ORA-00600: internal error code, arguments: [ktrget2:kcbz_objdchk]

Error:==
ORA-00600:  [ktrget2:kcbz_objdchk]

select TIMESLOT_emp,TIMESLOT2US_imp from emp ,emp a, b,timeslot
where usedby2emp=a.empid
and uses2emp=b.empid
and a.emp2emptype=0000010
and b.emp2emptype=0000009
and TIMESLOT_emp=a.empid
and TIMESLOT_imp=b.empid
group by TIMESLOT_emp,TIMESLOT_imp
having count(*)>1;
*
ERROR at line 1:
ORA-00600: internal error code, arguments: [ktrget2:kcbz_objdchk], [12], [0],[31], [], [], [], [], [], [], [], []





Solution :===

flush the shared pool 3 times :-
alter system flush shared_pool

Please run following query to check which objects the block belongs to:
SQL> SELECT tablespace_name, segment_type, owner, segment_name
FROM dba_extents
WHERE relative_fno = 26
AND 58378 between block_id AND block_id + blocks - 1;

TABLESPACE_NAME SEGMENT_TYPE OWNER SEGMENT_NAME
------------------------------ ------------------ ------------------------------ ---------------------------------------------------------------------------------
USR INDEX CMD EMP_CC_FK_I

SELECT object_id, data_object_id, status FROM dba_objects WHERE owner = 'CMD AND object_name = 'EMP_CC_FK_I'
AND object_type = 'INDEX';

OBJECT_ID DATA_OBJECT_ID STATUS
---------- -------------- -------
244663 1156881 VALID

Please rebuild the index:
SQL> ALTER INDEX cmd.emp_cc_fk_i REBUILD ONLINE;

Than analyze the index again to check it ORA-8103 are solved:

SQL> ANALYZE INDEX cmd.emp_cc_fk_i VALIDATE STRUCTURE;

after both the (Rebuild & Analyze) complete please try again same SQL QUERY.