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v$librarycache [message #201316]

Fri, 03 November 2006 08:34

Anand Ramaswamy
Messages: 111
Registered: January 2005

Senior Member

Hi All,
I recently queried v$librarycache of a database. Below is the output:

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NAMESPACE	GETHITRATIO	PINHITRATIO	RELOADS		INVALIDATIONS
SQL AREA	0.89		0.98		4,089,675.00	4,234,997.00
TABLE/PROCEDURE	0.94		0.91		43,911.00	0.00
BODY		1.00		1.00		132.00		0.00
TRIGGER		1.00		1.00		346.00		0.00
INDEX		0.88		0.82		3.00		0.00
CLUSTER		0.99		0.98		0.00		0.00
OBJECT		1.00		1.00		0.00		0.00
PIPE		1.00		1.00		0.00		0.00
JAVA SOURCE	1.00		1.00		0.00		0.00
JAVA RESOURCE	1.00		1.00		0.00		0.00
JAVA DATA	0.97		0.99		5.00		0.00

As seen the GetHitRatio & PinHitRatio of some namespace is less than 90%. Is it normal to have such a low hit ratios?
If not how can we improve them.

Thanks in advance
qA

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Re: v$librarycache [message #201490 is a reply to message #201316]

Sat, 04 November 2006 15:46

kimant
Messages: 201
Registered: August 2006
Location: Denmark

Senior Member

Have You any performance problems on the database, or are You bored and just looking for switches and knobs to turn?

Are You sad that some objects are not kept in the cache at all times?

You could increase shared pool.
But if You are lowering db cache to do so, it might make performance worse.

Have You looked at using Automatic memory tuning?

Br
Kim

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