Re: [RFC] CLUSTER VERBOSE

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.
yup.

>> 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 ?

thanks.

--
Grzegorz Jaskiewicz

C/C++ freelance for hire