Right now in the background operations default user setting is used, what can cause problems in the background, where different settings are expected. The only way to do it now is to change the default profile.

More continent solution will be to introduce new user for the background operations, and allow clickhouse user to modify its settings in same way they do with other users.

There are many places where Context::getGlobalInstance()->getSettingsRef() are used, whey should be replaced by new background user settings.