Wednesday, July 28, 2010

Catalog view xmlstrings for simpler access to stringID information

The XML support in DB2 is tightly integrated into the database engine and provides fast and sophisticated processing of XML data. In the past I had explained why - for compactness and speed - element and attribute names, namespace information is replaced with so-called stringIDs. The string to stringID mappings are stored in a cached dictionary which is persisted in a system catalog.

That system catalog, SYSIBM.SYSXMLSTRINGS, an internal table, has undergone some changes over the past database versions. In DB2 9.1, pureXML support was restricted to databases using a Unicode codepage. Hence, the string information was stored in clear text in the database codepage. Users could easily access AND display the system information. In DB2 9.5, the pureXML feature could also be used in non-Unicode databases. The VARCHAR-based string column was then changed into a VARCHAR FOR BIT DATA column to store the UTF-8 codes properly. Via a new function XMLBIT2CHAR it was possible to turn the encoded information back into a readable string.

Now, in the current version DB2 9.7, life got much simpler because a catalog view SYSCAT.XMLSTRINGS was introduced. It shows the stringID, the string in the database codepage (by calling the mentioned XMLBIT2CHAR function), and the string as bit data (hex format).

Thursday, July 22, 2010

New generation of mainframes and an integrated accelerator for warehouse workloads

IBM today announced a new generation of its mainframe computers, labeled zEnterprise. Based on a hybrid architecture, zEnterprise BladeCenter Extensions (zBX), it allows to integrate and manage POWER7 blades or System x blades from within the mainframe infrastructure. (One of) the first to exploit the zBX feature is the IBM Smart Analytics Optimizer. The latter allows to significantly speed up analytic queries running on DB2 for z/OS. Queries that qualify a transparently routed to the accelerator and return in a fraction of the time.

A small step for mankind, but a good day for mainframe customer, especially those using DB2.

Wednesday, July 21, 2010

Two days in France (in August for pureXML)

If you live in France or are in Paris in the middle of August or want to be in Paris on August 17/18, here is what I **would** do: Attend a DB2 pureXML bootcamp.

Susan Malaika and I will be running an intense, packed bootcamp which covers everything pureXML from basics over XML storage and indexing to performance best practices. The bootcamp will be held at the IBM Forum Paris. And yes, it's free to attend.

Tuesday, July 13, 2010

Another year gone by: Energy consumption in our passive house

We had a long and cold Winter in Germany and also several upgrades to our electrical equipment in our passive house. So I was curious how our energy consumption would be for the last 12 months compared to the year before. This morning was the time to read out our two energy meters (still old fashioned and not smart):

  • Household consumption: 2473 kWh (previous year 2244 kWh)
  • Heating/ventilation/water: 2858 kWh (previous year 2782 kWh)
As mentioned, the Winter was long and cold and thus the small increase for heating makes sense. It would have been even bigger if we would not have "cheated" when we bought (and used) a table-top fireplace. That small fireplace has a nice flame, burns Ethanol and, of course, produces some heat. It's stronger than some candles and only needs about 0.15 l of Ethanol an hour.

For the increased household consumption one big factor is my work: I traveled less over the past 12 months and worked more and longer at home, started using a 2nd screen, and am now using an automatic coffee/espresso maker to keep the spirits high. Now add in some kids asking for more TV and computer time, some more washing cycles, and extended cooking, then the increase for the household is surprisingly small.

Friday, July 2, 2010

Passive Houses in the US

One of the many questions I got regarding our passive house (see the Wikipedia entry for many links) is whether there is a similar standard in the USA or whether I know of resources to learn more about what is available. I promised that in a blog post I would try to list some resources I found and learned about the last few years. Guess what, you just started reading that promised post.
Passive house scheme.Image via Wikipedia

When my wife and I started to look into building a passive house we - by chance - also heard an interesting radio story on NPR about such a house built out of straw in Southern California and also saw a documentary in the German children TV show "Die Sendung mit der Maus". I found the documentary on youtube:

Although it is in German, you will find several videos in your language, e.g., English, by searching for "passive house".

In Germany, the Passivhaus-Institut is trying to set and coordinate standards, provide help and research technologies. It also offers information in English. In the US there is now a Passive House Institute US. In addition to information material it also has contact data for Certified Passive House Consultants all over the US.

A passive house combines several technologies to reduce energy consumption. So it is a good idea to learn about those components individually:
  • solar panels are used to either heat water or to produce power
  • ventilation systems with heat recovery are in place to allow constant ventilation while preserving energy in the Winter and helping to keep the inside cooler in the Summer
  • in many houses a heat pump is used for heating and warm water
  • windows have to be of good quality and should be constructed such that they let sunshine in during the Winter and are covered by shade in the Summer
That's probably already more than I wanted to write in this first installment. Let me know if you have specific questions.

Forrester Analyst: Customers report success with DB2's out-of-the-box compatibility to Oracle's SQL

Forrester Research analyst Noel Yuhanna posted a blog entry titled "Database Migrations are Finally Becoming Simpler". Based on customer feedback he got, one can see 90% or more compatibility and hence the migration effort for moving from Oracle to DB2 requires only days or weeks instead of months or years. Noel Yuhanna says "This is huge".

Database customer want to save millions of dollars, but earlier a migration was costly and painful and required a larger investment of their own. With the DB2 compatibility layer the migration becomes simpler.