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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
	Luke Koops <luke.koops@entrust.com>, Pg Bugs <pgsql-bugs@postgresql.org>
Subject: Re: BUG #4958: Stats collector hung on WaitForMultipleObjectsEx while
	attempting to recv a datagram
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Thu, 06 Sep 2012 14:40:55 -0400"
Date: Thu, 06 Sep 2012 16:58:11 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> Well, bad news.  Dave built an installer off the 9.1 tip, we provided
> it to the customer, and they can still reproduce the problem.  It's
> not clear whether we've narrowed the scope of the problem without
> eliminating it, or whether that fix just didn't help at all.  But they
> still can't reproduce it on 9.2.  This suggests that there's some
> other difference between 9.1 and 9.2 that is relevant here, but I'm
> not sure what.  Any ideas?

I guess that's reassuring, in a way: it means that all the thrashing
about we did to get the latch-ified stats collector logic to work on
Windows actually brought us to a better place.

However, for the purposes of fixing the older branches, it's not so
nice.  I think it means that we'd have to back-port some or all of the
latch-related changes in pgstat.c:

commit 966970ed636586b80739c0d21aec7561f0fafedd
commit f1ca51549e9e7045a2db95a61744334f1dbb4d64
commit d461d0502b6e20c6d4ec326ba2faec8212fd5dee
commit 9b63e9869ffaa4d6d3e8bf45086a765d8f310f1c

and maybe even some of these fixes in win32_latch.c:

commit e42a21b9e6c9b9e6346a34b62628d48ff2fc6ddf
commit f40022f1adaeff85b01d98fea38cf5aa16814aa7
commit 8ebc908c575b3378c9d4096412d16d91d107311c

At least, that's where I'd go looking if I were responsible for fixing
this, which is a responsibility I disclaim.  Looking through this
history reminds me how much time I've already wasted on that miserable
excuse for an operating system.

			regards, tom lane