RE: Capacity Planner from OEM VS Statspack

  • From: "Guang Mei" <gmei@xxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 2 Feb 2004 14:08:05 -0500

Statspack is just one of the tools which I think (based on my experience) is
useful for performance monitoring and tuning. We have a weekly build program
that took about 80 hours (with multihread programs running) to finish, it's
been running the same code for 2+ years. For the past year, I implmented
Statspack and took snapshot hourly, I identified the top sqls in each hour
and their individual programs. By studing the program I improved some of
their performacen dramatically (by changing program logic and re-writing
sqls). Together with dbms_profiler and 10046 trace, I found many places that
code could be improved (big and small). I reduced the weekly build program
down to 60 hours while the data has grown 100%. And I am still in the middle
of optimization efforts.

Guang



-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Andy Rivenes
Sent: Monday, February 02, 2004 1:51 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Capacity Planner from OEM VS Statspack


However, what you're really collecting is "workload" information. It's only
useful, as Cary stated, for capacity planning, or what you stated, for
trends. You're not going to solve a "performance" problem with this level
of information.

Andy Rivenes
arivenes@xxxxxxxx

At 10:00 AM 2/2/2004 -0800, MacGregor, Ian A. wrote:
>I have to disagree here.  Sometimes one needs to take a top-down approach
>to tuning.  Measuring things such as CPU usage and I/O counts can be
>useful.  For instance here's a report for a very lightly loaded system
>based on statspack data.
>
>
>DATABASE   BEGIN_TIME           END_TIME             Physical Reads
>Physical Writes CPU SECONDS ELAPSED SECONDS
>---------- -------------------- -------------------- --------------
>--------------- ----------- ---------------
>ORAP       12-JAN-2004:00:00:03
>12-JAN-2004:01:00:05          14725            7697     224.005
>3602
>ORAP       12-JAN-2004:01:00:05
>12-JAN-2004:02:00:02           6271            2125        5.03
>3597
>ORAP       12-JAN-2004:02:00:02
>12-JAN-2004:03:00:04          66066            1043       6.105
>3602
>ORAP       12-JAN-2004:03:00:04
>12-JAN-2004:04:00:02           1496            1125        3.68
>3598
>ORAP       12-JAN-2004:04:00:02
>12-JAN-2004:05:00:04           1716            1462       3.995
>3602
>ORAP       12-JAN-2004:05:00:04
>12-JAN-2004:06:00:01            961            1721        3.71
>3597
>ORAP       12-JAN-2004:06:00:01
>12-JAN-2004:07:00:03           3779            1032       3.985
>3602
>ORAP       12-JAN-2004:07:00:03
>12-JAN-2004:08:00:06          16436            2026        5.84
>3603
>ORAP       12-JAN-2004:08:00:06
>12-JAN-2004:09:00:03         231051            2634       14.43
>3597
>ORAP       12-JAN-2004:09:00:03
>12-JAN-2004:10:00:05         137762            1245      15.605
>3602
>ORAP       12-JAN-2004:10:00:05
>12-JAN-2004:11:00:03         183870            1163       15.21
>3598
>ORAP       12-JAN-2004:11:00:03
>12-JAN-2004:12:00:05         143757            1166      12.975
>3602
>ORAP       12-JAN-2004:12:00:05
>12-JAN-2004:13:00:02          20349            1088       4.705
>3597
>ORAP       12-JAN-2004:13:00:02
>12-JAN-2004:14:00:04         195781            1827      13.355
>3602
>ORAP       12-JAN-2004:14:00:04
>12-JAN-2004:15:00:02          26901            1538        9.53
>3598
>ORAP       12-JAN-2004:15:00:02
>12-JAN-2004:16:00:04          43434            1039       8.205
>3602
>ORAP       12-JAN-2004:16:00:04
>12-JAN-2004:17:00:01          61892            1747       8.485
>3597
>ORAP       12-JAN-2004:17:00:01
>12-JAN-2004:18:00:04          36268             819        5.99
>3603
>ORAP       12-JAN-2004:18:00:04
>12-JAN-2004:19:00:01          87842            1302         8.4
>3597
>ORAP       12-JAN-2004:19:00:01
>12-JAN-2004:20:00:03           1256             653       4.625
>3602
>ORAP       12-JAN-2004:20:00:03
>12-JAN-2004:21:00:01         197415            1086      99.765
>3598
>ORAP       12-JAN-2004:21:00:01
>12-JAN-2004:22:00:03            556            1386       3.235
>3602
>ORAP       12-JAN-2004:22:00:03
>12-JAN-2004:23:00:06           1074             697        3.22
>3603
>ORAP       12-JAN-2004:23:00:06
>13-JAN-2004:00:00:03          14856             927       4.495
>3597
>ORAP       13-JAN-2004:00:00:03
>
>
>
>If I have a report which deviates from this, then I can start
>looking  more closely.  The statspack information is gathered every ten
>minutes.  I can then propely trace the statements  which are candidate
>problems.  I can also get more information.  If the CPU count goes up is
>it due to an increase of logical I/Os.  How much of the physical I/O is
>direct and to what tablespaces etc.
>
>There are many problems with statspack and the virtual views upon which it
>is based.  Counters resetting are going negative, the frequency of the
>updates etc.  I have made elaborate systems, chucked them out of
>frustration, changed tactics and tried again.
>
>At one time I was totally against such systems because they were not
>perfect, actually far from it.  But I came to realize that though
>statspack is inadequate, it is not useless.
>
>Ian MacGregor
>Stanford Linear Accelerator Center
>ian@xxxxxxxxxxxxxxxxx

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