Mark Callaghan over at Facebook wrote a note recently about InnoDB disk IO counters in SHOW STATUS, with some extra things that he wanted to track. I posted a quick comment over there, but I thought this deserved it’s own write up.

MySQL 5.5’s PERFORMANCE_SCHEMA has had a fair bit written about it in terms of tracking synchronization point contention (mutexes etc.), but it currently tracks two orders within the wait class - these are /wait/synch and /wait/io.

Actually, allow me to detour first, it’s not clear from the documentation, though it is clear in the worklog. Each …

The UK Oracle User Group (UKOUG) is an independent non-profit organisation of users of Oracle products in the UK, which organizes over 80 events per year all across the UK and Ireland. They have more that 15.000 members and were established over 25 years ago. Currently, they are in the final stretch of the preparations for their annual Technology & E-Business Conference, which will take place from November, 29th - December, 1st in Birmingham (UK).

For the first time, the conference will host a dedicated stream of presentations related to MySQL, which is scheduled for Wednesday (Dec. 1st). Targeted at database administrators, developers as well as users new to MySQL, there will be presentations from well-known speakers and participants of the MySQL community as well …

Over the weekend I updated my Drupal 7 test appliance in SUSE Studio to the Drupal 7.0-beta2 release, which was released on Oct. 23rd. I also added phpMyAdmin upon a user request, to provide a web-based method to work with the MySQL instance, if needed.

In addition to the lightweight "headless" appliance (which can only be accessed and configured via a remote network connection), I've now also created a GUI-based version. This appliance starts a minimal GNOME desktop and a Mozilla Firefox browser, which in turn opens the …

During the MySQL Users Conference, Edward Screven did a keynote presentation that made many of us feel warm and fuzzy about Oracle's future plans for MySQL. If you advance 16m 25s into the presentation, it even gives something to rejoice the MySQL Enterprise customers: "Backup is now included". He didn't say much more after that. Asking around at the conference the days following this announcement, I couldn't get a straight answer about when and how would it be available for existing customers.

Now, 6 months later (give or take a couple of weeks), the MySQL Enterprise Features page has no signs of the now included MySQL Enterprise Backup (the utility previously known as InnoDB Hot Backup) and there has been no other news supporting Edward's announcement …

We just released the latest Drizzle tarball (2010-10-11 milestone). There are a whole bunch of bug fixes, but there are two things that are interesting from a storage engine point of view:

• The Innobase plugin is now based on innodb_plugin 1.0.6
• The embedded_innodb engine is now named HailDB and requires HailDB, it can no longer be built with embedded_innodb.

Those of you following Drizzle fairly closely have probably noticed that we’ve lagged behind in InnoDB versions. I’m actively working on fixing that – both for the innobase plugin and for the HailDB library.

If building the HailDB plugin (which is planned to replace the innobase plugin), you’ll need the latest …

While reading through the manual I ran across something I had totally forgotten about from the early MySQL days. Early on, Monty (or was it Jani?) decided to name many development servers variants of “bitch” in different languages. I have no idea what the back-story was, but maybe Monty or Jani can fill it in. All of these names live on all over the place, such as in the MySQL and InnoDB documentation, bug reports, and mailing list messages. See:

• bitch.mysql.fi — English, of course.
• hundin.mysql.fi — German
• hynda.mysql.fi — Swedish
• narttu.mysql.fi — …

Announced at MySQL Sunday was the Release Candidate edition of MySQL 5.5.6. Also noted by Geert where he points out the default storage engine is now InnoDB.

However, for those from a background other then MySQL there is still a gotcha.

mysql> show global variables like 'autocommit';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | ON    |
+---------------+-------+

Unlike Oracle for example, the default autocommit is on.

Doing some other boundary conditions, it is no longer possible to disable InnoDB on startup which you would of course expect.

$ bin/mysqld_safe --skip-innodb &
$ tail error.log

101003 15:33:32 [Note] Plugin 'InnoDB' is disabled.
101003 15:33:32 [ERROR] Unknown/unsupported storage engine: InnoDB
101003 15:33:32 [ERROR] Aborting

MyISAM however can’t be removed and …

Yes, I said InnoDB+ with a plus sign at the end (also see the first comment here).

Please note that this blog post is only based on public information. It has absolutely nothing in it that I only could have learned from back when I worked at Sun or MySQL AB. Everything has links or pointers to where you can find the information out on the Internet and all thoughts are based on stringing these things together.

There was a lot of talk around the acquisition of Sun Microsystems by Oracle about MySQL (MySQL AB was bought by Sun). Some of the talk centred around Oracle and their ability to make a closed source version of MySQL with added bits that wouldn’t …

Here is the comparison between mysql and postgresql for selects (only). I had used the same table that i had created earlier http://jayant7k.blogspot.com/2010/09/database-speed-tests-mysql-and.html while comparing insertion speed. I have created approximately 1,000,000 records in the table and ran selects on them. I also modified the configuration of both mysql and postgresql to enable faster

Update: Also read A brief update on NUMA and MySQL.

The “swap insanity” problem, in brief

When running MySQL on a large system (e.g., 64GB RAM and dual quad core CPUs) with a large InnoDB buffer pool (e.g., 48GB), over time, Linux decides to swap out potentially large amounts of memory, despite appearing1 to be under no real memory pressure. Monitoring reveals that at no time is the system in actual need of more memory than it has available; and memory isn’t leaking, mysqld‘s RSS is normal and stable.

Normally a tiny bit of swap usage could be OK (we’re really concerned about activity—swaps in and out), but in many cases, “real” useful memory is being swapped: primarily parts of InnoDB’s buffer pool. When it’s needed …