Chaining Exactly-Once Operations With Kafka

Ben Stopford shows how you can use Kafka to chain together services while maintaining exactly-once guarantees:

Any service-based architecture is itself a distributed system, a field renowned for being difficult, particularly when things go wrong. We have thought experiments like The Two Generals Problemand proofs like FLP which highlight that these systems are difficult to work with.

In practice we make compromises. We rely on timeouts. If one service calls another service and gets an error, or no response at all, it retries that call in the knowledge that it will get there in the end.

The problem is that retries can result in duplicate processing—which can cause very real problems. Taking a payment, twice, from someone’s account will lead to an incorrect balance. Adding duplicate tweets to a user’s feed will lead to a poor user experience.  The list goes on.

I just had a discussion at SQL Saturday Albany about this exact thing, and the pain of rolling your own solutions.

Related Posts

Kafka Topic Reuse

Martin Kleppmann walks through the trade-offs of reusing Apache Kafka topics for different event types: The common wisdom (according to several conversations I’ve had, and according to a mailing list thread) seems to be: put all events of the same type in the same topic, and use different topics for different event types. That line of […]

Read More

Set Operations In Spark

Fisseha Berhane compares SparkSQL, DataFrames, and classic RDDs when performing certain set-based operations: In this fourth part, we will see set operators in Spark the RDD way, the DataFrame way and the SparkSQL way. Also, check out my other recent blog posts on Spark on Analyzing the Bible and the Quran using Spark and Spark […]

Read More

Categories

July 2017
MTWTFSS
« Jun Aug »
 12
3456789
10111213141516
17181920212223
24252627282930
31