Presto at Varsity Tutors: Using Federated Queries to Power External Reporting – John Cross

Presto at Varsity Tutors: Using Federated Queries to Power External Reporting – John Cross

Varsity Tutors is a learning platform that enables online academic, professional, and enrichment learning. A growing part of their offering partners with school districts to provide customized support for teachers and students. Varsity Tutors for Schools provides external reporting capabilities including student assessments, progress reports, and more. To provide these timely reports, Varsity Tutors (an AWS shop) uses Presto scripts to perform federated queries across MySQL, Postgres, and Redshift and writes data back to S3. They use Ahana Cloud as their managed service for Presto. In this session, John will discuss what technologies they evaluated, why they chose Presto, and their current data architecture including how they handle security for cross-account writes and how they perform upserts into the final reporting database.

Presto Query Analysis for Data Layout Formatting and Query Result Caching – Gurmeet Singh, Uber

Presto Query Analysis for Data Layout Formatting and Query Result Caching – Gurmeet Singh, Uber

In this talk, I will be talking about a microservice that we have built at Uber to be able to analyze Presto queries. The Presto Query Engine does not provide endpoints for query analysis purposes. One has to either execute the query or gather insights from the query explain plan. In this talk, I will talk about 1. The work that we had to do to do the query analysis in a microservice using Presto as a library. 2. Doing predicate analysis on the queries to come up with data formatting recommendations in order to improve query performance. 3. Using the analysis service for query result cache invalidation. The analysis figures out whether the results from a previous run of the query are still valid and can be reused.