From: Mark Kirkwood <markir@paradise.net.nz>
To: Luke Lonergan <llonergan@greenplum.com>
Cc: Dave Cramer <pg@fastcrypt.com>
Cc: Greg Stark <gsstark@mit.edu>
Cc: Joshua Marsh <icub3d@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Hardware/OS recommendations for large databases (
Date: Sun, 20 Nov 2005 10:28:57 +1300
Message-ID: <437F9919.20305@paradise.net.nz> (raw)
In-Reply-To: <BFA3ABF0.14124%llonergan@greenplum.com>
References: <BFA3ABF0.14124%llonergan@greenplum.com>
Luke Lonergan wrote:
> Mark,
>
> On 11/18/05 3:46 PM, "Mark Kirkwood" <markir@paradise.net.nz> wrote:
>
>
>>If you alter this to involve more complex joins (e.g 4. way star) and
>>(maybe add a small number of concurrent executors too) - is it still the
>>case?
>
>
> 4-way star, same result, that's part of my point. With Bizgres MPP, the
> 4-way star uses 4 concurrent scanners, though not all are active all the
> time. And that's per segment instance - we normally use one segment
> instance per CPU, so our concurrency is NCPUs plus some.
>
Luke - I don't think I was clear enough about what I was asking, sorry.
I added the more "complex joins" comment because:
- I am happy that seqscan is cpu bound after ~110M/s (It's cpu bound on
my old P3 system even earlier than that....)
- I am curious if the *other* access methods (indexscan, nested loop,
hash, merge, bitmap) also suffer then same fate.
I'm guessing from your comment that you have tested this too, but I
think its worth clarifying!
With respect to Bizgres MPP, scan parallelism is a great addition...
very nice! (BTW - is that in 0.8, or are we talking a new product variant?)
regards
Mark
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: markir@paradise.net.nz, llonergan@greenplum.com, pg@fastcrypt.com, gsstark@mit.edu, icub3d@gmail.com
Subject: Re: Hardware/OS recommendations for large databases (
In-Reply-To: <437F9919.20305@paradise.net.nz>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox