Another question related to Statspack [message #281753] |
Mon, 19 November 2007 03:33 |
orausern
Messages: 826 Registered: December 2005
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Senior Member |
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Hi,
I am analyzing a Stataspack report and have a question for which I need some help. The Statspack report is a one hour report and it contains in part, the following info:
Top 5 Timed Events
~~~~~~~~~~~~~~~~~~ % Total
Event Waits Time (s) Ela Time
-------------------------------------------- ------------ ----------- --------
CPU time 2,911 74.26
db file sequential read 388,744 397 10.13
db file scattered read 124,211 254 6.48
direct path read 412,291 153 3.89
global cache cr request 689,368 120 3.05
-------------------------------------------------------------
So it means that the application is CPU Bound as CPU waits are 75%. Is this conclusion correct. and in this case to reduce the CPU waits I should identify the SQLs that cause max. load on CPU and try to tune it right?
Now the section on "SQL ordered by Gets for DB" contains the following:
SQL ordered by Gets for DB: db1 Instance: inst1 Snaps: 10162 -10163
-> End Buffer Gets Threshold: 10000
-> Note that resources reported for PL/SQL includes the resources used by
all SQL statements called within the PL/SQL code. As individual SQL
statements are also reported, it is possible and valid for the summed
total % to exceed 100
CPU Elapsd
Buffer Gets Executions Gets per Exec %Total Time (s) Time (s) Hash Value
--------------- ------------ -------------- ------ -------- --------- ----------
BEGIN dbms_stats.gather_schema_stats('Schema1',estimate_percent=>nul
l,cascade=>true,method_opt=>'for all indexed columns size auto',
granularity=>'all'); END;
1,559,149 1 1,559,149.0 14.9 1200.86 1541.56 797380495
There are two such other statements for other 2 schemas and totally all three statements account for 30% of Total Time.
Similarly on the section of SQL ordered by Reads , the same statements are there, and they account for about 90% of Total time.
So to tune this what should I do?
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Re: Another question related to Statspack [message #281843 is a reply to message #281753] |
Mon, 19 November 2007 08:42 |
JRowbottom
Messages: 5933 Registered: June 2006 Location: Sunny North Yorkshire, ho...
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Senior Member |
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The processes you're looking at are the DBMS_STATS package gathering table statistics for your schemas. YOu probably shouldn't be running that during peak load times.
You should also look into the 'GATHER STALE' options for DBMS_STATS.
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