X-Original-To: pgsql-sql@postgresql.org Received: from luckydigital.com (www.luckydigital.com [203.109.157.4]) by postgresql.org (Postfix) with ESMTP id 48491476022 for ; Wed, 5 Mar 2003 19:54:49 -0500 (EST) Received: from jax (203-109-198-1.akl.ihugultra.co.nz [203.109.198.1]) by luckydigital.com (8.11.6/8.10.0) with SMTP id h260soh01034 for ; Thu, 6 Mar 2003 13:54:50 +1300 Message-ID: <003701c2e37a$fe0bb2d0$c900a8c0@jax> From: "James Cooper" To: "sql" Subject: INTERSECT / where id IN (etc..) Date: Thu, 6 Mar 2003 13:54:50 +1300 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0034_01C2E3E7.F4C1B040" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Archive-Number: 200303/163 X-Sequence-Number: 12203 This is a multi-part message in MIME format. ------=_NextPart_000_0034_01C2E3E7.F4C1B040 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Greetings. I was wondering if somone out there could shed some light on a query perfor= mance issie I have. I have a large lookup table that I query with nested selects to gain the IN= TERSECT result from. the bigger this table gets the slower the performance. 1. is creating a temp table and only intersecting from this a good idea? 2. does having a where clause in your select before your nested intersects = change the amount of work the query i.e. select person_id from person where person_id < 5000 And person_id IN as opposed to select person_id from person where person_id IN(etc) thoughts? ------=_NextPart_000_0034_01C2E3E7.F4C1B040 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Greetings.
 
I was wondering if somone out there could = shed some=20 light on a query performance issie I have.
I have a large lookup table that I query w= ith=20 nested selects to gain the INTERSECT result from.
 
the bigger this table gets the slower the= =20 performance.
 
1. is creating a temp table and only=20 intersecting from this a good idea?
2. does having a where clause in your sele= ct before=20 your nested intersects change the amount of work the query
 
i.e. select person_id from person where pe= rson_id=20 < 5000 And person_id IN
    as opposed to
    select person_id from p= erson=20 where person_id IN(etc)
 
thoughts?
 
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