backup – Is it possible to reduce WhatsApp “msgstore.db” file size?

My WhatsApp backup file (msgstore-**.db.crypt12) size can reach up to 380MB+ for a single file. Because WhatsApp automatically backup chats every day and will keep the 7 most recent backups, my phone will store up to 2GB worth of these files.

In case anyone’s wondering, my phone is not rooted, but I have the WhatsApp key and wa.db files, so I can decrypt (and re-encrypt) the msgstore.db file. What I have tried is to manually delete some messages in the messages table in the msgstore.db file, it sure reduces the file size, but then it fails when I try to restore WhatsApp chats using that file. Also, I have tried to clear chats in some groups that have a lot of messages using the Clear chat feature, this deletes the messages in the messages table, but doesn’t reduce the msgstore.db file size, I guess the deleted messages are moved to another table which I don’t know where.

I don’t need a trick to stop WhatsApp auto backup, I just want to reduce the msgstore.db file size, is it possible?