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ORA-00600: internal error code, arguments: [13030], [20],

Learnt new thing today, thanks to my colleague Gagan.

Alert log showing this error, whilst checking the trace shows an update statement into a table which is capturing the sid,serial# from gv$session.

So then why ora-600, As per metalink note:- Ora-00600 [13030], [20] During Update Statement Using V$ tables [ID 1400439.1]

For updates we use […]

Resolving Library cache: mutex X

According to notes 9282521.8 and 9239863.8 describing the patches, the enhancements should be used: When there is true contention on a specific library cache object….

For example:- A package that is so hot (heavily accessed ) in library cache will be contended and the sessions appear to be waited on Library Cache: mutex X.

There […]

Buffer states: How many consistent read (cr) clones in buffer cache, verified.

We all know to maintain the consistency of the buffers and its integrity oracle has to clone the current copy of the buffer to consistent read and change the latest one. There are different buffer states in x$bh column out of all our interest to this post is only to cr and xcur.

First lets […]

Oracle SCN: Many SCN’s ? Explained here!

How many types of SCN, well the better question would be how many places the SCN is stored.

Well, there are not MANY types of SCN which are there actually but stored many places with different names and different purposes.

The SCN will be only one number, a incremented value of every 3?(5 seconds […]

Internals: Control File Records

What kind of records that control file maintains in Oracle database?

Lets have a look.

SQL> oradebug setmypid Statement processed. SQL> oradebug unlimit; Statement processed. SQL> alter session set events ‘immediate trace name controlf level 9’; Session altered. SQL> oradebug tracefile_name; /home/oracle/app/oracle/diag/rdbms/testdb/testdb/trace/testdb_ora_1238.trc SQL> exit Disconnected from Oracle Database 11g Enterprise Edition Release – 64bit […]