Re: Reducing stats collection overhead

From: Arjen van der Meijden <acm(at)tweakers(dot)net>
To: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: Reducing stats collection overhead
Date: 2007-05-19 14:12:04
Message-ID: 464F05B4.8030800@tweakers.net
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Afaik Tom hadn't finished his patch when I was testing things, so I
don't know. But we're in the process of benchmarking a new system (dual
quad-core Xeon) and we'll have a look at how it performs in the postgres
8.2dev we used before, the stable 8.2.4 and a fresh HEAD-checkout (which
we'll call 8.3dev). I'll let you guys (or at least Tom) know how they
compare in our benchmark.

Best regards,

Arjen

On 18-5-2007 15:12 Alvaro Herrera wrote:
> Tom Lane wrote:
>> Arjen van der Meijden told me that according to the tweakers.net
>> benchmark, HEAD is noticeably slower than 8.2.4, and I soon confirmed
>> here that for small SELECT queries issued as separate transactions,
>> there's a significant difference. I think much of the difference stems
>> from the fact that we now have stats_row_level ON by default, and so
>> every transaction sends a stats message that wasn't there by default
>> in 8.2. When you're doing a few thousand transactions per second
>> (not hard for small read-only queries) that adds up.
>
> So, did this patch make the performance problem go away?
>

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