Learned Indexes for a Google-scale Disk-based Database

Hussam Abu-Libdeh
Alex Beutel
Lyric Pankaj Doshi
Tim Klas Kraska
Chris Olston


There is great excitement about learned index structures, but understandable skepticism about the practicality of a new method uprooting decades of research on B-Trees. In this paper, we work to remove some of that uncertainty by demonstrating how a learned index can be integrated in a distributed, disk-based database system: Google’s Bigtable. We detail several design decisions we made to integrate learned indexes in Bigtable. Our results show that integrating learned index significantly improves the end-to-end read latency and throughput for Bigtable.

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