A system and method for excluding from a transaction accesses to one or more data sources marked as read-only. Data sources may be designated as read-only at a data source level, connection level, or on a registry. A global transaction may be delayed until two or more non-read-only data sources are being used. A transaction involving multiple data sources may still be managed as a non-global transaction if only one of the data sources is non-read-only. The other read-only data sources may be left out of the transaction.