14.3.5 Global buffer pool statistical information

The following shows the statistical information about the global buffer pool:

pdstedit VV-RR(Object Option) ***** GLOBAL BUFFER INFORMATION *****
INPUT          :/tmp/stjdata [1]
OUTPUT RANGE   :**/**/** **:**:** - **/**/** **:**:** [2]
-----------------------------------------------------------------------------
HOST = test [3]
-----------------------------------------------------------------------------
EDIT TIME 2003/04/03 22:00:00 - 2003/04/03 23:00:00 [4]
              [5]   [6]   [7]   [8]  [9]    [10]  [11]  [12] [13]  [14]
        *LN1* SYNCW MAXB  UPGET UPHIT(HIT)  UPFLS RFGET RFHIT(HIT) RFFLS
              ----- ----- ----- ----- ---   ----- ----- ----- ---  -----
              [15]  [16]  [17]  [18]  [19]  [20]  [21]  [22] [23]  [24]
        *LN2* READ  WRITE WAITR WAITW WAITL BFINS PRRED PRHIT(HIT) PRINS
              ----- ----- ----- ----- ----- ----- ----- ----- ---  -----
              [25]  [26]  [27]  [28]  [29]  [30]  [31]  [32]       [33]
        *LN3* GBHIT CURRF CURUP TRGUP SYNCC PRRDR LRDRC LWTRC      LBBKR
              ----- ----- ----- ----- ----- ----- ----- -----      -----
              [34]  [35]  [36]  [37]  [38]     [39]  [40]     [41]  [42]
        *LN4* LBBKW CINSM CFMAX CFAVG SLEPC    SLEPR SLEPA    SPINR SPINA
              ----- ----- ----- ----- -------- ----- -------- ----- -----
              [43]  [44]  [45]  [46]
        *LN5* SYNCL SYNCB ALTRW ALTUW
              ----- ----- ----- -----
SERVER :  sds [47]
 *BUFFER NAME:bp01 [48]            BUFFER:   10 [49]
        *LN1*     0     2   160   114( 52)     14    60    60( 27)     8
        *LN2*     6    72     0     2     0     0     0     0(  0)     0
        *LN3*    79     0     0     0     1     0     0     0          0
        *LN4*     0     0     0  ****  0.0e+00   0.0  *******   0.1 2.05k
        *LN5*     0     0     0     0
 *BUFFER NAME:bp02                 BUFFER:   10
        *LN1*     0     3 1.51k   933(  4)    278 20.8k 19.7k( 88)   657
        *LN2* 1.30k   607     0    36     0     0     0     0(  0)     0
        *LN3*    93     0     0     0     1     0     0     0          0
        *LN4*     0     0     0  ****  0.0e+00   0.0  *******   0.1 2.05k
        *LN5*     0     0     0     0
 *BUFFER NAME:bp03                 BUFFER:   10
        *LN1*     0     4 1.22k   647( 15)     50 3.15k 1.50k( 34) 1.73k
        *LN2* 2.22k   561     0    69     1     0     0     0(  0)     0
        *LN3*    49     0     0     0     1     0     0     0          0
        *LN4*     0     0     0  ****  0.0e+00   0.0  *******   0.4 2.05k
        *LN5*     0     0     0     0
 *TOTAL* [50]
        *LN1*     0     4 2.89k 1.69k(  6)    342 24.0k 21.3k( 79) 2.39k
        *LN2* 3.52k 1.24k     0   107     1     0     0     0(  0)     0
        *LN3*    85     0     0     0     3     0     0     0          0
        *LN4*     0     0     0  ****  0.0e+00   0.0  *******   0.2 2.05k
        *LN5*     0           0     0
-----------------------------------------------------------------------------
FILE KIND   LOG KIND   FIRST                 LAST                         NUM
STJ         buf        2003/04/03 22:46:32   2003/04/03 22:56:45            6
-----------------------------------------------------------------------------

NO FILE KIND:LOG FILE NAME
 LOG KIND             FIRST                 LAST                         NUM
1 STJ      :/tmp/stjdata/pdstj01
 sys                  2003/04/03 22:46:30   2003/04/03 22:46:30            2
 uap                  2003/04/03 22:45:56   2003/04/03 22:47:53           32
 sql                  2003/04/03 22:45:56   2003/04/03 22:47:53          898
 sop                  2003/04/03 22:45:56   2003/04/03 22:47:53          105
 dop                  2003/04/03 22:45:56   2003/04/03 22:47:52          113
 pcd                  2003/04/03 22:45:56   2003/04/03 22:47:53          759
 obj                  ****/**/** **:**:**   ****/**/** **:**:**            0
 sqh                  2003/04/03 22:45:56   2003/04/03 22:47:53          145
 buf                  2003/04/03 22:46:32   2003/04/03 22:46:32            3
 fil                  2003/04/03 22:46:32   2003/04/03 22:46:32           28
 dfw                  2003/04/03 22:45:58   2003/04/03 22:47:31           53
 idx                  2003/04/03 22:46:32   2003/04/03 22:46:32            1
 fsv                  ****/**/** **:**:**   ****/**/** **:**:**            0
 hba                  ****/**/** **:**:**   ****/**/** **:**:**            0
2 STJ      :/tmp/stjdata/pdstj02
 sys                  2003/04/03 22:48:31   2003/04/03 22:56:35           10
 uap                  2003/04/03 22:47:54   2003/04/03 22:56:24           67
 sql                  2003/04/03 22:47:53   2003/04/03 22:56:24          623
 sop                  2003/04/03 22:47:53   2003/04/03 22:54:12           74
 dop                  2003/04/03 22:47:53   2003/04/03 22:56:23          102
 pcd                  2003/04/03 22:47:53   2003/04/03 22:56:24          516
 obj                  ****/**/** **:**:**   ****/**/** **:**:**            0
 sqh                  2003/04/03 22:47:53   2003/04/03 22:56:24          144
 buf                  2003/04/03 22:56:45   2003/04/03 22:56:45            3
 fil                  2003/04/03 22:56:45   2003/04/03 22:56:45           28
 dfw                  2003/04/03 22:48:04   2003/04/03 22:56:45           18
 idx                  2003/04/03 22:56:45   2003/04/03 22:56:45            1
 fsv                  ****/**/** **:**:**   ****/**/** **:**:**            0
 hba                  ****/**/** **:**:**   ****/**/** **:**:**            0

Explanation
  1. Name of input statistics unload file or name of the directory containing the input statistics unload file (maximum of 58 bytes)
  2. Output range (output start date/time to output end date/time)
  3. Name of host requesting output of global buffer pool statistical information
  4. Edit period (collection start time to collection end time)
  5. Number of pages output during synchronization point dump
    This is the maximum number of pages output from the global buffer pool to the HiRDB file during a synchronization point dump.
    If this value is large, many pages may be updated in the corresponding global buffer pool, and the updated page output rate may be low during a deferred write trigger, resulting in many pages kept in the global buffer pool. Evaluate whether the updated page output rate can be reduced during a deferred write trigger.
  6. Maximum number of concurrently requested buffer sectors
    This is the number of global buffer pool acquisition requests issued concurrently from multiple transactions.
    If this value is almost the same as the number of global buffer sectors and the buffer shortages count is not 0, the buffer may be insufficient.
  7. Update GETs count
    This is the number of times buffer acquisition was requested to the global buffer pool for updating purposes.
  8. Update buffer hits count
    This is the number of times a page requested for the global buffer pool for updating purposes was found as the updated buffer.
  9. Update buffer hit rate (%)
    This is the ratio of update buffer hits count to the total of update GETs count and reference GETs count. It is the probability of finding a requested page (for updating or referencing purposes) as updated buffer in the global buffer pool without executing a physical input/output operation.
    This value is obtained from the following formula:

    Update buffer hit rate = (update buffer hits count [Figure] (reference GETs count + update GETs count)) [Figure] 100

    If this value is small, the deferred write processing may not be effective. In this case, you need to increase the number of global buffer pool sectors or reduce the updated page output rate during a deferred write trigger.
  10. Update buffer flushes count
    This is the number of times the buffer was invalidated after writing its contents to a HiRDB file to create an empty buffer for reading new pages, because the referenced buffer had been updated.
    If this value is large, the deferred write processing may not be effective.
  11. Reference GETs count
    This is the number of times buffer acquisition was requested for the global buffer pool for referencing purposes.
  12. Reference buffer hits count
    This is the number of times a page requested for the global buffer pool for referencing purposes was found as the referenced (not updated) buffer.
  13. Reference buffer hit rate (%)
    This is the ratio of reference buffer hits count to the total of reference GETs count and update GETs count. It is the probability of finding a requested page (for referencing or updating purposes) as referenced buffer in the global buffer pool without executing a physical input/output operation.
    This value is obtained from the following formula:

    Reference buffer hit rate = (reference buffer hits count [Figure] (reference GETs count + update GETs count)) [Figure] 100

    The reference buffer hit rate should be about 80%. If it is less than 80%, you need to increase the number of buffer sectors.
  14. Reference buffer flushes count
    This is the number of times the buffer was invalidated to create an empty buffer for reading new pages, because the referenced buffer had not been used since that time.
  15. Actual READs count
    This is the number of times pages were read from HiRDB file.
  16. Actual WRITEs count
    This is the number of times pages were written to a HiRDB file.
  17. Input waits count
    This is the number of times wait status occurred because a requested page was being read from a HiRDB file by another user.
  18. Output waits count
    This is the number of times wait status occurred because a requested page was being written to a HiRDB file by another user.
  19. Buffer lock release waits count
    This is the number of times wait status occurred because a requested page was being used by another user.
  20. Buffer shortages count
    This is the number of times there was no available buffer because all buffers (defined buffer sectors) were being used for referencing or update processing.
    This value must be 0.
  21. Number of prefetched input pages
    This is the number of pages read in memory as being subject to prefetch processing.
  22. Prefetch hits count
    This is the hits count on the pages that were read in memory as being subject to prefetch processing.
  23. Prefetch hit rate (%)
    This is the ratio of the prefetch hits count to the number of prefetched input pages.
  24. Prefetch resource shortages count
    This is the number of times a shortage occurred on the resources required for prefetch processing.
  25. Global buffer hit rate (%)
  26. Number of current reference buffers
  27. Number of current update buffers
  28. Number of update buffers that triggers output operation when deferred write trigger is on
  29. Number of synchronization point dumps that occurred
  30. Number of prefetch READ requests
  31. Number of LOB global buffer READ requests
  32. Number of LOB global buffer WRITE requests
  33. Number of LOB global buffer pages input in batch mode
  34. Number of LOB global buffer pages output in batch mode
  35. Information used by the system (not for the user)
  36. Information used by the system (not for the user)
  37. Information used by the system (not for the user)
  38. Information used by the system (not for the user)
  39. Percentage of buffer contention-lock release waits resulting from buffer lock processing (%)
  40. Information used by the system (not for the user)
  41. Information used by the system (not for the user)
  42. Information used by the system (not for the user)
  43. Buffer pool lock exclusive time during synchronization point processing (microseconds)
  44. Number of buffers processed within buffer pool lock exclusive time during synchronization point processing
  45. Take-over count of database write processing by reference request hit during synchronization point processing
  46. Take-over count of database write processing by update request hit during synchronization point processing
  47. Server name
    This is the server requesting output of global buffer pool statistical information.
  48. Global buffer pool name
    This is the name of the global buffer pool for which statistical information was edited.
  49. Number of buffer sectors in the global buffer pool
    This is the number of buffer sectors in the corresponding global buffer pool.
  50. Totals for each item