Group Buffer Pool Statistics Detail
This panel shows detailed near-term history information about activities in a specified Db2 group buffer pool during a specified report interval.
This panel is only available in a data sharing environment.
You can view information about a different group buffer pool by entering a buffer pool ID next to HGBD.
________________ ZHGBD VTM O2 V550.#P SN12 11/06/13 11:50:05 2
> Help PF1 Back PF3 Up PF7 Down PF8
>
> Enter a selection letter on the top line.
>
> A-SUBSYSTEM SUPPORT B-BIND C-BUFFER POOL *-GROUP BP
> E-DISTRIBUTED DATABASE F-EDM POOL G-LOG MANAGER H-OPEN/CLOSE
> I-SQL/RID/PARALLEL/PROC J-LOCK/CLAIM/DRAIN K-GLOBAL LOCK L-DB2 COMMANDS
> M-THREAD HISTORY
===============================================================================
> GROUP BUFFER POOL STATISTICS DETAIL
HGBD 0
+ Collection Interval: 1 min Start: 11/06 11:44
+ Report Interval: 1 min Combine Level: NONE End: 11/06 11:45
+
+ Allocated Size = 1024 Current Directory/Data Ratio = 5
+ Checkpoint Interval = 4 Pending Directory/Data Ratio = 5
+ GBP Castout Threshold = 30% Number Directory Entries = 1357
+ Castout Class Threshold = 0% Number of Data Pages = 271
+ Read Hit % = 20.0%
+
+ INTERVAL /MINUTE /THREAD /COMMIT
+ QUANTITY ( 1) ( 1) ( 74)
+ -------- ------- ------- -------
+ Reads - Cross-Invalidation:
+ Data Returned 1 1.00 1.00 .01
+ Data not in GBP-R/W Interest 4 4.00 4.00 .05
+ Reads - Page Not Found:
+ Data Returned 0 .00 .00 .00
+ Data not in GBP-R/W Interest 0 .00 .00 .00
+
+ Writes - Synchronous:
+ Changed Pages 5 5.00 5.00 .06
+ Clean Pages 0 .00 .00 .00
+ Writes - Asynchronous:
+ Changed Pages 0 .00 .00 .00
+ Clean Pages 0 .00 .00 .00
+ Write Failed - No Storage 0 .00 .00 .00
+
+ Pages Castout to DASD 4 4.00 4.00 .05
+ GBP Castout Threshold Reached 0 .00 .00 .00
+ Castout Class Threshold Reached 0 .00 .00 .00
+ Other Requests 4 4.00 4.00 .05
===============================================================================Navigation
For additional information about
- related topics, select one of the options from the menu.
- other topics, use the PF keys.
Fields
- Collection Interval
- The time interval specified for the collection of near-term history data. This unit of time was specified when the Near-Term History Data Collector was started.
- Start
- The start time of the first interval in this display.
- Report Interval
- This field determines the report interval. It is set on the Near-Term History Report Option panel.
- Combine Level
- This field reflects the selected combine level.
If Combine Level is NONE, the report interval is the same as the collection
interval. Possible values:
- HOURLY
- Data will be reported in hourly intervals.
- NONE
- Data will be reported in the time unit specified by the collection interval.
- End
- The end time of the last interval in this display.
- Allocated Size
- The allocated size of the group buffer pool in 4KB blocks.
- Current® Directory/Data Ratio
- The current ratio of directory entries to data pages.
- Checkpoint Interval
- The checkpoint interval for the group buffer pool, in minutes.
- Pending Directory/Data Ratio
- The pending ratio of directory entries to data pages. This value will be different from the current ratio if an ALTER GROUPBUFFERPOOL command has been issued with a new value for the RATIO parameter. The change will not take effect until the next time the group buffer pool is allocated.
- GBP Castout Threshold
- Group buffer pool castout threshold. When the number of changed pages in the group buffer pool exceeds this threshold, castout will be initiated. You can change this value with the GBPOOLT parameter on the ALTER GROUPBUFFERPOOL command.
- Number Directory Entries
- The actual number of allocated directory entries.
- Castout Class Threshold
- Group buffer pool castout class threshold. When the number of changed pages for a particular castout class exceeds this threshold, castout will be initiated. You can change this value with the CLASST parameter on the ALTER GROUPBUFFERPOOL command.
- Number of Data Pages
- The actual number of allocated data pages.
- Read Hit %
- The percentage of all Reads to the group buffer pool for which the needed data was found and returned to the member.
For each of the following fields, the
following statistics are provided:
- INTERVAL QUANTITY
- The amount of activities that occur during the interval.
- /MINUTE
- Rate per minute. The number under /MINUTE (in parentheses) is the number of minutes in the interval.
- /THREAD
- Rate per thread. The number under /THREAD (in parentheses) is the number of Create Threads during the interval.
- /COMMIT
- Rate per Commit. The number under /COMMIT (in parentheses) is the number of Commit requests (including abort requests) during the interval.
- Reads - Cross Invalidation: Data Returned
- The number of reads to the group buffer pool required because the page in the member's buffer pool was invalidated, where the data was found and returned to the member.
- Reads - Cross Invalidation: Data not in GBP-R/W Interest
- The number of reads to the group buffer pool required
because the page in the member's buffer pool was invalidated, where:
- The data was not found in the group buffer pool and the member had to go to DASD to read the page
- Other members had read/write interest in the pageset, so Db2 created a directory entry for this page if it did not already exist.
- Reads - Page Not Found: Data Returned
- The number of reads to the group buffer pool required because the page was not in the member's buffer pool where the data was found and returned to the member.
- Reads - Page Not Found: Data not in GBP-R/W Interest
- The number of reads to the group buffer pool required because
the page was not in the member's buffer pool, where:
- The data was not found in the group buffer pool and the member had to go to DASD to read the page
- Other members had read/write interest in the pageset, so Db2 created a directory entry for this page if it did not already exist.
- Writes - Synchronous: Changed Pages
- The number of changed pages that are synchronously written to the group buffer pool. Pages can be forced out before the application commits if a buffer pool threshold is reached, or when P-lock negotiation forces the pages on the Vertical Deferred Write queue to be written to the group buffer pool.
- Writes - Synchronous: Clean Pages
- The number of clean pages that are synchronously written to the group buffer pool. Db2 writes clean pages for pagesets and partitions defined with GBPCACHE ALL.
- Writes - Asynchronous: Changed Pages
- The number of changed pages asynchronously written to the group buffer pool. Pages can be forced out before the application commits if a buffer pool threshold is reached, or when P-lock negotiation forces the pages on the Vertical Deferred Write queue to be written to the group buffer pool.
- Writes - Asynchronous: Clean Pages
- The number of clean pages asynchronously written to the group buffer pool. Db2 writes clean pages for pagesets and partitions defined with GBPCACHE ALL.
- Write Failed - No Storage
- The number of group buffer pool write requests that failed because of a shortage of coupling facility resources.
- Pages Castout to DASD
- The number of pages that this member has castout to DASD from the group buffer pool.
- GBP Castout Threshold Reached
- The number of times that castout was initiated because the group buffer pool castout threshold was reached.
- Castout Class Threshold Reached
- The number of times that castout was initiated because the castout class threshold was reached.
- Other Requests
- The number of other requests.