From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jignesh K. Shah <J.K.Shah@Sun.COM>
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 16:57:34 -0400
Message-ID: <15343.1184965054@sss.pgh.pa.us> (raw)
In-Reply-To: <46A1205B.8010205@sun.com>
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>
<46A1205B.8010205@sun.com>
"Jignesh K. Shah" <J.K.Shah@Sun.COM> writes:
> 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
That's a perfect example of the sort of useless overhead that I was
complaining of just now in pgsql-patches. Having malloc/free use
an internal mutex is necessary in multi-threaded programs, but the
backend isn't multi-threaded. And yet, apparently you can't turn
that off in Solaris.
(Fortunately, the palloc layer is probably insulating us from malloc's
performance enough that this isn't a huge deal. But it's annoying.)
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, J.K.Shah@Sun.COM, josh@agliodbs.com, alvherre@commandprompt.com
Subject: Re: User concurrency thresholding: where do I look?
In-Reply-To: <15343.1184965054@sss.pgh.pa.us>
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