Log Buffer #160: A Carnival of the Vanities for DBAs

Sep 4, 2009 / By David Edwards

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Welcome to the 160th edition of Log Buffer, the weekly review of database blogs.

MySQL

Blame it on MyISAM, says Mark Callaghan of High Availability MySQL, on considering sql_mode and type coercion. “I think that MyISAM has its place,” writes Mark. “It does fast table scans, but InnoDB is much faster on just about everything else. I am just not thrilled with the impact it has had on MySQL.”

Not that those other engines are without flaw. Peter Zaitsev reports on an InnoDB performance gotcha with larger queries.

Here on the Pythian Blog, Singer Wang unearthed a MySQL 5.1 and InnoDB hot backup gotcha.

Eric Bergen offers his InnoDB deadlock count patch, which he introduces thus: “[Deadlocks] usually aren’t a problem until they start happening too frequently.  . . .  [SHOW ENGINE INNODB STATUS] can be useful for debugging but it’s almost impossible to get the rate at which deadlocks are occurring. [This patch] adds a counter to show table status that tracks the number of deadlocks.”

Baron Schwartz had a script snippet to relative-ize numbers embedded in text to share.

From Planet Geek! came a fix for a OSX Snow Leopard MySQL startup problem.

SQL Server

While we’re on the subject of flaws, let’s begin our look at SQL Server blogs with Musings on Database Security and its post on passwords leakage from MS SQL Server. “Turns out that SQL Server saves in memory in clear text user credentials (passwords) of users logging in using SQL Server native authentication.  . . .  We . . . were convinced that SQL Server administrators out there should be aware of the danger and also should have a way to mitigate it so we’ve decided to publicize it and release a free tool to remove the clear text passwords from memory.”

Anyone who reads code of any kind can tell you that unreadable code is a sometimes fatal flaw. With that is mind, Buck Woody of Carpe Datum collected some T-SQL prettifiers.

Jamie Thomson examined extracting insert, update, delete rowcounts from T-SQL MERGE. Jamie writes, “Just lately I’ve been using T-SQL’s MERGE statement . . . and one thing that I needed to do was extract rowcounts for each DML operation . . . conducted by a MERGE. I was surprised to find that while @@ROWCOUNT is supported for MERGE, it only returns the total number of affected rows and there are no built in functions for getting the counts for each DML operation . . . ” Jamie’s workaround code follows.

Pythian’s André Araujo shared his procedure making for easier SQL Server database restores.

Kalen Delaney wondered, What’s a SQL Server Education Worth?. It’s not just a rhetorical question, either. It’s addressed to you. Yes, YOU!

Maybe conferences such as the PASS Summit are worth it? But the cost! Here’s Jeremiah Peschka with his tips on getting to PASS on the cheap.

Oracle

11gR2 was released. Let’s see what Oracle bloggers had to say about it. Here’s Doug Burns’s take on the 11.2 release—two highlights: Parallel Query, and changes to ASH.

The Oracle Security Blog itemizes new security features Oracle 11g Release 2.

On the AMIS Technology Blog, Marco Gralike writes, “I noticed yesterday a new feature that could have the potential to be a small, by me unnoticed, gem called ‘Flash Cache’.

It was quiz night again at the Oracle Scratchpad. In this second one, Jonathan Lewis and his contestants submit their explanations for bundle of statements in the library cache using bind variables.

Kevin Closson related his experience using Linux /proc To identify ORACLE_HOME and instance trace directories. In the post, Kevin writes, “ . . . you’ll see how to find the ORACLE_HOME and trace directories for an instance by looking at /proc//fd and /proc//exe of the LGWR process.”

DB2

Rav Ahuja says, moving to DB2 is easy, sharing a video that, he writes, “ . . . highlights some of the new features in DB2 9.7 that make it very easy to enable Oracle applications to DB2.”

Easy and fun, apparently. Willie Favero, for instance, knows how to have fun and learn about DB2 LUW. It involves tuning in to the new “DB2night Show” on September 24th.

Over and out, for now. Please add your favourite DB blogs from this week in the comments, and we’ll meet again next week. Till then!

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