We're running a two storage node (64 GB with 32GB for ES), two query node (32GB with 16GB for ES) Elasticsearch 1.4.7 setup. We have monitoring for the various counters available in the _cat API. Sometimes we notice an increase in the search.queue value for one of the storage nodes. At the same time, the server itself doesn't seem to be particularly busy with anything (according to atop logs), and no impact can be measured for end users.
Is there a way do determine what kind of queries are queued? I'm trying to determine if I need to optimize something, or if the counter is not worth monitoring.