Database Administration (MOSC)

MOSC Banner

Hit-Ratio after change *.sga_max_size, *.sga_target and

edited Aug 19, 2014 5:07AM in Database Administration (MOSC) 7 commentsAnswered

Hello,

  On  our Cluster ( 4 instance),  we have config  form sga ( parameter for instance, and parameter for cluster) :

  • Init.ora

…

INSTANCE1.sga_max_size=10737418240

INSTANCE2.sga_max_size=10737418240

INSTANCE3.sga_max_size=10737418240

INSTANCE4.sga_max_size=10737418240

*.sga_max_size=21474836480

INSTANCE1.sga_target=10737418240

INSTANCE2.sga_target=10737418240

INSTANCE3.sga_target=10737418240

INSTANCE4.sga_target=10737418240

*.sga_target=21474836480

…

We change init to have  only parameter *.sga_ , and restart database Cluster :

  • Init.ora

*.sga_max_size=21474836480

*.sga_target=21474836480

After Change we have a hit ratio 2.3% , before change it’s was about 98%

I need your help to understand why this change for Hit Ratio, Maybe after restart Oracle flash Buffers  like Library Cache !!

Howdy, Stranger!

Log In

To view full details, sign in to My Oracle Support Community.

Register

Don't have a My Oracle Support Community account? Click here to get started.

Category Leaderboard

Top contributors this month

Instructions for posting

×

1. Select a discussion category from the picklist.


2. Enter a title that clearly identifies the subject of your question.


3. In the body, insert detailed information, including Oracle product and version.


Please abide by the Oracle Community guidelines and refrain from posting any customer or personally identifiable information (PI/CI).


Cloud / Fusion customers - Our Cloud community has moved! Please go to Cloud Customer Connect .


New to My Oracle Support Community? Visit our Welcome Center

MOSC Help Center