On Fri, Mar 29, 2013 at 4:35 PM, sean_ohare@...
<sean_ohare@...>wrote:

>
> Unfortunately, the problems we are experiencing are only visible when the
> system is under load, so it is tricky to simulate/emulate the environment.
> If we run a few users, we have no problems, so hence my questions about
> multi user transactions and isolation levels.
>

Is the problem that transactions aren't seeing concurrent changes?

You started by saying that Firebird loses transactions. That's very
unlikely. Then you suggested that the application was rolling back
transactions under load. That's possible, but would require active code to
cause it to happen. Unlike some other databases, Firebird never rolls back
a user transaction unless the connection is broken by a server crash,
client crash, or network failure. What may be happening is that the
application starts a read-only transaction with a stable view of the
database as of that instant. Other transactions do things. The old stable
transaction doesn't see the changes. New transactions do see the changes.
How mystic, the database is in two places at once!

So, can you explain the problem a little more. Does work go away
completely or is it not visible to all running transactions?

Good luck,

Ann


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