Robert's Blog

Thursday, October 16, 2008

DB2 Notes from Warsaw (Day 4)

The 2008 International DB2 Users Group European Conference concluded a little while ago, and I'm looking forward to seeing many of my fellow attendees (and some new people) at the 2009 conference that will take place October 5 - 9 in Rome. This was another good day, from my perspective. Some snapshots:
  • Mainframe DB2 is rockin' and rollin'. Roger Miller, a veteran member of the DB2 for z/OS development team at IBM's Silicon Valley Lab, gave his session attendees an update on the topic of DB2 for z/OS performance. He talked up the z10, IBM's top-of-the-line mainframe server. Processing capacity has long been a core strength of the mainframe platform, but this thing is a monster (in a good way, of course). The z10's engines are more 50% faster than those of its predecessor, and you can get up to 64 of the CPUs in one box (and z/OS manages a large number of processors very effectively). Want a lot of memory on your z10 server? You can get up to 1.5 terabytes. What will people do with all those MIPS? How about running a lot of the native SQL stored procedures that you can deploy in a DB2 V9 environment? Roger talked about performance tests of DB2 V9 on a z/10 server, with thousands of stored procedure calls per second. Native SQL procedures generally consume 30-40% less CPU time than external SQL procedures, AND - when invoked via DDF (the Distributed Data Facility component of DB2 for z/OS) - they can run on zIIP processors (specialty engines that - unlike general-purpose CPUs - do not factor into mainframe software pricing). Roger also talked about advances in disk I/O technology and mainframe I/O connections that benefit DB2 for z/OS performance: a chunk of 32 4KB pages can be brought into a DB2 buffer pool via prefetch in one millisecond. A number of organizations are migrating their DB2 Version 8 subsystems to Version 9, and Roger indicated that these companies can expect to see CPU reductions of around 3% upon migrating to Version 9 in Conversion Mode, and another 3% or so (for a total CPU efficiency gain of about 6%) once DB2 9 is in New Functon Mode and new performance-enhancing features are being exploited. Some of the best performance gains are expected for programs that access LOB (large object) data, as multiple improvements have been made to this component of DB2. Roger also told attendees that the multi-row fetch and insert capability provided with DB2 V9 can dramatically reduce CPU costs for data-intensive programs, with the magnitude of this positive effect perhaps being greatest for distributed database applications that access DB2 via DDF. Roger concluded by offering up some goodies that people can look for in "version next" of DB2 for z/OS, including lots more concurrently active threads, lots more stuff moved above the 2 GB level in the DB2 database services address space, and a hash technique for super-fast data row location.
  • The IBM panel did well, collectively and individually. Several leaders of IBM's DB2 development group, including Curt Cotner (IBM Fellow and CTO for DB2) and Matt Huras (chief kernal architect for DB2 for Linux/UNIX/Windows) answered a variety of questions from attendees during a lively 90-minute session. Some of the panel's answers had to do with new features expected to be delivered in the next release of DB2, with Jeff Josten of the DB2 for z/OS team mentioning an ALTER capability that will facilitate conversion of existing tablespaces to the new universal format (a combination of segmented and partitioned). Others had to do with outreach to various application programming communities (Curt spoke of IBM initiatives that are making it easier for people coding in languages such as PERL, Python, PHP, and Ruby to interact with DB2). This being DB2's 25th anniversary year, the panelists were asked to name their favorite all-time DB2 technology advances. On the DB2 for z/OS side, data sharing on the parallel sysplex got a mention, as did stored procedures and distributed database application support. Matt Huras cited the change to a threaded process model (from an agent model) for DB2 on Linux and UNIX servers, and John Hornibrook talked up the real-time statistics updates that enable the DB2 for LUW optimizer to make better access path decisions.
  • Curt Cotner delivered a good "state of DB2" keynote address. IBM's DB2 CTO talked about the enduring strength of DB2 for z/OS in the large-enterprise market, noting that 59 of the world's top 59 banks run DB2 for z/OS. He also pointed out that UPS took top honors in a recent Winter Corporation survey of the world's largest databases and database workloads, with a peak load of over 1 billion SQL statements executed per hour on a DB2 for z/OS system. The aforementioned (in the above item on the panel discussion) switch to a threaded process model for DB2 on Linux and UNIX servers (it already used a threaded process model in a Windows environment) was cited as an enabler of a more unified design for DB2 on the mainframe and Linux/UNIX/Windows platforms, since DB2 for z/OS has always used that process model (a fact not well known due to nomenclature differences: the pieces of work that execute in a mainframe DB2 address space are called TCBs and SRBs, but they equate to Linux/UNIX/Windows threads). Near the end of his presentation, Curt spoke of the importance of IBM's new Data Studio tool, particularly as a means of enabling DB2 DBAs to much more effectively support application developers whose programs access DB2 databases from Java-based and other application server environments. Previously, it could be very difficult to tie a poor-performing SQL statement noticed by a DB2 DBA to the Java (for example) program that issued it. With Data Studio in the mix, DB2 can build a repository of application metadata that can greatly facilitate the linking of an SQL statement with the issuing program, thereby providing a DBA with information that he (or she) can use to help the associated programmer code a more efficient data-accessing statement.
Tomorrow morning, it's back to Atlanta for me. I've enjoyed my first visit to Poland, and I hope to return at some point in the future.


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