Happy Thanksgiving 2017

Today, November 23rd, in the United States of America, we celebrate Thanksgiving by gathering together with our loved ones and giving thanks for what we have. 

Typically, this involves celebrations with food, traditionally a big turkey dinner with stuffing, mashed potatoes and gravy, as we watch a parade and football games. I plan to follow this tradition to the letter this year and I wish you the same!

And with the general notion of giving thanks on this fine day, I want to also pause and thank each and every one of you for reading my blog, whether just today, or all year long. Hopefully you'll keep coming back and we can keep discussing all things Db2 here.

But for today, wherever you may be, I am thankful for you and I wish you a very happy day!

Oh... and try not to get trampled on Friday if you're going out shopping for bargains!

The Db2 12 for z/OS Blog Series - Part 19: Profile Monitoring Improvements

The ability to monitor Db2 using profile tables is a newer, though by no means brand new capability for Db2 DBAs. You can use profile tables to monitor and control various aspects of Db2 performance such as remote connections and certain DSNZPARMs.

But this blog post is not intended to describe what profile monitoring is, but to discuss the new capabilities added in Db2 12 to enhance profile monitoring.

There are four new enhancements offered by Db2 12 for the use of system profiles.

The first enhancement is the ability to automatically start profiles when you start up a Db2 subsystem. This can be accomplished using a new subsystem parameter called PROFILE_AUTOSTART. Setting the parameter to YES causes Db2 to automatically execute START PROFILE command processing. The default is NO, which means that Db2 will not initiate START PROFILE when the subsystem starts up.

The second improvement is the addition of support for global variables. As of Db2 12 you can specify the following global variables as a KEYWORDS column value in the SYSIBM.DSN_PROFILE_ATTRIBUTES table:

• GET_ARCHIVE
• MOVE_TO_ARCHIVE
• TEMPORAL_LOGICAL_TRANSACTION_TIME
• TEMPORAL_LOGICAL_TRANSACTIONS

If a profile filter matches a connection, Db2 will automatically apply the built-in global variable value to the Db2 process of that connection when the connection is initially established, and when a connection is reused.

Wildcarding support is the third enhancement for profiles in Db2 12. One row for each profile is contained in the SYSIBM.DSN_PROFILE_TABLE. Each column in the table informs Db2 which connection to monitor. Without wildcarding, handling various connections required multiple rows to be defined in the table. But with Db2 12, you can have one row representing more than one connection. Wildcarding is available for AUTHID (authorization IDs), LOCATION (IP addresses of monitored connections), and PRDID (product specific identifier, for example DSN for Db2).

The fourth and final enhancement is for managing idle threads. The MONITOR IDLE THREADS column in the SYSIBM.DSN_PROFILE_ATTRIBUTES table directs DB2 to monitor (for an approximate amount of time) an active server thread’s idle time. The ATTRIBUTE1 column, which is used to specify the type of messages and level of detail of messages issued for monitored threads, has been enhanced to allow the following values: 

• EXCEPTION_ROLLBACK
• EXCEPTION_ROLLBACK_DIAGLEVEL1
• EXCEPTION_ROLLBACK_DIAGLEVEL2 

Note: This particular change to idle threads
for EXCEPTION_ROLLBACK was made available
in Db2 11 after general availability, and will be
available on a Db2 12 system after new function
is activated.

For more details on any of these capabilities, or indeed, on profile monitoring in general, refer to the IBM Db2 12 for z/OS Managing Performance manual, SC27-8857.