Federated Query Pushdown

Concepts: paPredicatePushdown

What They Want to Hear 'Federated query engines like Trino and Presto push predicates to each data source independently. When I join an S3 Parquet table with a PostgreSQL table, the engine pushes the WHERE clause to both connectors: Parquet partition pruning on S3, and a SQL WHERE clause to PostgreSQL. But pushdown capability varies by connector: the Hive connector supports partition pruning and column pushdown, while a generic JDBC connector may only push simple equality predicates. Knowing what each connector supports is the difference between a 10-second query and a 10-minute one.' This is the answer that shows you understand that pushdown in federated queries is only as strong as the weakest connector. Candidates who say 'just use a federated query engine and it handles everything' rev