which to tune first [message #65351] |
Mon, 16 August 2004 23:20 |
Ravikumar.V
Messages: 26 Registered: July 2004
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Junior Member |
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Sir
performance is very low in system
which part to tune first ,taken memory, tune shared pool(data dictionary or library ) or buffer or redo log..
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Re: which to tune first [message #65360 is a reply to message #65351] |
Wed, 18 August 2004 07:23 |
shoblock
Messages: 325 Registered: April 2004
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Senior Member |
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you should tune your code first - always.
poorly written code may increase disk reads - so should you buy bigger, faster disks, or should you create some indexes, and change a subquery to a correlated subquery, improving the sql, reducing the disk reads, and freeing up resources to other processes?
find out what is slow (either use v$sql to get elapsed time, turn on sql_trace for the whole db and search every trc file, add log messages to all your code with timestamps, or just ask the users "what things are slow"), then tune it.
After you've tuned all the code, then if something is still slow, you can look at the other stuff.
This is based on my 17 years of oracle performance tuning - not once has the culprit been anything other than crap code.
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