MC Which statement is NOT CORRECT? Primary site 2PL comes down to applying the centralized Two-Phase Locking protocol in a distributed environment. incorrect Even if the database contains replicated data, applying the basic 2PL protocol still suffices to guarantee serializability. correct A disadvantage of Primary site 2PL is that the central lock manager may become a bottleneck. incorrect With distributed 2PL, every site has its own lock manager, which is responsible for managing all locking data pertaining to the fragments stored on that site. incorrect MC With BASE transactions, conflict resolution... always happens at the moment of writing the data. incorrect may be postponed until the data is actually read. correct MC Optimistic concurrency may considerably increase transaction throughput and overall data availability in a... tightly coupled setting. incorrect loosely coupled setting. correct MC Which statement is NOT CORRECT? A disadvantage of Primary site 2PL is that the central lock manager may become a bottleneck. incorrect Primary site 2PL comes down to applying the centralized Two-Phase Locking protocol in a distributed environment. incorrect With distributed 2PL, every site has its own lock manager, which is responsible for managing all locking data pertaining to the fragments stored on that site. incorrect Even if the database contains replicated data, applying the basic 2PL protocol still suffices to guarantee serializability. correct MC A schedule in 2PL is deadlock free if... the local wait-for graph contains only a limited number of cycles. incorrect both the local and global wait-for graphs contain no cycles. correct the local wait-for graphs contain no cycles. incorrect the global wait-for graph contains only a limited number of cycles. incorrect MC With horizontal fragmentation... each fragment consists of a subset of the columns of the global data set. incorrect each fragment consists of rows that satisfy a certain query predicate. correct MC Which statement is NOT CORRECT? Primary site 2PL comes down to applying the centralized Two-Phase Locking protocol in a distributed environment. incorrect With distributed 2PL, every site has its own lock manager, which is responsible for managing all locking data pertaining to the fragments stored on that site. incorrect Even if the database contains replicated data, applying the basic 2PL protocol still suffices to guarantee serializability. correct A disadvantage of Primary site 2PL is that the central lock manager may become a bottleneck. incorrect MC With BASE transactions, conflict resolution... always happens at the moment of writing the data. incorrect may be postponed until the data is actually read. correct MC Which statement is NOT CORRECT? Even if the database contains replicated data, applying the basic 2PL protocol still suffices to guarantee serializability. correct With distributed 2PL, every site has its own lock manager, which is responsible for managing all locking data pertaining to the fragments stored on that site. incorrect Primary site 2PL comes down to applying the centralized Two-Phase Locking protocol in a distributed environment. incorrect A disadvantage of Primary site 2PL is that the central lock manager may become a bottleneck. incorrect MC With BASE transactions, conflict resolution... always happens at the moment of writing the data. incorrect may be postponed until the data is actually read. correct