Re: query slow in 9i, but not slow in 8i

From: Juan Cachito Reyes Pacheco <jreyes_at_dazasoftware.com>
Date: Tue, 2 Mar 2004 15:35:50 -0400
Message-ID: <00ce01c4008d$9a0a94f0$2501a8c0@dazasoftware.com>

The problem here is you are doing several things like != what is forcing to do full scans

What I'll try if this query is really important is -- Create indexes on all columns you query, toget a full index scan instead a full table scan.
-- Be sure, there is an index on nvl(seqtable.valid, 'Y') -- test to add to pid is not null to nvl(pid,'~') ='~' and create a index on that

I think you have to optimize the access table by table, and then the order of tables, I agree you should try to find a way, if possible, to avoid distinct.

Original Message ----- From: "Jamadagni, Rajendra" <Rajendra.Jamadagni_at_espn.com> To: <oracle-l_at_freelists.org> Sent: Tuesday, March 02, 2004 3:29 PM Subject: RE: query slow in 9i, but not slow in 8i

removing redundant "distinct" might help in this query too ...

Raj

Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. select standard_disclaimer from company_requirements; QOTD: Any clod can have facts, having an opinion is an art !

-----Original Message-----
Guang Mei wrote:

> I understand that the cost value does not mean anything. But from my
> experience, when I see a query's cost from explain plan reaches six
> digits, usually something is not right.
>
> Anyway the actual query has much more stuff in it. The sql I showed in my
> orginal post was only part of it and that was the part that slowed the
thing down.
> I can not run the sql on 9i now since they are other stuff running. But
> the orgianl complex query took 20 minutes to finish on 8i, and the
> exact query produced this in 9i's alert log file:
>
> ORA-01555 caused by SQL statement below (Query Duration=199335 sec, SCN:
> 0x0000.01db218e):
> Sun Feb 29 23:20:46 2004
> select distinct accession, id
> from (
> select distinct to_char(PID) accession, identifier.ID
> from mt.genbankinfo, mt.seqtable, mt.identifier
> where seqtable.ID = genbankinfo.SeqtabID
> and seqtable.GeneID = identifier.GeneID
> and PID is not null
> and identifier.type != 'A'
> and identifier.speciesid in
> (24,31,2,19,18,17,23,21,27,32,20,34,30,22,25,26,28,29)
> and nvl(seqtable.valid, 'Y') != 'N'
> union all
> select distinct upper(strings.strtok(protein_id, '.')) accession,
> identifier.id
> from mt.genbankinfo, mt.seqtable, mt.identifier
> where seqtable.ID = genbankinfo.SeqtabID
> and seqtable.GeneID = identifier.GeneID
> and protein_id is not null
> and identifier.t
> .....

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Received on Tue Mar 02 2004 - 13:35:52 CST