Message-ID: <4AC5A60F.5050503@enterprisedb.com>
Date: Fri, 02 Oct 2009 10:04:47 +0300
From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Organization: EnterpriseDB
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To: Simon Riggs <simon@2ndQuadrant.com>
CC: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Hot Standby on git
References: <1253958559.4449.833.camel@ebony.2ndQuadrant>	
	<4AC2FBB9.7060304@enterprisedb.com>	
	<1254408330.17864.233.camel@ebony.2ndQuadrant>	
	<4AC4CF18.50309@enterprisedb.com>
	<1254413624.17864.243.camel@ebony.2ndQuadrant>
In-Reply-To: <1254413624.17864.243.camel@ebony.2ndQuadrant>
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Simon Riggs wrote:
> @@ -7061,6 +7061,15 @@ ShutdownXLOG(int code, Datum arg)
>     else
>     {
>         /*
> +        * Take a snapshot of running transactions and write this to WAL.
> +        * This allows us to reconstruct the state of running transactions
> +        * during archive recovery, if required. We do this even if we are
> +        * not archiving, to allow a cold physical backup of the server to
> +        * be useful as a read only standby.
> +        */
> +       GetRunningTransactionData();
> +
> +       /*
>          * If archiving is enabled, rotate the last XLOG file so that all the
>          * remaining records are archived (postmaster wakes up the archiver
>          * process one more time at the end of shutdown). The checkpoint
> 

I don't think this will do any good where it's placed. The checkpoint
that follows will have its redo-pointer beyond the running-xacts record,
so WAL replay will never see it.

-- 
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com