Defining or allocating a buffer pool

Use the Define Buffer Pool window to allocate a buffer pool as an active virtual buffer pool.

Authorities and privileges

To define or allocate a buffer pool:

  1. Open the Define Buffer Pool window.

  2. Specify a buffer pool from the list of undefined or inactive buffer pools. A buffer pool is named sequentially and for its page size. BP0 - BP49 use 4 KB buffers. BP8K0 - BP8K9 use 8 KB pages. BP16K0 - BP16K9 use 16 KB pages. BP32K - BP32K9 use 32 KB buffers.

  3. Type a valid number in any of the fields that you want to set thresholds or sizes. The fields in this window relate to sizes or thresholds of a buffer pool or hiperpool . Each field has a range from 0 to some number of kilobytes. The exception is for BP0, which requires a minimum of 56 KB. If you set Virtual buffer pool size (VPSIZE) to 0 after you activate the buffer pool, you will delete the buffer pool. DB2 for OS/390 quiesces all current database access and fails all subsequent page set open requests.

  4. Repeat step 3 for any additional fields that you want to define a threshold.

  5. In the Vertical deferred write buffer pool field, the size you specify can be expressed as a percentage of total buffer pool size, or as an absolute number. Select the radio button that defines the format of VDQT.

  6. Select one of the following Discard hiperpool data radio buttons:

    Yes

    MVS discards the data cached in the hiperpool when a shortage of expanded storage arises.

    No

    MVS assigns a high priority to keeping the data cached in the hiperpool. You should select No only for buffer pools associated with databases for which response time is critical.

  7. In the Page stealing algorithm radio buttons, specify if you want DB2 to manage the buffer pool buffers for page stealing with the Least recently used algorithm (LRU) or the First-in-first-out algorithm (FIFO).

  8. Click OK to apply the threshold and size values and close this window.

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