Is it safe to delete useless tables

hello, is it safe to delete tables such as [piwik_archive_blob_2018_05] or [piwik_archive_numeric_2015_10] etc ?

i have disk space issues and i would like to cleanup a bit

thank you for advices


You can always delete piwik_archive_numeric_somedate tables, but this permanently deletes all archives of this month (so you can’t view reports for this month anymore

You can recreate them, but only if you still have the raw visitor logs.

Always make a backup before deleting anything

Hello thank you for reply. i did that, however it doesnt free any space even after truncating these tables (somes of them more than 100Mo). it seems it has to do with innoDb which doesnt free space when emptying tables, any idea how to fix that ?
thanks !