Applies to Exchange 2003
I had a case a couple weeks ago I thought I'd write about. What was happening is the Version Store would run out of memory and a 623 error would throw. Version Store buckets allocated would climb from 4 to over 2000 in less than 5 minutes. The store would then rollback its transactions for a bit, recover, run for 10-15 minutes and repeat the whole cycle over.
This is atypical 623 behavior to say the least.
What we ended up doing to fix it was capture an adplus dump, 3 actually, triggered at Version Store buckets allocated crossing 1600. We captured 3 dumps at 1 minute intervals.
The 1st dump caught the problem transaction, the last 2 were both capturing rollbacks, so this was a quick ramp up.
Turns out the problem was being caused by a bad meeting request being processed over and over again. We tried all kinds of ways to delete the message, all of which caused Version Store buckets allocated to climb. A MFCMapi hard delete ended up doing the trick.