Easy Freshness with Pequod Cache Joins

Abstract

Pequod is a distributed application-level key-value cache that supports declaratively defined, incrementally maintained, dynamic, partially-materialized views. These views, which we call cache joins, can simplify application development by shifting the burden of view maintenance onto the cache. Cache joins define relationships among key ranges; using cache joins, Pequod calculates views on demand, incrementally updates them as required, and in many cases improves performance by reducing client communication. To build Pequod, we had to design a view abstraction for volatile, relationless key-value caches and make it work across servers in a distributed system. Pequod performs as well as other inmemory key-value caches and, like those caches, outperforms databases with view support.