Troubleshooting Internal Errors

Abstract of Tamzin Oscroft wrote at Oracle Magazine

Thu Jan 20 13:35:52 2011
Errors in file /DATA/oracle/admin/
prod/udump/prod_ora_2131.trc:
ORA-00600: internal error code,
arguments: [ktfbtgex-7], [1015817],
[1024], [1015816], [], [], [], []

ORA-600 or ORA-7445: What Is the Difference?

ORA-600 is a catchall message that indicates an error internal to the database code. The key point to note  is that it is signaled when a code check fails within the database. At points throughout the code, Oracle Database performs checks to confirm that the information being used in internal processing is healthy, that the variables being used are within a valid range, that changes are being made to a consistent structure, and that a change won’t put a structure into an unstable state. If a check fails, Oracle Database signals an ORA-600 error and, if necessary, terminates the operation to protect the health of the database.

The first argument error message indicates the location in the code where the check is performed; in the example above, that is ktfbtgex-7 (which indicates that the error occurred at a particular point during tablespace handling).

An ORA-7445 error, on the other hand, traps a notification the operating system has sent to a process and returns that notification to the user. Unlike the ORA-600 error, the ORA-7445 error is an unexpected failure rather than a handled failure.

ORA-07445: exception encountered:
core dump [kocgor()+96] [SIGSEGV]
[ADDR:0xF000000104] [PC:0x861B7EC]
[Address not mapped to object] []

 
the failing function is kocgor, which is associated with the handling of user-defined objects. The trapped signal is SIGSEGV (signal 11, segmentation violation), which is an attempt to write to an illegal area of memory. Another common signal is SIGBUS (signal 10, bus error), and there are other signals that occur less frequently, with causes that range from invalid pointers to insufficient OS resources.

Both ORA-600 and ORA-7445 errors will 

• Write the error message to the alert.log, along with details about the location of a trace containing further information
• Write detailed information to a trace file in the location indicated in the alert.log
• In Oracle Database 11g Release 1 onward, create an incident and place the relevant files in the incident directory in the location defined by the diagnostic_dest initialization file parameter
• Write the error message to the user interface if the server process is not terminated or signal ORA-3113 if it is

Often you will see multiple errors reported within the space of a few minutes, typically starting with an ORA-600. It is usually, but not always, the case that the first is the significant error and the others are side effects.

Can I Resolve These Errors Myself?

Check the whole Oracle Magazine article