More efficient wildcard-only queries

[heikki]

When you do a query that has only *, it results in the following Lucene query:

GUI: +ConstantScore(any:*) +(_op0:1 _op0:0) +_isTemplate:n

CSW: +(+*:* +_isTemplate:n) +(_op0:1 _op0:0)

This is functionally equivalent to doing a completely empty query (return all results you're allowed to view), which both for the GUI and CSW creates this query which is much more efficient in very large indexes:

+(_op0:1 _op0:0) +_isTemplate:n

It is desired to add logic to convert wildcard-only queries to the empty query, before creating the Lucene query.

[heikki]

committed to 2.6.x and trunk