Friends searching Google on Duplicati’s vaccum, I found this from here: SQLite VACUUM
After reading the article, I decided to test on a client that has a database of 163MB, I ran the following command:
sqlite3 72667174897076837983.sqlite VACUUM;
After running this command, the database was cleaned up to a size of 145MB.
With the vacuum done, I did the test trying to run the Backup Job again and it ran 100% without fail. \o/
In this way, I believe that at least for me, it is more feasible to run the vaccum outside of Duplicati via script (powershell or shell script), than with Duplicati.CommandLine.exe