On Nov 22, 2006, at 1:51 PM, John D. Burger wrote:
However, Cluster might work for you, but you need to re-cluster after
every updates or inserts, so it will probably be fine for static
data.
This reminds me of a (somewhat off-topic) question I have had:
I have a static database, and most of the tables are 100%
correlated with one column or another (because I build them that
way, or due to clustering). In some cases I join two tables on one
of these perfectly correlated columns, and so the planner wants to
sort the two on that column. Of course, this is unnecessary, and
for large tables, the sorts get spilled to disk (I suppose) and can
take a while. Is there any way to convince the planner that the
sorts are unnecessary, and it can just zip the two tables together
as is?
This is under PG 7.4, by the way. Any comments welcome.
The problem is that there's no way to actually guarantee that the
table is already pre-sorted. If we had the concept of read-only
tables, and you clustered one of them, it could be made to work...
--
Jim Nasby jim.nasby@xxxxxxxxxxxxxxxx
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
