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PHYSICAL: Why does Managed Recovery spawn so many slaves? (Doc ID 885872.1)

Last updated on FEBRUARY 26, 2019

Applies to:

Oracle Database - Enterprise Edition - Version 11.1.0.6 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
Oracle Database Cloud Exadata Service - Version N/A and later
Information in this document applies to any platform.

Symptoms

In 11.1 and up, Managed recovery spawns a lot of parallel slaves and limiting the parallel_max_servers parameter setting does not help.

Example:

If you set parallel_max_servers=1 on the Physical standby, you will still see managed recovery start with parallelism equal to the number of CPU's.

Completed: alter database recover managed standby database disconnect
Wed Aug 26 17:51:03 2009
ALTER SYSTEM SET parallel_max_servers=1 SCOPE=BOTH;
alter database recover managed standby database cancel
Wed Aug 26 17:51:10 2009
MRP0: Background Media Recovery canceled with status 16037
..........
RP0: Background Media Recovery process shutdown (V1116P)
Managed Standby Recovery Canceled (V1116P)
Completed: alter database recover managed standby database cancel
Wed Aug 26 17:51:22 2009
alter database recover managed standby database parallel 6 disconnect
Attempt to start background Managed Standby Recovery process (XXXXX)
Wed Aug 26 17:51:22 2009
MRP0 started with pid=21, OS id=11708
MRP0: Background Managed Standby Recovery process started (XXXXXX)
Fast Parallel Media Recovery enabled
Managed Standby Recovery not using Real Time Apply
parallel recovery started with 6 processes                           <--- starts even though I set parallel_max_servers=1
Waiting for all non-current ORLs to be archived...
Clearing online redo logfile 1 /<PATH>/<FILE_NAME>.log
Clearing online log 1 of thread 1 sequence number 290
Errors in file /<PATH>/trace/<FILE_NAME>.trc:
ORA-19527: physical standby redo log must be renamed
ORA-00312: online log 1 thread 1: '/<PATH>/<FILE_NAME>.log'
Clearing online redo logfile 1 complete
Media Recovery Waiting for thread 1 sequence 291
Completed: alter database recover managed standby database parallel 6 disconnect



Cause

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In this Document
Symptoms
Cause
Solution
References

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