Re: Regression in IN( field, field, field ) performance

From: Gregory Stark <stark(at)enterprisedb(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Decibel! <decibel(at)decibel(dot)org>, Postgres Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Regression in IN( field, field, field ) performance
Date: 2008-10-21 22:54:20
Message-ID: 87wsg1sgo3.fsf@oxford.xeocode.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Works fine for me, eg
...
> -> Bitmap Heap Scan on tenk1 b (cost=0.79..4.82 rows=3 width=244)
> Recheck Cond: (b.unique2 = ANY (ARRAY[a.unique1, a.ten, a.hundred]))
> -> Bitmap Index Scan on tenk1_unique2 (cost=0.00..0.79 rows=3 width=0
> )
> Index Cond: (b.unique2 = ANY (ARRAY[a.unique1, a.ten, a.hundred])

But that's an index on the lhs of the =ANY which in his example was just a
constant.

> You'll need to provide a concrete test case if you think there's
> something broken here.

I think he's looking for something like:

5 IN (col1,col2,col3)

resulting in a bitmap or of three index scans of three different indexes on
col1, col2, and col3.

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
Ask me about EnterpriseDB's RemoteDBA services!

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Gregory Stark 2008-10-21 23:00:08 Re: Bitmap Indexes: request for feedback
Previous Message Myron Scott 2008-10-21 22:50:33 Re: Multi CPU Queries - Feedback and/or suggestions wanted!