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Oracle Tips by Burleson |
Buffer Cache Tuning
The first case deals with a typical
problem. A trouble ticket has been opened and assigned to the DBA.
The complaint is that the application is running slowly. Therefore,
the DBA is asked to “make the database faster”. This is not a
foreign request to a DBA.
STATSPACK was previously installed, and the
DBA is unable to immediately determine that any specific userid is
being affected more than others; therefore, the DBA will take a few
snapshots and gather about a two-minute interval of data.
After getting the snapshots, the DBA runs
spreport.sql and looks at the report. Figure 7.10 shows the first
section to be viewed.
Instance Efficiency Percentages (Target
100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 100.00 Redo
NoWait %: 100.00
Buffer Hit %: 30.48 In-memory Sort
%: 99.27
Library Hit %: 89.09 Soft Parse
%: 92.36
Execute to Parse %: 28.67 Latch
Hit %: 100.00
Parse CPU to Parse Elapsed%: 81.37 %
Non-Parse CPU: 89.55
The above book excerpt is from:
Oracle Wait Event Tuning
High Performance with Wait
Event Iinterface Analysis
ISBN 0-9745993-7-9
Stephen Andert
http://www.rampant-books.com/book_2004_2_wait_tuning.htm |
