On Wed, 2007-04-04 at 14:20 +0200, Markus Schiltknecht wrote:
> Both proposals do not have much to do with the missing multi-table
> indices. It's clear to me that we have to implement those someday,
> anyway.
I agree with much of your post, though this particular point caught my
eye. If you'll forgive me for jumping on an isolated point in your post:
Multi-table indexes sound like a good solution until you consider how
big they would be. The reason we "need" a multi-table index is because
we are using partitioning, which we wouldn't be doing unless the data
was fairly large. So the index is going to be (Num partitions *
fairly-large) in size, which means its absolutely enormous. Adding and
dropping partitions also becomes a management nightmare, so overall
multi-table indexes look unusable to me. Multi-table indexes also remove
the possibility of loading data quickly, then building an index on the
data, then adding the table as a partition - both the COPY and the
CREATE INDEX would be slower with a pre-existing multi-table index.
My hope is to have a mechanism to partition indexes or recognise that
they are partitioned, so that a set of provably-distinct unique indexes
can provide the exact same functionlity as a single large unique index,
just without the management nightmare.
-- Simon Riggs EnterpriseDB http://www.enterprisedb.com