From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-hackers(at)postgreSQL(dot)org |
Subject: | Re: [HACKERS] Bizarre coding in _bt_binsrch |
Date: | 1999-11-30 02:13:23 |
Message-ID: | 199911300213.VAA21480@candle.pha.pa.us |
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Lists: | pgsql-hackers |
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Tom, I assume you have dealt with this, right?
>
> >> I have been puzzling out the coding in _bt_binsrch() in
> >> backend/access/nbtree/nbtsearch.c, with an eye to speeding it up for
> >> the many-equal-keys case.
>
> I tweaked the code to go faster in the equal-keys case, but Vadim later
> pointed out that what we *really* should do is force the algorithms to
> never consider two index keys equal (eg, by including the heap tuple id
> as the last part of the comparison key). See his pgsql-hackers message
> dated 06 Jun 1999 21:32:36 +0800. Getting the full benefit would
> require ripping out the BTP_CHAIN logic and doing some other major
> surgery, so I don't feel like I know the btree code well enough to
> tackle it. It should be on the TODO list though:
>
> * Include heap CTID in btree index keys, remove equal-key cruft from btree
Thanks. That's what I needed.
--
Bruce Momjian | http://www.op.net/~candle
maillist(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
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