This method manages reference buffers and update buffers in independent LRUs. If a shortage of global buffers occurs, the reference buffer in the global buffer that was accessed least recently is purged from the memory. If the number of references and updates per transaction is relatively small, as in the case of online jobs, managing reference buffers and update buffers in independent LRUs improves processing performance.

To apply LRU management to global buffers, SEPARATE (default value) must be specified in the pd_dbbuff_lru_option operand. For details about the pd_dbbuff_lru_option operand, see the HiRDB Version 8 System Definition.

This method manages all global buffers in a single LRU. If a shortage of global buffers occurs, the buffer in the global buffer pool that was accessed least recently is purged from the memory. If a large number of retrievals and updates coexist, as in a combination of online jobs and batch jobs, managing the reference buffers in a single LRU improves processing performance.

One of the following actions must be taken to manage global buffers in a single LRU:

• Specify MIX in the pd_dbbuff_lru_option operand.
• Specify the updated output page rate at the deferred write trigger in the -w option of the pdbuffer operand.

For details about the pd_dbbuff_lru_option and pdbuffer operands, see the HiRDB Version 8 System Definition.