Clean a PostgreSQL database directory

After building a database using an ill-judged algorithm, I ended up with junk in the database that consumed 600MB of space in the Postgres data directory. Deleting the bad data did not free this space immediately, and I was too impatient to wait for the auto vacuuming to kick in.

Here are the steps I took to clean up the database and data directory — with extreme prejudice.

In the psql console:

On the command line:

Running all of these steps is a brutal process. Do not run the

command if you have important data, because you will probably want to keep your write ahead log.