Elasticsearch_dsl set query size to 0 automaticly

[Aviran]

Im getting very odd behavior from elasticseach_dsl

Im running the following from python

es_controller.es_dsl.index('management_users') \
        .doc_type('user') \
        .filter('term', email=email).execute()

When it's translated by elasticsearch_dsl into a query, in some cases it will add size: 0 to the query which will return 0 results.

Here's the query I see in the debug info

{
  "query": {
    "bool": {
      "filter": [
        {
          "term": {
            "email": "aviran@domain.com"
          }
        }
      ],
      "must": [
        {
          "regexp": {
            "first_name": ".*"
          }
        }
      ]
    }
  },
  "aggs": {
    "total_cost": {
      "sum": {
        "field": "cost"
      }
    },
    "total_liters": {
      "sum": {
        "field": "liters"
      }
    }
  },
  "size": 0
}

The response is:

{
  "took": 13,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "total_cost": {
      "value": 0
    },
    "total_liters": {
      "value": 0
    }
  }
}

What am I doing wrong?

The described behavior is not consistent, on some case the outgoing query will be:

{
  "query": {
    "bool": {
      "filter": [
        {
          "term": {
            "email": "aviran@domain.com"
          }
        }
      ]
    }
  }
}

Which works fine.

Im using:

elasticsearch          5.5.3
elasticsearch-dsl      5.4.0

[Aviran]

the issue was with the web server running the calls to ES.

When I increased the allowed processes amount, the issue resolved itself.