From: Nick Matheson <Nick.D.Matheson@noaa.gov>
To: Marti Raudsepp <marti@juffo.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Simple (hopefully) throughput question?
Date: Thu, 04 Nov 2010 14:34:55 +0000
Message-ID: <4CD2C48F.1040208@noaa.gov> (raw)
In-Reply-To: <AANLkTik9sP6cNubT1VVW+qEJ2cRxz7TEEP96sYZMbRSX@mail.gmail.com>
References: <4CD1853F.2010800@noaa.gov>
<AANLkTik9sP6cNubT1VVW+qEJ2cRxz7TEEP96sYZMbRSX@mail.gmail.com>
Marti-
> Just some ideas that went through my mind when reading your post
> PostgreSQL 8.3 and later have 22 bytes of overhead per row, plus
> page-level overhead and internal fragmentation. You can't do anything
> about row overheads, but you can recompile the server with larger
> pages to reduce page overhead.
>
>
>> Is there any way using stored procedures (maybe C code that calls
>> SPI directly) or some other approach to get close to the expected 35
>> MB/s doing these bulk reads?
>>
>
> Perhaps a simpler alternative would be writing your own aggregate
> function with four arguments.
>
> If you write this aggregate function in C, it should have similar
> performance as the sum() query.
>
You comments seem to confirm some of our foggy understanding of the
storage 'overhead' and nudge us in the direction of C stored procedures.
Do you have any results or personal experiences from moving calculations
in this way? I think we are trying to get an understanding of how much
we might stand to gain by the added investment.
Thanks,
Nick
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To: pgsql-performance@postgresql.org
Cc: Nick.D.Matheson@noaa.gov, marti@juffo.org
Subject: Re: Simple (hopefully) throughput question?
In-Reply-To: <4CD2C48F.1040208@noaa.gov>
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