Some KNN clarification.

Author: aetter

docs/install/plugins.md

@@ -38,6 +38,7 @@ opendistro_index_management     1.4.0.0
 opendistro_performance_analyzer 1.4.0.0
 opendistro_security             1.4.0.0
 opendistro_sql                  1.4.0.0
+opendistro-knn                  1.4.0.0
 </pre>
     </td>
   </tr>
@@ -186,9 +187,8 @@ sudo bin/elasticsearch-plugin install https://d3g5vo6xdbdb9a.cloudfront.net/down
 
 ### KNN
 
-```bash
-sudo bin/elasticsearch-plugin install
-```
+KNN is currently only available as part of the Docker image.
+{: .warning }
 
 
 ### Anomaly Detection

docs/knn/index.md

@@ -8,6 +8,9 @@ has_toc: false
 
 # KNN
 
+KNN is currently only available as part of the Docker image.
+{: .warning }
+
 Short for its associated *k-nearest neighbors* algorithm, the KNN plugin lets you search for points in a vector space and find the "nearest neighbors" for those points by Euclidean distance. Use cases include recommendations (for example, an "other songs you might like" feature in a music application), image recognition, and fraud detection. For background information on the algorithm, see [Wikipedia](https://en.wikipedia.org/wiki/K-nearest_neighbors_algorithm).
 
 

docs/knn/settings.md

@@ -28,9 +28,9 @@ Setting | Default | Description
 `knn.algo_param.index_thread_qty` | 1 | The number of threads used for graph creation. Keeping this value low reduces the CPU impact of the KNN plugin, but also reduces indexing performance.
 `knn.cache.item.expiry.enabled` | false | Whether to remove graphs that have not been accessed for a certain duration from memory.
 `knn.cache.item.expiry.minutes` | 3h | If enabled, the idle time before removing a graph from memory.
-`knn.circuit_breaker.unset.percentage` | 75.0 | The native memory usage threshold for the circuit breaker.
+`knn.circuit_breaker.unset.percentage` | 75.0 | The native memory usage threshold for the circuit breaker. Memory usage must be below this percentage of `knn.memory.circuit_breaker.limit` for `knn.circuit_breaker.triggered` to remain false.
 `knn.circuit_breaker.triggered` | false | True when memory usage exceeds the `knn.circuit_breaker.unset.percentage` value.
-`knn.memory.circuit_breaker.limit` | 60% | The native memory limit for graphs. If this limit triggers, KNN removes the least recently used graphs.
+`knn.memory.circuit_breaker.limit` | 60% | The native memory limit for graphs. At the default value, if a machine has 100 GB of memory and the JVM uses 32 GB, KNN uses 60% of the remaining 68 GB (40.8 GB). If memory usage exceeds this value, KNN removes the least recently used graphs.
 `knn.memory.circuit_breaker.enabled` | true | Whether to enable the KNN memory circuit breaker.
 `knn.plugin.enabled`| true | Enables or disables the KNN plugin.
 
@@ -43,13 +43,19 @@ KNN includes statistics that can give you a sense for how the plugin is performi
 GET _opendistro/_knn/stats
 ```
 
+You can also filter by node and/or statistic:
+
+```
+GET /_opendistro/_knn/nodeId1,nodeId2/stats/statName1,statName2
+```
+
 Statistic |  Description
 :--- | :---
-totalLoadTime | asdf
-evictionCount | asdf
-hitCount | asdf
-cacheCapacityReached | asdf
-loadSuccessCount | asdf
-graphMemoryUsage | asdf
-missCount | asdf
-loadExceptionCount | asdf
+totalLoadTime | The time in nanoseconds that KNN has taken to load graphs into the cache.
+evictionCount | The number of graphs that have been evicted from the cache due to memory constraints or idle time.
+hitCount | The number of cache hits.
+cacheCapacityReached | Whether `knn.memory.circuit_breaker.limit` has been reached.
+loadSuccessCount | The number of times KNN successfully loaded a graph into the cache.
+graphMemoryUsage | Current cache size (total size of all graphs in memory) in kilobytes.
+missCount | The number of cache misses.
+loadExceptionCount | The number of times an exception occurred when trying to load a graph into the cache.

version-history.md

@@ -25,8 +25,11 @@ Open Distro for Elasticsearch version | Release highlights | Release date | Elas
 
 For detailed release notes, see these GitHub repositories:
 
+- [Open Distro for Elasticsearch](https://github.com/opendistro-for-elasticsearch/opendistro-build/tree/master/release-notes)
 - [Security](https://github.com/opendistro-for-elasticsearch/security/releases)
 - [Alerting](https://github.com/opendistro-for-elasticsearch/alerting/releases)
 - [SQL](https://github.com/opendistro-for-elasticsearch/sql/releases)
 - [Index State Management](https://github.com/opendistro-for-elasticsearch/index-management/releases)
 - [Performance Analyzer](https://github.com/opendistro-for-elasticsearch/performance-analyzer/releases)
+- [KNN](https://github.com/opendistro-for-elasticsearch/k-NN/releases)
+- [Anomaly Detection](https://github.com/opendistro-for-elasticsearch/anomaly-detection/releases)