Use EXPLAIN to inspect a query plan without executing it:

EXPLAIN
SELECT category, count(*)
FROM events
GROUP BY category;

Supported plan formats:

EXPLAIN (FORMAT TEXT) SELECT * FROM events;
EXPLAIN (FORMAT GRAPHVIZ) SELECT * FROM events;

The alternate utility syntax is also accepted:

EXPLAIN FORMAT GRAPHVIZ SELECT * FROM events;

Use EXPLAIN ANALYZE to execute the query and print an execution report:

EXPLAIN ANALYZE
SELECT category, count(*)
FROM events
GROUP BY category;

EXPLAIN ANALYZE currently supports text output.

Unsupported options include VERBOSE, QUERY PLAN, ESTIMATE, and non-text EXPLAIN ANALYZE formats.

In the REPL

EXPLAIN and EXPLAIN ANALYZE are SQL statements, so they must end with ;:

EXPLAIN SELECT 1;