Author Archive

Log Buffer #104: a Carnival of the Vanities for DBAs

By David Edwards July 4th, 2008 at 11:15 am
Posted in Log BufferMySQLNon-Tech ArticlesOraclePostgreSQLSQL Server
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Andrew Clarke has published to 104th edition of Log Buffer, the weekly review of database blogs, on Radio Free Tooting, marking LB’s second year. Happy Birthday, LB!

Log Buffer always needs editors, so if you you’d like to present your view of the week that was in DB blogs, contact me, the Log Buffer coordinator. You’ll be joining some of the best bloggers around, and making yourself and your blog a little better known to readers around the world.

And now, here’s Andrew Clarke’s Log Buffer #104.

P.S.: To our readers in the U.S. — Happy 4th of July!

Log Buffer #103: a Carnival of the Vanities for DBAs

By David Edwards June 27th, 2008 at 11:33 am
Posted in Log BufferMySQLNon-Tech ArticlesOraclePostgreSQLSQL Server
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Welcome to the 103rd edition of Log Buffer, the weekly review of database blogs.

Starting with Oracle stuff, Chen Shapira (just a simple DBA on a complex production system) is looking for great PL/SQL. Why? To become a better PL/SQL programmer. “But,” she writes, “for PL/SQL , I’m a bit stuck. I can still read my own code for bad examples, but where can I find examples for great code?  . . .  Somehow, there is simply no open-source code written in PL/SQL that I can read to get a good idea of how PL/SQL should be written.” Niall Litchfield recommends the contents of $ORACLE_HOME/rdbms/admin. Any other ideas to help Chen?

There was no shortage of people offering their help, as always. Beginning here on the Pythian blog, Grégory Guillou posted the fifth of his ten-part series on Oracle silent mode, this part covering adding a node to a 10.2 RAC. Says Grégory, “Even if you don’t leverage RAC’s ability to add or remove nodes to gain in agility, it’s still very likely you’ll come to these techniques when you want to upgrade some of your Servers or Operating Systems.” The post includes links to the earlier articles in the series.

On his Core IT for geeks and pros, Tanel Poder expounds another use case for WaitProf. He begins, “I recently diagnosed a performance issue where the ‘events in waitclass Other’ occasionally took significant part of the session’s response time.  . . . So, what to do when this ‘events in waitclass Other’ wait becomes significant in the response time profile?” This is where waitprof, his custom tool, comes into play.

Jeff Hunter of the So What Co-operative posts Something to be aware of, Part II, in which he and Oracle Support tussle over NUMA in Linux, and where he is heard to say, “My next step is talking to a Duty manager. I really don’t want to do that.” And Part III, which Jeff begins, “I escalated my issue to a duty manager . . .”

On Oracle Applications DBA, Aviad Elbaz knows how to do tricks with a pipe, as he shows in his article on how to execute TKPROF on trace files larger than 2GB. Aviad, I think Bilbo and Gandalf would be proud.

Are you like me, shamefully ignorant about the whole Business Intelligence thing? Do you, too, secretly believe it might be an oxymoron? Mark Rittman is here to help, with an introduction to the Oracle BI Applications.

Vivek Sharma of Database/SQL Experiences informs us that he will be contributing a seminar on “Real Time Performance Tuning” to the very first event mounted by the IOUG (All India Oracle User Group). This is their TechNight, taking place in Hyderabad on Friday, July 18th.

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Log Buffer #102: a Carnival of the Vanities for DBAs

By David Edwards June 20th, 2008 at 11:33 am
Posted in Log BufferMySQLOraclePostgreSQLSQL Server
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Welcome to the 102nd edition of Log Buffer, the weekly review of database blogs.

Since it was DB2’s 25th birthday this week, as Anant Jhingran reports, let’s start with it.

From ZDNet this week came a story that IBM was considering the open-sourcing of DB2 — big news, naturally, whether true or not. Matthew Aslett of 451 CAOS Theory says, Open source DB2? I don’t think so, suggesting that it was merely theorizing on the part of one IBM executive, and hype on the part of ZDNet. “Then of course,” Matthew continues, “there is the issue of why IBM would open source DB2. Where is the business driver? Despite solid competition from Oracle and Microsoft, the company is doing pretty well with DB2 as it stands, thanks very much, and open source databases have had minimal impact on the established vendors.”

Matt Asay of The Open Road likewise comes down on the uh-uh side of this. “It was . . . no surprise to see IBM quickly follow up ZDNet’s article with a blunt statement: ‘IBM has no plans to open source DB2.’ Of course it doesn’t.  . . . The day that it needs DB2 to undermine Oracle’s database, however, we may see IBM making a similarly bald statement…in the other direction.”

On An Expert’s Guide to DB2 Technology, Chris Eaton offers some news on DB2 videos, including ChannelDB2’s video tutorials, IDUG’s video competition, and a funny video from IBM on the making of a “viral” industrial video. Such as itself.

On to MySQL now. Keith Murphy made his debut on the Pythian blog this week, with a link to some video tutelage of his own — his presentation to the Boston MySQL Users Group on backups. Jay Pipes also offers the slides for his address on Join-Fu: The Art of SQL (I and II). (I rarely cover presentation materials when I do Log Buffer, but these ones of Jay’s looks fantastic.)

Mark Schoonover reports that Keith’s and his 2008 MySQL Magazine survey is officially closed, adding, “Now the fun begins compiling all the data and pretty charts made. We’ve had 432 responses!”

Baron Schwartz of xaprb describes how to write a lazy UNION in MySQL. No, it doesn’t deal with posting a complaint about undefended job benefits. Baron explains: “Something occurred to me a couple of weeks ago: why not write a UNION that stops executing as soon as one part of it finds a row? Then you can UNION to your heart’s content and not incur the overhead of that second lookup unless you need it. For lack of a better term, I’m calling this a lazy UNION.”

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Log Buffer #101: a Carnival of the Vanities for DBAs

By David Edwards June 13th, 2008 at 11:43 am
Posted in Log BufferMySQLOraclePostgreSQLSQL Server
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Welcome the the 101st edition of Log Buffer, the weekly review of database blogs.

This edition was originally claimed by Ward Pond for his SQL Server Blog. Unfortunately, Ward is, in his own words, “dealing with the aftermath of a burst appendix,” which is a very good reason not to spend your time at the computer. Ward, heal up soon! We’ll see you on LB before too long.

In lieu of the normal Log Buffer, I throw it open to our readers. Please leave a comment mentioning your favourite database blog items from the week that was, and anything else you care to say about them.

LB will be back to normal next Friday. See you then!

Log Buffer #100: a Carnival of the Vanities for DBAs

By David Edwards June 6th, 2008 at 11:02 am
Posted in Log BufferMySQLOraclePostgreSQLSQL Server
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Log Buffer, the weekly review of database blogs, is 100 editions (and almost two-years) old today! Lewis Cunningham has returned to LB to publish The Big 100th edition of LB on An Expert’s Guide to Oracle Technology.

No speech, but I would like to thank Log Buffer’s readers and especially all of Log Buffer’s editors for making LB a worthwhile and fun stop in the database “blogosphere”. It’s very easy to see why LB editors are successful in what they do — they are consistently enthusiastic, diligent, and adaptable. And I enjoy working with them.

Okay, okay — I can hear the orchestra starting to play me off, so let’s get to it. Here’s Lewis’s Log Buffer #100.

Emacs Keybindings in Bash

By David Edwards June 2nd, 2008 at 5:03 pm
Posted in Not on HomepageSysAdmin
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Or, How to Be a Command-Line Commando

Does it surprise you to learn that I’m a Linux guy? I’ve been using Linux, to the exclusion more-or-less of everything else, since about 1999. In the past, I’ve done a little programming and some junior system administration. I’m even LPI-certified.

With this background, I’m quite comfortable working in the shell (AKA the command-line), the natural habitat of the sysadmin[1]. I frequently open a shell to do some quick work, and when I do, I use GNU’s Bash, which is the default on most Linux distributions. (I believe it’s also the default shell in Mac OS X.)

One of Bash’s features is editable command-line history, which makes your current command-line and its entire history available to you as an editable buffer. That offers a great way to streamline your work in the shell.

I suspect, however, that many shell users don’t even know about this better way. And it baffles me that many SAs I have seen in action — including some of Pythian’s own — don’t use this. They almost seem to prefer unnecessary effort — smashing away at their keyboards, repeating themselves, deleting with the Backspace key, scrolling, forwarding their cursor one character at a time, copying and pasting with the mouse, and so on. That’s a lot of elbow grease.

With Bash, or any other shell that uses the GNU readline library, you can use the following Emacs-like key-chords to make your life better. The point of this (as with so many things sysadmins and programmers do) is to save you effort, viz. typing. These aren’t all of them; they’re the ones I use:

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Log Buffer #99: a Carnival of the Vanities for DBAs

By David Edwards May 30th, 2008 at 11:43 am
Posted in Log BufferMySQLOraclePostgreSQLSQL Server
Tags:

Welcome the the 99th edition of Log Buffer, the weekly review of database blogs.

Since PGCon recently happened right here in Ottawa, let’s start with some posts about it, and about PostgreSQL. Josh Berkus came to the conference with his Database Soup. It sounds like he enjoyed himself: “So, that’s pgCon. It was exciting and fun. All of you PG geeks who missed it should be kicking yourselves about now, and putting in budget requests for next year.” He has day one highlights; day two highlights, and also some photos from the conference.

On Tending the Garden, Selena Deckelmann (who knows a thing or two about Postgres conferences) has her PGCon review, with links to conference webpages.

Robert Treat of zillablog also has his take-aways. “The biggest thing to come out of this past week to me was recognition of the continued growth of the postgresql community. With a number of regional conferences springing up over the past year, I wondered if PGCon would be able to match the experience from last time, and was happy to see that it far exceeded it. . . . One thing I noted was that we have a very large presence of Postgres in Ottawa, I think larger than what we had at PGEast for the Baltimore/Washington Area.”

On Greg’s Postgres stuff, Greg Sabino Mullane has an item on verifying master-slave replication with check_postgres.pl, a montoring script for Nagios and other systems.

Hubert Lubaciewski of select * from depesz; looks at different approaches to counting the number of distinct elements, such as distinct sessions per day.

On An Expert’s Guide to Oracle Technology, Lewis Cunningham examines the recent news of the worlds largest database running on Postgres. How large? 2 Petabytes! “Let’s put that in perspective,” writes Lewis. “1 petabyte is 1,000,000,000,000 bytes. Yahoo has two of those. . . . [They use] this database to analyze the browsing habits of its half a billion monthly visitors. How would you like to tune those queries?” Lewis also notes that this is not the plain-vanilla PostgreSQL that you or I would download and run on our website box.

There are conferences on the horizon of the Oracle world too. Dan Norris reminds us that ODTUG is just around the corner. That’s the Oracle Developer Tools User Group’s Kaleidoscope 2008 event, taking place in mid-June in New Orleans.

Gareth Roberts of In Depth Apps announces the call-for-papers of the New Zealand Oracle Users Group’s (NZOUG) 2008 conference, coming in October.

In other Oracle matters — Chen Shapira, just a simple DBA on a complex production system, has some thoughts on cumulative distribution. “How do we calculate Cumulative Normal Distribution? This means calculating the probability that a random variable from a normal distribution, will end up equal to or less than X.”

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Log Buffer #98: a Carnival of the Vanities for DBAs

By David Edwards May 23rd, 2008 at 11:03 am
Posted in Log BufferMySQLOraclePostgreSQLSQL Server
Tags:

The 98th edition of Log Buffer, the weekly review of database blogs, has been published on Jeff’s SQL Server Blog.

Log Buffer is a shared project of the DBA blogging community, so you’re welcome to edit and publish an edition yourself. LB’s 100th anniversary edition is still up-for-grabs (and there’s plenty of room besides that), so read the Log Buffer homepage and the guidelines, and then email me.

Here’s Jeff Smith’s Log Buffer #98.

Log Buffer #97: a Carnival of the Vanities for DBAs

By David Edwards May 16th, 2008 at 12:28 pm
Posted in Log BufferMySQLOraclePostgreSQLSQL Server
Tags:

The 97th edition of Log Buffer, the weekly review of database blogs, has been published on Brian “Krow” Aker’s Idle Thoughts.

We have Jeff Smith and Ward Pond standing by for two upcoming editions. And if you’d like to contribute, make yourself known in the DBA community-at-large (and have some fun in the process), you too can do Log Buffer! Read the homepage and send me, the Log Buffer coordinator, an email.

And now, Brian Aker’s Log Buffer #97.

Log Buffer #96: a Carnival of the Vanities for DBAs

By David Edwards May 9th, 2008 at 11:37 am
Posted in Log BufferMySQLOracleOracle E-Business SuitePostgreSQLSQL Server
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This is the 96th edition of the weekly review of database blogs, Log Buffer.

Let’s start this one in SQL Server Land, with a question from Dennis Goboshould SQL Server have the CREATE [OR REPLACE] PROCEDURE syntax? There are, he writes, advantages: “When scripting out a database you don’t have to generate if exists…..drop statements,” and disadvantages: “I can overwrite a proc without even knowing it.” Of course, the commenters have opinions of their own, and the piece becomes a straw poll for the desirability of that syntax as a feature.

Aaron Bertrand has one too: when was my database/table last accessed? Writes Aaron, “SQL Server does not track this information for you. SELECT triggers still do not exist. Third party tools are expensive and can incur unexpected overhead. And people continue to be reluctant or unable to constrain table access via stored procedures, which could otherwise perform simple logging.” He looks at 2008’s built-in auditing, and for those who can’t wait for that, illustrates a workaround for 2005.

Linchi Shea explores something else from 2008, Page Compression, focusing on how the number of processors affects the rebuilding a table with page compression.

Jamie Thomson, the SSIS Junkie writes that he has made a submission to Connect on the matter of absolute and relative paths in SSIS. “. . . I have always agreed that stipulating the use of absolute paths within SSIS was the right thing to do (and indeed I have championed it) however of late I have changed my mind. Support for relative paths would greatly simplify package deployment and package management . . . What do you think? Should SSIS support relative paths?” So far, it looks like a shoo-in.

Brian Knight also explains another little quirk, SSIS Case Sensitivity: “The case sensitivity can in some cases create behavior that is not expected and may give you bad results if you’re not careful.  . . . One such example is with the Lookup Transform, where comparisons against the cache are case sensitive. If you do not expect this, you may have a miss in a match that is actually a hit.”

In the MySQL ’sphere this week, there is plenty of talk about the openness or otherwise of MySQL. (more…)