I've added support for RSM in disco#items and it works quite well. It will limit the number of requests to the database to load node configuration. I've not modified stored procedure as there was no point to do so as filtering is partially done in the Java code so prefiltering on the database would not make it faster as the list of nodes is already available in memory.

NOTE: RSM is enabled by default but will return paged results only if disco#items query contains RSM element. It is done intentionally as not all XMPP client libraries support RSM in disco#items, so those which support will get the benefit of this feature while others will work​ just as before.

As for jabber:search there is no standard way to query PubSub nodes (for is not defined for that), so I've skipped this part.