EXPLAIN plan visualizer

Get a plan

Run your query with EXPLAIN (ANALYZE, BUFFERS) in front of it, and paste everything it prints:

EXPLAIN (ANALYZE, BUFFERS)
SELECT u.name, count(*)
FROM users u JOIN orders o ON o.user_id = u.id
GROUP BY u.id;

ANALYZE runs the query for real to time each step. For an INSERT, UPDATE or DELETE, wrap it in a transaction you roll back:

BEGIN;
EXPLAIN (ANALYZE, BUFFERS) UPDATE orders SET status = 'shipped' WHERE id = 42;
ROLLBACK;

Text output and FORMAT JSON both work, with or without psql’s frame around them. Without ANALYZE, the visualizer shows the planner’s estimated costs instead of times.

Reading the result

• Own time is the time a step spent itself: its total minus its children’s. The bars compare steps by it, and the step with the most is marked slowest. Start there.
• Rows shows how many rows a step really returned beside how many the planner expected. A badge like ↑ 120× means the planner expected far fewer rows. Bad estimates lead to bad plans (a nested loop over thousands of rows instead of a hash join, say), and they usually come from stale statistics: run ANALYZE <table>.
• Loops: a step under a nested loop runs once per outer row. Its time per loop is multiplied by the loops.
• Click a step to see its details: filters, rows removed, buffers, sort and hash memory. Each step’s name links to what it does and when it’s a problem.

Private by design

The plan is read by this page, in your browser. It isn’t uploaded or stored. Copy a link puts the plan, compressed, in the part of the address after the #, which browsers never send to a server.