In a database management system (DBMS), concurrency control manages simultaneous access to a database. It prevents two users from editing the same record at the same time and also serializes transactions for backup and recovery.
It covers database systems and data models; design concepts (the relational database model, entity relationship modeling, advanced data modeling, and normalization of database tables); advanced design and implementation; advanced database concepts (transaction management and concurrency control, database performance tuning and query optimization, distributed database management systems, and business intelligence and data warehouses); database connectivity and web technologies; and administration and security.
While managing large increments and simultaneously running analyses can result in long wait times, Fujitsu has adopted a solution in the form of MultiVersion Concurrency Control (MVCC (3)), which allows analyses to run at the same time that data domains are managed.
• The Google Wave protocol is the underlying format for storing and the means of sharing waves, and includes the "live" concurrency control, which allows edits to be reflected instantly across users and services.
Other topics include concurrency control mechanisms in data service layers, compositional verification of UML dynamic models, checking distributed programs with partially ordered atoms, and aspect mining for Linux.
Oracle Berkeley DB Release 4.5 now supports multi-version concurrency control, non-stop upgrades for replicated environments and a pre-built replication framework to simplify development of highly available applications.