Usage data for OSAM sequential buffering

If you are using OSAM Sequential Buffering, you can use the Sequential Buffering Summary report and the Sequential Buffering Detail report to see how the SB buffers were used during a your program's execution.

By default, four buffer sets exist in each SB buffer pool. If the reports indicate that a large percentage of random read I/O operations were used, and you know that the program was processing your database sequentially, increasing the number of buffer sets to six or more can improve performance. By increasing the number of buffer sets, it is more likely that a block is still in an SB buffer when requested, and a read I/O operation is not necessary.

If only a few random reads were used during your program's execution, it indicates that the database is very well organized and most requests were satisfied from the SB buffer pool or with sequential reads. If this happens, you can save virtual storage space by decreasing the number of buffer sets in each SB buffer pool to two or three.