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Clear cache
Introduced 1.0
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 is 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 indexeshidden – 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 are cleared out of the cache. Does not support objects or field aliases. Defaults to all fields. |
| file | Boolean | If true, clears the unused entries from the file cache on nodes with the Search role. Defaults to false. |
| index | String | Comma-delimited list of index names that are 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
The following request clears the query cache only:
POST /my-index/_cache/clear?query=true
The following request clears the request cache only:
POST /my-index/_cache/clear?request=true
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
Clear caches for specific data streams or indexes
The following request clears the cache for two specific indexes:
POST /my-index,my-index2/_cache/clear
Clear caches for all data streams and indexes
The following request clears the cache for all data streams and indexes:
POST /_cache/clear
Clear unused entries from the cache on search-capable nodes
POST /*/_cache/clear?file=true
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. |