I have a scenario where I need to update 500,000 Accounts in production to change their Record Type, but I want to avoid writing a Batch class for one-time use. In addition, using DataLoader would require an extreme amount of documentation (don't ask, its a validated org). For whatever reason, code is easer to be validated than using DataLoader.
In our scenario, the Account Trigger updates on average 3,000 records for each 200 Accounts.
Could I run an Execute Anonymous code block that updates 10,000 accounts in a single DML statement? Since the update in the Execute Anonymous block will already hit the 10,000 limit, will the first attempt to update a (for example) Contact fail because it will be the 10,0001st update? Or do the DML limits start over for the first block of 200 trigger records?