Deleting data & reducing size of DB

[hmebane]

If I delete a Thing & its associated ValueStream, should I expect to see the size of the DB go down? I'm using Postgresql & looking at the size with pgadmin (statistics tab). I deleted a Thing & then its valuestream & did not see the DB go down at all.

Also, Ive heard different recommendations on whether all things should use the same valuestream (by setting it at the template level), or whether I should have each Thing use its own valuestream - thoughts? Its not clear what the tradeoffs are.

Finally, if I want to only keep the last 3 months of data, its clear how to use the PurgePropertyHistory service - but again, should I see a reduction in the size of the DB?

Obviously an unbounded DB is not going to work long term, so I need to understand how the platform behaves.

Thank you.

[sgreywilson]

This is a good question and it makes me check my answer.

I purged logged properties using PurgePropertyHistory and I did see a reduction in return rows 47 thousand plus.

A question did you Purge from the Thing - The value Stream services can only be run on the Thing but you can get the impression you can run from the Template.

You could build a service for all Things based on a template (GetImplementingThings)  and run the PurgePropertyHistory based on dates or even write them to another date store or file system