| From: | Craig Ringer <craig(at)postnewspapers(dot)com(dot)au> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | david(at)lang(dot)hm, Simon Riggs <simon(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, henk de wit <henk53602(at)hotmail(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Transparent table partitioning in future version of PG? |
| Date: | 2009-05-09 01:25:38 |
| Message-ID: | 4A04DB92.1060405@postnewspapers.com.au |
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| Lists: | pgsql-performance |
Robert Haas wrote:
> Well, even if the table is not partitioned at all, I don't see that it
> should preclude parallel query access. If I've got a 1 GB table that
> needs to be sequentially scanned for rows meeting some restriction
> clause, and I have two CPUs and plenty of I/O bandwidth, ISTM it
> should be possible to have them each scan half of the table and
> combine the results. Now, this is not easy and there are probably
> substantial planner and executor changes required to make it work, but
> I don't know that it would be particularly easier if I had two 500 MB
> partitions instead of a single 1 GB table.
The point of partitioning in this scenario is primarily that you can put
the different partitions in different tablespaces, most likely on
independent disk devices. You therefore get more I/O bandwidth.
--
Craig Ringer
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