Set PostgreSQL configuration parameter in SQLAlchemy

You can register a Pyramid event handler which would set the parameter on any new request:\n\nfrom pyramid import events\n\ndef on_new_request(event):\n \"\"\"\n you can access request as event.request \n and the current registry settings as event.request.registry.settings\n \"\"\"\n session = DBSession()\n session.execute(\"SET blah TO 'foo'\")\n\n\ndef app(global_config, **settings):\n\n config = Configurator(...)\n config.add_subscriber(on_new_request, events.NewRequest)\n\n\nSee Deployment Settings and events.NewRequest for more details.\n\nOne thing to watch out is to make sure you're always using the same session object - SQLAlchemy maintains a pool of connections and, if you commit your session, all subsequent operations will use a brand-new session which is not pre-configured with your settings. In other words, you should not do session.commit(), session.rollback(), transaction.commit() etc. in your code and instead rely on ZopeTransactionExtension committing/rolling back the transaction at the end of the request/response cycle. Which is a recommended practice anyway. ",