New features are being added to the Enhanced 3270 User Interface in each release of OMEGAMON XE for Db2 Performance Expert on z/OS. A continued investment in the 3270 UI provides more synergy and integration with the entire OMEGAMON family of products. One of the most important features introduced for version 5.3.0 is the ability to display Thread History.
In OMEGAMON for Db2, there are two types of history. The Snapshot type of history takes a sample of what is happening in Db2 at a specific point in time. This is the type of history in the Enhanced 3270 UI using the Persistent Data Store (PDS). The other type of history is DB2 Event History. To a DBA, while snapshot history might capture a thread in suspension if the snapshot was recorded at that very moment, thread history/event history is the more important tool for evaluating DB2 performance history.. In event history, data is recorded when an event takes place in DB2. The most important event is thread termination. At thread termination, Db2 produces an IFCID 3 Accounting record with metrics about the resource utilization of that thread. The Enhanced 3270 UI Thread History feature allows metrics from the Accounting records to be displayed on Enhanced 3270 UI.
The PTF for APAR PI82090 needs to be installed on the 5.3.0 release of OMEGAMON for Db2. Parmgen will need to be run to configure collection of Thread History.
Accessing Thread History
The remaining sections of this blog provide a detailed walk-thru of the panels that are especially useful to newer users of the OMEGAMON family of products. The enhanced 3270 UI Thread History is accessed by a new selection code ‘R’ from the Enterprise Summary. Selecting ‘R’ will take you to the filter workspaces where filter values can be entered to focus and limit the threads you are looking for to find performance problems.
The first filter workspace is time ranges.
Using this filter workspace, you can narrow down a time range by minutes, hours or a specific date and time range, so you can find poorly performing threads.
Clicking the Counts/Time tab will bring you to the Counts/Time filter workspace.
This filter workspace allows you to set filters by time or count of events. For example you might want to set Deadlock/Timeout greater than 1, or DB2 CPU time greater than 30 seconds.
Clicking on the Thread ID tab will bring you to the Thread Identification filter screen.
On this screen, you can enter any identification fields to limit the threads you are looking for.
For example, if I was looking for a specific CICS transaction I could enter in the CICS TX field QMFE.
The ‘*’ or ‘?’ can be used for wild cards. ‘?’ for a single character. ‘*’ for multiple characters at the end of the field. The connection type cannot be a wild card it must be one of the specific types like DRDA.
From any of the filter workspaces, you can click the ‘OK’ button when you have completed entering your filters. The filters you entered will remain set for your entire session. Clicking the ‘Clear’ button on any of the filter workspaces will set all filters back to their default values.
Thread History Summaries
There are five different Thread History Summary workspaces. The first general Thread Summary always is displayed when the ‘OK’ button is clicked. The other summaries are accessed by clicking one of the tabs on all of the thread summary workspaces.
This is the general Thread Summary.
By clicking the ‘BP Summ’ tab summary information related to Buffer Pools is displayed.
Clicking the ‘DB2 Time Summ’ tab will display a summary workspace with DB2 time related data.
Clicking on the ‘Lock Summ’ tab will display Lock related summary information.
Clicking on the ‘Alt Summ’ tab will display a collection of some of the fields shown on each of the other summary workspace.
From any of the summary workspaces there are two different select codes to display more detail about a thread in history. The ‘S’ select is to display Thread Accounting Detail and the ‘W’ select is to display Thread Wait Time detail. ‘S’ is the default.
The Thread Accounting Detail displays the Thread Identification, the DB2 Class 1 and Class 2 times.
Elapsed times and CPU times spend running the thread and used within Db2 can be review
Clicking the Class 3 tab or using the ‘W’ select from one of the summary workspaces will display the Thread Detail Class 3 wait times for a thread.
Thread History on Enhanced 3270 UI feature will enable users to quickly locate threads that were performing badly in the past and diagnose and resolve their performance problems.