Background Thread Summary
This panel provides an overview of the activity of all background threads connected to Db2®.
________________ ZBACKT VTM O2 V610.#P SN11 S 11/05/13 12:37:22 2
> Help PF1 Back PF3 Up PF7 Down PF8 Sort PF10 Zoom PF11
> T.E
> Thread Activity: Enter a selection letter on the top line.
> A-All-Idle B-TSO C-CICS D-IMS *-Background F-Dist Allied
> G-Dist DBAC H-Util I-Inact J-Filter K-Functions L-Stored Proc
> M-Triggers N-Sysplex O-Enclaves P-Worksta Q-All+Idle
===============================================================================
> Background Thread Summary
BATA
+ Job Name CPU% Connection Threads
+ -------- ----- ---------- -------
+ D843DMBS 00.0 1 1
+ MIS302 00.0 1 1
THDB
+ *
+ Elapsed Planname CPU Status GetPg Update Commit Jobname
+ ---------- -------- ----- ------------ ------ ------ ------ --------
+ 04-19:04 KO2PLAN 00.0% NOT-IN-DB2 0 0 0 D843DMBS
+ 00:02:18.0 DSNACLI 00.0% NOT-IN-DB2 126 0 0 MIS302
===============================================================================
The top part of the panel summarizes all background jobs currently connected to Db2. The bottom part of the panel summarizes the activity of each background thread (ordered by elapsed time since thread creation or reuse).
Highlighting
The following table shows the fields that might be highlighted in the panel above to indicate
that an exception that is related to this field exceeded its threshold
value:
| Field | Exception | Reason |
|---|---|---|
| Elapsed | ETIM | This thread has reached the Elapsed Time threshold value. |
| CPU | TCPU | The thread address space has excessive CPU utilization. |
| GetPg | GETP | The Getpage to Read I/O ratio indicates poor read efficiency. |
| Update | PGUP | The rate for system page updates is high. |
| Commit | COMT | The ratio of Commits to Updates indicates a low Commit frequency. |
Navigation
For additional information about:
- Summary information about individual threads that originated from a
particular background job, place the cursor to the line that contains that
job and press F11 (Zoom).
The information might not be displayed if individual threads do not work the address space of the background job, for example, if threads work inside of a Db2 address space.
- Detail information about a particular thread, place the cursor to the line that contains that thread and press F11 (Zoom).
- A different Db2 subsystem, data sharing group, or member of a data sharing group, enter the name of a Db2 subsystem, group, or member in the topmost row and press Enter.
- Related topics, select one of the options on the top of the panel.
- Other topics, use the PF keys.
Fields
Background connection
information:
- Job Name
- The name of the background job connected to Db2.
- CPU %
- The total CPU usage rate (percent) of background jobs that have active threads to Db2.
- Connection
- The number of connections to Db2 that originated from this background thread.
- Active Threads
- The number of active threads that originated from the background connection.
Background thread information:
- Elapsed
- The elapsed time since thread creation, or since Db2 signon if the thread is reused. When the elapsed
time of the thread exceeds 24 hours, the format is
dd-hh:mm.If this thread is involved in parallel processing or if it invoked autonomous procedures, one of the following identifiers is displayed after the elapsed time:
- *
- This thread is a parallel task that is initiated on behalf of another (originating) thread to process a query request in parallel.
- O
- This thread is the originating thread that invoked autonomous procedures.
- P
- This thread is the parent or the originating thread of the parallel tasks that are created to process a query request in parallel. Activity performed for this (originating) thread is reflected under the parallel tasks.
- X
- This thread is a parallel task that is initiated on behalf of another (originating) thread on another Db2 for sysplex parallelism.
- Planname or Package
- The Db2 plan name (or package name) of the active thread. If you selected option T from the Realtime Main Menu, this panel shows the information by plan. If you selected option U, this panel shows the information by package.
- CPU (if monitoring a Db2 subsystem or a data sharing group member)
- The current CPU rate (percent) of the batch or utility region from which the active thread originates. This includes both TCB and SRB time.
- Db2 (if monitoring a data sharing group or remote Db2 subsystem while XCF component is not activated for remote CPU)
- The Db2 subsystem name of the data sharing group member that is currently monitored.
- Status
- The current Db2 status of the thread.
- GetPg
- The number of thread Getpage requests.
Getpage requests are logical Read requests that might not actually result in physical I/O if the requested page is currently in the buffer pool. Db2 resets this count at thread creation and signon.
- Update
- The number of Db2 page updates made by the thread since thread creation. This value is incremented each time a row in a page is updated, not just once for each page updated. Db2 might update pages when it creates intermediate result tables because of a qualified SELECT statement, even though SELECT statements are generally thought of as read only operations. Pages that have been updated are written asynchronously by Db2, according to Db2's internal Deferred Write algorithm, not immediately after update or commit. Db2 resets the page update count at Create Thread and Signon. If Signon is not driven, the page update count is cumulative.
- Commit
- The number of times the thread successfully completed
Commit processing.
Db2 resets the Commit count at thread creation and signon. If Signon is not driven, the count is cumulative.
- Jobname
- The name of the connected batch job or utility.