it will decide the method for disable statement_timeout upon
per transaction or per session, based on how it's called.
When calling with a block, block will be executed and it will use
session based statement_timeout, otherwise will default to existing
behavior.
add_column_with_default is implemented in terms of update_column_in_batches, but
update_column_in_batches can be used independently. Neither of these should be
used on the specified large tables, because they will cause issues on large
instances like GitLab.com.
This also ignores the cop for all existing migrations, renaming
AddColumnWithDefaultToLargeTable where appropriate.
Jan Provaznik