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