Difference between two adapters

[DarioCrivelli]

BTW, what will happen if I configured both clients for "unfiltered" subscriptions, how this will affect the performance?

Preventing filtering can have an effect when the overall update flow to a client is so huge (or the client/network so slow) that it is impossible that all available updates are processed by the client.
In this case, some updates have to be filtered out and this requires that some subscription with a huge flow is not "unfiltered".
But other items with a low flow can still be subscribed "unfiltered".
As long as the update flow is manageable, there is no significant performance difference between "unlimited" and "unfiltered".
Only in rare cases of race conditions (like two subsequent updates in short sequence), "unfiltered" prevents possible filtering-out of some update.

Another case in which "unfiltered" makes the difference is when there are licensing restrictions that put an a-priori limit on the update frequency of an item.
But, in this case, this only works if the average update frequency of the item is lower than the license limit.

Note that, for MERGE mode, you can reduce filtering in almost the same way by enlarging the buffer, which by default is 1, through setRequestedBufferSize.

That said, I'm still not sure what of the above applies to your scenario.