Default Size Of SGA

[paddy04]

Hi All,

On what assumptions does oracle allocate size for various parameters when oracle is first installed. What are the default percentages of various SGA parameters.

Thanking you in advance.

Paddy

[davey23uk]

look in the default init.ora file, they are small

[prakashs43]

I think the default size of the SGA lies within following o/s kernel settings like SHMMAX, SHMMIN, SHMMNI

there could be some other parameters like oracle version , edition , operating system

pls confirm this from experts.

[sandycrab]

I think davey23uk is right...

[prakashs43]

hi sandy and davey

u are absolutely right that SGA SIZE CAN BE obtained from init.ora file .

but how will u get default values set in init.ora file before creating the database

.i guess it dynamically picks kernel parameters and then SGA values in init.ora file is calculated .

aprt from this it may also depend on these options oracle version , edition , operating system

[paddy04]

Thanks sandy,davey and Siva Prakash for the valuable suggestions...
Just as Siva Praakash pointed out Looking into the init.ora is fine..but how is it determined that the Shared pool should get 40% of the SGA space(this is just an example)...and likewise for the DB Buffer cache.. etc...Is there any standard formula or assumptions by which oracle does this..Supposing That I want to predetermine the Size of SGA before creating the database.

Any information in this regard will be highly appreciated.


Warm Regards,


Paddy