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TROUBLESHOOT ORA-07445: EXCEPTION ENCOUNTERED: CORE DUMP

Scope : Oracle Database – Enterprise Edition – Version 11.2.0.3.0

Symptoms : Occasional errors found like: ORA-07445: exception encountered: core dump [kglic0()+756] [SIGSEGV] [ADDR:0x430000010B8AE910] [PC:0x107AB7474] [Address not mapped to object] []

Cause :

During SQL statistics analysis for query execution, we load dependency information into the Library Cache. These dependency memory pieces can be overwritten by other sessions without causing an error. When the original session runs into the wrong dependency information it can lead to the internal error and performance issues during subsequent queries of these Library Cache objects.

Solution:

There are so-many bugs related to 11.2.0.3.0 If you are getting more, raise SR with Oracle Support for recommended patch-set or solution. I have some workaround on this. My database version is 11.2.0.3.0, But have the same error in my prod database. I set the following parameter and bounced the database and current issue resolved.

SQL> ALTER SYSTEM SET “_cursor_stats_enabled”=false SCOPE=SPFILE;

Explanation:

Setting “_cursor_stats_enabled”=false will disable information being maintained under the fixed view V$SQLSTATS. Therefore, OEM, AWR, and ADDM reports will not include information on SQL statistics.

To reset “_cursor_stats_enabled” to its default value use:

SQL> ALTER SYSTEM RESET “_cursor_stats_enabled”;

Do only after Oracle recommendation in production env.

Caution : This recommendation can be applied in prod database with Oracle support only. If you are applying it is your own risk.

Note: Any hidden parameter value should not be touched without Oracle Support recommendation.

To See Hidden parameters :

SQL> SELECT a.ksppinm Param, b.ksppstvl SessionVal, c.ksppstvl InstanceVal, a.ksppdesc Descr
FROM x$ksppi a, x$ksppcv b, x$ksppsv c
WHERE a.indx = b.indx AND a.indx = c.indx
AND a.ksppinm LIKE ‘/_%’ escape ‘/’
ORDER BY 1;

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