From: Andres Freund <andres@anarazel.de>
To: Simon Riggs <simon@2ndquadrant.com>
Subject: Re: Small locking bugs in hs
Date: Mon, 28 Dec 2009 01:16:25 +0100
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Cc: pgsql-hackers@postgresql.org
References: <200912272012.32556.andres@anarazel.de>
	<1261951809.18116.458.camel@ebony>
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On Sunday 27 December 2009 23:10:09 Simon Riggs wrote:
> On Sun, 2009-12-27 at 20:12 +0100, Andres Freund wrote:
> > While unlikely to cause issues two new LWLockAcquire calls use the wrong
> > locking mode.
> > Patch attached.
> It's important to explain why you think something is a bug, rather than
> make that claim on its own.
Youre right.

My idea was that another SIGINT handler (e.g. normal client query cancel) is 
running while CONFLICT_MODE_FATAL is issued that might get ignored. Thus the 
fatal error might get ignored.
But actually that was mostly my gut feeling - I am not really understanding 
the whole query cancellation process yet.
(Its not exactly unlikely that my patch does not fix that though)

I think that if under protection of a shared lock the protected objects gets 
altered, that definitely needs to be commented from my pov...
In the reverse case its not as important but still a good idea.

> However, I think I see a different issue with conflict handling, so
> looking at this again was worthwhile, thanks. Will come back with more
> over next few days.
Cool.

Andres