Querying the full _field_names or using _field_names in an aggregation, leads to a CircuitBreakingException. According to the _mapping API, the index holds about 10,000 different field names. Since the _field_names is autogenerated and is probably indexed, doc_values cannot be used.
As a workaround I use the mapping API on the full index, but what is the suggested workaround to get field names over aggregations?
Query:
{
"size" : 0,
"aggregations" : {
"fields" : {
"terms" : {
"field" : "_field_names",
"size" : 1000,
"order" : {
"_count" : "desc"
},
"include" : "c.*"
}
}
}
}
Exception
{
"took": 138,
"timed_out": false,
"_shards": {
"total": 11,
"successful": 6,
"failed": 5,
"failures": [{
"shard": 0,
"index": "bits",
"node": "L_u3ef-pRwCV5BWBXulq_Q",
"reason": {
"type": "exception",
"reason": "ElasticsearchException[CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]]]; nested: UncheckedExecutionException[CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]]]; nested: CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]];",
"caused_by": {
"type": "unchecked_execution_exception",
"reason": "ElasticsearchException[CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]]]; nested: UncheckedExecutionException[CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]]]; nested: CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]];",
"caused_by": {
"type": "exception",
"reason": "CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]]",
"caused_by": {
"type": "unchecked_execution_exception",
"reason": "CircuitBreakingException[[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]]",
"caused_by": {
"type": "circuit_breaking_exception",
"reason": "[fielddata] Data too large, data for [_field_names] would be larger than limit of [623326003/594.4mb]",
"bytes_wanted": 985496399,
"bytes_limit": 623326003
}
}
}
}
}
}]
},
"hits": {
"total": 63,
"max_score": 0.0,
"hits": []
},
"aggregations": {
"fields": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": []
}
}
}