ES 6.2 Percolator causes very high CPU utilization

[meghna1292 (Meghna)]

Hi,
I am currently using AWS ES 6.2 for the percolator. I have a dedicated cluster for the percolator which has a single index that contains ~16,000 percolator queries (~30MB).
I have about 10000 percolator query invocations to the cluster per minute. With this, I am experiencing a max CPU of about 80%.

Here's my cluster configuration:

Instance type: c4.4xlarge.elasticsearch
Nodes: 20 data + 3 master
Shards: 8 Primary + 9 Replica

Sample percolator query:

{
 "parentNode": "123",
 "isActive": true,
 "query": {
            "bool": {
              "should": [
                {
                  "bool": {
                    "must": [
                      {
                        "query_string": {
                          "query": "\"great results\", \"good results\", \"excellent results\"",
                          "analyzer": "english"
                        }
                      }
                    ]
                  }
                }
              ]
            }
          }

Sample request sent to the percolator:

{
            "size": 100,
            "_source": False,
            "query": {
                "bool": {
                    "filter": {
                        "percolate": {
                            "field": "query",
                            "documents": [contains a list of 100 documents with same metafields]
                        }
                    },
                    "must": [
                        {
                            "terms": {
                                "parentNode": ['123', '234']
                            }
                        },
                        {
                            "term": {
                                "isActive": true
                            }
                        }
                    ]
                }
            }
        }

I am using the 2 filters to narrow down the candidate queries to percolate on.

Am I using the percolator wrong? The documentation states that performance of the percolator has improved a lot from earlier versions (I used AWS ES 1.5 earlier) but I only see the performance degrading. Can I get any suggestions on this?

Thank you

[Daniel_Penning]

Could you enable profiling to see which step of executing the query takes too long.

Yesterday i encountered some slow percolate queries which took very long to create the scorers for the candidate query. I am not sure yet if this is caused by the low amount of available memory on my development server or if there is an actual performance bottleneck.