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ORA-600 [kcbzpbuf_1] ORA-600 [kcbzpb_1] Troubleshooting and workarounds (Doc ID 1560270.1)

Last updated on JULY 30, 2019

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 8.0.5 to 12.2]
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 Exadata Express Cloud Service - Version N/A and later
Information in this document applies to any platform.


The purpose of this article is to describe the possible causes of ORA-600 [kcbzpbuf_1] and potential workarounds.

ORA-600 [kcbzpbuf_1] ORA-600 [kcbzpb_1] are produced by the DBWR background process because it encounters a corrupt block in the buffer cache (SGA Memory) before writing it to disk.  The error is produced to prevent DBWR from writing the corrupt block to DISK.  The block is not physically corrupt on disk but there is a possibility that it is logically corrupt or is free of corruptions on disk. Refer to <Note 840978.1> for Physical and Logical Block corruptions.


One example of this error is in the alert log is:


The buffer cache block corruption can be caused by any of these sources:

  1. Memory hardware/OS problem that overwrote the block in the buffer cache (stray writes).
  2. The block is already logically corrupt on disk or modification to other logically corrupt blocks is causing stray writes.  Any modification to an already logically corrupt block may overwrite other blocks in the buffer cache and cause unexpected results.
  3. There is a block modification that is corrupting this block in the buffer cache.   Refer to <Note 337018.1> for known issues.

Troubleshooting Steps

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In this Document
Troubleshooting Steps
 Enable checking parameters
 Identify other corrupt blocks on disk
 Additional parameter if checking does not detect a problem

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