Is it ok if index length and data length are shorter after a backup

I created a backup of my mysql db 5.x using wp-db-backup plugin. I noticed that the rows, auto-increment counter all look like the original. Except, the data length an开发者_开发技巧d index length which shows smaller values. Do you know if this is a sign that the backup is not good?

Thanks,

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Yes, because, when you restore a database the data are written from scratch in your tables and you have no unused space in the data-store, it's like running an OPTIMIZE table on the tables of your database. Your data and indexes are re-created.

Unused space is normal when you do a lot of insert/delete , and tipically is present in the wp-options table which is used by plugins to save the options.