title: ElasticSearch SearchContextMissingException - No search context found for id
body: <p>I am using ES version 1.6.0 and the Python plugin for ES. I have a large collection of documents inside my index and I want to iterate through each and every document inside the index. In this sense I am using scan to get each document and retrieve the sentences it contains. I have written my function using an iterator to yield back each and every sentence. My code is this:</p>
  
  <pre><code>es1 = Elasticsearch(["http://localhost:9200"], timeout=30)
  
  class Sentences(object):
  
  def __init__(self, index, query):
  
      self.index = index
  
      self.query = query
  
  def __iter__(self):
  
      for doc in scan(es1, query=self.query, index=self.index):
  
          doc_sentences = doc["_source"]["doc_sentences"]
  
          for sentence in doc_sentences:
  
              yield sentence
  </code></pre>
  
  <p>The iterator appers to be running initially, but after a while I get the error: "SearchContextMissingException - No search context found for id" followed by a list of document ids. I tried to increase the ES timeout, but didn't help. What can I do to overcome this?</p>