Beehive server makes a huge effort to allow server side searches, and only clients like Zimbra or Thunderbird make use of it.
There were plans to leverage that search on the OBEO side, but those are currently not considered for implementation any more:
ER 8740438: ALLOW FULL TEXT SERVER SIDE SEARCHES IN OBIO
If you agree that Oracle should think twice about its plans not to implement server side search in OBEO please second this enhancement request through MOS or voice your assent here in the forum.
Thanks and regards, Tom