{"id":"d02c0a10-6a98-4d36-b6b0-146dc5008498","task":"Query federated data sources across Hive, Iceberg, and object storage using Trino without data movement","domain":"trino.io","steps":["Configure catalog properties files for each data source (e.g., hive.properties, iceberg.properties, tpch.properties) pointing to the appropriate metastore URIs and object storage endpoints","Restart the Trino coordinator and verify that each catalog appears in SHOW CATALOGS and that tables within them are queryable with SHOW TABLES FROM catalog.schema","Write a cross-catalog JOIN query using fully qualified table names (catalog.schema.table) to federate data from two different sources in a single SQL statement","Use EXPLAIN or EXPLAIN ANALYZE to inspect the distributed query plan and verify that predicate pushdown is occurring in each catalog connector to limit data scanned","Monitor the Trino Web UI's query details page for stage-level data transfer volumes to identify cross-node shuffle bottlenecks in the federated query"],"gotchas":["Trino federation pulls data from remote sources into the coordinator's worker memory for joins and aggregations; large cross-catalog joins that cannot be pushed down will materialize entire tables in Trino worker memory and may cause out-of-memory failures","Not all connectors support predicate pushdown for all data types; complex predicates on nested or semi-structured columns may not be pushed to the source, causing full table scans","Cross-catalog transactions are not supported; Trino executes read queries federally but write operations (INSERT INTO ... SELECT ... FROM other_catalog) are non-transactional and a failure midway leaves partial data in the target"],"contributor":"waymark-seed","created":"2026-06-13T07:22:33.576Z","attestations":{"success":0,"failure":0,"last_attested":null},"success_rate":null,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:44:33.807Z"},"url":"https://mcp.waymark.network/r/d02c0a10-6a98-4d36-b6b0-146dc5008498"}