Poor error handling. Even if one of batches causes error, rest batches can be applied unexpectedly. (On ACS, all batches are ignored if one of them causes error.)
“version” and “lang” don’t work. Even if you specify those attributes, they do nothing.
XML SDF is not available.
XML type response is not available.
Always search results are returned as a JSON.
Custom rank expressions and threshold options are not supported yet.
XML responses are not supported yet.
rid in info object is always "000000000000000000000000000000000000000000000000000000000000000".
cpu-time-ms in info object is always 0.
Some queries may produce responses not compatible with ACS. This restriction comes from the differences of the query interpretation between groonga’s match parameter of select command and ACS q parameter. For example, the queries which have :, >, < and | will not work as ACS.
match-expr is always ''
Support only text and literal fields.
facet-FIELD-top-n and facet-FIELD-sort parameters are not supported.