On Mar 16, 2007, at 9:53 AM, Heikki Linnakangas wrote:

Grzegorz Jaskiewicz wrote:
Because CLUSTER is divided into two major operations, (data reordering, index rebuild) - I see it this way:
CLUSTER on I: <index name> T: <table name>, data reordering
CLUSTER on I: <index name> T: <table name>, index rebuild

Something like that would be nice to see how long each step takes, like vacuum verbose.

I am looking for opinions, on what information should be presented.

What would be useful is some kind of a metric of how (de)clustered the table was before CLUSTER, and the same # of dead vs. live row counts that vacuum verbose prints.
Is that information available in cluster.c atm ? I am looking for some hints here. One of the reasons I decided to go with this patch, is to learn something - and cluster seems to be touching very 'bone' of postgres, tuples system (just like vacuum), and indices. I would appreciate any hints.

We don't really have a good metric for clusteredness, as have been discussed before, so if you can come up with a good one that would be useful in the planner as well, that would be great.

I really don't know where and how should I calculate such param. Any hints ?


Grzegorz Jaskiewicz

C/C++ freelance for hire

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