title: ElasticSearch filtered query _search 400 error response
body: <p>I am trying to use filter with search query. Search requset works correctly without filter. But using filter I get 400 error as response.
  This is type mapping:</p>
  
  <pre><code>var mapp = new
              {
                  mappings = new
                  {
                      posts = new
                      {
                          properties = new
                          {
                              FullText = new
                              {
                                  type = "string",
                                  analyzer = "russian"
                              },
                              Title = new
                              {
                                  type = "string",
                                  analyzer = "russian"
                              },
                              PostPubDate = new
                              {
                                  type = "date"
                              },
                              Link = new
                              {
                                  type = "string",
                                  index = "not_analyzed"
                              },
                              RubricsIds = new
                              {
                                  type = "integer"
                              },
                              ObjectsIds = new
                              {
                                  type = "integer"
                              },
                              SourceId = new
                              {
                                  type = "integer"
                              }
                          }
                      }
                  }
              };
  </code></pre>
  
  <p>This is a request to index with filtered query:</p>
  
  <pre><code>string url = "http://localhost:9200/neg_collector/posts/_search";
              var request = (HttpWebRequest)HttpWebRequest.Create(url);
              var o = new
              {
                  size = 20,
                  query = new
                  {
                      filtered = new
                      {
                          query = new
                          {
                              query_string = new
                              {
                                  fields = new[] { "Title" },
                                  query = search_query
                              }
                          },
                          filter = new
                          {
                              @bool = new
                              {
                                  should = new
                                  {
                                      term = new
                                      {
                                          SourceId = sIds
                                      }
                                  }
                              }
                          }
                      }
                  }                
              };
  
  
              request.Method = "POST";
              var jsonObj = JsonConvert.SerializeObject(o);
              var data = Encoding.UTF8.GetBytes(jsonObj);
              request.ContentType = "application/x-www-form-urlencoded";
              request.ContentLength = data.Length;
  </code></pre>
  
  <p>I want to use an array of integers to filter result with certain SourceId-s. But I got error 400. 
  What am I doing wrong? Thank you</p>