| Veiw synonym performs differently in diferent users [message #215124] |
Fri, 19 January 2007 07:05  |
omkar@tcs
Messages: 16
Registered: September 2006
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Junior Member |
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HI all,
I have a view and its public synonym. If the public synonym is queried from other user than its owner, the performance is degraded.
If I query the view from the owner, it takes less thime to execute.
Can any body explain me why this might be happening?
Regards.
Omkar
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| Re: Veiw synonym performs differently in diferent users [message #215287 is a reply to message #215273] |
Sat, 20 January 2007 09:31  |
omkar@tcs
Messages: 16
Registered: September 2006
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Junior Member |
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Dear Mahesh,
I got the following inforrmation use of Public Synonyms.
1)For Public Synonym to be accessed,
the synonym must be loaded into the library cache,
and a dependency structure must be established.
2)Each library cache lookup establishes a lock structure,
for which memory must be allocated.
Each library cache object access establishes a pin structure,
which also needs memory.
3)For a statement that refers to a single table only,
the CPU usage during the parse phase is approximately
1:2:4 for a fully-qualified reference, a private synonym and a public
synonym respectively.For complex SQL statements, the cost
of synonym usage is even greater.
4) In an instance with high parse rates, the use of
synonyms increases CPU usage dramatically, and often
causes contention on the latches that control access to the library
cache, dictionary cache and shared pool.
Shall I safely assume that due to contention mentioned in the point number 4 is
causing performance delay in my case?
Please guide me.
Regards.
Omkar.
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