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Aanlyze Query
Dear Sir/Madam,
I have recently joined as a junior DBA in a company.I am supposed to tune the database on which all the application on it are running very slow.
I have gathered information from users and there problem and i want to start with SQL Tuning.
Kindly clear my following doubts.
I have few questions to ask.
1. How I should start my work
2. What exactly happens in Oracle Database when table is analyzed.
3. Which table should be analyzed, the tables belonging to the schema in which application users are working or all?
4. Whether column should also be analyzed.
5. The statistics which we gather, are they one on which database should work on ?
6. How can I compare the present statistics value to the value which has been changed?
7. Do we need to shift from optimizer mode 'CHOOSE' to 'FIRST ROWS'.
8. Do views also need to be analyzed?If yes, with which option estimate or compute.
9. Will any users will face any problem while table will be analyzed.
10. Which option I should choose to analyze tables,estimate or compute.
11. Is 10% sample size is good for tables having rows more than 10000.
12. How will I judge the results of analyzing the tables.
13. At what interval tables should normally be analyzed.
14. What should be my next step after analyzing the table in SQL Tuning.
Regards,
Saurabh
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Dear Saurabh,
I strongly advice you to go through the Oracle documentation first, before undertaking any performance tuning...
It can have uncertain repurcussions, unless you can afford to throw away a hard day's work :-).
Oracle documentation on performance (Oracle Performance Methods and Oracle Performance Guide and Reference) need to be studied, which answers all or most of ur questions.
Once u r familiar with the basics, u can start experimenting with a test database.. All the best !
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performance tuning a production system seems a strange task to throw at a junior DBA
You've got your work cut out
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Re: Aanlyze Query
Originally posted by saurabhvtechno
1. How I should start my work
Answer: If you don't have a test system, build one.
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I would also check that the code is making proper use of bind variables -- if it isn't then that would be a prime cause of performance problems.
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Originally posted by slimdave
I would also check that the code is making proper use of bind variables -- if it isn't then that would be a prime cause of performance problems.
You want to elaborate on that one Dave, I'm interested.
MH
I remember when this place was cool.
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I remember when this place was cool.
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