In this blog post, we’ll look at a solving Sudoku using MySQL 8.0 recursive common table expression.

Vadim was recently having a little Saturday morning fun solving Sudoku using MySQL 8. The whole idea comes from SQLite, where Richard Hipp has come up with some outlandish recursive query examples — WITH clause.

The SQLite query:

WITH RECURSIVE
 input(sud) AS (
   VALUES('53..7....6..195....98....6.8...6...34..8.3..17...2...6.6....28....419..5....8..79')
 ),
 digits(z, lp) AS (
   VALUES('1', 1)
   UNION ALL SELECT
   CAST(lp+1 AS TEXT), lp+1 FROM digits WHERE lp<9
 ),
 x(s, ind) AS (
   SELECT sud, instr(sud, '.') FROM input
   UNION ALL
   SELECT …

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Beyond spending time getting ready for Velocity and Open Source Summit Europe this week, there was some feature testing this week that compared MySQL and MariaDB. Naturally, a long report/blog is coming soon. Stay tuned.

Releases

I reckon a lot of folks are swamped after Percona Live Europe Dublin and Oracle OpenWorld, so the releases in the MySQL universe are a bit quieter.

• Percona Monitoring and Management 1.3.2. Fixes around Query Analytics
• …

One for the road…

The social events at Percona Live Europe provide the community with more time to catch up with old friends and make new contacts. The formal sessions provided lots of opportunities for exchanging notes, experiences and ideas. Lunches and coffee breaks proved to be busy too. Even so, what’s better than chilling out over a beer or two (we were in Dublin after all) and enjoying the city nightlife in good company?

Percona Live Europe made it easy for us to get together each evening.  A welcome reception (after tutorials) at Sinnott’s Pub in the heart of the City hosted a lively crowd. The Community Dinner at the Mercantile Bar, another lively city center hostelry, was a sell-out. While our closing reception was held at the conference venue, which had proven to be an excellent base. 

Many delegates took the chance to enjoy the best of Dublin’s hospitality late into the night. It’s …

In this blog, I’ll use ClickHouse and Tabix to look at a new very large dataset for research.

It is hard to come across interesting datasets, especially a big one (and by big I mean one billion rows or more). Before, I’ve used on-time airline performance available from BUREAU OF TRANSPORTATION STATISTICS. Another recent example is NYC Taxi and Uber Trips data, with over one billion records.

However, today I wanted to mention an interesting dataset I found recently that has been available since 2015. This is Reddit’s comments and submissions dataset, made possible thanks to Reddit’s generous API. The …

In my previous blog post, I talked about new general tablespaces in MySQL 8.0. Recently MySQL 8.0.3-rc was released, which includes a new data dictionary. My goal is to create one million tables in MySQL and test the performance.

Background questions

Q: Why million tables in MySQL? Is it even realistic? How does this happen?

Usually, millions of tables in MySQL is a result of “a schema per customer” Software as a Service (SaaS) approach. For the purposes of customer data isolation (security) and logical data partitioning (performance), each “customer” has a dedicated schema. You can think of a WordPress hosting service (or any CMS based hosting) where each …

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Percona Live Europe 2017 Dublin

We’ve spent a lot of time in the last few months organizing Percona Live Europe Dublin. I want to thank all the speakers, sponsors and attendees for helping us to pull off yet another great event. While we’ll provide some perspectives, thoughts and feedback soon, all the early mornings, jam-packed meetings and the 4 am bedtimes means I’ll probably talk about this event in my next column!

In the meantime, save the date for …

Day one of the Percona Live Europe Conference was a huge hit. The first day of sessions went well. People spoke on many different open source database topics, and talks were well-attended.

One such talk I got to sit in was on Spatial Data in MySQL 8.0, given by Norvald Ryeng of Oracle.

MySQL 8.0 is still in development, but we already see a lot of improvement in GIS support. The latest development release comes with support for around 5000 different spatial reference systems, improved standard compliance and a lot of new functionality. How does it all work, and how can it be used to build applications? 

This talk started with the basics of GIS and spatial data in MySQL: geometries, data types, …

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

We are five weeks out to the conference! The tutorials and the sessions have been released, and there’s an added bonus – you can now look at all this in a grid view: tutorials, day one and day two. Now that you can visualize what’s being offered, don’t forget to register.

If you want a discount code, feel free to email me at …

TL;DR: unless you know what you are doing, you should always have a primary key on your tables when replicating in RBR (and maybe even all the time).

TL;DR2: MariaDB 10.1 has an interesting way to protect against missing a primary key (innodb_force_primary_key) but it could be improved.

A few weeks ago, I was called off hours because replication delay on all the slaves from a replication chain

In recent months, there had been some really exciting news from the MySQL team: (Recursive) Common Table Expressions in MySQL Introducing Window Functions These two SQL standard language features are among the most powerful SQL features that are available from most other databases. I frequently include them in conference talks about SQL (see my article … Continue reading jOOQ 3.10 Supports Exciting MySQL 8.0 Features →