Oracle parameter change

[Former Member]

Hi Friends,

We have to change the parameter db_cache_size in our oracle 10g database.

What is the unit (kb, mb or gb) of value to be assigned. We have to increase it upto 16gb currently it is 8 gb.

What are the precaution should be taken to change this parameter, application down , user lock etc.

Please help me ?

Regards

Ganesh Datt Tiwari

[Former Member · Accepted solution]

You can see the current unit that is in use in the initSID.ora file.. If noting is mentioned m/g, then bytes are being used..

The only thing you have to take into account, is that sufficient physical memory is available on the server.

Kind regards,

Mark

[audunlea_hansen · Accepted solution]

Hi!

You can use e.g.

alter system set sga_max_size=8g scope=spfile;

alter system set sga_target=8g scope=spfile;

Now You need to bounce the database.

Be aware of some few things about large sga.

Due to the way Oracle handle addresses to memoryblocks, a SGA larger than 8-10GB can slow down the database due to long address list for the memory. If You need a larger SGA than 7gb, take a look to see if You can implement use of hugepages.

See SAP Note Number: 1384753 and Metalink note 361323.1,

Regards

Audun

Oracle DBA

[Former Member · Accepted solution]

Dear Friends,

Thanks to all of you for your valuable help to me.

My issue has resolved.

I have used command # alter system set db_cahe_size=16G scope=spfile;

Regards

Ganesh Datt Tiwari

[Former Member]

What are the precaution should be taken to change this parameter

Make sure you have 8gb memory free on the server

Kind regards, Michael

[fidel_vales]

>

> Hi Friends,
> We have to change the parameter db_cache_size in our oracle 10g database.
> 
> What is the unit (kb, mb or gb) of value to be assigned. We have to increase it upto 16gb currently it is 8 gb.

Hi

Look at the documentation:

http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/initparams043.htm

there you can see that you can specify it in several units

> DB_CACHE_SIZE = integer [K | M | G]

>

> 
> What are the precaution should be taken to change this parameter, application down , user lock etc.

It depends (as usual)

I prefer to change the parameter in the spfile and then stop SAP and restart oracle.

Keep in mind other parameters that you may have set (like SGA_TARGET and SGA_MAX_SIZE) as you may have to modify them aswell