Apr 3, 2018

Getting Groovy with Mongo Monitoring

MongoDB does something interesting that we aren’t used to in the Java world – if you use the MongoClient object, it manages the pooling for you on the server side. This is different than how most databases connect, which leaves pooling up to the application or the Java server.

Anyway, I was working with a Grails application that used MongoClient and the Mongos kept running out of memory. Therefore tickets were opened, words were said, and fingers were pointed. In the past, they had used Grails connection pooling for Mongo, ran into these problems, and switched to a single MongoClient. They said it was happening again but we developers needed evidence to show that (or, disprove it).

Doing some research showed that the Java Driver for Mongo has some good JMX endpoints to monitor. But the problem was that we needed to track these values over a long period of time – more than just what VisualVM would show. And I didn’t have access to the server but they did have the Grails console running inside the applications.

So I wrote a simple Groovy script that queries the Mongo’s JMX values every second and prints it out in something resembling a CSV file. I wrote this to run inside a Grails console, but there is no Grails in it – it’s pure Groovy. You may have to make minor changes to get it to run on the command line. Anyway, here is the Gist:

https://gist.github.com/squarepegsys/faff5dff8666ffddaa06cd0ea14752d8

About the Author

Mike Hostetler profile.

Mike Hostetler

Principal Technologist

Mike has almost 20 years of experience in technology. He started in networking and Unix administration, and grew into technical support and QA testing. But he has always done some development on the side and decided a few years ago to pursue it full-time. His history of working with users gives Mike a unique perspective on writing software.

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Blog Posts
Understanding Mutual TLS Options in the Public Cloud
When delivering an API over the public internet via a cloud provider, some organizations and frameworks require mutual TLS verification as a part of the interaction for that API. Mutual TLS can be used to […]
Performance Test Liquibase Update
When doing a liquibase update to a database if you’re having performance issues, it can be hard to find out which updates are causing problems. If you need to measure the time to apply each […]
TICK Stack Monitoring for the Non-Technical
TICK – Telegraf, Influx, Chronograf, and Kapacitor – is a method of monitoring your systems and applications. In this article, I discuss in non-technical terms what the difference is between TICK and Prometheus Grafana A […]
Design Systems, Part 1 • Introduction
Business leaders need a practical guide to plan and execute Design System Initiatives. The aim of this series is to be that guide. This installment introduces terms and definitions as a primer on Design Systems.