[Xapian-tickets] [Xapian] #49: Ensure OP_ELITE_SET matches at least some documents

[Xapian]

#49: Ensure OP_ELITE_SET matches at least some documents
-------------------------+--------------------------------------------------
 Reporter:  olly         |        Owner:  olly     
     Type:  enhancement  |       Status:  assigned 
 Priority:  lowest       |    Milestone:  1.3.0    
Component:  Library API  |      Version:  SVN trunk
 Severity:  minor        |   Resolution:           
 Keywords:               |    Blockedby:           
 Platform:  All          |     Blocking:           
-------------------------+--------------------------------------------------
Changes (by olly):

  * owner:  nobody => olly
  * status:  new => assigned
  * milestone:  1.2.x => 1.3.0


Comment:

 Revisiting this ticket, I'm now thinking that we should just note in the
 documentation that this can happen when OP_ELITE_SET is used with non-term
 subqueries.  The natural use case for OP_ELITE_SET is to pick a sane-sized
 set of terms from a larger set and it's fine there.

 Also, {{{FILTER(OP_ELITE_SET(A,B,C,...),Z)}}} might match some or no
 documents, depending which of {{{A,B,C,...}}} are selected, so why should
 {{{OP_ELITE_SET(FILTER(A,Z),FILTER(B,Z),FILTER(C,Z),...)}}} be handled so
 differently?

 So unless there's disagreement, I suggest we document this and do it for
 1.3.0 (and then backport to 1.2.x).

-- 
Ticket URL: <http://trac.xapian.org/ticket/49#comment:7>
Xapian <http://xapian.org/>
Xapian