Really clean up after deleting tasks and run the vacuum command

[kakulukia]

I just noticed that my DB just went up in size even tho i regularly cleaned up the old tasks. Turns out i need an additional command when creating the DB but in general both SQLite and Postgres have kinda the same problem.

So i enhanced the prune_db_task_results command and my DB went from 8GB down to 160MB while deleting about 17M old tasks and the freeing up the space of probably some millions more that were deleted before that.

Yes, i know, im probably a heavy user of tasks and the problem will not be as bad for others that fast, but it will build up eventually so i made this general fix.

[RealOrangeOne]

I'm a little hesitant to make this change - the database server itself should be responsible for running vacuuming, and most will do it automatically. Does your database have vacuuming enabled?

[kakulukia]

I just learned after this incident that vacuum needs to be enabled at creation time for sqlite DBs so I'm currently out of options. 🤔

What about putting a notice in the docs instead? Or adding a --vacuum for the prune command to have it as an option rather than the default?

[RealOrangeOne]

On SQLite, you can set it with a PRAGMA. I think for SQLite specifically, some tuning examples would be ideal, yes. But I don't think tooling should be VACUUMing itself - that's for the infrastructure to handle.