MySQL isolation level


Is it mandatory to use “READ COMMITED”? Or is it OK to use (the default, and more stricter) “REPEATABLE READ” isolation level?

Our environment has a shared SQL server, that has multiple other databases besides the OwnCloud DB, so changing the isolation level would affect multiple different systems.



yes, it is actually mandatory to use READ COMMITTED as ownCloud is using the TRANSACTION_READ_COMMITTED transaction isolation level.

This is even documented in the DB requirements: System Requirements :: ownCloud Documentation

You will see a warning in the Security & setup warnings section of the admin page in case this is not set: core/securitywarning.php at master · owncloud/core · GitHub

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Hi Pako81!

Thank you for your reply!

We have a test installation of Owncloud, but regardless of what the isolation level is set to, we can not produce any error related to SQL on the “Security & setup warnings” site, not even when it was set to READ-UNCOMMITED.

Best regards,

This is strange. The only case that I can imagine where the setting is not checked and warned, is when ownCloud actually uses sqlite instead of MariaDB.

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