_tier field

_tier field

When performing queries across multiple indexes, it is sometimes desirable to target indexes held on nodes of a given data tier (data_hot, data_warm, data_cold or data_frozen). The _tier field allows matching on the tier_preference setting of the index a document was indexed into. The preferred value is accessible in certain queries :

  1. PUT index_1/_doc/1
  2. {
  3.   "text": "Document in index 1"
  4. }
  6. PUT index_2/_doc/2?refresh=true
  7. {
  8.   "text": "Document in index 2"
  9. }
  11. GET index_1,index_2/_search
  12. {
  13.   "query": {
  14.     "terms": {
  15.       "_tier": ["data_hot", "data_warm"] 
  16.     }
  17.   }
  18. }

Querying on the _tier field

Typically a query will use a terms query to list the tiers of interest but you can use the _tier field in any query that is rewritten to a term query, such as the match, query_string, term, terms, or simple_query_string query, as well as prefix and wildcard queries. However, it does not support regexp and fuzzy queries.

The tier_preference setting of the index is a comma-delimited list of tier names in order of preference i.e. the preferred tier for hosting an index is listed first followed by potentially many fall-back options. Query matching only considers the first preference (the first value of a list).