You have to limit the search string to a maximum of 512 bytes. This setting is universal for both Oracle and DB2 setup environments. Failing which you will not be able to see any output returned at the search result area even though the regex should validate to true and return search output.

Here is an example of a string that works verses one that does not work : 1. The figure below shows this search string works with the total length as only 308 characters - in this case the output is looking for a device named "DEVICE-SW-01" at the search and the output is shown correctly since this device exists : ^(DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01)$ 2) This search string does not work since its now 564 characters long but in terms of functionality it is a duplicate of the regular expression at bullet 1, ie this regular expression does not return any result: ^(DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01||DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01||DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01|DEVICE-SW-01)$