Patent attributes
Techniques are disclosed relating to concurrently processing transactions. A computer system may maintain a database table having a plurality of versions. Each of the versions may identify a corresponding portion of the database table that transactions associated with that version are permitted to access. The computer system may receive a first request to perform a first transaction to modify a definition of the database table. The computer system may receive a second request to perform a second transaction to modify data stored in the database table. In response to determining that the first and second transactions are associated with different versions of the plurality of versions, the computer system may concurrently process the first and second transactions.