Index APIs - Clear Index or Data Stream Cache - 《OpenSearch v2.6 Documentation》

Clear index or data stream cache

Clear index or data stream cache

The clear cache API operation clears the caches of one or more indexes. For data streams, the API clears the caches of the stream’s backing indexes.

If you use the security plugin, you must have the manage index privileges.

Path parameters

Parameter	Data type	Description
target	String	Comma-delimited list of data streams, indexes, and index aliases to which cache clearing will be applied. Wildcard expressions () are supported. To target all data streams and indexes in a cluster, omit this parameter or use `_all` or . Optional.

Query parameters

All query parameters are optional.

Parameter	Data type	Description
allow_no_indices	Boolean	Whether to ignore wildcards, index aliases, or `_all` target (`target` path parameter) values that don’t match any indexes. If `false`, the request returns an error if any wildcard expression, index alias, or `_all` target value doesn’t match any indexes. This behavior also applies if the request targets include other open indexes. For example, a request where the target is `fig,app` returns an error if an index starts with `fig` but no index starts with `app`. Defaults to `true`.
expand_wildcards	String	Determines the index types that wildcard expressions can expand to. Accepts multiple values separated by a comma, such as `open,hidden`. Valid values are: `all` – Expand to open, closed, and hidden indexes. `open` – Expand only to open indexes. `closed` – Expand only to closed indexes `hidden` – Expand to include hidden indexes. Must be combined with `open`, `closed`, or `both`. `none` – Expansions are not accepted. Defaults to `open`.
fielddata	Boolean	If `true`, clears the fields cache. Use the `fields` parameter to clear specific fields’ caches. Defaults to `true`.
fields	String	Used in conjunction with the `fielddata` parameter. Comma-delimited list of field names that will be cleared out of the cache. Does not support objects or field aliases. Defaults to all fields.
index	String	Comma-delimited list of index names that will be cleared out of the cache.
ignore_unavailable	Boolean	If `true`, OpenSearch ignores missing or closed indexes. Defaults to `false`.
query	Boolean	If `true`, clears the query cache. Defaults to `true`.
request	Boolean	If `true`, clears the request cache. Defaults to `true`.

Example requests

The following example requests show multiple clear cache API uses.

Clear a specific cache

The following request clears the fields cache only:

POST /my-index/_cache/clear?fielddata=true

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The following request clears the query cache only:

POST /my-index/_cache/clear?query=true

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The following request clears the request cache only:

POST /my-index/_cache/clear?request=true

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Clear the cache for specific fields

The following request clears the fields caches of fielda and fieldb:

POST /my-index/_cache/clear?fields=fielda,fieldb

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Clear caches for specific data streams and indexes

The following request clears the cache for two specific indexes:

POST /my-index,my-index2/_cache/clear

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Clear caches for all data streams and indexes

The following request clears the cache for all data streams and indexes:

POST /_cache/clear

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Example response

The POST /books,hockey/_cache/clear request returns the following fields:

{
  "_shards" : {
    "total" : 4,
    "successful" : 2,
    "failed" : 0
  }
}

Response fields

The POST /books,hockey/_cache/clear request returns the following response fields:

Field	Data type	Description
_shards	Object	Shard information.
total	Integer	Total number of shards.
successful	Integer	Number of index shards with caches successfully cleared.
failed	Integer	Number of index shards with caches that failed to clear.