Since we upgraded to elastic 2.3.3 we started to see new errors in cirrus logs:
2016-06-03 12:30:45 [] mw1245 jawiki 1.28.0-wmf.4 CirrusSearch WARNING: Search backend error during full_text search for 'query text' after 97: query_phase_execution_exception: Result window is too large, from + size must be less than or equal to: [10000] but was [90360]. See the scroll api for a more efficient way to request large data sets. This limit can be set by changing the [index.max_result_window] index level parameter. {"queryType":"full_text","query":"query text","limit":20,"suggestion":null,"took":97,"message":"query_phase_execution_exception: Result window is too large, from + size must be less than or equal to: [10000] but was [90360]. See the scroll api for a more efficient way to request large data sets. This limit can be set by changing the [index.max_result_window] index level parameter."}
We should not send such queries to elasticsearch and block them in MW.