Ibrar Ahmed present "Joining Heterogeneous Databases is a reality, not a Myth."

PostgreSQL provides a way to communicate with external data sources. This could be another PostgreSQL instance or any other database.
The other database might be a relational database such as Clickhouse, MySQL or Oracle; or any NoSQL database such as MongoDB or Hadoop. To achieve this, PostgreSQL implements ISO Standard call SQL-MED in the form of Foreign Data Wrappers (FDW). This presentation will explain in detail how PostgreSQL FDWs work. It will include a detailed explanation of simple features and will introduce more advanced features that were added in recent versions of PostgreSQL. Examples of these would be to show how aggregate pushdown and join pushdown work in PostgreSQL.