Access performance metrics

Cluster performance metrics are available directly in the Elasticsearch Add-On for Heroku console. The graphs on this page include a subset of Elasticsearch Add-On for Heroku-specific performance metrics.

For advanced views or production monitoring, enable logging and monitoring. The monitoring application provides more advanced views for Elasticsearch and JVM metrics, and includes a configurable retention period.

To access cluster performance metrics:

The following metrics are available:

Shows the maximum usage of the CPU resources assigned to your Elasticsearch cluster, as a percentage. CPU resources are relative to the size of your cluster, so that a cluster with 32GB of RAM gets assigned twice as many CPU resources as a cluster with 16GB of RAM. All clusters are guaranteed their share of CPU resources, as Elasticsearch Add-On for Heroku infrastructure does not overcommit any resources. CPU credits permit boosting the performance of smaller clusters temporarily, so that CPU usage can exceed 100%.

Shows your remaining CPU credits, measured in seconds of CPU time. CPU credits enable the boosting of CPU resources assigned to your cluster to improve performance temporarily when it is needed most. For more details check How to use vCPU to boost your instance.

Shows the number of requests that your cluster receives per second, separated into search requests and requests to index documents. This metric provides a good indicator of the volume of work that your cluster typically handles over time which, together with other performance metrics, helps you determine if your cluster is sized correctly. Also lets you check if there is a sudden increase in the volume of user requests that might explain an increase in response times.

Indicates the amount of time that it takes for your Elasticsearch cluster to complete a search query, in milliseconds. Response times won’t tell you about the cause of a performance issue, but they are often a first indicator that something is amiss with the performance of your Elasticsearch cluster.

Indicates the amount of time that it takes for your Elasticsearch cluster to complete an indexing operation, in milliseconds. Response times won’t tell you about the cause of a performance issue, but they are often a first indicator that something is amiss with the performance of your Elasticsearch cluster.

Indicates the total memory used by the JVM heap over time. We’ve configured Elasticsearch’s garbage collector to keep memory usage below 75% for heaps of 8GB or larger. For heaps smaller than 8GB, the threshold is 85%. If memory pressure consistently remains above this threshold, you might need to resize your cluster or reduce memory consumption. Check how high memory pressure can cause performance issues.

Indicates the overhead involved in JVM garbage collection to reclaim memory.

Performance correlates directly with resources assigned to your cluster, and many of these metrics will show some sort of correlation with each other when you are trying to determine the cause of a performance issue. Take a look at some of the scenarios included in this section to learn how you can determine the cause of performance issues.

It is not uncommon for performance issues on Elasticsearch Add-On for Heroku to be caused by an undersized cluster that cannot cope with the workload it is being asked to handle. If your cluster performance metrics often shows high CPU usage or excessive memory pressure, consider increasing the size of your cluster soon to improve performance. This is especially true for clusters that regularly reach 100% of CPU usage or that suffer out-of-memory failures; it is better to resize your cluster early when it is not yet maxed out than to have to resize a cluster that is already overwhelmed. Changing the configuration of your cluster may add some overhead if data needs to be migrated to the new nodes, which can increase the load on a cluster further and delay configuration changes.

To help diagnose high CPU usage you can also use the Elasticsearch nodes hot threads API, which identifies the threads on each node that have the highest CPU usage or that have been executing for a longer than normal period of time.

Work with the metrics shown in Cluster Performance Metrics section to help you find the information you need:

Cluster performance metrics are shown per node and are color-coded to indicate which running Elasticsearch instance they belong to.

For clusters that suffer out-of-memory failures, it can be difficult to determine whether the clusters are in a completely healthy state afterwards. For this reason, Elasticsearch Add-On for Heroku automatically reboots clusters that suffer out-of-memory failures.

You will receive an email notification to let you know that a restart occurred. For repeated alerts, the emails are aggregated so that you do not receive an excessive number of notifications. Either resizing your cluster to reduce memory pressure or reducing the workload that a cluster is being asked to handle can help avoid these cluster restarts.