Re: Is there any limitations - Mailing list pgsql-performance

From li li
Subject Re: Is there any limitations
Date
Msg-id Pine.GSO.4.33.0212031150100.6166-100000@ix.cs.uoregon.edu
Whole thread Raw
In response to Re: Is there any limitations  (Nikk Anderson <Nikk.Anderson@parallel.ltd.uk>)
List pgsql-performance
Hi Nikk,

> I thought of doing this recently, as queries were taking so long.  Instead
> of breaking the table up, we clustered the data.  This physically moves all
> the data by key close to each other on disk (sounds kind of like defragging
> a disk).  This boosts query responses no end - for example our table has ~
> 10 million rows, a query that was taking 45 seconds to return, now takes 7
> seconds.  To keep the table tidy, we run the cluster regularly.
>
I've clustered the data with a non-key attribute. Now the query time is
about couple of minutes, but I expect less than one minute. Is there any trick
in using cluster? I found that the primary key disappeared after
clustering. Or it's better to cluster with primary key? My primary key is
a composite. I picked one attribute as cluster key.

> > As the size of the original table is increasing fast, I want
> > to get it separated once the size grows up to a limit. So there
> > will be a large amount of tables (having same structure) in a
> > database. Is
> > there any potential performance problem with this design?
> >
>
> I think the problems would mainly be in management, as you would have to
> keep track of the new table names, key names, and index names.
>
You are right. I have to keep track of these table names.
However, I don't see any necessity for key names or index names. Because,
as I metioned above, all these tables have exactly same structure.

Thanks for quick response.

Li Li


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