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To: "Jignesh K. Shah" <J.K.Shah@Sun.COM>
cc: Simon Riggs <simon@2ndquadrant.com>, Josh Berkus <josh@agliodbs.com>,
	pgsql-performance@postgresql.org,
	Alvaro Herrera <alvherre@commandprompt.com>
Subject: Re: User concurrency thresholding: where do I look? 
In-reply-to: <46A8BD62.2080904@sun.com> 
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Comments: In-reply-to "Jignesh K. Shah" <J.K.Shah@Sun.COM>
	message dated "Thu, 26 Jul 2007 11:27:30 -0400"
Date: Thu, 26 Jul 2007 11:42:48 -0400
Message-ID: <27577.1185464568@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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"Jignesh K. Shah" <J.K.Shah@Sun.COM> writes:
> For  600-850 Users: that potential mislabeled CheckPointStartLock  or 
> LockID==12 comes from various sources where the top source (while system 
> is still doing great) comes from:

>               postgres`LWLockAcquire+0x1c8
>               postgres`SimpleLruReadPage_ReadOnly+0xc
>               postgres`TransactionIdGetStatus+0x14

That path would be taking CLogControlLock ... so you're off by at least
one.  Compare the script to src/include/storage/lwlock.h.

			regards, tom lane