Re: Small locking bugs in hs - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Small locking bugs in hs
Date
Msg-id 200912280116.25771.andres@anarazel.de
Whole thread Raw
In response to Re: Small locking bugs in hs  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
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


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