sqlalchemy.exc.SAWarning: Dialect bigquery:bigquery will not make use of SQL compilation caching as it does not set the 'supports_statement_cache' attribute to True. This can have significant performance implications including some performance degradations in comparison to prior SQLAlchemy versions. Dialect maintainers should seek to set this attribute to True after appropriate development and testing for SQLAlchemy 1.4 caching support. Alternatively, this attribute may be set to False which will disable this warning. (Background on this error at: https://sqlalche.me/e/14/cprf)

https://source.cloud.google.com/results/invocations/98c79c9a-dc03-49b5-bba9-db389866d284/targets/cloud-devrel%2Fclient-libraries%2Fpython%2Fgoogleapis%2Fpython-bigquery-sqlalchemy%2Fpresubmit%2Fpresubmit/log

More info here: https://sqlalche.me/e/14/cprf

Also, I recall caching may have been the root cause in #368 ?