Re: insert/update tps slow with indices on table > 1M rows

From: Matthew Wakeling <matthew(at)flymine(dot)org>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: insert/update tps slow with indices on table > 1M rows
Date: 2008-06-04 15:10:38
Message-ID: Pine.LNX.4.64.0806041607120.3987@aragorn.flymine.org
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On Wed, 4 Jun 2008, andrew klassen wrote:
> I am using multiple threads, but only one worker thread for insert/updated to this table.
> I don't mind trying to add multiple threads for this table, but my guess is it would not
> help because basically the overall tps rate is decreasing so dramatically. Since
> the cpu time consumed by the corresponding postgresĀ server process for my thread is
> small it does not seem to be the bottleneck. There has to be a bottleneck somewhere else.
> Do you agree or is there some flaw in my reasoning?

There is indeed a flaw in your reasoning - there may be very little CPU
time consumed, but that just indicates that the discs are busy. Getting
Postgres to do multiple things at once will cause a more efficient use of
the disc subsystem, resulting in greater overall throughput. This is
especially the case if you have multiple discs in your box.

Matthew

--
Contrary to popular belief, Unix is user friendly. It just happens to be
very selective about who its friends are. -- Kyle Hearn

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