Find waiter with Oradebug 11gR2

Posted by oraclue on October 29, 2009 · 2 Comments 

There is small addition to oradebug unit_test command in 11g R2 . oradebug unit_test per_session_find_one_waiter This command has four mandatory arguments and one optional. First parameter is find_waiters_for which can have two different values : current_sess or all_local_sess .Self descriptive. Second parameter is wait_event.This is name of the wait event which search is done.Third and … Read more

Filed under Internals

ORION (Oracle I/O Calibration Tool) included in 11g R2

Posted by oraclue on October 27, 2009 · 4 Comments 

Apparently Oracle  included this tool into 11g release 2 database.Orion binary is located under  $ORACLE_HOME/bin . Quick run with help command will give very detail explanation how to use this tool.Also Kevin Closson’s Oracle blog got post about Orion: http://kevinclosson.wordpress.com/2006/12/11/a-tip-about-the-orion-io-generator-tool/ -bash-3.2$ orion -help ORION: ORacle IO Numbers — Version 11.2.0.1.0 ORION runs IO performance tests … Read more

Filed under Performance

Uncommitted transactions

Posted by oraclue on October 20, 2009 · 6 Comments 

Let say someone have an update,insert or delete statement that runs but has not been commited yet.So question is how to show uncommitted transactions ? First some background about transaction management in Oracle. A transaction is a logical unit of work that contains one or more SQL statements. A transaction ends when any of the … Read more

Filed under Troubleshooting

Blocking locks history

Posted by oraclue on October 15, 2009 · 8 Comments 

In my previous blogs I have already wrote script for   monitoring blocking locks in real time. http://oraclue.com/2009/05/18/procedure-to-kill-blocking-session-in-rac-11g/ But what if I am accessing database next day or week later and trying to find out who caused blocking lock? I know there are trace files etc but this time I will use v$views. Let me start … Read more

Filed under Troubleshooting

Deffered Segment Creation

Posted by oraclue on October 13, 2009 · 2 Comments 

Oracle 11g release 2 introduced new initialization  parameter DEFERRED_SEGMENT_CREATION . This parameter specifies the semantics of deferred segment creation. If set to true ( which is DEFAULT ) then segments for non-partitioned tables and their dependent objects (LOBs, indexes) will not be created until the first row is inserted into the table. According to Oracle … Read more

Filed under Bugs