How to Truncate a Table in PostgreSQL

TRUNCATE deallocates whole pages rather than deleting row by row, so it is effectively instant and, unlike DELETE, leaves no dead tuples for VACUUM to clean up. Because it is transactional here you can BEGIN, truncate, check something, and ROLLBACK. It does take an ACCESS EXCLUSIVE lock, so it waits for current readers to finish.

TRUNCATE TABLE session_logs;

Reset sequences and cascade

RESTART IDENTITY resets owned sequences so IDs start from 1 again; without it, the next insert continues from wherever the counter had reached. TRUNCATE refuses to run on a table referenced by a foreign key unless you add CASCADE, which then truncates the referencing tables too. That cascade is easy to underestimate, so check pg_constraint first.

TRUNCATE TABLE orders RESTART IDENTITY CASCADE;