Pulling the Thread on Kafka's Compacted Topics

engineering Last Updated: March 01, 2017 Tom Crayford, Engineer

At Heroku, we're always working towards improving operational stability with the services we offer. As we recently launched Apache Kafka on Heroku, we've been increasingly focused on hardening Apache Kafka, as well as our automation around it. This particular improvement in stability concerns Kafka's compacted topics, which we haven't talked about before. Compacted topics are a powerful and important feature of Kafka, and as of 0.9, provide the capabilities supporting a number of important features.

Meet the Bug

The bug we had been seeing is that an internal thread that's used by Kafka to implement compacted topics (which we'll explain more of shortly) can die in...

Dawn of the Dead Ends: Fixing a Memory Leak in Apache Kafka

news Last Updated: June 03, 2024 Tom Crayford, Engineer

At Heroku, we're always working towards increased operational stability with the services we offer. As we recently launched the beta of Apache Kafka on Heroku, we've been running a number of clusters on behalf of our beta customers.

Over the course of the beta, we have thoroughly exercised Kafka through a wide range of cases, which is an important part of bringing a fast-moving open-source project to market as a managed service. This breadth of exposure led us to the discovery of a memory leak in Kafka, having a bit of an adventure debugging it, and then contributing a patch to the Apache Kafka community to fix it.

Issue Discovery

For the most part, we’ve seen very few issues...

Apache Kafka 0.10

engineering Last Updated: June 03, 2024 Tom Crayford, Engineer

At Heroku, we're always striving to provide the best operational experience with the services we offer. As we’ve recently launched Heroku Kafka, we were excited to help out with testing of the latest release of Apache Kafka, version 0.10, which landed earlier this week. While testing Kafka 0.10, we uncovered what seemed like a 33% throughput drop relative to the prior release. As others have noted, “it’s slow” is the hardest problem you’ll ever debug, and debugging this turned out to be very tricky indeed. We had to dig deep into Kafka’s configuration and operation to uncover what was going on.

Background

We've been benchmarking Heroku Kafka for some time, as we prepared for the...