From: Jignesh K. Shah <J.K.Shah@Sun.COM>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Josh Berkus <josh@agliodbs.com>
Cc: pgsql-performance@postgresql.org, Alvaro Herrera <alvherre@commandprompt.com>
Subject: Re: User concurrency thresholding: where do I look?
Date: Fri, 20 Jul 2007 16:51:39 -0400
Message-ID: <46A1205B.8010205@sun.com> (raw)
In-Reply-To: <14909.1184962561@sss.pgh.pa.us>
References: <200707190828.59088.josh@agliodbs.com>
<200707191819.13899.josh@agliodbs.com>
<15685.1184895926@sss.pgh.pa.us>
<200707192138.39679.josh@agliodbs.com>
<46A0FA31.2080208@sun.com>
<12002.1184955831@sss.pgh.pa.us>
<46A1055F.9010304@sun.com>
<12445.1184958793@sss.pgh.pa.us>
<46A11116.5030905@sun.com>
<14909.1184962561@sss.pgh.pa.us>
sorry..
The are solaris mutex locks used by the postgresql process.
What its saying is that there are holds/waits in trying to get locks
which are locked at Solaris user library levels called from the
postgresql functions:
For example both the following functions are hitting on the same mutex
lock 0x10059e280 in Solaris Library call:
postgres`AllocSetDelete+0x98
postgres`AllocSetAlloc+0x1c4
I need to enable the DTrace probes on my builds
-Jignesh
Tom Lane wrote:
> "Jignesh K. Shah" <J.K.Shah@Sun.COM> writes:
>
>> Tom Lane wrote:
>>
>>> So follow that up --- try to determine which lock is being contended
>>> for. There's some very crude code in the sources that you can enable
>>> with -DLWLOCK_STATS, but probably DTrace would be a better tool.
>>>
>
>
>> Using plockstat -A -s 5 -p $pid
>>
>
> I don't know what that is, but it doesn't appear to have anything to do
> with Postgres LWLocks or spinlocks, which are the locks I was thinking of.
> Try asking Robert Lor about this --- IIRC he had some dtrace probes to
> work with our locks.
>
> regards, tom lane
>
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: J.K.Shah@Sun.COM, tgl@sss.pgh.pa.us, josh@agliodbs.com, alvherre@commandprompt.com
Subject: Re: User concurrency thresholding: where do I look?
In-Reply-To: <46A1205B.8010205@sun.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox