Update documentation for ignore_unavailable search request parameter

_api-reference/document-apis/delete-by-query.md

@@ -48,7 +48,7 @@ default_operator | String | Indicates whether the default operator for a string
 df | String | The default field in case a field prefix is not provided in the query string.
 expand_wildcards | String | Specifies the type of index that wildcard expressions can match. Supports comma-separated values. Valid values are `all` (match any index), `open` (match open, non-hidden indexes), `closed` (match closed, non-hidden indexes), `hidden` (match hidden indexes), and `none` (deny wildcard expressions). Default is `open`.
 from | Integer | The starting index to search from. Default is 0.
-ignore_unavailable | Boolean | Specifies whether to include missing or closed indexes in the response. Default is false.
+ignore_unavailable | Boolean | Specifies whether to include missing or closed indexes in the response and ignores unavailable shards during the search request. Default is `false`.
 lenient | Boolean | Specifies whether OpenSearch should accept requests if queries have format errors (for example, querying a text field for an integer). Default is false.
 max_docs | Integer | How many documents the delete by query operation should process at most. Default is all documents.
 preference | String | Specifies which shard or node OpenSearch should perform the delete by query operation on.

_api-reference/document-apis/update-by-query.md

@@ -55,7 +55,7 @@ default_operator | String | Indicates whether the default operator for a string
 df | String | The default field if a field prefix is not provided in the query string.
 expand_wildcards | String | Specifies the type of index that wildcard expressions can match. Supports comma-separated values. Valid values are `all` (match any index), `open` (match open, non-hidden indexes), `closed` (match closed, non-hidden indexes), `hidden` (match hidden indexes), and `none` (deny wildcard expressions). Default is `open`.
 from | Integer | The starting index to search from. Default is 0.
-ignore_unavailable | Boolean | Whether to exclude missing or closed indexes in the response. Default is false.
+ignore_unavailable | Boolean | Whether to exclude missing or closed indexes in the response and ignores unavailable shards during the search request. Default is `false`.
 lenient | Boolean | Specifies whether OpenSearch should accept requests if queries have format errors (for example, querying a text field for an integer). Default is false.
 max_docs | Integer | How many documents the update by query operation should process at most. Default is all documents.
 pipeline | String | ID of the pipeline to use to process documents.

_api-reference/multi-search.md

@@ -63,7 +63,7 @@ allow_no_indices | Boolean | Whether to ignore wildcards that don't match any in
 cancel_after_time_interval | Time | The time after which the search request will be canceled. Supported at both parent and child request levels. The order of precedence is:<br> 1. Child-level parameter<br> 2. Parent-level parameter<br> 3. [Cluster setting]({{site.url}}{{site.baseurl}}/api-reference/cluster-settings).<br>Default is -1. | Yes
 css_minimize_roundtrips | Boolean | Whether OpenSearch should try to minimize the number of network round trips between the coordinating node and remote clusters (only applicable to cross-cluster search requests). Default is `true`. | No
 expand_wildcards | Enum | Expands wildcard expressions to concrete indexes. Combine multiple values with commas. Supported values are `all`, `open`, `closed`, `hidden`, and `none`. Default is `open`. | Yes
-ignore_unavailable | Boolean | If an index from the indexes list doesn’t exist, whether to ignore it rather than fail the query. Default is `false`. | Yes
+ignore_unavailable | Boolean | If an index or shard from the indexes list doesn’t exist, whether to ignore it rather than fail the query. Default is `false`. | Yes
 max_concurrent_searches | Integer | The maximum number of concurrent searches. The default depends on your node count and search thread pool size. Higher values can improve performance, but risk overloading the cluster. | No
 max_concurrent_shard_requests | Integer | Maximum number of concurrent shard requests that each search executes per node. Default is 5. Higher values can improve performance, but risk overloading the cluster. | No
 pre_filter_shard_size | Integer | Default is 128. | No

_api-reference/search.md

@@ -56,7 +56,7 @@ expand_wildcards | String | Specifies the type of index that wildcard expression
 explain | Boolean | Whether to return details about how OpenSearch computed the document's score. Default is false.
 from | Integer | The starting index to search from. Default is 0.
 ignore_throttled | Boolean | Whether to ignore concrete, expanded, or indexes with aliases if indexes are frozen. Default is true.
-ignore_unavailable | Boolean | Specifies whether to include missing or closed indexes in the response. Default is false.
+ignore_unavailable | Boolean | Specifies whether to include missing or closed indexes in the response and ignores unavailable shards during the search request. Default is `false`.
 lenient | Boolean | Specifies whether OpenSearch should accept requests if queries have format errors (for example, querying a text field for an integer). Default is false.
 max_concurrent_shard_requests | Integer | How many concurrent shard requests this request should execute on each node. Default is 5.
 phase_took | Boolean | Whether to return phase-level `took` time values in the response. Default is false.