Subject: Re: Synchronization primitives (Was: Re: An example of
	bugs for Hot Standby)
From: Simon Riggs <simon@2ndQuadrant.com>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>,
	pgsql-hackers@postgresql.org, Hiroyuki Yamada <yamada@kokolink.net>
In-Reply-To: <4B5744C1.40806@enterprisedb.com>
References: <200912151111.AA00168@silver.kokolink.net>
	<201001201740.22069.andres@anarazel.de>
	<14578.1264006776@sss.pgh.pa.us>
	<201001201841.15760.andres@anarazel.de>
	<4B5744C1.40806@enterprisedb.com>
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Date: Wed, 20 Jan 2010 18:45:07 +0000
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On Wed, 2010-01-20 at 20:00 +0200, Heikki Linnakangas wrote:

> Hot standby also has a polling loop where it waits for a
> transaction a transaction to die, though I'm not sure if that can be
> fit into the same model

I prefer that in the context of HS because the Startup process is
waiting for things to die. Given that their death may not be handled
sweetly, I would not wish to rely on that to wake Startup.

In the other two cases you mention all processes are working together
normally and we aren't expecting the other processes to die.

-- 
 Simon Riggs           www.2ndQuadrant.com