Overview Presto’s architecture originally only supported a single coordinator and a pool of workers. This has worked well for many years but created some challenges. To overcome these challenges, we came up with a new design with a disaggregated coordinator that allows the coordinator to be horizontally scaled out across a single pool of workers….
Unnest is a common operation in Facebook’s daily Presto workload. It converts an ARRAY, MAP, or ROW into a flat relation. Its original implementation used deep copy all the time and was very inefficient. In Unnest Operator Performance Enhancement with Dictionary Blocks, the author improved the Unnest operator by up to 10x in CPU and…
In a multi-tenant system like Presto careful memory management is required to keep the system stable and prevent individual queries from taking over all the resources. However, tracking the memory usage of data structures in an application (Presto) running on the Java Virtual Machine (JVM) requires a significant amount of work. In addition, Presto is…