Currently , the index Issues has some fields managed by the fielddata feature (opposite to doc_values feature).
This feature consumes a lot of Java heap's memory and frequently raises the circuit breaker.
Doc_values are the on-disk data structure and don't consume memory.
They store the same values as the _source but in a column-oriented fashion that is way more efficient for sorting and aggregations.
Doc values are supported on almost all field types, with the notable exception of analyzed string fields.
Doc values is enabled by default in ES 2.X but not in ES 1.X.
We must change the property Doc_values from FALSE to TRUE for :
(project, language, type, resolution, rulekey, key, severity, filepath, tags, assignee, status)