Buffer Manager Information

This panel provides information about the performance of the Db2 buffer manager and the activity in each of the buffer pools.

This information helps you analyze buffer pool utilization.

________________ ZBMGR    VTM     O2       V550.#P SN12 11/05/13 14:05:45   2 
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> R.A.A                                                                        
> *-BUFFER POOL             B-GROUP BUFFER POOL                                
>                           BUFFER MANAGER INFORMATION                         
+  Current Number Open Datasets         =     197                              
+  High Water Mark Open Datasets        =     197                              
+  Maximum Number Open Datasets Allowed =   10000                              
+  Open Dataset Count In Active Pools   =     250                              
+ *                                                                            
+ Pool     VP       Pages    Pages    Getp       Read       Prefetch   Write   
+ ID       Size     Alloc    In Use   Rate       I/O Rate   Req Rate   I/O Rate
+ ------   ------   ------   ------   --------   --------   --------   --------
+ BP0        5000     5000       29     138.00       7.00        .00        .00
+ BP1        2000     2000        0        .00        .00        .00        .00
+ BP2        2000     2000        1       6.00       1.00        .00       1.00
+ BP3        2000     2000        0        .00        .00        .00        .00
+ BP4        2000     2000        0        .00        .00        .00        .00
+ BP7        1000     1000        3        .00        .00        .00        .00
+ BP32K       250      250        2        .00        .00        .00        .00
+ BP8K0     10000    10000        2      10.00        .00        .00        .00
+ BP16K0      500      500        0        .00        .00        .00        .00


OMEGAMON® for Db2 PE highlights some fields in this panel to draw your attention to their current status.
Table 1. Highlighted fields on Buffer Manager Information panel
Field Exception Reason
Pages In Use BMTH The percentage of pages in use has reached the predetermined threshold.


For additional information about
  • a buffer pool, move the cursor to the buffer pool line and press F11 (Zoom). For more information, see the description of panel Buffer Pool Detail.
  • other topics, use the PF keys.


Current® Number Open Datasets
The number of data sets that are currently open in Db2.
High Water Mark Open Datasets
The largest number of data sets that were open simultaneously in Db2 since Db2 started.
Maximum Number Open Datasets Allowed
Determines how much initial memory to allocate for the data sets at startup time (defined by DSNZPARM DSMAX). The maximum number of data sets that can be open at one time is determined by TIOT SIZE, which is specified in SYS1.PARMLIB(ALLOCxx).
Open Dataset Count in Active Pools
The total number of opens issued for the buffer pools that are currently active. This value represents the number of times the data sets have been opened (and reopened) since Db2 started. (Buffer pools not currently in use might have issued opens that are not reflected in this count.)
Pool ID
The ID of the buffer pool.
VP Size
The number of buffers allocated for an active virtual buffer pool.
Pages Alloc
The number of pages currently allocated to the buffer pool. If a buffer pool is in use, Pages Alloc will be between the minimum and maximum values. Otherwise, it will be zero.
Pages In Use
The number of 4K, 8K, 16K, or 32K pages that are currently in use by the buffer pool.
Getp Rate
The number of Getpage requests per second made by the buffer pool.
Read I/O Rate
The total number of Read I/Os per second made by the buffer pool.
Prefetch Req Rate
The number of Sequential Prefetch and List Prefetch requests per second made by the buffer pool.
Write I/O Rate
The number of Write I/Os per second.