Author: Sarthak Aggarwal

As part of an indexing operation, the ingested documents are stored as immutable segments. Each segment is a collection of various data structures, such as inverted index, block K dimensional tree (BKD), term dictionary, or stored fields, and these data structures are responsible for retrieving the document faster during the search operation. Out of these data structures, stored fields, which are largest fields in the segment, are compressed when stored on the disk and based on the compression strategy used, the compression speed and the index storage size will vary. In this post, we discuss the performance of the Zstandard algorithm, which was introduced in OpenSearch v2.9, amongst other available compression algorithms in OpenSearch.