Quick Stats – Runtime ANALYZE for Better Query Plans – Anant Aneja, Ahana

Quick Stats – Runtime ANALYZE for Better Query Plans – Anant Aneja, Ahana

An optimizer’s plans are only as good as the estimates available for the tables its querying. For queries over recently ingested data that is not yet ANALYZE-d to update table or partition stats, the Presto optimizer flies blind; it is unable to make good query plans and resorts to syntactic join orders. To solve this problem, we propose building ‘Quick Stats’ : By utilizing file level metadata available in open data lake formats such as Delta & Hudi, and by examining stats from Parquet & ORC footers, we can build a representative stats sample at a per partition level. These stats can be cached for use be newer queries, and can also be persisted back to the metastore. New strategies for tuning these stats, such as sampling, can be added to improve their precision.

Presto on Elastic Capacity – Neerad Somanchi & Abhisek Saikia, Meta

Presto on Elastic Capacity – Neerad Somanchi & Abhisek Saikia, Meta

Presto on elastic capacity – Elasticity of a shared fleet is one of the fundamental pillars of the IaaS (Infrastructure-as-a-Service) world. The ability of services to efficiently use both guaranteed and non-guaranteed (opportunistic) capacity is important in such a setting. Presto is great when it runs on guaranteed capacity (i.e, capacity that is fixed and stable). But what if we want Presto to leverage elastic (opportunistic) capacity, i.e, capacity that is shifting, but in a predictable manner (think Amazon EC2 Spot Blocks)? In this lightning presentation, Neerad Somanchi and Abhisek Saikia will talk about how a recent feature developed for Presto can help it efficiently utilize such elastic compute.