Re: Concurrent COPY commands

> Define low. 2 disks maxed out doing random I/O could show as little as 2
or
> 3 MB/sec in vmstat.

While the copy commands are not at 100% CPU it is about that low. It does go
up at times, but not by much (maybe 5-7 MB/sec). Does a COPY command count
as random I/O if the data it's reading is actually a memory FIFO and it's
only reading data in for the current (not completed) transaction? The disks
are completely dedicated to the database, so postgres is the only app using
it.

> You say one CPU core is maxed out - what state is it mostly in at 100% -
> user, system, or wait?

I'll double-check, but I'm certain that it was user. The behavior didn't
seem to change when I changed the table layout either.

- Phillip

On Wed, Jul 9, 2008 at 9:45 AM, Alan Hodgson <ahodgson(at)simkin(dot)ca> wrote:

> On Wednesday 09 July 2008, "Phillip Sitbon" <phillip(at)sitbon(dot)net> wrote:
> > I only have two fast SATA drives on software RAID, but that really isn't
> > the issue- while the copy commands are going, disk activity is relatively
> > low.
>
> Define low. 2 disks maxed out doing random I/O could show as little as 2 or
> 3 MB/sec in vmstat.
>
> You say one CPU core is maxed out - what state is it mostly in at 100% -
> user, system, or wait?
>
>
> --
> Alan
>
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