saatchibhalla opened a new pull request #2040: URL: https://github.com/apache/lucene-solr/pull/2040
<!-- _(If you are a project committer then you may remove some/all of the following template.)_ Before creating a pull request, please file an issue in the ASF Jira system for Lucene or Solr: * https://issues.apache.org/jira/projects/LUCENE * https://issues.apache.org/jira/projects/SOLR You will need to create an account in Jira in order to create an issue. The title of the PR should reference the Jira issue number in the form: * LUCENE-####: <short description of problem or changes> * SOLR-####: <short description of problem or changes> LUCENE and SOLR must be fully capitalized. A short description helps people scanning pull requests for items they can work on. Properly referencing the issue in the title ensures that Jira is correctly updated with code review comments and commits. --> # Description Please provide a short description of the changes you're making with this pull request. The Overseer work queues stored in ZK and abstracted by the Overseer can give us a good indication of the health of the cluster - if messages are taking too long to dequeue or the queue is growing too large, we know that the Overseer is overloaded and we are going to overwhelm the cluster. This work adds metrics to track the size of the Overseer queues (ClusterStateUpdate queue and Collections Work Queue). # Solution Please provide a short description of the approach taken to implement your solution. Registered these two size metrics in a shared metrics registry for the Overseer. The Overseer shared metrics registry is only initialized upon reference so this shouldn't have any impact on metrics when run in non-cloud mode. Also updated the local solr-exporter-config.xml so that these metrics are exported and can be viewed locally in Grafana. # Tests Please describe the tests you've developed or run to confirm this patch implements the feature or solves the problem. Local testing was accomplished by sending CreateCollection load and monitoring a local grafana dashboard which accessed the metrics through prometheus-exporter. As the size of these queues change extremely quickly, it was difficult to see changes in these metrics quickly enough--and if the requests were sent too quickly we'd see local solr hosts OOMing. However, I was able to verify that the metrics are updating as the size of the queues change, and in a real environment with more sustained load we should see these metrics more accurately represent the state of the Overseer. Testing confirmed that we don't see the Overseer metrics registry in non-cloud mode. **/admin/metrics response containing added metrics** <img width="298" alt="Screen Shot 2020-10-27 at 5 56 48 PM" src="https://user-images.githubusercontent.com/16807693/97367278-32600980-187f-11eb-98b5-98a321c0f5c9.png";> **local testing sending CreateCollection request load and seeing metrics update in real time**  # Checklist Please review the following and check all that apply: - [x] I have reviewed the guidelines for [How to Contribute](https://wiki.apache.org/solr/HowToContribute) and my code conforms to the standards described there to the best of my ability. - [x] I have created a Jira issue and added the issue ID to my pull request title. - [x] I have given Solr maintainers [access](https://help.github.com/en/articles/allowing-changes-to-a-pull-request-branch-created-from-a-fork) to contribute to my PR branch. (optional but recommended) - [x] I have developed this patch against the `master` branch. - [x] I have run `./gradlew check`. - [ ] I have added tests for my changes. - [x] I have added documentation for the [Ref Guide](https://github.com/apache/lucene-solr/tree/master/solr/solr-ref-guide) (for Solr changes only). ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
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