The XBRL Extention, a no cost add-on extention on XML-DB targeting the Extensible Business Reporting Language area, is now available for download. This second release ( p12388668_112020_Generic.zip ) of the Oracle XBRL Extension can be downloaded from the Oracle Support site (https://support.oracle.com). Once you have downloaded the file, please follow the instructions in the README.txt file to install the software.
Here are what’s new in the new in this release:
For more info about the Oracle XBRL Extention see also “Oracle XBRL Extension Ready for Download”.
We’ve been joking around at the office about whether the Exadata X2-8 model has actually been observed in the wild. Some of the guys have been affectionately referring to it as Sasquatch because we’ve never actually seen one. Well we actually got our hands on real one today.
Not as pretty as the X2-2, but as long as it’s fast it doesn’t really matter what it looks like I guess. Thanks to Andy Colvin for the iPhone snap. We’ll be doing some testing with it soon so stay tuned. By the way, we’ve got our T-Shirts on order:
The Cost Based Optimizer (CBO) supports since at least Oracle 9i the automatic generation of additional predicates based on transitive closure.
In principle this means:
If a = b and b = c then the CBO can infer a = c
As so often with these optimizations the purpose of these automatically generated additional predicates is to allow the optimizer finding potentially more efficient access paths, like an index usage or earlier filtering reducing the amount of data to process.
June 6, 2011 You might expect to see some differences when upgrading from one release version of Oracle Database to another release version (edit June 6, 2011: see this article for expected changes when upgrading from 10g to 11g). For instance, you might find that Oracle Database 220.127.116.11 deadlock when Oracle Database 10.2.0.5 and below [...]
You should save this link in your bookmarks, for the next time you accidentally remove your database’s online redologs or overwrite some ASM disks:
Laurent Demaret has written a good article about how he systematically troubleshooted cache buffers chains latch contention, starting from wait interface and drilling down into details with my latchprofx tool:
A common cause for cache buffers chains latch contention is that some blocks are visited and re-visited way too much by a query execution. This usually happens due to nested loops joins or FILTER loops retrieving many rows from their outer (driving) row sources and then visiting the inner row-source again for each row from driving row source. Once you manage to fix your execution plan (perhaps by getting a hash join instead of the loop), then the blocks will not be re-visited so much and the latches will be hammered much less too.
The moral of the story is that if you have latch contention in a modern Oracle database, you don’t need to start tweaking undocumented latching parameters, but reduce the latch usage instead. And Laurent has done a good job with systematically identifying the SQL that needs to be fixed.
If you don’t know what LatchProfX is, read this:
The annual OUG Scotland conference takes place next Wednesday (8th June) at a familiar location to me - the Sun Microsystems site in Linlithgow where I spent a happy 6 months on contract many years back. I've always looked forward to this event but sadly will be beavering away at a client site in London. I recommend you make it if you can and, best of all, it's free
More information here.
I wonder if I ought to create an “Argh” category on my blog for articles about some of the nastier, and sometimes unbelievable, bugs in the Oracle code. Here’s one (that’s just about forgivable in terms of failing to test) published by Sokrates a couple of months ago.
If you’re using the merge command without including insert/delete options then Oracle will ignore check constraints. (What’s the most important requirement of a database – many people would say that it’s the correctness of the data.)
Early this year, my friend Mike Riley from ODTUG asked me to write a little essay in response to the question, “Why Kscope?” that he could post on the ODTUG blog. He agreed that cross-posting would help the group reach more people, so I’ve reproduced my response to that question here. I’ll hope to see you at Kscope11 in Long Beach June 26–30. If you develop applications for Oracle systems, you need to be there.
MR: Why KScope?
I started to write a quick review of the latest X-Men film and I realized I hadn’t written anything about that pirate film, so here goes a double whammy…