Returns low-level information about the Lucene segments in index shards

GET /_cat/segments/{index}

For data streams, the API returns information about the backing indices. IMPORTANT: cat APIs are only intended for human consumption using the command line or Kibana console. They are not intended for use by applications. For application consumption, use the index segments API.

Path parameters

  • index string | array[string] Required

    A comma-separated list of data streams, indices, and aliases used to limit the request. Supports wildcards (*). To target all data streams and indices, omit this parameter or use * or _all.

Query parameters

  • bytes string

    The unit used to display byte values.

    Values are b, kb, mb, gb, tb, or pb.

Responses

  • 200 application/json
    Hide response attributes Show response attributes object
    • index string
    • shard string

      The shard name.

    • prirep string

      The shard type: primary or replica.

    • ip string

      The IP address of the node where it lives.

    • id string
    • segment string

      The segment name, which is derived from the segment generation and used internally to create file names in the directory of the shard.

    • generation string

      The segment generation number. Elasticsearch increments this generation number for each segment written then uses this number to derive the segment name.

    • docs.count string

      The number of documents in the segment. This excludes deleted documents and counts any nested documents separately from their parents. It also excludes documents which were indexed recently and do not yet belong to a segment.

    • docs.deleted string

      The number of deleted documents in the segment, which might be higher or lower than the number of delete operations you have performed. This number excludes deletes that were performed recently and do not yet belong to a segment. Deleted documents are cleaned up by the automatic merge process if it makes sense to do so. Also, Elasticsearch creates extra deleted documents to internally track the recent history of operations on a shard.

    • size number | string

      One of:
      _types:ByteSize number _types:ByteSize string

    • size.memory number | string

      One of:
      _types:ByteSize number _types:ByteSize string
    • committed string

      If true, the segment is synced to disk. Segments that are synced can survive a hard reboot. If false, the data from uncommitted segments is also stored in the transaction log so that Elasticsearch is able to replay changes on the next start.

    • searchable string

      If true, the segment is searchable. If false, the segment has most likely been written to disk but needs a refresh to be searchable.

    • version string
    • compound string

      If true, the segment is stored in a compound file. This means Lucene merged all files from the segment in a single file to save file descriptors.
GET /_cat/segments/{index} 
curl \
 -X GET http://api.example.com/_cat/segments/{index}
Response examples (200) 
[
  {
    "index": "string",
    "shard": "string",
    "prirep": "string",
    "ip": "string",
    "id": "string",
    "segment": "string",
    "generation": "string",
    "docs.count": "string",
    "docs.deleted": "string",
    "": 42.0,
    "committed": "string",
    "searchable": "string",
    "version": "string",
    "compound": "string"
  }
]