Getting "An item with this key has already been added" when performing a DeleteByQuery with Nest (Elasticsearch)

Question

I am trying to run a delete query to delete documents between two timestamps in an index, and I am getting a very strange result.

Here is my code:

// how the index is created
if (!es.IndexExists(indexName).Exists)
{
    es.CreateIndex(descriptor => descriptor
        .Index(indexName)
        .AddMapping<MyDocument>(m => m
            .MapFromAttributes()));
}

// event object that is mapped
public class MyDocument
{
    public long Id { get; set; }

    public long EventTime { get; set; }

    [ElasticProperty(Index = FieldIndexOption.NotAnalyzed)]
    public string EventType { get; set; }

    public DateTime CreatedAt { get; set; }

    public IDictionary<string, object> Values { get; set; }
    // snip
}

// delete call
IElasticClient es;
es.DeleteByQuery<MyDocument>(q => q
    .Query(rq => rq
        .Range(t => t.OnField("eventTime").GreaterOrEquals(startTimestamp).LowerOrEquals(endTimestamp)));

This throws an exception saying "An item with the same key has already been added". What am I doing wrong with this delete query that would throw this exception?

Here is a sample document from a search I did through elasticsearch:

{
  "took" : 8,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 96,
    "max_score" : 1.0,
    "hits" : [ {
      "_index" : "testing2",
      "_type" : "mydocument",
      "_id" : "112",
      "_score" : 1.0,
      "_source":{"id":112,"eventTime":12345690,"eventDate":"1970-05-23T17:21:30-04:00","eventTypeId":0,"ready":false,"name":"","doccount":0,"wordcount":0,"createdAt":"2015-06-25T09:29:33.8996707-04:00","values":{"internal_timestamp":76890.0},"childDocuments":[],"parentDocuments":[]}
    }, /* snip */]
  }
}

Answer 1

Rob and I just worked this out.

The problem that was occurring here is that my project is using Newtonsoft.Json version 7.0.0 with Nest version 1.5.1, whereas Nest 1.5.1 requires 6.0.1. This mismatch was causing the serialization of queries to throw exceptions.

This can be solved by either upgrading Nest to version 1.6.1 or downgrading Newtonsoft.Json to version 6.0.1.