postgresql

PostgreSQL Hash Join

Learn how PostgreSQL performs Hash Joins between two tables.

SELECT * FROM orders o JOIN users u ON o.user_id = u.id;

A Hash Join builds a hash table from the smaller table (the inner relation) and then scans the larger table (the outer relation), probing the hash table for matches. It is efficient for joining large unsorted datasets.

Interactive Execution Plan

EXPLAIN Output

Run: EXPLAIN (ANALYZE, COSTS, VERBOSE, BUFFERS, FORMAT TEXT) your_query;

Enter SQL EXPLAIN output to visualizeSupports PostgreSQL EXPLAIN ANALYZE, MySQL EXPLAIN, and SQLite EXPLAIN QUERY PLAN formats