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Re: SQL statement tuning

From: Finn Jorgensen <finn.oracledba_at_gmail.com>
Date: Wed, 28 Nov 2007 10:29:07 -0500
Message-ID: <74f79c6b0711280729m51c3b0f9gc943c7fef1d18faf@mail.gmail.com>


Clearly the "Eagle", "(0=0)" and "'Eagle = ' '" is generated by code somewhere, somehow and without the details of how and why it's generated like this, it's going to be difficult to suggest a solution.

Finn

On 11/28/07, Robin Li <rli_at_nyp.org> wrote:
>
> Yes, I did try this one and got the result as fast as without the 'OR'.
> The remedy application support group said that they had to contact BMC to
> see what they could do, because this query is only a small subset of the
> full query (lots of 'OR'), and a lot of other queries are like this.
>
> Thanks
>
> Robin
>
>
> Finn Jorgensen wrote:
>
> How about :
>
> SELECT T143.C1,C490021100,C1000000001,C200000020
> FROM aradmin.T143
> WHERE ((T143.C200000020 LIKE ('Eagle' || '%')) AND (0 = 0))
> union
> SELECT T143.C1,C490021100,C1000000001,C200000020
> FROM aradmin.T143
> WHERE ('Eagle' = ' ');
>
> Finn
>
>
> On 11/27/07, Robin Li <rli_at_nyp.org> wrote:
> >
> > -- Hi all,
> >
> > Can someone shed some light on how to tune this sql statement? Oracle
> > version 10.2
> >
> > SELECT T143.C1,C490021100,C1000000001,C200000020
> > FROM aradmin.T143
> > WHERE (((T143.C200000020 LIKE ('Eagle' || '%')) AND (0 = 0)) OR ('Eagle'
> > = ' '));
> >
> > Execution Plan
> > ----------------------------------------------------------
> > Plan hash value: 1317490582
> > ------------------------------------------------------------------------
> > | Id | Operation | Name | Rows | Bytes |
> > ------------------------------------------------------------------------
> >
> > | 0 | SELECT STATEMENT | | 7375 | 388K|
> > | 1 | TABLE ACCESS BY INDEX ROWID| T143 | 7375 | 388K|
> > |* 2 | INDEX RANGE SCAN | I143_200000020_1 | 7624 | |
> >
> > ------------------------------------------------------------------------
> > Predicate Information (identified by operation id):
> > ---------------------------------------------------
> > 2 - access("T143"."C200000020" LIKE 'Eagle%')
> > filter("T143"."C200000020" LIKE 'Eagle%')
> >
> > From the trace:
> >
> > SELECT T143.C1,C490021100,C1000000001,C200000020
> > FROM aradmin.T143
> > WHERE (((T143.C200000020 LIKE (:"SYS_B_0" || :"SYS_B_1")) AND
> > (:"SYS_B_2" = :"SY
> > S_B_3")) OR (:"SYS_B_4" = :"SYS_B_5"))
> >
> > call count cpu elapsed disk query
> > current rows
> > ------- ------ -------- ---------- ---------- ---------- ----------
> > ----------
> > Parse 1 0.00 0.00 0 0
> > 0 0
> > Execute 1 0.00 0.00 0 0
> > 0 0
> > Fetch 2 12.10 42.49 126166 130472
> > 0 1
> > ------- ------ -------- ---------- ---------- ---------- ----------
> > ----------
> > total 4 12.10 42.49 126166 130472
> > 0 1
> > Misses in library cache during parse: 0
> > Optimizer mode: ALL_ROWS
> > Parsing user id: 51
> >
> > Rows Row Source Operation
> > ------- ---------------------------------------------------
> > 1 TABLE ACCESS FULL T143 (cr=130472 pr=126166 pw=0 time=129302 us)
> >
> >
> > Elapsed times include waiting on following events:
> > Event waited on Times Max. Wait Total
> > Waited
> > ---------------------------------------- Waited ----------
> > ------------
> > SQL*Net message to client 2 0.00
> > 0.00
> > db file sequential read 824 0.03
> > 1.10
> > db file scattered read 8641 0.06
> > 33.40
> > SQL*Net message from client 2 0.00
> > 0.00
> >
> > There are 3.1 million rows for this table, the "Eagle" = " " is used in
> > workflow for a specific function on a remedy application. If I take out the
> > 'OR'(I figure it's always not true), the query runs in milliseconds, the
> > execution plan is the same . The problem is that we can't take the 'OR' out.
> > How can I solve this?
> >
> > TIA
> >
> > Robin
> >
> >
> >
> >
> >
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> >
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Received on Wed Nov 28 2007 - 09:29:07 CST

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