Add docs for new item_count API for field data cache

_api-reference/cluster-api/cluster-stats.md

@@ -180,7 +180,8 @@ response = client.cluster.stats(
         },
         "fielddata": {
             "memory_size_in_bytes": 664,
-            "evictions": 0
+            "evictions": 0,
+            "item_count": 1
         },
         "query_cache": {
             "memory_size_in_bytes": 0,

_api-reference/index-apis/stats.md

@@ -340,7 +340,8 @@ By default, the returned statistics are aggregated in the `primaries` and `total
       },
       "fielddata": {
         "memory_size_in_bytes": 0,
-        "evictions": 0
+        "evictions": 0,
+        "item_count": 0
       },
       "completion": {
         "size_in_bytes": 0
@@ -507,7 +508,8 @@ By default, the returned statistics are aggregated in the `primaries` and `total
       },
       "fielddata": {
         "memory_size_in_bytes": 0,
-        "evictions": 0
+        "evictions": 0,
+        "item_count": 0
       },
       "completion": {
         "size_in_bytes": 0
@@ -678,7 +680,8 @@ By default, the returned statistics are aggregated in the `primaries` and `total
         },
         "fielddata": {
           "memory_size_in_bytes": 0,
-          "evictions": 0
+          "evictions": 0,
+          "item_count": 0
         },
         "completion": {
           "size_in_bytes": 0
@@ -845,7 +848,8 @@ By default, the returned statistics are aggregated in the `primaries` and `total
         },
         "fielddata": {
           "memory_size_in_bytes": 0,
-          "evictions": 0
+          "evictions": 0,
+          "item_count": 0
         },
         "completion": {
           "size_in_bytes": 0

_api-reference/nodes-apis/nodes-stats.md

@@ -333,7 +333,8 @@ Select the arrow to view the example response.
         },
         "fielddata" : {
           "memory_size_in_bytes" : 356,
-          "evictions" : 0
+          "evictions" : 0,
+          "item_count": 1
         },
         "completion" : {
           "size_in_bytes" : 0,
@@ -1008,6 +1009,7 @@ query_cache.evictions | Integer | The number of evictions from the query cache.
 fielddata | Object | Statistics about the field data cache for all shards in the node.
 fielddata.memory_size_in_bytes | Integer | The total amount of memory used for the field data cache for all shards in the node.
 fielddata.evictions | Integer | The number of evictions in the field data cache.
+fielddata.item_count | Integer | The number of items in the field data cache.
 fielddata.fields | Object | Contains all field data fields.
 completion | Object | Statistics about completions for all shards in the node.
 completion.size_in_bytes | Integer | The total amount of memory used for completion for all shards in the node, in bytes.

_install-and-configure/configuring-opensearch/index-settings.md

@@ -64,7 +64,7 @@ OpenSearch supports the following dynamic cluster-level index settings:
 
 - `indices.replication.max_bytes_per_sec` (String): Limits the total inbound and outbound replication traffic for each node. If a value is not specified in the configured value the `indices.recovery.max_bytes_per_sec` setting is used, which defaults to 40 mb. If you set the replication traffic value to less than or equal to 0 mb, rate limiting is disabled, which causes replication data to be transferred at the highest possible rate.
 
-- `indices.fielddata.cache.size` (String): The maximum size of the field data cache. May be specified as an absolute value (for example, `8GB`) or a percentage of the node heap (for example, `50%`). This value is static so you must specify it in the `opensearch.yml` file. If you don't specify this setting, the maximum size is unlimited. This value should be smaller than the `indices.breaker.fielddata.limit`. For more information, see [Field data circuit breaker]({{site.url}}{{site.baseurl}}/install-and-configure/configuring-opensearch/circuit-breaker/#field-data-circuit-breaker-settings).
+- `indices.fielddata.cache.size` (String): The maximum size of the field data cache. May be specified as an absolute value (for example, `8GB`) or a percentage of the node heap (for example, `50%`). This value is static so you must specify it in the `opensearch.yml` file. If you don't specify this setting, the default size is `35%`. This value should be smaller than the `indices.breaker.fielddata.limit`. For more information, see [Field data circuit breaker]({{site.url}}{{site.baseurl}}/install-and-configure/configuring-opensearch/circuit-breaker/#field-data-circuit-breaker-settings).
 
 - `indices.query.bool.max_clause_count` (Integer): Defines the maximum product of fields and terms that are queryable simultaneously. Before OpenSearch 2.16, a cluster restart was required in order to apply this static setting. Now dynamic, existing search thread pools may use the old static value initially, causing `TooManyClauses` exceptions. New thread pools use the updated value. Default is `1024`.
 

_search-plugins/caching/field-data-cache.md

@@ -33,7 +33,7 @@ If you want to enable sorting or aggregation directly on the text field, set `"f
 Setting | Data type  | Default | Level | Static/Dynamic | Description
 :--- |:-----------|:--------| :--- | :--- | :---
 `indices.breaker.fielddata.limit` | Percentage  | `40%`  | Cluster | Dynamic | Sets the field data cache size limit, beyond which incoming requests that would require more entries in the cache will be stopped by the circuit breaker. 
-`indices.fielddata.cache.size` | Byte size or percentage of total heap size | -1 | Cluster | Static | Sets the maximum field data cache size, beyond which evictions will occur. Must be smaller than the circuit breaker limit. With the default value of -1, this limit does not apply and only the circuit breaker limit will be relevant.
+`indices.fielddata.cache.size` | Byte size or percentage of total heap size | `35%` | Cluster | Static | Sets the maximum field data cache size, beyond which evictions will occur. Must be smaller than the circuit breaker limit. If this value is set to `-1`, this limit does not apply and only the circuit breaker limit will be relevant.
 
 ## Monitoring the field data cache 
 
@@ -53,7 +53,8 @@ The response contains the cache statistics:
       "indices" : {
         "fielddata" : {
           "memory_size_in_bytes" : 0,
-          "evictions" : 0
+          "evictions" : 0,
+          "item_count" : 0
         }
       }
     }