: I've been using q.alt=-*:* because *:* is said to be the most efficient way
of
: querying for every document. is -*:* the most efficient way of querying for
: no document?
I don't think so ... solr internally reverse pure negative queries so that
they are combined with a matchalldocsquery that is positive ... which
means your final query would look like (*:* -*:*) ... there's no toehr
query optimization that would happen, so that query sould produce a
DisjunctionScorer that can't ever "skipTo" past any docs.
once it gets cached it shouldn't matter -- but hey, you asked.
The most efficient way i can think of (besides a new Query class like John
suggested) is along the lines of what Erik mentioned...
<fieldtype name="ignored" stored="false" indexed="false" multiValued="true"
class="solr.StrField" />
<field name="match_nothing" type="ignored"/>
...
q.alt=match_nothing:0
...it has to be a real field or the query parsing code will freak out, but
making it indexed=false will ensure that there will *never* be any terms
in that field so the term "0" will never be there so the entire query
process will short circut out almost immediately (it won't even construct
a Scorer let alone iterate over any docs)
-Hoss
