Prefetching Enhancements with Block-Based Buffer Pools
DB2 UDB v8.1 can help the performance of prefetching algorithms through the use of a new block-based buffer pool.
When a block-based buffer pool is available to DB2 UDB, the prefetching code recognizes this and uses block I/Os to read multiple pages into the buffer pool in a single I/O operation. This significantly improves the performance of prefetching. The blocksize parameter of the CREATE and ALTER BUFFERPOOL statements defines the size of the blocks, and hence the number of pages read from disk in a block I/O.
By default, the buffer pools are page-based, which means that contiguous pages on disk are prefetched into noncontiguous pages in memory. Sequential prefetching can be enhanced ...
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