Horton

Re: Win2K Questions

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jean-Luc Lachance <jllachan@nsd.ca>
Cc: Neil Conway <neilc@samurai.com>, "scott.marlowe" <scott.marlowe@ihs.com>, Bruce Momjian <pgman@candle.pha.pa.us>, "Charles H. Woloszynski" <chw@clearmetrix.com>, Richard Huxton <dev@archonet.com>, pgsql-general@postgresql.org
Date: 2002-11-11T17:55:32Z
Lists: pgsql-general 
Jean-Luc Lachance <jllachan@nsd.ca> writes:
> What would be involved in adding version and visibility to the index?

* Index bloat.  An index entry is currently 8 bytes plus the index key,
eg 12 bytes for an int4 index.  Version info would add 12 bytes.
Doubling the size of indexes would double the time for index scans.

* Update costs.  Instead of one place to update when a row is updated,
now all the associated index entries would have to be updated too.

			regards, tom lane