Message-ID: <4ACF77E7.6040603@enterprisedb.com>
Date: Fri, 09 Oct 2009 13:50:31 -0400
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>	
	<4ABF4522.6060601@enterprisedb.com>	
	<1254743455.4691.153.camel@ebony.2ndQuadrant>	
	<4ACA6EDE.4020407@enterprisedb.com>
	<1254813572.26302.38.camel@ebony.2ndQuadrant>
In-Reply-To: <1254813572.26302.38.camel@ebony.2ndQuadrant>
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Simon Riggs wrote:
>> Tom Lane wrote:
>>> [ scratches head ... ]  Why is hot standby messing with this sort of
>>> thing at all?  It sounds like a performance optimization that should
>>> be considered separately, and *later*.
>> Yeah, I too considered just ripping it out. Simon is worried that
>> locking all the lock partitions and scanning the locks table can take a
>> long time. We do that in the master, while holding both ProcArrayLock
>> and XidGenLock in exclusive mode (hmm, why is shared not enough?), so
>> there is some grounds for worry. OTOH, it's only done once per checkpoint.
> 
> I could live with ripping it out, but what we have now doesn't make
> sense, to me.

Ok, let's just rip it out for now.

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