 
during their session.  Modifying the defaults and then executing the 
sighup procedure will make those new defaults active, but not for any 
clients that already have open connections.

I recommend using SHOW or looking at pg_settings after making a change 
and reloading the server config to confirm it took.

-- 
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us