How to take a Strobe DB2 DDF Measurement |
Strobe ISPF Measurement There are many options to consider when taking a Strobe measurement of a DB2 DDF (Distributed Data Facility) Address Space and this write up will detail these options. From the Strobe ISPF Main Menu, select option 1 - Add Active, enter the DDF Address Space Name (typically xxxxDIST where xxxx is the DB2 Subsystem ID) in the Jobname Field, set Session Duration for the number of minutes to measure this DDF - typically 5 to 15 minutes, set Target Sample Size to anywhere from 10,000 to 30,000 for the number of Samples to take during the measurement, and set Data Collector to ‘Y’ then press enter. It is not necessary to set the Data Collector to ‘Y’ each time you take a Strobe measurement, but this will show what to set some of the next options the first time or whenever the options may need to change. On the next panel (Strobe – Data Collectors), put a ‘Y’ next to DB2 and press enter. On this next panel (Strobe - DB2/DDF Data Collector Capture Option), an ‘N’ for SQL Capture will disable the capture of Trace data, so put a ‘Y’ for SQL Capture to specify that Strobe capture trace data for the DB2 Subsystem. This SQL Capture set to ‘Y’ is needed for the following Capture Options. Setting the DB2 Trace filtering can be a little confusing so set LOCAL/DDF Trace Filter Field to ‘N’ for None then move to the next field LOCAL/DDF Report Type and set it to ‘B’ for Both Performance and Accounting Traces which will set the filtering option to allow Strobe to filter IBM DB2 Instrumentation Facility Interface (IFI) trace data for DB2. Using ‘N’ for No Filtering, garners the most captured DB2 data (and the most overhead) and is recommended when first taking a DDF measurement. Next, set DDF Requester to one of the following values (Y,F,N). If ‘N’ is entered, no filtering will take place. Setting Always use as default to ‘Y’ will save all these values each time a user takes a DDF Measurement. Pressing Enter will start the DDF Measurement. If ‘Y’ is entered, another panel (Strobe – DDF Requester) will appear when Enter is pressed which will allow the display of DDF Requesters (P – Primary and S – Secondary) to be changed in the Performance Profile created after the measurement is completed. Pressing Enter will now start the Strobe DDF Measurement. If ‘F’ (for Filter) is entered, a different panel (Strobe – DDF Requester Filtering) will appear when Enter is pressed which will facilitate the entering of values in the various fields (Authorization ID’s, Correlation ID’s, Location which is IP Address, Enduser USERID’s, Enduser TRANSACTION’s, Enduser WORKSTATION’s, and Free Form) to be used in the DB2 trace filtering. At the top of this Requester Filtering panel is another option Display DDF Requesters which if set to ‘Y’ will display the Strobe – DDF Requester panel when Enter is pressed which will allow the display of DDF Requesters (P – Primary and S – Secondary) to be changed in the Performance Profile created after the measurement is completed. Pressing Enter will start the Strobe DDF Measurement. iStrobe Measurement From iStrobe (the Web-based version of Strobe), select Measurement from the iStrobe Main Menu, login to the specific LPAR for that DDF Address Space, and select New Measurement. From the Target Section of the Measurement Form, select Active and enter the DDF Address Space Name (typically xxxxDIST where xxxx is the DB2 Subsystem ID) in the Job/Process field – and from the Environment and System drop-down menus, select the environment and system. Below Override in the Sampling Section, click on DB2 which will expand to show various capture and filter options. From the DB2 Report Type drop-down menu, select Both SQL Detail Activity & SQL Activity Summary. To change how the SQL activity is displayed in the iStrobe Performance Profile, click on Override DDF Requesters which will show the Primary and Secondary drop-down menus for DDF Requester Names. There are six selections available – Location (default – IP Address), Correlation ID, Authorization ID, End User ID, End User Workstation, and End User Transaction. The Primary requester is required but the Secondary requester is optional and can be deselected. Again, this is only for the display of the data. Clicking on Literal (Dynamic SQL) will enable the display of the content of literals in the SQL Statement Text. If DB2 Trace Filtering is desired, click on the SQL Filters drop-down menu and select DDF which will display the six filtering options (Authorization IDs, Correlation IDs, Location which is IP address, User IDs, Transactions, Workstations). After entering the required fields in the Reporting Section to create the iStrobe Performance Profile with SQL Analysis, click on Submit to start the Strobe DDF measurement. |