Extending Presto at LinkedIn with a Smart Catalog Layer LinkedIn

Extending Presto at LinkedIn with a Smart Catalog Layer LinkedIn

In this talk, Walaa describes how LinkedIn extended its Presto Hive Catalog with a smart logical abstraction layer that is capable of reasoning about logical views with UDFs by using two core components, Coral and Transport UDFs. Coral is a view virtualization library, powered by Apache Calcite, that represents views using their logical query plans. Walaa shows how LinkedIn leverages Coral abstractions to decouple view expression language from the execution engine, and hence execute non-Presto-SQL views inside Presto, and achieve on-the-fly query rewrite for data governance and query optimization.

Query Execution Optimization for Broadcast Join using Replicated-Reads Strategy – George Wang, Ahana

Query Execution Optimization for Broadcast Join using Replicated-Reads Strategy – George Wang, Ahana

Today presto supports broadcast join by having a worker to fetch data from a small data source to build a hash table and then sending the entire data over the network to all other workers for hash lookup probed by large data source. This can be optimized by a new query execution strategy as source data from small tables is pulled directly by all workers which is known as replicated reads from dimension tables. This feature comes with a nice caching property given that all worker nodes N are now participating in scanning the data from remote sources. The table scan operation for dimension tables is cacheable per all worker nodes. In addition, there will be better resource utilization because the presto scheduler can now reduce the number plan fragment to execute as the same workers run tasks in parallel within a single stage to reduce data shuffles.