Is there a logging configuration enabling the logging of all SQL queries issued by OpenERP to a file?
OpenERP does not provide a mechanism specifically to log SQL queries, but it has a generic logging feature. By adding
--log-level=debug_sql to the command line used to launch OpenERP it will print the normal debugging messages + the sql commands. You can redirect that output to a file if you want.
You could also configure PostgreSQL to log the queries. I would personally prefer that solution if the goal is to optimize the database usage.