Re: PGA allocation

On 2003.05.17 22:56 Ashish wrote:

> so why is it growing beyond 1G target (which equals to 100% SGA) and not
> getting released?

Your PGA is not growing over the whole SGA area because that is impossible. It is not getting released because it hasn't reached it's target value. Setting it to 100% of the SGA size is an extreme setting that I do not recommend.
Your overallocation statistics is meaningless because your target size is set to the whole SGA, which means that the PGA would swallow the whole SGA and then some. Anyway, it's a brand new feature and my advice is to use the traditional SORT_AREA_SIZE, and HASH_ASREA_SIZE if the automatic management doesn't work for you. Tuning that is not difficult. One of the crucial queries is shown below:

  1 select n.name,s.value from v$statname n, v$sysstat s   2 where n.STATISTIC#=s.STATISTIC#
  3* and n.name like '%sort%'
SQL> /

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
sorts (memory)                                                          766
sorts (disk)                                                              0
sorts (rows)                                                           2286

You can find instructions about how to tune those two in any of the tuning books. The "101 Oracle Performance Tuning" and "Building Efficient Databases" are not the worst books you can read.

-- 
Mladen Gogala
Oracle DBA
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
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Author: Mladen Gogala
  INET: mgogala_at_adelphia.net

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