djhworld

thoughts

Using HyperLogLog in production, a retrospective

A few years ago I was involved in a project that required us to provide a time series metric on how many concurrent users were using our products, and what quality of service they were receiving. On embarking on this journey, it quickly became apparent that the tricky part would be doing the count of unique concurrent users, over a set of dimensions in one minute windows. We’d run into the classic count-distinct problem.

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Running Go AWS Lambda functions locally

AWS recently announced Go support for Lambda, giving developers more choice over how their functions are written. In an attempt to kick the tires of the new runtime, I found myself rummaging around the open source library required when writing Lambda functions in Go, and was delighted to find a glimpse into what happens when your function is invoked. This post is a brief tour of what I’ve gathered, and describes a simple way of invoking your function in a local environment.

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