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Elastic Docs ›Elasticsearch Guide [8.11] ›REST APIs ›Compact and aligned text (CAT) APIs

cat shards API

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cat shards API

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cat APIs are only intended for human consumption using the command line or Kibana console. They are not intended for use by applications.

The shards command is the detailed view of what nodes contain which shards. It will tell you if it’s a primary or replica, the number of docs, the bytes it takes on disk, and the node where it’s located.

For data streams, the API returns information about the stream’s backing indices.

Request

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GET /_cat/shards/<target>

GET /_cat/shards

Prerequisites

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  • If the Elasticsearch security features are enabled, you must have the monitor or manage cluster privilege to use this API. You must also have the monitor or manage index privilege for any data stream, index, or alias you retrieve.

Path parameters

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<target>
(Optional, string) 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

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bytes
(Optional, byte size units) Unit used to display byte values.
format
(Optional, string) Short version of the HTTP accept header. Valid values include JSON, YAML, etc.
h

(Optional, string) Comma-separated list of column names to display.

If you do not specify which columns to include, the API returns the default columns in the order listed below. If you explicitly specify one or more columns, it only returns the specified columns.

Valid columns are:

index, i, idx
(Default) Name of the index.
shard, s, sh
(Default) Name of the shard.
prirep, p, pr, primaryOrReplica
(Default) Shard type. Returned values are primary or replica.
state, st

(Default) State of the shard. Returned values are:

  • INITIALIZING: The shard is recovering from a peer shard or gateway.
  • RELOCATING: The shard is relocating.
  • STARTED: The shard has started.
  • UNASSIGNED: The shard is not assigned to any node.
docs, d, dc
(Default) Number of documents in shard, such as 25.
store, sto
(Default) Disk space used by the shard, such as 5kb.
dataset.size
(Default) Disk space used by the shard’s dataset, which may or may not be the size on disk, but includes space used by the shard on object storage. Reported as a size value such as 5kb.
ip
(Default) IP address of the node, such as 127.0.1.1.
id
(Default) ID of the node, such as k0zy.
node, n
(Default) Node name, such as I8hydUG.
completion.size, cs, completionSize
Size of completion, such as 0b.
dense_vector.value_count, dvc, denseVectorCount
Number of indexed dense vector.
fielddata.memory_size, fm, fielddataMemory
Used fielddata cache memory, such as 0b.
fielddata.evictions, fe, fielddataEvictions
Fielddata cache evictions, such as 0.
flush.total, ft, flushTotal
Number of flushes, such as 1.
flush.total_time, ftt, flushTotalTime
Time spent in flush, such as 1.
get.current, gc, getCurrent
Number of current get operations, such as 0.
get.time, gti, getTime
Time spent in get, such as 14ms.
get.total, gto, getTotal
Number of get operations, such as 2.
get.exists_time, geti, getExistsTime
Time spent in successful gets, such as 14ms.
get.exists_total, geto, getExistsTotal
Number of successful get operations, such as 2.
get.missing_time, gmti, getMissingTime
Time spent in failed gets, such as 0s.
get.missing_total, gmto, getMissingTotal
Number of failed get operations, such as 1.
indexing.delete_current, idc, indexingDeleteCurrent
Number of current deletion operations, such as 0.
indexing.delete_time, idti, indexingDeleteTime
Time spent in deletions, such as 2ms.
indexing.delete_total, idto, indexingDeleteTotal
Number of deletion operations, such as 2.
indexing.index_current, iic, indexingIndexCurrent
Number of current indexing operations, such as 0.
indexing.index_time, iiti, indexingIndexTime
Time spent in indexing, such as 134ms.
indexing.index_total, iito, indexingIndexTotal
Number of indexing operations, such as 1.
indexing.index_failed, iif, indexingIndexFailed
Number of failed indexing operations, such as 0.
merges.current, mc, mergesCurrent
Number of current merge operations, such as 0.
merges.current_docs, mcd, mergesCurrentDocs
Number of current merging documents, such as 0.
merges.current_size, mcs, mergesCurrentSize
Size of current merges, such as 0b.
merges.total, mt, mergesTotal
Number of completed merge operations, such as 0.
merges.total_docs, mtd, mergesTotalDocs
Number of merged documents, such as 0.
merges.total_size, mts, mergesTotalSize
Size of current merges, such as 0b.
merges.total_time, mtt, mergesTotalTime
Time spent merging documents, such as 0s.
query_cache.memory_size, qcm, queryCacheMemory
Used query cache memory, such as 0b.
query_cache.evictions, qce, queryCacheEvictions
Query cache evictions, such as 0.
recoverysource.type, rs
Type of recovery source.
refresh.total, rto, refreshTotal
Number of refreshes, such as 16.
refresh.time, rti, refreshTime
Time spent in refreshes, such as 91ms.
search.fetch_current, sfc, searchFetchCurrent
Current fetch phase operations, such as 0.
search.fetch_time, sfti, searchFetchTime
Time spent in fetch phase, such as 37ms.
search.fetch_total, sfto, searchFetchTotal
Number of fetch operations, such as 7.
search.open_contexts, so, searchOpenContexts
Open search contexts, such as 0.
search.query_current, sqc, searchQueryCurrent
Current query phase operations, such as 0.
search.query_time, sqti, searchQueryTime
Time spent in query phase, such as 43ms.
search.query_total, sqto, searchQueryTotal
Number of query operations, such as 9.
search.scroll_current, scc, searchScrollCurrent
Open scroll contexts, such as 2.
search.scroll_time, scti, searchScrollTime
Time scroll contexts held open, such as 2m.
search.scroll_total, scto, searchScrollTotal
Completed scroll contexts, such as 1.
segments.count, sc, segmentsCount
Number of segments, such as 4.
segments.memory, sm, segmentsMemory
Memory used by segments, such as 1.4kb.
segments.index_writer_memory, siwm, segmentsIndexWriterMemory
Memory used by index writer, such as 18mb.
segments.version_map_memory, svmm, segmentsVersionMapMemory
Memory used by version map, such as 1.0kb.
segments.fixed_bitset_memory, sfbm, fixedBitsetMemory
Memory used by fixed bit sets for nested object field types and type filters for types referred in join fields, such as 1.0kb.
seq_no.global_checkpoint, sqg, globalCheckpoint
Global checkpoint.
seq_no.local_checkpoint, sql, localCheckpoint
Local checkpoint.
seq_no.max, sqm, maxSeqNo
Maximum sequence number.
suggest.current, suc, suggestCurrent
Number of current suggest operations, such as 0.
suggest.time, suti, suggestTime
Time spent in suggest, such as 0.
suggest.total, suto, suggestTotal
Number of suggest operations, such as 0.
sync_id
Sync ID of the shard.
unassigned.at, ua
Time at which the shard became unassigned in Coordinated Universal Time (UTC).
unassigned.details, ud
Details about why the shard became unassigned. This does not explain why the shard is currently unassigned. To understand why a shard is not assigned, use the Cluster allocation explain API.
unassigned.for, uf
Time at which the shard was requested to be unassigned in Coordinated Universal Time (UTC).
unassigned.reason, ur

Indicates the reason for the last change to the state of this unassigned shard. This does not explain why the shard is currently unassigned. To understand why a shard is not assigned, use the Cluster allocation explain API. Returned values include:

  • ALLOCATION_FAILED: Unassigned as a result of a failed allocation of the shard.
  • CLUSTER_RECOVERED: Unassigned as a result of a full cluster recovery.
  • DANGLING_INDEX_IMPORTED: Unassigned as a result of importing a dangling index.
  • EXISTING_INDEX_RESTORED: Unassigned as a result of restoring into a closed index.
  • FORCED_EMPTY_PRIMARY: The shard’s allocation was last modified by forcing an empty primary using the Cluster reroute API.
  • INDEX_CLOSED: Unassigned because the index was closed.
  • INDEX_CREATED: Unassigned as a result of an API creation of an index.
  • INDEX_REOPENED: Unassigned as a result of opening a closed index.
  • MANUAL_ALLOCATION: The shard’s allocation was last modified by the Cluster reroute API.
  • NEW_INDEX_RESTORED: Unassigned as a result of restoring into a new index.
  • NODE_LEFT: Unassigned as a result of the node hosting it leaving the cluster.
  • NODE_RESTARTING: Similar to NODE_LEFT, except that the node was registered as restarting using the Node shutdown API.
  • PRIMARY_FAILED: The shard was initializing as a replica, but the primary shard failed before the initialization completed.
  • REALLOCATED_REPLICA: A better replica location is identified and causes the existing replica allocation to be cancelled.
  • REINITIALIZED: When a shard moves from started back to initializing.
  • REPLICA_ADDED: Unassigned as a result of explicit addition of a replica.
  • REROUTE_CANCELLED: Unassigned as a result of explicit cancel reroute command.
help
(Optional, Boolean) If true, the response includes help information. Defaults to false.
master_timeout
(Optional, time units) Period to wait for a connection to the master node. If no response is received before the timeout expires, the request fails and returns an error. Defaults to 30s.
s
(Optional, string) Comma-separated list of column names or column aliases used to sort the response.
time
(Optional, time units) Unit used to display time values.
v
(Optional, Boolean) If true, the response includes column headings. Defaults to false.

Examples

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Example with a single data stream or index

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response = client.cat.shards
puts response
GET _cat/shards

The API returns the following response:

my-index-000001 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA

Example with a wildcard pattern

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If your cluster has many shards, you can use a wildcard pattern in the <target> path parameter to limit the API request.

The following request returns information for any data streams or indices beginning with my-index-.

response = client.cat.shards(
  index: 'my-index-*'
)
puts response
GET _cat/shards/my-index-*

The API returns the following response:

my-index-000001 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA

Example with a relocating shard

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response = client.cat.shards
puts response
GET _cat/shards

The API returns the following response:

my-index-000001 0 p RELOCATING 3014 31.1mb 192.168.56.10 H5dfFeA -> -> 192.168.56.30 bGG90GE

The RELOCATING value in state column indicates the index shard is relocating.

Example with a shard states

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Before a shard is available for use, it goes through an INITIALIZING state. You can use the cat shards API to see which shards are initializing.

response = client.cat.shards
puts response
GET _cat/shards

The API returns the following response:

my-index-000001 0 p STARTED      3014 31.1mb 192.168.56.10 H5dfFeA
my-index-000001 0 r INITIALIZING    0 14.3mb 192.168.56.30 bGG90GE

Example with reasons for unassigned shards

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The following request returns the unassigned.reason column, which indicates why a shard is unassigned.

response = client.cat.shards(
  h: 'index,shard,prirep,state,unassigned.reason'
)
puts response
GET _cat/shards?h=index,shard,prirep,state,unassigned.reason

The API returns the following response:

my-index-000001 0 p STARTED    3014 31.1mb 192.168.56.10 H5dfFeA
my-index-000001 0 r STARTED    3014 31.1mb 192.168.56.30 bGG90GE
my-index-000001 0 r STARTED    3014 31.1mb 192.168.56.20 I8hydUG
my-index-000001 0 r UNASSIGNED ALLOCATION_FAILED
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