Hints

Hint is a known SQL feature

the syntax for hints is adding it on comment before the fields after the select keyword.

select /*! YOUR_HINT*/ yourField from yourIndex

Some of the Available hints:

• IGNORE_UNAVAILABLE - read about it here
  

SELECT /*! IGNORE_UNAVAILABLE */ * FROM index1,index2 

• DOCS_WITH_AGGREGATION(number) Use it if you want docs to return on aggregation query
  It sets the size parameter on query to the number specified
  Otherwise size will be zero
  Example:

SELECT /*! DOCS_WITH_AGGREGATION(10) */ count(*) from account