Hi.
>does that mean that I should always execute a VACUUM to recover the
>wasted space when an error is triggered or will the auto-vacuum mechanism
>do the job by itself ?
If you have autovacuum enabled it will clean up tablespace. However, space will not be returned to filesystem but will
bereused by database.
You may run VACUUM FULL manually to return it to filesystem.
https://www.postgresql.org/docs/9.1/static/routine-vacuuming.html
Ilya Kazakevich
JetBrains
http://www.jetbrains.com
The Drive to Develop