2 Large Pool

Large Pool’s purpose is similar to Shared Pool. The major difference is it would be only used in the certain circumstances.

• In MTS( Multi-threaded server) env, use for soft area and hash area.
• Parallel Query
• Large file’s IO Buffer
• RMAN’s IO Buffer

* Image is from Oracle

Default value for Large Pool is 0. Max size is 2GB ( vary by os).

Unlike shared pool, Large Pool does not use LRU. Memory only can be free up when it is done using.

In MTS environment, if it large Pool is set. use large pool for UGA, otherwise, UGA is in the shared pool.

 

How to check the large pool size?

show parameter large_pool

select * from v$sgainfo;

select * from v$sgastat where pool='large pool';

 

_LARGE_POOL_MIN_ALLOC

Allocation size for the large pool.

col Parameter format a30

col value format a30

select a.ksppinm "Parameter", b.ksppstvl "Value" from x$ksppi a, x$ksppcv b 

where a.indx = b.indx and a.ksppinm like ('%large_pool_min_alloc%');

How to change the large Pool size?

alter system set large_pool_size=XXX; 

parallel_automatic_tuning

parallel_automatic_tuning is to enable the parallel execution.

 

Reference

http://docs.oracle.com/cd/E14072_01/server.112/e10820/initparams105.htm