Bug 30159581 - A DB open hangs after switchover due to a detected deadlock (Doc ID 30159581.8)

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Bug 30159581  A DB open hangs after switchover due to a detected deadlock

 This note gives a brief overview of bug 30159581. 
 The content was last updated on: 04-FEB-2021
 Click here for details of each of the sections below.

Affects:

Product (Component) Oracle Server (Rdbms)
Range of versions believed to be affected Versions BELOW 20.1
Versions confirmed as being affected
Platforms affected Generic (all / most platforms affected)

 Note that this fix can cause / expose the problem described in Bug:31747989 

 Note that this fix has been superseded by the fix in Bug:31747989 

Fixed:

This fix has been superseded - please see the fixed version information for Bug:31747989 . The box below only shows versions where the code change/s for 30159581 are first included - those versions may not contain the later improved fix.
 
The fix for 30159581 is first included in

Symptoms:

Related To:

Description

This bug manifests as a hang during the opening of a database in read-write mode or during the switchover
of a standby instance to the role of a primary instance. We speed up the opening of the database by using
parallel slaves to perform first-pass transaction recovery. This phase detects all in-flight transactions from 
the past and mark them as such for subsequent recovery.  The hang occurs due to a deadlock between two
parallel recovery slaves on dictionary cache objects.
  
 
Rediscovery Notes
A hang during the opening of a database in read-write mode or during the switchover of a standby instance 
to the role of a primary instance. The database needs to have enough undo segments in "in-use" or
"partially-available" states to warrant parallelization of FPTR. Typically this is 100 
(controlled by parameter _min_undosegs_for_parallel_fptr).
 
Note:	
This fix supersedes the fix in bug 28770119. 
  
Workaround
Turn off parallelization of first-pass transaction recovery (occurs as part of database open) 
by setting _min_undosegs_for_parallel_fptr = 0 in the initialization file and open the database.

 

Please note: The above is a summary description only. Actual symptoms can vary. Matching to any symptoms here does not confirm that you are encountering this problem. For questions about this bug please consult Oracle Support.

 

References

Bug:30159581 (This link will only work for PUBLISHED bugs)
Note:245840.1 Information on the sections in this article