Bug 47445

Bug: 47445

Impact:

Product:

GemStone/S 64 Bit

Versions:

3.4.1, 3.4, 3.3.9, 3.3.8, 3.3.7, 3.3.6, 3.3.5, 3.3.4, 3.3.3, 3.3.1, 3.3, 3.2.15, 3.2.14, 3.2.13, 3.2.12, 3.2.11, 3.2.10, 3.2.9, 3.2.8, 3.2.7, 3.2.6, 3.2.5, 3.2.4, 3.2.3, 3.2.2, 3.2.1, 3.2, 3.1.0.6, 2.4.8, 2.4.7, 2.4.4.8, 2.4.4.7, 2.2.6.5, earlier versions

Platform:

Fixed In:

3.4.2

RcQueue may rarely and incorrectly return a nil element

There is a sequence of events in which an RcQueue may return a nil rather than the next element in the queue. No data is lost in this scenario.

The sequence required to get this case is where a session is performing a cleanupQueue and encounters a concurrency conflict against another session that is performing a read.  The cleanup session aborts and retries the cleanupQueue, which succeeds.  However, the cleanup session has written the removalSequence numbers when it should not, and a read by the other session may now get a nil from the RcQueue.