Db2 SRM BPD Attributes
Use the Db2 SRM BPD attributes to create situations to monitor activity details associated with specific buffer pools.
Buffer Pool Hit Percent Random The random buffer pool hit percentage calculated as follows: ( (# of Random Getpages - # Random Sync Read I/O) / # of Random Getpages) * 100. Valid entry ranges from 0.0 to 100.0.
Buffer Pool Hit Percent Sequential The sequential buffer pool hit percentage calculated as follows: ( (# of Sequential Getpages - #Getpage Fails - # pages read from DASD) / # of Sequential Getpages - #Getpage Fails) * 100. The # pages read from DASD is the sum of Sequential Sync Read I/O, Sequential Prefetch Pages, List Prefetch Pages, and Dynamic Prefetch Pages. Valid entry ranges from 0.0 to 100.0.
| Value | Description |
|---|---|
| Yes | MVS is allowed to discard data cached in the hiperpool when a shortage of expanded storage arises. |
| No | MVS is prevented from discarding data cached in the hiperpool unless expanded storage pages are reconfigured out of the system. |
It is an alphanumeric text string, with a maximum length of four characters.
Deferred Write Thresh The deferred write threshold for the virtual buffer pool - DWQT. Write operations are scheduled when the percentage of unavailable pages in the virtual buffer pool exceeds this threshold in order to decrease the unavailable pages to 10% below the threshold.
Dyn Prefetch Per IO The ratio of dynamic prefetch requests to dynamic prefetch I/Os.
Dyn Prefetch Per IO Extended Precision The ratio of dynamic prefetch requests to dynamic prefetch I/Os.
Getpages Per Syn IO The ratio of getpage requests to read I/Os.
GetPages Per Synchronous IO Extended Precision The ratio of getpage requests to read I/Os.
Interval Time The number of seconds since last sample.
List Prefetch Per IO The ratio of list prefetch requests to list prefetch I/Os.
List Prefetch Per IO Extended Precision The ratio of list prefetch requests to list prefetch I/Os.
Max Concur Prefetch The highest number of concurrent prefetch I/O streams allocated to support I/O parallelism.
Maximum Concurrent Prefetch Extended Precision The highest number of concurrent prefetch I/O streams allocated to support I/O parallelism.
Originating System ID The managed system name of the agent. It is an alphanumeric text string, with a maximum of 32 characters; for example, DB91:SYS1:DB2.
Page Reads Per Dyn Prefetch The ratio of pages read by dynamic prefetch to dynamic prefetch requests.
Page Reads Per Dyn Prefetch Extended Precision The ratio of pages read by dynamic prefetch to dynamic prefetch requests.
Page Reads Per List Prefetch The ratio of pages read by list prefetch to list prefetch requests.
Page Reads Per List Prefetch Extended Precision The ratio of pages read by list prefetch to list prefetch requests.
Page Reads Per Prefetch The ratio of pages read by prefetch processing to total prefetch requests.
Page Reads Per Prefetch Extended Precision The ratio of pages read by prefetch processing to total prefetch requests.
Page Reads Perseq Prefetch The ratio of pages read by sequential prefetch to sequential prefetch requests.
Page Reads Per Sequential Prefetch Extended Precision The ratio of pages read by sequential prefetch to sequential prefetch requests.
Page Writes Per Write IO The ratio of page writes to physical I/Os.
Page Writes Per Write IO Extended Precision The ratio of page writes to physical I/Os.
Pages In Use The number of virtual buffer pool pages in use at the end of the interval (a snapshot value of the current number of non-stealable buffers). A non-stealable buffer is either one which has an outstanding getpage (someone is currently looking at this page) or one which has been updated and not yet written out to DASD.
Pool ID Buffer Pool ID.
Prefetch Per IO The ratio of prefetch requests to physical I/Os.
Prefetch Per IO Extended Precision The ratio of prefetch requests to physical I/Os.
Sequential Prefetch Per IO The ratio of pages read by sequential prefetch to sequential prefetch I/O.
Sequential Prefetch Per IO Extended Precision The ratio of pages read by sequential prefetch to sequential prefetch I/O.
Sysplex Parallel Thresh Parallel I/O sequential threshold - VPPSEQT. This threshold determines how much of the virtual buffer pool might be used for parallel I/O operations. It is a percentage of the VPSEQT. If set to zero, I/O parallelism is disabled.
Time The date and time, as set on the monitored system, indicating the instance when the agent collects information.
Use Count The number of open table spaces and index spaces in this buffer pool.
Vert Deferred Write Thresh The vertical deferred write threshold for the virtual buffer pool - VDWQT. This is the percentage of the buffer pool that might be occupied by updated pages from a single data set.
Virtual Page Steal Method Identifies the page stealing algorithm (PGSTEAL) that is used for the virtual buffer pool (Field name: QDBPPGST). It controls when and whether performance-critical objects in buffer pools are removed from buffer pools when the space is needed by other objects. Possible values are:
- LRU
- Least recently used (LRU) objects are removed first. This means it takes away pages that are not used so that more recently used pages can remain in the virtual buffer pool. This is used by default.
- FIFO
- This results in a small decrease in the cost of a Getpage operation. It can reduce internal Db2 latch contention in environments that require very high concurrency.
- NONE
- Objects are not removed from buffer pool (no page stealing). This setting provides the highest availability for business-critical objects.
VP Buffers Allocated The number of pages allocated to the virtual buffer pool.
VP Buffers Delete The number of pages to be deleted from an active virtual buffer pool as a result of pool contraction.
VP Parallel Sequential Thresh The parallel I/O sequential threshold - VPPSEQT. This threshold determines how much of the virtual buffer pool might be used for parallel I/O operations. It is a percentage of the VPSEQT. If set to zero, I/O parallelism is disabled.
VP Sequential Thresh The sequential steal threshold for the virtual buffer pool - VPSEQT. This is the percentage of the virtual buffer pool that might be occupied by sequentially accessed pages. If set to zero, prefetch is disabled.
VP Size The size of the virtual buffer pool.
Workfile Maximum The maximum number of work files that were allocated during sort/merge processing during the current statistics period.
Workfile Maximum Extended Precision The maximum number of work files that were allocated during sort/merge processing during the current statistics period.