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Resolving Logical Block Corruption Errors in a Physical Standby Database (Doc ID 2821699.1)

Last updated on NOVEMBER 08, 2022

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.2 to 19.13.0.0.0 [Release 12.1 to 19]
Oracle Cloud Infrastructure - Exadata Cloud Service - Version N/A to N/A [Release N/A]
Gen 2 Exadata Cloud at Customer - Version All Versions to All Versions [Release All Releases]
Information in this document applies to any platform.

Symptoms

 

With DB_BLOCK_CHECKING=MEDIUM or FULL on the standby, the standby database is effective mechanism to detect logical corruptions on the primary database especially when the primary database may not have DB_BLOCK_CHECKING enabled due to the performance overhead.   This note describes repair options when standby redo apply detects logical corruptions that were introduced by the primary database due to DB_BLOCK_CHECKING settings described above.

Warning:

Before enabling block checking with this parameter, Oracle recommends that you detect and repair any logical corruptions in the database.
Otherwise, a block that contains logical corruption will be marked as "soft corrupt" after block checking is enabled and the block is modified
by a DML statement. This will result in ORA-1578 errors and the block will be unreadable. For more information about detecting and repairing
logical corruptions, see Oracle Database Backup and Recovery User’s Guide.

 

Also Refer to Best Practices for Corruption Detection, Prevention, and Automatic Repair - in a Data Guard Configuration (Doc ID 1302539.1) and RESOLVING ORA-752, ORA-753 or ORA-600 [3020] DURING PHYSICAL STANDBY RECOVERY (Doc ID XXXXX)

The following is a list of the block checking errors, note that the errors are only reported is db_block_checking is set to MEDIUM or FULL:

CAUTION: Unless directed by Oracle Support Services, DO NOT attempt to bypass this error by copying blocks or data files from the primary database to the standby database because that would propagate the block corruption from the primary to the standby database.

 

Changes

 

Cause

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In this Document
Symptoms
Changes
Cause
Solution
  
 Determining Root Cause
 Primary Database Logical Corruptions
 Repair Option 1: Determine if affected objects can be recreated and recovery allowed to continue:
 Repair Option 2: Use Block Media Recovery(BMR) to Repair the Corrupted Block
 Repair Option 3: Activate the standby database
 Protecting Against Logical Corruptions
References

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