Oracle-L: RE: AQ query from dequeuw procedure not using index -URGENT

From: <Rajesh.Rao_at_jpmchase.com>
Date: Mon, 09 Dec 2002 12:49:10 -0800
Message-ID: <F001.005158B3.20021209124910@fatcity.com>

Shaleen,

The use of FIRST_ROWS hint with an order by clause is ridiculous. The hint is ignored.

Raj

                                                                                                                     
                    John Kanagaraj                                                                                   
                    <john.kanagara        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>        
                    j_at_hds.com>            cc:                                                                        
                    Sent by:              Subject:     RE: AQ  query from dequeuw procedure not using index -URGENT  
                    root_at_fatcity.c                                                                                   
                    om                                                                                               
                                                                                                                     
                                                                                                                     
                    December 09,                                                                                     
                    2002 02:49 PM                                                                                    
                    Please respond                                                                                   
                    to ORACLE-L

Shaleen,

Have you considered using Outlines?
John Kanagaraj
Oracle Applications DBA
DBSoft Inc
(W): 408-970-7002

So WHO is the Reason for the Season?! Write me for details!

The opinions and statements above are entirely my own and not those of my employer or clients **

-----Original Message-----
Sent: Monday, December 09, 2002 10:04 AM To: Multiple recipients of list ORACLE-L

All,

We are using a third party application (Retek Warehouse management) which uses AQ as communication mechanism between processes. The problem we are facing is that the AQ query behind Dequeue is doing a full tablescan on queue table which is causing about 5Billion logical reads/day and is bringing the DB to its knees.

Following is the query which I gleaned from tracing the process

select /*+ FIRST_ROWS */ qt.rowid, qt.msgid, qt.corrid, qt.priority,

qt.delay, qt.expiration, qt.retry_count, qt.exception_qschema,
qt.exception_queue, qt.chain_no, qt.local_order_no, qt.enq_time,
qt.time_manager_info, qt.state, qt.enq_tid, qt.step_no from

PAR3214.GENERICTCP qt where q_name = :1 and state = :2 order by q_name, state, enq_time, step_no, chain_no, local_order_no for update skip locked

The procedure call is following
DBMS_AQ.DEQUEUE( 'par3214.' || qname, queueopts, msgprops, msg_obj, msgid );

Since this is an internal query, I can not change the HINT ( Itested that removing the hint drops logical reads from 2400 to 3).

Any ideas?

Thanks
Shaleen

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Received on Mon Dec 09 2002 - 14:49:10 CST