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:


About the Author

Object Partners profile.
Leave a Reply

Your email address will not be published.

Related Blog Posts
A security model for developers
Software security is more important than ever, but developing secure applications is more confusing than ever. TLS, mTLS, RBAC, SAML, OAUTH, OWASP, GDPR, SASL, RSA, JWT, cookie, attack vector, DDoS, firewall, VPN, security groups, exploit, […]
Building Better Data Visualization Experiences: Part 1 of 2
Through direct experience with data scientists, business analysts, lab technicians, as well as other UX professionals, I have found that we need a better understanding of the people who will be using our data visualization products in order to build them. Creating a product utilizing data with the goal of providing insight is fundamentally different from a typical user-centric web experience, although traditional UX process methods can help.
Kafka Schema Evolution With Java Spring Boot and Protobuf
In this blog I will be demonstrating Kafka schema evolution with Java, Spring Boot and Protobuf.  This app is for tutorial purposes, so there will be instances where a refactor could happen. I tried to […]
Redis Bitmaps: Storing state in small places
Redis is a popular open source in-memory data store that supports all kinds of abstract data structures. In this post and in an accompanying example Java project, I am going to explore two great use […]