Robert

when database encryption was first introduced it was determined that for a particular application that  was very I/O intensive (5,000  block read or writes per second) , encryption would add about 4% to the CPU usage and it can add a tiny amount to disk block latency. 

That is an extreme case, so it is probably an upper bound  for any considerations.

In my experience, very few Ensemble solutions are at all IO intensive, with more time spent on network traffic or CPU usage. So I would be surprised if it is possible to measure the difference in your case.

I don't know about disk encryption.

dave

Scott

what type of messages are they? I guess since you are using a routing rule they are HL7 v2  or X12 messages, but perhaps not.

If you want to block or route a message based on a field in the message and you are dealing with more than a very small number of customers then I would use a lookup table as you suggest that maps customer identifiers to 0 or 1 so it is easy to reference them in a routing rule.

For a small number of customers that don't change, you could use an In(...) function but I am guessing that is not the case.