Re: Equivalent praxis to CLUSTERED INDEX? - Mailing list pgsql-performance

From Gaetano Mendola
Subject Re: Equivalent praxis to CLUSTERED INDEX?
Date
Msg-id 41306EF3.2030304@bigfoot.com
Whole thread Raw
In response to Re: Equivalent praxis to CLUSTERED INDEX?  (Greg Stark <gsstark@mit.edu>)
List pgsql-performance
Greg Stark wrote:

> Bruce Momjian <pgman@candle.pha.pa.us> writes:
>
>
>>>Don't you think this will permit also to avoid extra disk seek and cache
>>>invalidation? If you are updating the row (0,1) I think is less expensive
>>>put the new version in (0,2) instead of thousand line far from that point.
>
>
> Well if the other buffer "a thousand lines far from that point" is already in
> ram, then no, there's no penalty at the time for storing it there.

I was wandering about the cache invalidation, may be the ram is big enough but I
doubt about the cache, the recommendation in this case is to modify adjacent
memory address instead of jumping.


Regards
Gaetano Mendola



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