IndiLog: Bridging Scalability and Performance in Stateful Serverless Computing with Shared Logs

State management has long been a challenge for serverless applications. Owing to their failure resilience and consistency guarantees, distributed shared logs have been recently proposed as a promising storage substrate enabling stateful serverless applications. We show that, unfortunately, state-of-the-art sacrifices compute tier scalability for log access performance, a particularly undesirable exchange for the dynamic serverless environment. The culprit is the log indexing architecture, namely relying on complete local indexes colocated with serverless functions. This design prevents efficient scaling and even risks out-of-memory errors.