I vividly remember 2004 when I decided to specialize in MySQL because the year before I was homeless and living in my car. It’s been a long road and an amazing journey ever since.

A relational database is more than a data bank, it’s a profound philosophical expression. This is the second and final part of “Lessons From 20 Years Hacking MySQL”.

PS_history is a tool which collects historical snapshots of the PERFORMANCE_SCHEMA (P_S). This allows you to trend P_S values over time, for example, it is possible to look at the 95 th percentile response time for a query over time.

PS_history is stored procedure and event based, and thus it resides entirely inside of the database with no external dependencies. It uses a clever technique to capture all of the P_S data in one consistent snapshot. This ensures that all of the sys_history views (bundled now with PS_history) have a consistent set of data.

By default, as long as the event_schedule is enabled, PS_history will collect data every 30 seconds. If a snapshot takes 30 seconds, there will be a 30 second delay before the next snapshot starts. This value can be changed by calling the `ps_history`.`set_collection_interval`(N) where N is the number of seconds between samples.

The `sys_history` schema is …

PS_history is a tool which collects historical snapshots of the PERFORMANCE_SCHEMA (P_S). This allows you to trend P_S values over time, for example, it is possible to look at the 95 th percentile response time for a query over time.

PS_history is stored procedure and event based, and thus it resides entirely inside of the database with no external dependencies. It uses a clever technique to capture all of the P_S data in one consistent snapshot. This ensures that all of the sys_history views (bundled now with PS_history) have a consistent set of data.

By default, as long as the event_schedule is enabled, PS_history will collect data every 30 seconds. If a snapshot takes 30 seconds, there will be a 30 second delay before the next snapshot starts. This value can be changed by calling the `ps_history`.`set_collection_interval`(N) where N is the number of seconds between samples.

The `sys_history` schema is …

See Part 1 and Part 2.

We rejoin our story with a lawsuit. While MySQL suing Progress NuSphere is not perhaps the first GPL lawsuit that comes to mind, it was the first time that the GPL was tested in court. Basically, the GEMINI storage engine was a proprietary storage engine bundled with a copy of MySQL. Guess what? The GPL was found to be valid and GEMINI was eventually GPLed, and it didn’t really go anywhere after that. Why? Probably some business reasons and also, InnoDB was actually rather good and there wasn’t a lawsuit to enforce the GPL there, making business relationships remarkably easier.

In 2003 there was a second round of VC funding. The development team increased …

You can watch the video of my linux.conf.au 2014 talk here: http://mirror.linux.org.au/linux.conf.au/2014/Wednesday/28-Past_Present_and_future_of_MySQL_and_variants_-_Stewart_Smith.mp4

But let’s talk about things in blog form rather than video form :)

Back in 1979, there was UNIREG. A text UI to records (rows) in a database (err, table). The reason I mention UNIREG is that it had FoRMs which as you may have guessed by my capitalization there is where the FRM file comes from.

In 1986, UNIREG came to UNIX. That’s right kids, the 80×24 VT100 interface to ISAM (Index Sequential Access Method – basically rows are written in insert order and indexes point to them) came to UNIX. There was no generic query language, just FoRMs and reports. In fact, to this day, that …

MySQL has a long history since its birth 18 years ago when Monty Widenius and David Axmark started it. Planet MySQL started in 2004 and all its history is archived.  Let us dig in it. It is always good to look back at the past to get some lessons for the future. Here are the [...]

When the mysql librarian closed, I didn’t think too much about it; it was a feature I probably never used. However this month brings the end of the mysql forge. The MySQL Forge was something I worked on while I was at MySQL so I am a little sad to see it go. 

Now for a little bit of a history lesson. We wanted some kind of “forge” back in 2005, because sourceforge was all the rage then (today, you can’t even find mariadb or mongodb listed there). We didn’t want to pay the exorbitant fees associated with sourceforge, so we investigated …

A special extended edition of Tech Messages for 2011-01-07 through 2011-01-08:

• The Services Used By Y Combinator Startups [Infographic] – ReadWriteCloud
  "The results show that the majority of Y Combinator startups depend on cloud services instead of self-hosted servers, traditional web hosting or co-location services."
• Tom Limoncelli on Time Management | O'Reilly Time Management for System Administrators | Sysadmins
  Video companions to to Time Management for System Administrators by Thomas A. Limoncelli.
• Guidelines …

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 …