Todd's MySQL Blog

Tiny tidbits of trivia from Todd

14 May 2013
2 Comments

How to tell whether MySQL Server uses yaSSL or OpenSSL

Starting with MySQL 5.6, MySQL commercial-license builds use OpenSSL.  yaSSL – previously used as the default SSL library for all builds – remains the implementation for Community (GPL) builds, and users comfortable building from source can choose to build with OpenSSL instead.  Daniel van Eeden recently requested a global variable to indicate which SSL library was used to compile the server (bug#69226), and it’s a good request.  It’s something I’ve previously requested as well, having been fooled by the use of have_openssl as a synonym for have_ssl (I’m sure it made sense at the time, right?).  Read more…

Posted in MySQL and tagged , ,
13 May 2013
2 Comments

MySQL 5.6 general query log behavior change

The MySQL general query log can be a useful debugging tool, showing commands received from clients.  In versions through MySQL 5.5, you could count on the GQL to log every command it received – the logging happened before parsing.  That can be helpful – for example, the GQL entries might have records of somebody unsuccessfully attempting to exploit SQL injection vulnerabilities that result in syntax exceptions.

Here’s a sample, which I’ll run in both 5.5 and 5.6 and show the resulting GQL: Read more…

Posted in MySQL and tagged , ,
10 May 2013

Connector/J 5.1.25 Released

MySQL Connector/J 5.1.25 has been released, and is available in Community and Enterprise flavors on dev.mysql.com and My Oracle Support, respectively.  I’ve already noted the addition of support for connection attributes for MySQL 5.6 – 5.1.25 adds this functionality.  This release also includes a fix for Bug#68733, which caused the special light-weight ping operation to execute only against the master and currently-selected slave, rather than the master plus all active slave connections.  The ping operation exists to help ensure connections aren’t left idle for excessive durations in the internal load-balancing and replication “pools”, so failure to ping *all* active slave connections will make CommunicationFailureExceptions more likely after a rebalance operation selects a non-active, long-idle physical connection.  This bug was found by Dominic Tootell and reported via the community forums in a wonderfully-researched post.  It’s a great example of the type of community feedback and interaction that helps improve MySQL quality – thanks for the great contribution, Dominic!

In working through the bug Dominic reported, I found a couple other small bugs to fix.  The first is Bug#68763, which caused ReplicationConnection.isMasterConnection() to incorrectly always report false.  The second (Bug#68664) was an Ant build script bug which caused builds in Eclipse to produce a .JAR file – but it contained no .class files.  Our standard builds are done from the Ant script rather than Eclipse, and I’ve typically worked around it by running Ant from the command-line when I needed to package (compiling has worked in Eclipse for some time thanks to Mark Matthews, just not packaging).  Now you can package a .JAR file without leaving Eclipse.  In another bug report, Alex Soklakov fixed Bug#68801, making Connector/J play nicely with Maven.

I hope you enjoy Connector/J 5.1.25!

Posted in Java, MySQL and tagged , , , , | Leave a Comment
22 Apr 2013

My Oracle Support 6.5: Key new features

If you are a MySQL support customer, the recent release of My Oracle Support (MOS) 6.5 has some features which may interest you (if you’re not a customer, this post likely won’t interest you). MOS 6.5 was introduced on 06 April, and with it came the ability to opt in to receive service request (SR) update details via email. This was a feature some MySQL Support customers missed after the migration to MOS. Thanks to feedback from MySQL Support customers and others with similar needs, this feature has now been implemented. Because email is an inherently insecure delivery mechanism, not all customers will wan this, and the feature requires customers to explicitly opt in before SR update content is sent via email.  Coupled with the MOS Mobile interface, Support customers have a number of flexible ways to access and manage SRs.

The second major enhancement is the ability to participate in live chat with support staff via MOS. You can set your availability flag in MOS, and a support engineer can see your status to initiate a chat, if needed. For me, chats are better than emails when interaction is more “conversational”, and better than phone calls when specific instructions or diagnostic information needs to be shared.

If either of these new features interest you, Chris Warticki’s blog post or the actual release notes for MOS 6.5 are good references for more information.

Thanks again to MySQL Support customers who advocated for these features – Oracle is listening, and your efforts improve the support experience for all Oracle support customers.

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22 Apr 2013
1 Comment

Fresh dogfood: Migrating to InnoDB fulltext search on bugs.mysql.com

Even frequent visitors to bugs.mysql.com can sometimes miss the little note in the bottom right corner of each page:

Page generated in 0.017 sec. using MySQL 5.6.11-enterprise-commercial-advanced-log

That text changed this past weekend, going from MySQL Enterprise 5.6.10 to 5.6.11.  But more importantly, the collection of MyISAM tables which support the bugs system were also converted to InnoDB.  There’s a little story to tell here about eating this particular helping of dogfood which also amplifies changelog comments, so here it is:
Read more…

Posted in MySQL and tagged , , ,
19 Apr 2013
9 Comments

Spring cleaning: Useless clients and programs

Stewart Smith recently questioned the current relevance of the MERGE storage engine, and it prompted me to finish a similar recent exercise I’ve been thinking about related to MySQL clients (UPDATE: and programs).  This originally came up when I listed the contents of the MySQL bin directory:

Read more…

Posted in MySQL and tagged , ,
18 Apr 2013
2 Comments

Not-so-light reading: 5.6.11 changelog

Looking for some substantial reading material as the days grow longer?  You might consider dedicating a good chunk of time to review the MySQL 5.6.11 changelog.  The MySQL Engineering team at Oracle has been busy, and it shows in this maintenance release.  Stewart Smith recently noted the growth of the code base in 5.6 compared to 5.5.  That may or may not be the best measure of productivity, but the number of fixed bugs in a maintenance release like 5.6.11 is sure a good indicator.  A few general observations based on my quick study: Read more…

Posted in MySQL and tagged ,
09 Apr 2013

MySQL Utilities meets the world’s ugliest table

In case you missed it, MySQL Utilities 1.3.0 (alpha) was released last week.  MySQL Utilities is a component of MySQL Workbench, but it’s been broken out into a separate download allowing command-line users access unencumbered by a pretty GUI interface.  Plus, it has some new features – most importantly to me, a utility (mysqlfrm) which can read .FRM files and produce CREATE TABLE statements as a result.  This will be very useful for recovery processes, in conjunction with InnoDB transportable tablespaces in situations where the InnoDB system tablespace is corrupted, and you don’t know the exact table definition.

When we first started testing the FRM reader, it didn’t bootstrap mysqld to decipher .FRM file contents – Chuck Bell spent hours staring into the abyss that is FRM file formats and trying to shed light in the many dark corners that exist.  We started with simple tests, like:  can it read all the .FRM files in the data/mysql directory?  Then I hacked a quick program that created tables with many different data types, modifiers and variants.  But these tests were all dwarfed by the contribution of my colleague and bug-finder extraordinaire, Shane Bester, who gave us what may well be the world’s ugliest table.  Behold:

Read more…

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08 Apr 2013

Last week to submit for MySQL Connect!

The Call for Papers for MySQL Connect 2013 will close this Friday.  This is the premier Oracle-sponsored MySQL conference, and a great opportunity for community users and customers alike to connect with Oracle staff from engineering, support, consulting and other organizations, as well as community partners and peers.  Maybe you’d like to talk about your experiences integrating one of the new MySQL 5.6 features.  Or maybe you’d like to share best practices you’ve developed for integrating with Hadoop.  Perhaps you’ve extended MySQL and want to tell the community about it.  Take advantage of this opportunity and submit your proposal this week!

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26 Mar 2013

Connection attributes in MySQL 5.6

Introduced in 5.6.6, connection attributes haven’t been mentioned in any of the many overviews of new 5.6 features that I’ve seen.  You might not have even known they exist – there’s not really a “feature page” in the documentation that tells you what this is all about.  The best documentation is found in the description of the PERFORMANCE_SCHEMA tables which expose these connection attributes:

As of MySQL 5.6.6, application programs can provide key/value connection attributes to be passed to the server at connect time, using the mysql_options() and mysql_options4() C API functions. The Performance Schema provides tables that expose this information through SQL statements[.]

Here’s what that means in practice:  With connectors which support this feature, certain client information can be exposed via PERFORMANCE_SCHEMA tables, making it easier to get useful information about clients from the MySQL Server directly.
Read more…

Posted in Java, MySQL | Leave a Comment

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