| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
| Cc: | Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl>, Greg Stark <gsstark(at)mit(dot)edu>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Question about indexes |
| Date: | 2004-01-30 15:39:46 |
| Message-ID: | 13877.1075477186@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> Alvaro Herrera wrote:
>> Is there a reason sort the pages before scanning them? The result won't
>> come out sorted one way or the other.
> I think the goal would be to hit the heap in sequential order as much as
> possible.
Exactly. Also, it'll be harder to AND or OR two bitmaps together if you
don't presort their pages. (I think the hash representation could do OR
without presort, but not AND.)
regards, tom lane
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