--- layout: default title: Nodes hot threads parent: Nodes APIs nav_order: 30 --- # Nodes hot threads The nodes hot threads endpoint provides information about busy JVM threads for selected cluster nodes. It provides a unique view of the of activity each node. ## Example ```json GET /_nodes/hot_threads ``` {% include copy-curl.html %} ## Path and HTTP methods ```json GET /_nodes/hot_threads GET /_nodes//hot_threads ``` ## Path parameters You can include the following optional path parameter in your request. Parameter | Type | Description :--- | :--- | :--- nodeId | String | A comma-separated list of node IDs used to filter results. Supports [node filters]({{site.url}}{{site.baseurl}}/api-reference/nodes-apis/index/#node-filters). Defaults to `_all`. ## Query parameters You can include the following query parameters in your request. All query parameters are optional. Parameter | Type | Description :--- | :---| :--- snapshots | Integer | The number of samples of thread stacktraces. Defaults to `10`. interval | Time | The interval between consecutive samples. Defaults to `500ms`. threads | Integer | The number of the busiest threads to return information about. Defaults to `3`. ignore_idle_threads | Boolean | Don’t show threads that are in known idle states, such as waiting on a socket select or pulling from an empty task queue. Defaults to `true`. type | String | Supported thread types are `cpu`, `wait`, or `block`. Defaults to `cpu`. timeout | Time | Sets the time limit for node response. Default value is `30s`. #### Example request ```json GET /_nodes/hot_threads ``` {% include copy-curl.html %} #### Example response ```bash ::: {opensearch}{F-ByTQzVQ3GQeYzQJArJGQ}{GxbcLdCATPWggOuQHJAoCw}{127.0.0.1}{127.0.0.1:9300}{dimr}{shard_indexing_pressure_enabled=true} Hot threads at 2022-09-29T19:46:44.533Z, interval=500ms, busiestThreads=3, ignoreIdleThreads=true: 0.1% (455.5micros out of 500ms) cpu usage by thread 'ScheduledMetricCollectorsExecutor' 10/10 snapshots sharing following 2 elements java.base@17.0.4/java.lang.Thread.sleep(Native Method) org.opensearch.performanceanalyzer.collectors.ScheduledMetricCollectorsExecutor.run(ScheduledMetricCollectorsExecutor.java:100) ``` ## Response Unlike the majority of OpenSearch API responses, this response is in a text format. It consists of one section per each cluster node included in the response. Each section starts with a single line containing the following segments: Line segment | Description :--- |:------- :::  | Line start (a distinct visual symbol). `{global-eu-35}` | Node name. `{uFPbKLDOTlOmdnwUlKW8sw}` | NodeId. `{OAM8OT5CQAyasWuIDeVyUA}` | EphemeralId. `{global-eu-35.local}` | Host name. `{[gdv2:a284:2acv:5fa6:0:3a2:7260:74cf]:9300}` | Host address. `{dimr}` | Node roles (d=data, i=ingest, m=cluster manager, r=remote cluster client). `{zone=west-a2, shard_indexing_pressure_enabled=true}` | Node attributes. Then information about threads of the selected type is provided. ```bash ::: {global-eu-35}{uFPbKLDOTlOmdnwUlKW8sw}{OAM8OT5CQAyasWuIDeVyUA}{global-eu-35.local}{[gdv2:a284:2acv:5fa6:0:3a2:7260:74cf]:9300}{dimr}{zone=west-a2, shard_indexing_pressure_enabled=true} Hot threads at 2022-04-01T15:15:27.658Z, interval=500ms, busiestThreads=3, ignoreIdleThreads=true: 0.1% (645micros out of 500ms) cpu usage by thread 'opensearch[global-eu-35][transport_worker][T#7]' 4/10 snapshots sharing following 3 elements io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986) io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) java.base@11.0.14.1/java.lang.Thread.run(Thread.java:829) ::: {global-eu-62}{4knOxAdERlOB19zLQIT1bQ}{HJuZs2HiQ_-8Elj0Fvi_1g}{global-eu-62.local}{[gdv2:a284:2acv:5fa6:0:3a2:bba6:fe3f]:9300}{dimr}{zone=west-a2, shard_indexing_pressure_enabled=true} Hot threads at 2022-04-01T15:15:27.659Z, interval=500ms, busiestThreads=3, ignoreIdleThreads=true: 18.7% (93.4ms out of 500ms) cpu usage by thread 'opensearch[global-eu-62][transport_worker][T#3]' 6/10 snapshots sharing following 3 elements io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986) io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) java.base@11.0.14.1/java.lang.Thread.run(Thread.java:829) ::: {global-eu-44}{8WW3hrkcTwGvgah_L8D_jw}{Sok7spHISFyol0jFV6i0kw}{global-eu-44.local}{[gdv2:a284:2acv:5fa6:0:3a2:9120:e79e]:9300}{dimr}{zone=west-a2, shard_indexing_pressure_enabled=true} Hot threads at 2022-04-01T15:15:27.659Z, interval=500ms, busiestThreads=3, ignoreIdleThreads=true: 42.6% (212.7ms out of 500ms) cpu usage by thread 'opensearch[global-eu-44][write][T#5]' 2/10 snapshots sharing following 43 elements java.base@11.0.14.1/sun.nio.ch.IOUtil.write1(Native Method) java.base@11.0.14.1/sun.nio.ch.EPollSelectorImpl.wakeup(EPollSelectorImpl.java:254) io.netty.channel.nio.NioEventLoop.wakeup(NioEventLoop.java:787) io.netty.util.concurrent.SingleThreadEventExecutor.execute(SingleThreadEventExecutor.java:846) io.netty.util.concurrent.SingleThreadEventExecutor.execute(SingleThreadEventExecutor.java:815) io.netty.channel.AbstractChannelHandlerContext.safeExecute(AbstractChannelHandlerContext.java:989) io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:796) io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758) io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1020) io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:311) org.opensearch.transport.netty4.Netty4TcpChannel.sendMessage(Netty4TcpChannel.java:159) app//org.opensearch.transport.OutboundHan... ``` ## Required permissions If you use the Security plugin, make sure you set the following permissions: `cluster:monitor/nodes/hot_threads`.