Bug 42461

Bug: 42461

Impact:

Critical

Product:

GemStone/S 64 Bit

Versions:

3.1.0.1, 3.1, 3.0.1, 3.0, 2.4.5.3, 2.4.5.2, 2.4.5.1, 2.4.5, 2.4.4.8, 2.4.4.7, 2.4.4.6, 2.4.4.5, 2.4.4.4, 2.4.4.3, 2.4.4.2, 2.4.4.1, 2.4.4, 2.4.3, 2.4.2.1, 2.4.2, 2.4.1, 2.4, 2.2.6, 2.2.5.4.2, 2.2.5.4.1, 2.2.5.3, 2.2.5.2, 2.2.5.1, 2.2.5, 2.2.x

Platform:

All Platforms

Fixed In:

3.2, 3.1.0.2, 2.4.6, 2.2.6.1

Reclaiming dead while backup is running can corrupt repository

There is a small risk that if reclaim GC Gems are reclaiming dead objects while a full backup is running, internal tables tracking the dead objects will become corrupted.  This can cause a wide range of various types of page and object level corruption, including page cache errors, object does not exist errors, and corrupted application data.

Workaround

If backups do not take a long time to run and you don't mind disabling shadowed page reclaim as well as dead reclaim:

1.  Run:  System stopAllReclaimGcSessions.
2.  Perform the backup.
3.  Run:  System startAllReclaimGcSessions.

If backups take a long time to run and you would like to keep shadowed page reclaim running:

1.  Run:  System stopAllReclaimGcSessions.
2.  As GcUser:  set UserGlobals at: #reclaimDeadEnabled to false.
3.  Run:  System startAllReclaimGcSessions.
4.  Perform the backup.
5.  Run:  System stopAllReclaimGcSessions.
6.  As GcUser:  set UserGlobals at: #reclaimDeadEnabled to true.
7.  Run:  System startAllReclaimGcSessions.