Comments on: Oracle 11.2: Cursor Mutex S wait event and too many (2^30) child cursors http://www.usn-it.de/index.php/2010/08/04/oracle112-mutex-s-too-many-child-cursors/ Martin Klier - Oracle, Linux, MS SQL Server Fri, 17 Feb 2012 03:49:51 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Craig http://www.usn-it.de/index.php/2010/08/04/oracle112-mutex-s-too-many-child-cursors/comment-page-1/#comment-43095 Craig Mon, 03 Oct 2011 22:47:07 +0000 http://www.usn-it.de/?p=463#comment-43095 A workaround is to create a stored outline for the affected cursor using dbms_outln.create_outline(a,b) where a=sql_hash_value and b=child_number of the one of the child cursors associated with the one plan you wish to enforce. A workaround is to create a stored outline for the affected cursor using dbms_outln.create_outline(a,b) where a=sql_hash_value and b=child_number of the one of the child cursors associated with the one plan you wish to enforce.

]]> By: usn http://www.usn-it.de/index.php/2010/08/04/oracle112-mutex-s-too-many-child-cursors/comment-page-1/#comment-27400 usn Wed, 23 Feb 2011 21:35:53 +0000 http://www.usn-it.de/?p=463#comment-27400 (Un)fortunately I am no developer. From a DBA perspective, you have to avoid anything that makes a cursor different - in this case it has been different datatypes, coming from the default behaviour of the setter method for NULL, using VARCHAR2 as default datatype. Hopefully an abstraction layer as Hibernate has built in this knowledge. You can check by tracing the query as described in http://www.usn-it.de/index.php/2010/08/05/oracle-11g-trace-particular-sql-id/ Martin (Un)fortunately I am no developer. From a DBA perspective, you have to avoid anything that makes a cursor different – in this case it has been different datatypes, coming from the default behaviour of the setter method for NULL, using VARCHAR2 as default datatype.

Hopefully an abstraction layer as Hibernate has built in this knowledge. You can check by tracing the query as described in http://www.usn-it.de/index.php/2010/08/05/oracle-11g-trace-particular-sql-id/

Martin

]]> By: jetlag http://www.usn-it.de/index.php/2010/08/04/oracle112-mutex-s-too-many-child-cursors/comment-page-1/#comment-27389 jetlag Wed, 23 Feb 2011 19:51:49 +0000 http://www.usn-it.de/?p=463#comment-27389 What would that translate to in Hibernate? We don't do anything directly with the ojdbc code, and certainly not provider specific. I don't see anything about setNull.NUMBER in the oracle jdbc javadoc. the closest i could find was a setNull(int paramIndex, int sqlType) method on the Oracle prepared statement class. Are you saying we might need to override the behavior of Hibernate setting up the calls to jdbc to use specific Oracle types when setting our parameters to null in the prepared statements? What would that translate to in Hibernate? We don’t do anything directly with the ojdbc code, and certainly not provider specific. I don’t see anything about setNull.NUMBER in the oracle jdbc javadoc. the closest i could find was a setNull(int paramIndex, int sqlType) method on the Oracle prepared statement class. Are you saying we might need to override the behavior of Hibernate setting up the calls to jdbc to use specific Oracle types when setting our parameters to null in the prepared statements?

]]> By: Usn’s IT Blog » Oracle 11g trace particular SQL_ID http://www.usn-it.de/index.php/2010/08/04/oracle112-mutex-s-too-many-child-cursors/comment-page-1/#comment-16704 Usn’s IT Blog » Oracle 11g trace particular SQL_ID Thu, 05 Aug 2010 15:44:02 +0000 http://www.usn-it.de/?p=463#comment-16704 [...] a follow-up of my last post, I learned that creating traces is much simpler in 11g than I expected it to be. Dion Cho and Tanel [...] [...] a follow-up of my last post, I learned that creating traces is much simpler in 11g than I expected it to be. Dion Cho and Tanel [...]

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