Log Buffer #135: A Carnival of the Vanities for DBAs

Posted in: Technical Track

Welcome to the 135th edition of Log Buffer, the weekly review of database blogs.

How about a little DB2 news to whet the palette? On IT, Life, DB2 pureXML, House Construction, Henrik Loeser Friedrichshafen has an item about Organic Food and pureXML. Completely unrelated! In the on-topic second part of this duo, Henrik relates the news: “I am happy to tell you that the so far separately priced pureXML feature will now be included in the core DB2 for Linux, UNIX, and Windows.” And relevant links are included in this blog.

On the DB2PORTAL Blog, Craig Mullins admonishes, Don’t Forget DISPLAY as a Part of Your DB2 Tuning Efforts. Craig begins, “Although a DB2 performance monitor is probably the best solution for gathering information about your DB2 subsystems and databases, you can gain significant insight into ‘what is going on out there” using the simple DISPLAY command.” He goes on to provide, “a quick tour of the useful information provided by the DISPLAY command.”

On Informix Application Development, Guy Bowerman writes that it’s the last chance to submit papers for European IOD Conference, “taking place in Berlin, June 2-5 2009, and the deadline for submitting papers is Feb 13.” That’s today!

The Oracle world has had a conference on—RMOUG Training Days. Pythian’s Christo Kutrovsky is there, and he submitted his report on RMOUG Day 1. Christo says the highlight was Tanel Poder’s presentation, “Advanced Oracle troubleshooting”. Tanel has put his materials up.

Tanel also has an item on how to find the answer to the question, when was a table last changed?

Richard Foote tantalizes with the koan-like paradox, down is the new up, in the second part of his series on updates and indexes. Despite his assertions earlier in the series, that, ” . . . there’s no such things as an ‘update’ operation as such on a index and that an update is effectively a delete followed by an insert operation,” Richard ” . . . thought it might be worth going through a little demo of an index that does indeed experience lots of update operations and see what impact it actually has on the index.”

Our old friend Doug Burns and his readers discuss the case of throughput vs. response time, taking as their keynote an assertion by Niall Litchfield: ” . . . once you start to define workload, or transactions, in business terms (I need to get all these things done, what works best overall?) then workload response time does make sense, both as a metric, and more pertinently as a tuning target.”

On his Oracle on Windows blog, Edward Whalen illustrates using Oracle parallel query in a RAC environment.

Amongst the SQL Server blogs, Kendal Van Dyke’s gets the award for illustration this week, for the third part of his disk performance series, this one on RAID 5 performance.

Coming in a close second is Linchi Shea with the first part of a series, on the performance impact of a large number of virtual log files.

Dennis Gobo writes, “In SQL Server 2000 we got the uniqueidentifier data type and the newid() function.  . . .  Newid() is nice but it has a little side effect; it causes terrible page splits because it is a random value. SQL Server 2005 introduced newsequentialid() where each value generated by the function is always greater than the previous value.” Dennis offers some simple code to show the difference between newid and newsequentialid.

While we’re on splits, Michael Zilberstein and his readers discuss monitoring page splits with extended events.

PostgreSQL now! On select * from depesz;, Hubert Lubacziewski exposes an lpad() and rpad() gotcha.

Selena Deckelmann of tending the garden was at FOSDEM ’09 and reports on what she learned there of FSM, visibility map and new VACUUM awesomeness.

In the wake of MySQL’s Monty and Marten splitting from Sun, Josh Berkus (PostgreSQL Core Team Member), offered After Me, The Deluge: “I was expecting Monty’s departure … urged him to leave 6 months ago, actually … but Marten’s comes as a bit of a surprise. Still, as ‘first rat’ fleeing Sun’s rising losses, I shouldn’t be surprised that Marten was smart enough to follow me.  . . .  For MySQL-the-project, this is a good thing.”

Jay Pipes (now of the project) has some thoughts on Drizzle, MySQL, and the mess that is Dates and SQL_MODE: “The frustration builds.  . . .  I have come to despise MySQL’s sql_mode. It is a hack of the most gargantuan proportions.”

Chris Calender shares his recipe for recovering an InnoDB table from only an .ibd file.

Keith Murphy announces the release of MySQL Magazine – Winter 2009. Arjen Lentz comments on the bias inherent in the term “winter,” especially for those like him, in Australia, where it is anything but winter.

Pythian’s Alex Gorbachev is there too, and he has a link for those of you who might be interested in helping victims of the Victoria Bushfire.

Maggie Nelson elucidates what she deems an oldie but a goodie, denormalization with bitmasks. Very slick.

Finally, Sun/MySQL’s Kaj Arno got a really big hand at FOSDEM˜09.

That is all. Please add your favourite blogs of this week in the comments, or send me an email to publish a Log Buffer of your own. Till next time!

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About the Author

Dave Edwards is the Communications Specialist for the Pythian Group.

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