JVM Corruption and ORA-7445

The intention of this blog is to share a problem faced in a production instance. its strongly advised when you face ORA-7445 error is to contact Oracle Support and open a case with them.

So, my objective is to help here ….

what are the symptoms faced ?

Database version is 12cR1 (12.1.0.2.181016)

Database Alert log file has the following errors:

Exception [type: SIGSEGV, Address not mapped to object] [ADDR:0x7440038090] [PC:0x7FEA4DB100D4, java_nio_Bits__byteOrder()+204] [flags: 0x0, count: 1]

DDE: Problem Key ‘ORA 7445 [java_nio_Bits__byteOrder]’ was completely flood controlled (0x6) Further messages for this problem key will be suppressed for up to 10 minutes

When executing SQL Scripts using sqlplus….for example utlrp.sql the following errors were thrown:

SQL> @/rdbms/admin/utlrp.sql
ERROR at line 1:
ORA-03113: end-of-file on communication channel 

Process ID: 105404
Session ID: 2878 Serial number: 20833

Errors received from application side deployed in weblogic:

No More Data To Read From Socket

 

The reason of such symptoms is JVM Corruption !

To resolve this issue:

 

  1. Check JVM status by executing the following script:

 

spool jvm_info.log
—— REGISTRY INFO ——
SELECT SUBSTR(comp_name, 1, 30) comp_name, SUBSTR(version, 1, 20) version, status
FROM dba_registry
ORDER BY comp_name;
—— REGISTRY HISTORY ——-
SELECT TO_CHAR(action_time, ‘DD-MON-YYYY HH24:MI:SS’) act_time, action, version, id, comments
FROM dba_registry_history
ORDER BY action_time DESC;

—— JAVA OBJECT INFO ——
— Are there a substantial number of VALID Java objects in SYS?
SELECT owner, object_type, status, COUNT(*)
FROM dba_objects
WHERE object_type LIKE ‘%JAVA%’
GROUP BY owner, object_type, status
ORDER BY owner, object_type, status;
— Is the DBMS_JAVA package VALID?
SELECT owner, object_name, object_type, status
FROM dba_objects
WHERE object_name LIKE ‘DBMS_JAVA%’
OR object_name LIKE ‘%INITJVMAUX%’
ORDER BY owner, object_name, object_type;
— Are there any INVALID Java objects in SYS?
SELECT owner, NVL(longdbcs,object_name) long_name, object_type, status
FROM dba_objects, sys.javasnm$
WHERE object_type LIKE ‘%JAVA%’
AND status <> ‘VALID’
AND short (+) = object_name
ORDER BY owner, long_name, object_type;
—— JAVA ROLE INFO ——
— The number expected varies by release.
SELECT role
FROM dba_roles
WHERE role LIKE ‘%JAVA%’
ORDER BY role;
—— MEMORY INFO ——
SELECT *
FROM v$sgastat
WHERE pool = ‘java pool’ OR name = ‘free memory’
ORDER BY pool, name;
—— DATABASE PARAMETER INFO ——
show parameter pool_size
show parameter target
show parameter sga
—— TEST JAVAVM USAGE (and return the JDK version if > 11g) ——
— Calling routines in DBMS_JAVA will invoke the JavaVM and expose certain problems.
SET SERVEROUTPUT ON
DECLARE
ver NUMBER := 0;
val VARCHAR2(30);
BEGIN
BEGIN
SELECT TO_NUMBER( SUBSTR(version, 1, 2) )
INTO ver
FROM dba_registry
WHERE comp_name = ‘JServer JAVA Virtual Machine’;
EXCEPTION
WHEN OTHERS THEN NULL;
END;
IF ver >= 12 THEN
EXECUTE IMMEDIATE
‘SELECT ”JDK version is ” ||
dbms_java.get_jdk_version() FROM dual’
INTO val;
ELSE
val := dbms_java.longname(‘JDK version not available’);
END IF;
dbms_output.put_line(val);
END;
/

spool off;

  1. Repair JVM:

 

**** Note down the current value of parameters JAVA_JIT_ENABLED & JOB_QUEUE_PROCESSES

 

spool create_Java.log

set echo on

connect / as sysdba

Alter system set JAVA_JIT_ENABLED=FALSE scope=both;

alter system set “_system_trig_enabled” = false scope=memory;

alter system set JOB_QUEUE_PROCESSES=0;

create or replace java system

/

@?/rdbms/admin/utlrp.sql

set echo off

spool off

exit

Then reset it back to original values you noted down:

SQL> alter system set java_jit_enabled = true;

SQL> alter system set “_system_trig_enabled”=TRUE;

SQL> alter system set JOB_QUEUE_PROCESSES=50;

SQL> @?/rdbms/admin/utlrp.sql

  1. Test that everything is ok:

 

Check database components

SQL> select * from dba_registry;

SQL> SELECT dbms_java.longname(‘TEST’) long_name FROM dual;

 

 

 

 

 

 

 

 

 

 

 

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