How to increase the size of sort_area_size

Question

How to increase the size of sort_area_size and what size should be according to the PROD database
Thanks

Answer 1

user10869960 wrote:
Hi,
Many Thanks Charles
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."
--How can i know the instance is configured with the shared server option or not?This might be a tough question to answer. A shared server configuration may be enabled, but the clients may still connect using dedicated sessions, in which case PGA_AGGREGATE_TARGET would still apply.
From
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/dynviews_2088.htm
V$SESSION includes a column named SERVER which will contain one of the following for each of the sessions: DEDICATED, SHARED, PSEUDO, or NONE. As a quick check, you could query V$SESSION to see if any sessions are connected using a shared server connection.
From:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/manproc.htm
There are several parameters which are used to configure shared server support, as well as several views to monitor shared server.
As Robert mentioned, when the WORKAREA_SIZE_POLICY is set to AUTO, the SORT_AREA_SIZE setting is not used, unless a shared server configuration is in use.
--What default value is WORKAREA_SIZE_POLICY and SORT_AREA_SIZE ?From:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/initparams157.htm
"Setting PGA_AGGREGATE_TARGET to a nonzero value has the effect of automatically setting the WORKAREA_SIZE_POLICY parameter to AUTO. This means that SQL working areas used by memory-intensive SQL operators (such as sort, group-by, hash-join, bitmap merge, and bitmap create) will be automatically sized. A nonzero value for this parameter is the default since, unless you specify otherwise, Oracle sets it to 20% of the SGA or 10 MB, whichever is greater."
Actually I am facing performence issue since long time till now i did not get the solution even i have raised SRs but i could not.When the issue occur system seems hang.what i monitored whenever hdisk0 and hdisk1 use 100% the issue occur.
Regards,
SajidWhen you say that you have had a performance issue for a long time, is it a performance problem faced by a single SQL statement, a single user, a single application, or everything on the server? If you are able to identify a single user, or SQL statement that is experiencing poor performance, I suggest starting with a 10046 trace at level 8 (wait events) or level 12 (wait events and bind variables) to determine why the execution appears to be slow. If you have not yet determined a specific user or SQL statement that is experiencing performance problems, you might start with either a Statspack Report or an AWR Report (AWR requires a separate license).
If you believe that temp tablespace usage may be a contributing factor to the performance problem, you may want to periodically run this query, which will indicate currently in use temp tablespace usage:
{code}
SELECT /*+ ORDERED */
TU.USERNAME,
S.SID,
S.SERIAL#,
S.SQL_ID,
S.SQL_ADDRESS,
TU.SEGTYPE,
TU.EXTENTS,
TU.BLOCKS,
SQL.SQL_TEXT
FROM
V$TEMPSEG_USAGE TU,
V$SESSION S,
V$SQL SQL
WHERE
TU.SESSION_ADDR=S.SADDR
AND TU.SESSION_NUM=S.SERIAL#
AND S.SQL_ID=SQL.SQL_ID
AND S.SQL_ADDRESS=SQL.ADDRESS;
{code}
The SID and SERIAL# returned by the above could then be used to enable a 10046 trace for a session. The SQL_ID (and CHILD_NUMBER from V$SESSION in recent releases) could be used with DBMS_XPLAN.DISPLAY_CURSOR to return the execution plan for the SQL statement.
You could also take a look in V$SQL_WORKAREA_ACTIVE to determine which, if any, SQL statement are resulting in single-pass, or multi-pass executions, which both access the temp tablespace.
Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc.