| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Jim C(dot) Nasby" <decibel(at)decibel(dot)org> |
| Cc: | Neil Conway <neilc(at)samurai(dot)com>, Christopher Petrilli <petrilli(at)gmail(dot)com>, Ying Lu <ying_lu(at)cs(dot)concordia(dot)ca>, pgsql-general(at)postgresql(dot)org, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: [PERFORM] "Hash index" vs. "b-tree index" (PostgreSQL |
| Date: | 2005-05-10 18:07:00 |
| Message-ID: | 20884.1115748420@sss.pgh.pa.us |
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| Lists: | pgsql-general pgsql-performance |
"Jim C. Nasby" <decibel(at)decibel(dot)org> writes:
> Well, in a hash-join right now you normally end up feeding at least one
> side of the join with a seqscan. Wouldn't it speed things up
> considerably if you could look up hashes in the hash index instead?
That's called a "nestloop with inner index scan", not a hash join.
regards, tom lane
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