Oracle 11g - Memory used for sorting

Question

Hi everyone,
I would like to know how I could analyze memory used for sorting in Oracle 11g. When I run the below query, it returns 1531381.
select value from v$sysstat where name like 'sorts (memory)';But when I check sort_area_size parameter from v$parameter, it returns 65536. Does it mean my database is using more memory for sorting than sort_area_size. Or is the way I interpret v$sysstat view and sort_area_size wrong? What is the best way to monitor the memory usage for sorting? Thanks in advance.
Regards,
K.H
Edited by: K Hein on Apr 5, 2012 8:16 PM

Answer 1

check the valuse of pga_aggregate_target
http://docs.oracle.com/cd/B19306_01/server.102/b14237/initparams157.htm
Note:
Oracle does not recommend using the SORT_AREA_SIZE parameter unless the instance is configured with the shared server option. Oracle recommends that you enable automatic sizing of SQL working areas by setting PGA_AGGREGATE_TARGET instead. SORT_AREA_SIZE is retained for backward compatibility.
What is the best way to monitor the memory usage for sorting? try v$sort_usage
or v$tempseg_usage
col sid_serial for a44
col size for a22
col SID_SERIAL for a22
SELECT b.tablespace,
        ROUND(((b.blocks*p.value)/1024/1024),2)||' MB' "SIZE",
        a.sid||','||a.serial# SID_SERIAL,
        a.username,a.osuser,
        a.program
   FROM sys.v_$session a,
        sys.v_$sort_usage b,
        sys.v_$parameter p
  WHERE p.name  = 'db_block_size'
    AND a.saddr = b.session_addr
ORDER BY b.blocks;