> [...] from InterBase to DB2 [...]

We just happened to test DB2 support for one of our applications,
but this was dropped after finding out that DB2's transaction
concurrency support is very poor, leading, in our specific case,
to lots of cross-transaction locks, "freezes" and related performance
issues.

Many of our transactions are based on read/write/read/write sequences,
and DB2 locks on "writes" prevents "reads", meaning that all the
transactions are effectively serialized (including those that only read
and never write).

The only DBs we know to properly support concurrent transactions without
switching to a "serialized" mode are InterBase (thanks to the multi-
generational architecture) and Oracle. All the other DBs we tested failed,
succeeding only in unsafe "DirtyRead" modes... Came as quite a shock,
we had become accustomed to be able to read anything at any time...

Might be worth adding to your check-list.

Eric Grange