572 DS8800 Performance Monitoring and Tuning
The logger and the buffer pool manager cooperate and ensure that the updated data page is
not written to disk storage before its associated log record is written to the log. This behavior
ensures that the database manager can obtain enough information from the log to recover
and protect a database from being left in an inconsistent state when the database crashes as
a result of an event, such as a power failure.
Parallel operations
DB2 UDB extensively uses parallelism to optimize performance when accessing a database.
DB2 supports several types of parallelism, including query and I/O parallelism.
Query parallelism
There are two dimensions of query parallelism: inter-query parallelism and intra-query ...