How to clean up data from Audit Trail to get DB free space

Hi, Could someone help me to find a solution for the below issue.  we are using Audit Trail in the application and it  is occupying more space in the database. No we are planning to delete older entries from that entity to free up some space in the database. I have deleted some rows from the entity and have taken a database backup and restore but I couln’t see any space freed up from the database. Instead of that I could see some little MB is increased. we are using postgressql database. Shed some thoughts here. Thanks.
1 answers

Please see this docs. And if that doesn’t work maybe a VACUUM can help you free up the unused space.