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Re: Concurrent COPY commands

From: Alan Hodgson <ahodgson(at)simkin(dot)ca>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: Concurrent COPY commands
Date: 2008-07-02 17:02:48
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-novice
On Wednesday 02 July 2008, Phillip Sitbon <phillip(at)sitbon(dot)net> wrote:
> Hello,
> I am running some queries that use multiple connections to issue COPY
> commands which bring data into the same table via different files (FIFOs
> to be precise). This is being done on a SMP machine and I am noticing
> that none of the postgres worker processes operate in parallel, even
> though there is data available to all of them. The performance is nearly
> exactly the same as it is for issuing a single COPY command.
> Is this 
> normal behavior, even with all of the separate transactions still in
> progress? Would I be better off doing multithreaded bulk inserts from my
> C program rather than sending the data to FIFOs?

Sounds like you're I/O bound - I doubt any other concurrency mechanism will 
change that much.

> The machine I am using has 16GB of memory and 8 cores, so I've tried to
> optimize the configuration accordingly but I am a little lost in some
> places.

Ah, but what does your RAID controller and drives look like?


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