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ruth mhlanga
ruth mhlanga

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Treacherous Event Ingest: The Dark Side of Our Pipeline Rebuilds

The Problem We Were Actually Solving

When we first started building our event-driven system, our goal was to create a real-time analytics engine that could process millions of events per minute. Sounds simple enough, but the reality is that it took us three tries to get it right. Our initial pipeline design focused on batch processing large chunks of data, which led to latency skyrocketing to over 10 minutes. Not exactly what we were going for.

What We Tried First (And Why It Failed)

In our first iteration, we used Apache Kafka as the message broker and Apache Spark for batch processing. We thought it was the right choice because of its scalability and reliability. However, we soon realized that the batch processing approach was too time-consuming for our use case, leading to performance issues and unhappy customers. The 10-minute latency was the final nail in the coffin.

Another issue we encountered was data quality. Since we were processing large batches, any errors or inconsistencies in the data went undetected, leading to downstream problems. Our customers were complaining about inaccurate analytics, and it was a nightmare to troubleshoot.

The Architecture Decision

After our first failure, we decided to take a different approach. We switched to a streaming architecture using Apache Flink and Apache Cassandra as the event store. This allowed us to process events in real-time, reducing latency to just 2 seconds. We also implemented a more robust data quality check at the ingestion boundary, which caught any errors or inconsistencies as they happened.

But here's the thing: we didn't just stop at changing the architecture. We also implemented a more robust configuration management system that allowed us to monitor and troubleshoot our pipeline more effectively. We set up a series of metrics, including pipeline latency, query cost, and freshness SLAs, to ensure that we were meeting our performance requirements.

What The Numbers Said After

One of the key metrics we tracked was pipeline latency. With our new streaming architecture, we were able to reduce latency from 10 minutes to just 2 seconds. This was a huge improvement, especially for our customers who needed real-time analytics. We also saw a significant reduction in query cost, from an average of 1000 dollars per hour to just 50 dollars.

In terms of freshness SLAs, we were able to meet our requirement of 95% freshness for events within 10 minutes. This was a huge improvement over our previous batch processing approach, where events were often delayed by minutes or even hours.

What I Would Do Differently

Looking back on our journey, there are a few things I would do differently. First, I would have invested in a more robust data quality check from the very beginning. This would have caught errors and inconsistencies in real-time, preventing downstream problems.

Second, I would have implemented a more robust configuration management system earlier in the process. This would have made it easier to monitor and troubleshoot our pipeline, reducing our overall deployment time.

Finally, I would have taken a more incremental approach to our architecture changes. While it's tempting to try to solve everything at once, it's often better to take small steps and test as you go. This would have reduced our overall risk and allowed us to iterate more quickly towards our goal.

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