Erwin Wessels writes:
 > - The scan operation allows for (a.o.) hit-count information, but
 > only for a term in a specific index. How could we retrieve the
 > hitcount for a particular search string for *multiple* index fields
 > separately?

What's wrong with multiple scans -- one for each such index?

Or if you want the aggregate number of hits for your search-terms
across all relevant indexes, then define an index which is the union
of those indexes, and scan on that.

 > - Drill-down enabling information: information on hit counts for
 > refining for (possibly) indicated indexes.
 > In other words, functionally speaking, I'm looking for the
 > refinement options when searching for title 'rabbit', for the index
 > 'author' and a maximum records it would tell me 'Potter, Beatrix'
 > (105 results), 'Wells, Rosemary' (63 results), 'Carroll, Lewis' (41
 > results), and 954 more refinements.

To do this, I think you need "scan within result-set", which is not
supported in the SRU protocol.  The most economical way to provide
access to such functionality in an underlying database would be to
make an extension, using an <extraRequestInfo> element in SRW and an
equivalent x-Whatever parameter in SRU, to tell the server the name of
the result-set that you want it to scan.

 _/|_	 ___________________________________________________________________
/o ) \/  Mike Taylor  <[log in to unmask]>
)_v__/\  "The fighting must begin before another someone dies" -- Ritchie
	 Blackmore's Rainbow, _16th Century Greensleeves_.  Eh?