> Bruce,
>
> I did not know Postgresql had that. I have just looked at the docs and
> it seems that the postgresql CLUSTER is similar to the feature in MS SQL
> Server but at present is rather more limited as
It is in the FAQ under Performance too.
> a) It is static whereas CLUSTER can be set as an attribute on an index
> in MS SQL Server and then ther index is not created separately the table
> is kept permanently sorted by the index. This obviously is very very
> slow if you add to the middle of the index and wasteful of space if you
> delete rows from the table. However, for a sequential ID it is supposed
> to work well.
Well, sometimes it is better to have control over when this happens.
What is why cluster is nice, and we don't have time to add dynamic
cluster right now.
>
> b) as the Postgresql CLUSTER is static it does not replace the index.
>
> I should say at this point that I never actually used the CLUSTER
> feature in MS SQL Server as we decided not to use that product after
> evaluating it. So I have no practical experience to know how much of the
> speed improvement wanted by Leon it would deliver.
See the performance FAQ. If you look in
pgsql/contrib/fulltextindex/README, we mention it too because without
it, fulltext indexing is slow.
--
Bruce Momjian | http://www.op.net/~candle
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