Tip of the month - Index Sorting in Elasticsearch

When creating a new index in Elasticsearch it is possible to configure how the segments inside each shard will be sorted. By default Lucene does not apply any sort. The index.sort.* settings define which fields should be used to sort the documents inside each segment.

Advantages: It speeds up aggregations, especially for top N type queries. This can be defined only while creating index (note: you cannot add or update a sort on an existing index). It also decreases indexing throughput since documents must be sorted at flush and merge time.

Below is the setting:

PUT my_index

{

   “settings”: {

       “index”: {

               “sort.field”: [“username”,”date”],

                 “sort.order”: [“asc”,”desc”]

               }

}

“mappings” :{..}

}

- Technical Tip by Ayandeep Das | Technical Specialist - ETL, Ashnik