The Bucket Is the Log: Building an Append-Only Log on Object Storage in Go
How UnisonDB's object-store WAL replication became objlog: immutable segments, a bounded catalog, fencing, and replay by LSN or timestamp.
Ankur Anand
Staff Software Engineer at Walmart Global Tech, based in Bengaluru.
I work on distributed systems and platform infrastructure, mostly in Go. I write about databases, runtimes, performance, and the parts of software that are easy to use but difficult to understand.
Away from software, I make photographs and sometimes write poetry.
Projects
Things I build and maintain outside work.
Recent writing
All 25 articlesGo singleflight: Cancellation and Shutdown
Learn how Go singleflight prevents cache stampedes, why caller cancellation gets tricky, and how to safely cancel and drain shared work during shutdown.
Building a Key-Value Database on S3 in Go
How an LSM tree gives us the right building blocks, and where object storage changes the design.
Timing Wheels: Expiring 10 Million Keys in Go
How hierarchical timing wheels expire millions of cache entries efficiently in Go without periodic O(n) scans or a timer per key.
Elsewhere
I keep source code on GitHub, photographs on 500px, and poetry at Tangled Vibes.