Hello,

> In any DBMS, a deadlock occurs when you have two (or more) resources and
> you
> request locks on them in different sequences.
>
> If, within a transaction you update A then B, meanwhile you have another
> simultaneous transaction updating B then A, you will deadlock becaus both
> transactions are waiting on the other to release the same resource before
> they ocntinue.

These should be no problem becouse I tested only a few instances of the
same program - exactly the same sequences of stored procedures. Engine
reports deadlock but - may it be wrong message for update lock ?
Besides , what happen when update statement is in the middle of
transaction (concurrency no wait transaction with versioning) ? Must
another transaction fail to update the same row until the first
transaction commit or rollback ,even if the first transaction is just
process another part of stored procedure or another stored procedure in
chain ?

In case of rollback - Firebird 1.5 final does not have limited count of
rollback supported like in old Interbase 6.x , right?

--
Best Regards
Bogusław Brandys