This solution does work as a backup to an -im c (checkpoint) database, the problem was simple, the full path to the encrypted_conn.txt was missing which produced a mytxn.db result that had a large byte size but was empty of schema data. For anyone who needs a in-memory db backup solution, the contents in original thread will work for you, just remember to fully qualify paths. Thank you to those that took the time to review. The reason you see an 'unload' solution to backup the database, it is because in-memory databases cannot use standard backup commands/solutions, as documented here:

Because changes are never written to the original database files, if a persistent copy of current database contents is required, you must use the dbunload utility or the UNLOAD TABLE statement. You can also use SQL queries to retrieve the changes, but you must then manually write these changes to the database file.

Sorry about not having a definitive answer on how to backup an IM -c database. I have implemented several ways in the last year without consistent results, if anyone has a solution on how to backup an IM -c database that cannot be shutdown, always has connections with intensive writes/deletes, and has the DBA password changed regulary without shutdown's afterward (changing of passwords is not realized internally till after the DB is shutdown so encounter issues with internal operations passing/expecting old passwords-must be wired in catalog someplace not updated till after a bounce). The dbunload will only contain objects like tables and views if the database didn't have connections at the time of the dbunload statement. Unfortunately I'm unable to implement a consistent backup plan using backup database or dbunload for an IM -c database that will produce consistent recovery results. I welcome a solution that will work even when there are connections at the time of the backup, the database cannot be shutdown, and the DBA password is changed every 30 days without a DB bounce following the password change. The original, dbunload, solution seems to only work if there are no active connections at the time the cron fires. A code response for the backup/restore is preferred over text description of solution or a link to documentation text.