What is the significance of dumping the tablespaces?

Question

While recently running drush sql-dump on a server where there were never any error messages, I have started to get:

mysqldump: Error: 'Access denied; you need (at least one of) the PROCESS privilege(s) for this operation' when trying to dump tablespaces

It still produces a file I can import locally and I don't seem to be having any problems. But I am still curious: What is the significance of dumping the tablespaces when it comes to the average Drupal sysadmin?

Environment

• Drush: Drush Commandline Tool 10.3.2
• Drupal: 8.9.13
• DB: Server version: 5.7.31-34-log Percona Server (GPL), Release '34', Revision '2e68637'
• Acquia Cloud hosted

Answer 1

Tablespaces are used to define the physical file location of one (or more) tables - chances are if you were using them for something beyond the default innodb space, you'd know about it. It's likely safe to ignore.

The error will have started when MySQL was updated to 5.7.something, they introduced a breaking change in a minor version because it addressed a security flaw, and world + dog was greeted with this error message.

There's a way around it:

drush sql:dump --extra-dump=--no-tablespaces

or, if using drush 8:

drush sql:dump --extra=--no-tablespaces