While the whole Gerrit upgrade process seems to work fine, but at some points Gerrit wants to write to the database. Like increasing the database schema version. That of course fails with the current read-only user.
Could we get a writable copy of the current reviewdb on m2 that we can test against to make sure the upgrade on gerrit1001 does not get blocked by the (then writable) database?
(@jcrespo: Sorry for brashly assigning to you, but I'm not sure what the correct project would be, and you're a DBA and we've had contact around these databases already. Feel free to push back/re-assign/or simply tell what the correct tag would be)