Posts about Apache Druid from the LibreDB Studio blog.https://libredb.org/blog/engine/druid/enhttps://libredb.org/blog/druid-sql-cannot-write/https://libredb.org/blog/druid-sql-cannot-write/Update and delete are not in this SQL anywhere, create is not in the grammar, and the refusals are surfaced word for word instead of rewritten.Sun, 28 Jun 2026 09:00:00 GMTLibreDBApache DruidEngineeringDatabaseshttps://libredb.org/blog/druid-sessions-are-ingestion-tasks/https://libredb.org/blog/druid-sessions-are-ingestion-tasks/Rows come from the task table and every column is relabelled to say so, because there is no session catalog and no query log anywhere to read.Thu, 14 May 2026 09:00:00 GMTLibreDBApache DruidEngineeringDatabaseshttps://libredb.org/blog/druid-router-or-broker-connection/https://libredb.org/blog/druid-router-or-broker-connection/Both ports serve the identical SQL endpoint and nothing in the connection knows which it reached, and there is no database field because there is one catalog.Sat, 28 Mar 2026 09:00:00 GMTLibreDBApache DruidEngineeringDatabaseshttps://libredb.org/blog/druid-plan-tree-without-costs/https://libredb.org/blog/druid-plan-tree-without-costs/The plan returns the native query the cluster will run, rendered in its own operator vocabulary, and the planner publishes no cost and no row estimate.Mon, 09 Feb 2026 09:00:00 GMTLibreDBApache DruidEngineeringDatabaseshttps://libredb.org/blog/druid-catalog-shows-what-is-servable/https://libredb.org/blog/druid-catalog-shows-what-is-servable/Marking segments unused removes a datasource from the catalog entirely, and a stopped node makes an existing one answer with the same error as a typo.Wed, 24 Dec 2025 09:00:00 GMTLibreDBApache DruidEngineeringDatabases