Conference orarep::nomahs::dbms

2614.0. "Locks Are Lost When Locks Are Remastered" by NOMAHS::SECRIST (Rdb WWS; rsecrist@us.oracle.com) Mon Mar 24 1997 09:57

    	[from dsin -- rcs]
    
[OpenVMS] Locks Are Lost When Locks Are Remastered
Last Technical Review:  1-AUG-1996                            Size: 51 lines


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Copyright (c) Digital Equipment Corporation 1995, 1996. All rights reserved.

PRODUCT:    OpenVMS VAX, Versions 5.5-2 and Above

COMPONENT:  Lock Manager

SOURCE:     Digital Equipment Corporation


SYMPTOM:

Lock information is lost after lock trees containing database locks
have been dynamically remastered.  This frequently happens when
running DBMS and RDB.


DIGITAL RESPONSE:
Engineering is unable to reproduce this problem due to lack of
information.  If this problem impacts your system, please contact
Digital Support with further information.



ANALYSIS:

This problem is related to dangling or lost lock information.
Disabling the dynamic lock remastering on all nodes clears up the
problems and they do not reoccur.

When lock remastering is enabled again, this problem reoccurs.  The
behavior is intermittent and not reproducible at will, but does happen
fairly regularly when lock remastering is enabled.


WORKAROUND:

Either disable dynamic lock remastering or set PE1 to 100 so lock
trees for DBMS and RDB are not remastered (since their lock trees
are always greater than 100).
    

    That SPR was more or less speculation although the VMS locking folks do
    seem to feel they have a problem in their code.  I still believe there
    is a chance our code is wrong (or could be improved).