I'm a big fan of common_schema. It's a really powerful and flexible tool, and I'm always looking for new ways to use it.

Last week I had to update millions of rows across many databases to tokenize some persisted URL values, and I remembered reading Baron Schwartz's recent blog post about using the common_schema split feature. Baron's use case was deleting data, but I figured this could work well to break my large updates into chunks too. I had already written the update statements I wanted to execute, and after five minutes reading the common_schema documentation I was ready to try it out on a dev database.

One …

I'm a big fan of common_schema. It's a really powerful and flexible tool, and I'm always looking for new ways to use it.

Last week I had to update millions of rows across many databases to tokenize some persisted URL values, and I remembered reading Baron Schwartz's recent blog post about using the common_schema split feature. Baron's use case was deleting data, but I figured this could work well to break my large updates into chunks too. I had already written the update statements I wanted to execute, and after five minutes reading the common_schema documentation I was ready to try it out on a dev database.

One …

With real possibilities and opportunities, blogging is getting mature day by day, and so is the technology and its innovations. The combination of both becomes a dazzling medley, which is called as Log Buffer. Enjoy this week’s stunning Log Buffer #311.

Oracle:

Sudip Datta is writing about database as a service.

Premature optimization, (probably) because of Donald Knuth’s famous line “premature optimization is the root of all evil,” (see Structured Programming with go to Statements) is, at the very least, a controversial topic.

Are you using the application server that best serves your changing business needs? Maybe it’s time to consider an upgrade? Suggested by …

With MySQL 5.5 the default storage engine was changed to InnoDB. This was a good step as most users expected MySQL to support transactions, row level locking and all the other InnoDB features, but with 5.1 they sometimes forgot to choose the right storage engine. As most databases don't have multiple storage engines and many MySQL users changed the default storage engine to InnoDB this made the switch to MySQL easier and the default behaviour more in line with what people expect from a relational database.

Changing the storage engine can of course be done on a per table or per instance basis (default-storage-engine in my.cnf). The temporary tables created with 'CREATE TEMPORARY TABLE ...' should not be forgotten. The performance of InnoDB or MyISAM for temporary tables can have quite some impact, especially with slow storage, a buffer pool which is too small to hold the complete dataset or very small temporary tables. In MySQL 5.6 …

Take the MySQL and PHP - Developing Dynamic Web Applications course to learn to develop applications in PHP and how to use MySQL for those applications. This 4-day class helps you improve your PHP skills and combine them with time-proven database management techniques to create best-of-breed web applications that are efficient, solid and secure.

You can take this live instructor-led course as a:

• Live-virtual event: Take this class from your own desk, choosing from many events on the schedule to suit different time-zones.
• In-class: Travel to an education center. Some events already on the schedule include:

This is the current (and supposed to be the last) MONyog release in the 5.5x series.  Refer online documentation for details of changes in this and previous releases.  The major scope of all releases in 5.5x series has been improving stability, performance and responsiveness under heavy load -  such as large number of servers both registered and displayed at the same time, user activity by multiple users at the same time, ‘query sniffer’ running in the background etc.  We have worked with a number of customers using MONyog in such demanding environments during the 5.5x development phase.

Changes in this 5.57 release (as compared to 5.56) include:

Bug fixes:
* The rendering of Monitors and Dashboard …

Jaime at the MySQL Performance Blog had an interesting post regarding some unexpected behavior from the MySQL optimizer.  Although this particular case probably doesn't affect most people, it does give some insight into how the optimizer works, and how subtle changes to a query can change performance.

Jaime at the MySQL Performance Blog had an interesting post regarding some unexpected behavior from the MySQL optimizer.  Although this particular case probably doesn’t affect most people, it does give some insight into how the optimizer works, and how subtle changes to a query can change performance.

For this post I’m going to shamelessly exploit the litany of technical problems SimCity players encountered earlier this month and a few examples of how Thread Pool for MySQL and Percona Server for MySQL can help to prevent such incidents.

Users of SimCity, a city-building and urban planning simulation video game, encountered network outages, issues with saving progress and problems connecting to the game’s servers following a new release a couple of weeks ago featuring a new engine allowing for more detailed simulation than previous games. During this same time, we happened to be testing the Thread Pool feature in Percona Server for MySQL, and I saw a connection of how Thread Pool is supposed to help in such cases.

Basically SimCity users faced the same situation …

I just wrote an article about “Troubleshooting ‘Waiting for table metadata lock’ Errors for both MyISAM and InnoDB Tables” and then ran into a new, different metadata locking issue right after I posted it, and so I thought I’d share that too, just in case anyone ever encounters a similar situation.

In this case, mysqld kept crashing on restart, reporting “out of memory” errors:

/opt/app/mysql/product/mysql/bin//mysqld: Out of memory (Needed 840 bytes)
stack_bottom = 7fb4ebaeae58 thread_stack 0x40000
mysqld: /mysql/mysys/my_new.cc:52: int __cxa_pure_virtual():
  Assertion `! "Aborted: pure virtual method called."' failed.
mysqld: /mysql/mysys/my_new.cc:52: int __cxa_pure_virtual():
  Assertion `! "Aborted: pure virtual method called."' failed.
Fatal signal 6 while backtracing

There is a …