Date: Fri, 22 Jul 2016 19:43:12 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Jerry Sievers <gsievers19@comcast.net>
Cc: pgsql-admin@postgresql.org
Subject: Re: Pg-Upgrade standbys via rsync... and avoid sending
 UNlogged data?
Message-ID: <20160722234312.GA15377@momjian.us>
References: <86d1m5b6bi.fsf@jerry.enova.com>
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On Fri, Jul 22, 2016 at 06:29:05PM -0500, Jerry Sievers wrote:
> Has anyone found a clever way to $subject that doesn't involved
> calculating which are all of the  files unnecessary to send and then
> running rsync with an exclude list?
> 
> I'm pondering this right now. 
> 
> ISTM for each unlogged table/index/toast  in pg_class where
> relpersistence='u'...
> 
> rsync --exclude-from... (and exclude-from-file contains)
> 
> */base/$dbid/$relfilenode
> */base/$dbid/$relfilenode.*
> */base/$dbid/$relfilenode_*
> ...
> 
> The leading * will match the old/new data directoryes being sent to the
> standby.
> 
> MAster upgrade is done using hard-links and the rsync method generally
> as per the pg docs.
> 
> I have among others, a 5TB system  w/about 40G of unlogged data.
> 
> The rsync method of upgrade takes only several seconds during a snapshot
> based test however as the snap was off a live system, the crash recovery
> startup trunc'd all the unlogged data.
> 
> This will not be the case during the real upgrade and I just as soon
> avoid sending the unlogged data only to have it trunc'd away as soon as
> the standby is started after the upgrade. 

Good question --- I don't think there is an easy answer except to
truncate the unlogged tables before the upgrade.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I. As I am, so you will be. +
+                     Ancient Roman grave inscription +


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