Hi TailoredTech ,
Apologies for any inconvenience caused.
Yes, you're right. We're saving this meta even though it's empty. We'll fix that for the next ATUM version.
You can delete these meta fields by executing a SQL sentence from your MySql Admin interface like this:
DELETE FROM wp_postmeta WHERE meta_key = '_atum_attachments' AND meta_value = '[]'
(you must replace 'wp_' with your database's prefix)
Anyway, keep in mind that only one row per product for 5000 products cannot be the only reason for your bloated database. You should search for additional unneeded meta data.
Best Regards,
José Andrés