I found the answer. I needs to be wrapped in a transaction, like this:
engine = engine_from_config(config, 'sqlalchemy.')
connection = engine.connect()
trans = connection.begin()
try:
connection.execute('truncate table cms_history;')
not to answer every question today, but we also added an autocommit flag for
this kind of thing:
connection.execution_options(autocommit=True).execute(statement that normally
isn't autocommit)
some background:
http://www.sqlalchemy.org/docs/core/connections.html#understanding-autocommit
On
