| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Jean-Luc Lachance <jllachan(at)nsd(dot)ca> |
| Cc: | Neil Conway <neilc(at)samurai(dot)com>, "scott(dot)marlowe" <scott(dot)marlowe(at)ihs(dot)com>, Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, "Charles H(dot) Woloszynski" <chw(at)clearmetrix(dot)com>, Richard Huxton <dev(at)archonet(dot)com>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Win2K Questions |
| Date: | 2002-11-11 17:55:32 |
| Message-ID: | 3077.1037037332@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Jean-Luc Lachance <jllachan(at)nsd(dot)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
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