title: Elasticsearch: Working with frequently updated documents
body: <p>I have a forum application. There are multiple topics(posts) in the forums. Every topic has fields such as <code>viewCount</code>(how many times the topic was viewed by the forum users).</p>
  
  <p>I want that all fields of topics were taken from ES (id, date, title, content and viewCount). However, in this case, after every topic view, ES must reindex the entire document again.<br>
  I asked the question about partial update at stack overflow - <a href="https://stackoverflow.com/questions/28937946/partial-update-on-field-that-is-not-indexed">Partial update on field that is not indexed</a>. It's important to notice that <code>viewCount</code> field is not indexed, it's just stored in ES.</p>
  
  <p>There are two terms - partial update and partial index. There is partial update in ES where you can change only a few fields. But there is no partial reindex which means even if you change only one field, ES will reindex the entire document. It means that if the topic is viewed 1000 times, ES will index it 1000 times. And if I have a lot of users, many documents will be indexed again and again. This is first strategy.</p>
  
  <p>The second strategy is to keep some fields of the topic in the index and some in the database. In this case, I can take viewAcount from DB. Also, I can then store all fields in the DB and use index only as INDEX i.e to get ids of current topic.</p>
  
  <p>What is the best way to solve such problems?</p>