Log Buffer #160: A Carnival of the Vanities for DBAs
Sep 4, 2009 / By David Edwards
Welcome to the 160th edition of Log Buffer, the weekly review of database blogs.
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.
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.”
From Planet Geek! came a fix for a OSX Snow Leopard MySQL startup problem.
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.”
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.
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.
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.
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.”
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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