How to cleanup old Cases / Tasks?

There are two ways to do this, one directly in the system DB and one with an API call.

Delete via Public API

you can build a process/App around the Public API: void deleteCompletedCase(ICase completedCase) throws PersistencyException

A simple script which deletes old cases could look as follows:

public class HistoricCaseDeleter {
    public static void doIt()
    {
        CaseQuery oldCasesQuery = CaseQuery.create().where()
            .state().isEqual(CaseState.DESTROYED).or()
            .state().isEqual(CaseState.DONE).or()
            .state().isEqual(CaseState.ZOMBIE)
            .and()
            .startTimestamp().isLowerThan(new java.util.Date(2010, 0, 1));

        for(ICase oldCase : Ivy.wf().getCaseQueryExecutor().getResults(oldCasesQuery))
        {
            Ivy.wf().deleteCompletedCase(oldCase);
        }
    }
}

Delete directly in System DB

You may clean up cases and tasks in Done (2) and Destroyed (3) state as follows:

1. Stop Axon.ivy server v4.x or later
2. Backup your DB (of course)

3. Execute to know how many cases you are about to remove:
   SELECT COUNT() FROM [YourIvySystemDb].[dbo].[IWA_Case] WHERE State = 2 OR State = 3*

4. Execute to remove them:
   DELETE FROM [YourIvySystemDb].[dbo].[IWA_Case] WHERE State = 2 OR State = 3

5. You may shrink your DB to save disk space (e.g. MSSQL manager tool can do that)
6. Start Axon.ivy server again