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SMON:ORA-00600:[ktecgeb:kcbz_objdchk] during Dropping of Temporary Segments (Doc ID 2337962.1)

Last updated on AUGUST 01, 2019

Applies to:

Oracle Database - Enterprise Edition - Version and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.


SMON getting ORA-00600: [ktecgeb:kcbz_objdchk] during clean up the temporary segments of a permanent tablespace.
It can cause the instance to crash after hitting 100 hits.

Errors in file /dumps-01/diag/rdbms/dw8/dw8-5/trace/dw8-5_smon_5484.trc (incident=2972337):
ORA-00600: internal error code, arguments: [ktecgeb:kcbz_objdchk], [0], [0], [1], [], [], [], [], [], [], [], []
Incident details in: /dumps-01/diag/rdbms/dw8/dw8-5/incident/incdir_2972337/dw8-5_smon_5484_i2972337.trc
Use ADRCI or Support Workbench to package the incident.
See Note 411.1 at My Oracle Support for error and packaging details.
Non-fatal internal error happenned while SMON was doing temporary segment drop.
SMON encountered 1 out of maximum 100 non-fatal internal errors.

The SMON trace file will show a file/block as type: 0x21=SECOND LEVEL BITMAP BLOCK

OBJD MISMATCH typ=33, seg.obj=-2, diskobj=425932594, dsflg=0, dsobj=336849064, tid=336849064, cls=7

----- Beginning of Customized Incident Dump(s) -----
Input data (nil), 0, 0
Formatted dump of block:
buffer tsn: 709 rdba: 0x229f0001 (1024/580845569)
scn: 0x095d.806622ab seq: 0x01 flg: 0x04 tail: 0x22ab2101
frmt: 0x02 chkval: 0x62cf type: 0x21=SECOND LEVEL BITMAP BLOCK
Dump of Second Level Bitmap Block
number: 1 nfree: 1 ffree: 0 pdba: 0x229f0002
Inc #: 0 Objd: 425932594

 The entry points to tsn: 709. The SEG$ lists an entry to the TS# = 709

select FILE#, BLOCK#, TYPE#, TS#, BLOCKS, HWMINCR, SPARE1, SPARE2 from SEG$ where TS# = 709;

     FILE#     BLOCK#      TYPE#        TS#     BLOCKS    HWMINCR     SPARE1    SPARE2
---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
      1024   96780355          3        709  619398714  336849064    4364609

The entry at SEG$.HWMINCR points to the dsobj of the SMON trace file.

If we try to drop the segments manually, the same issue is reproduced.





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