Out of interest I looked to see what schema drifts are present for the GlobalBlocking extension.
From the globalblocks table on db2150 I saw:
- gb_id from the globalblocks table should be unsigned, but appears to be signed
- gb_address is type VARCHAR when it should be VARBINARY
- gb_address has a default set, when it should have no default
- gb_by_wiki has a default set, when it should have no default
From the global_block_whitelist table on enwiki db2174: