I would strongly recommend to update to version 7.6, as the batch version is the easiest and fastest version to clean up your database. If this is not an option here are some hints that might help:
- the tables that are probably interesting for you, are the
ACT_HI_* tables (have a look at the dabase schema for more information)).
- I just assume you are using the rest api:
- first you can query for all historic process instances that were finished previous to 30 days ago. Have a look here and there especially the
finishedBefore field might interest you.
- With the given process instance ids you can now delete them manually (see here).
The deletion of the historic process instance will cause the deletion of respective historic activities, historic tasks and historic details (variable updates, form properties) as well.