RE: PX Deq Waits

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Wed, 5 May 2004 08:39:38 -0500
Message-ID: <0186754BC82DD511B5C600B0D0AAC4D607B00577@EXCHMN3>

Deen
Here is what Jonathan Lewis wrote about PX Deq Waits:

http://www.faqchest.com/prgm/oracle-l/ora-02/ora-0205/ora-020531/ora02051804 _06040.html

Jared - Google strikes again!

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of deen dayal Sent: Tuesday, May 04, 2004 4:25 PM
To: oracle-l_at_freelists.org
Subject: PX Deq Waits

Hi,

I ran statspack report against one of my production databases(9.2.0.3) and following is part of it.

Top 5 Timed Events

~~~~~~~~~~~~~~~~~~                                                     %
Total
Event                                               Waits    Time (s) Ela

Time

-------------------------------------------- ------------ -----------
--------
CPU time                                                        1,596
55.05
PX Deq: Table Q qref                                  496         991
34.20
db file sequential read                            25,700         143
4.95
db file scattered read                             22,133         104
3.58
latch free                                          2,015          28
.96
         -------------------------------------------------------------

34.2% of time is spent on "PX Deq: Table Q qref", I do not know any thing about this event.
I searched metalink, did not find much except that it is a parallel query related.

The weird thing is we do not run much of parallel queries and yet this event appears on
the report every time I run it.

Does anybody know any thing about this wait event??

Here is my Instance Summary from statspack report

Instance Efficiency Percentages (Target 100%)

---

            Buffer Nowait %: 100.00 Redo NoWait %: 100.00

            Buffer Hit %: 92.21 In-memory Sort %: 100.00

            Library Hit %: 98.13 Soft Parse %: 93.91

         Execute to Parse %: 1.41 Latch Hit %: 99.79
Parse CPU to Parse Elapsd %: 78.44 % Non-Parse CPU: 95.70

 Shared Pool Statistics        Begin   End
                               ------  ------
             Memory Usage %:   77.89   75.72

    % SQL with executions>1: 66.56 72.19   % Memory for SQL w/exec>1: 99.59 99.59

Thanks
Deen

---

Please see the official ORACLE-L FAQ: http://www.orafaq.com

---

To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line.

--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------
----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to:  oracle-l-request_at_freelists.org
put 'unsubscribe' in the subject line.
--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------

Received on Wed May 05 2004 - 08:39:11 CDT