The LZMA algorithm implemented by the xz compression software package is one of the compression algorithms used by TokuDB for MySQL and TokuMX for MongoDB.  Unfortunately, valgrind's memcheck reports an uninitialized variable problem in the …

This article is the second in a two-part series on upgrading MySQL.  The first article, Upgrade from 5.0 directly to 5.7 using mysqldump, discussed performing an upgrade using the mysqldump utility.  We call that a ‘Dump’ Upgrade.  In this article, we will discuss what we call an ‘In Place’ Upgrade, also known as a Binary Upgrade or a Live Upgrade.…

This article is continuing the MySQL 5.7 Performance story, started from 1.6M QPS details post, and followed by 1M QPS OLTP_RO article. However, the current story will not be mostly about MySQL 5.7, but also about announced on the same time MariaDB 10.1 GA ;-)

So far, MySQL Team was proud to show 1.6M QPS on Point-Select (SQL) queries, and MariaDB 10.1 GA announce was also claiming an ability to reach 1M QPS, also on Point-Selects, but on …

I personally have always enjoyed the Ubuntu Developer Summits (UDS), but nowadays they have been converted to the Ubuntu Online Summits (UOS). Attending them is not always convenient (timezone issues, might be travelling, etc.) so I watched the recorded video of a session I was interested in: MySQL & Variants in 16.04.

My key takeaways

1. Ubuntu 16.04 Xenial Xerus is an LTS release.
2. The term “cross-grade” is used a lot (it is not about downgrading/upgrading, but being able to use MySQL or MariaDB or Percona Server interchangeably)
3. It would be nice to see MySQL 5.7 in this release (for Xenial as well as Debian Stretch). From Oracle there is a new packager taking over the task (Lars)
4. MySQL 5.5 is still the default in Debian, and there needs to be upgrades tested between 5.5 to 5.7 (it looks …

Continuing on with the cloud theme, I think its worth noting that since mid-2014, Rackspace has offered MariaDB (as well as MySQL and Percona Server) in the cloud, as part of their Cloud Databases offering. It’s powered by OpenStack.

Now there is an additional “High Availability instance” being offered — this gives you up to two replicas per database instance, you have the ability to load balance reads across all replicas (pretty standard), but the cool thing to try out: failover is automatic. …

Percona is pleased to announce the availability of Percona Toolkit 2.2.16, released on November 9, 2015. Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or complex for DBAs to perform manually. Percona Toolkit, like all Percona software, is free and open source.

This release is the current GA (Generally Available) stable release in the 2.2 series. It includes new features and bug fixes as well as continued preparation for MySQL 5.7 compatibility. Full details are below. Downloads are available here and …

During the MySQL 5.8 Dreaming and brainstorming session at PerconaLive, someone voiced a wish for an “option to make temporary tables created by the optimizer always go to disk”. By default, MySQL creates in-memory temporary tables in the MEMORY engine. The maximum size for in-memory temporary tables is the minimum of the tmp_table_size and max_heap_table_size.…

Edit1: With updates in SQLyog 12.1.9 and 12.2.0, SQLyog is now fully safe with Virtual Columns of both MariaDB and MySQL 5.7 (all SQLyog backup-, copy- and sync-tools).

Edit2: There are still problems with mysqldump as of 5.7.11 – refer http://bugs.mysql.com/bug.php?id=80790. I do think it was OK in 5.7.9 so this looks like a regression introduced in 5.7.10 or 5.7.11. But  I may be wrong here. 

Virtual columns have existed in MariaDB since version 5.2 and were recently introduced in MySQL 5.7. The recent MySQL 5.7.9 GA release includes this feature.

At first look the implementations in MariaDB and Oracle/MySQL do not seem much different. If you compare documentation …

Edit1: With updates in SQLyog 12.1.9 and 12.2.0, SQLyog is now fully safe with Virtual Columns of both MariaDB and MySQL 5.7 (all SQLyog backup-, copy- and sync-tools).

Edit2: There are still problems with mysqldump as of 5.7.11 – refer http://bugs.mysql.com/bug.php?id=80790. I do think it was OK in 5.7.9 so this looks like a regression introduced in 5.7.10 or 5.7.11. But  I may be wrong here. 

Virtual columns have existed in MariaDB since version 5.2 and were recently introduced in MySQL 5.7. The recent MySQL 5.7.9 GA release includes this feature.

At first look the implementations in MariaDB and Oracle/MySQL do not seem much different. If you compare documentation …

The "innodb_read_only" parameter is perhaps not among the most commonly used MySQL parameters. It may however influence server behaviour in a way that you may not expect. This post is a record of an investigation that revealed one of MySQL quirks caused by said parameter.
Background The MySQL 5.6 server topology I was looking at during this investigation consisted of a single main server (R/W) and multiple replicas serving read-only statements.
This is relatively simple and you wouldn't expect to run into issues on the replicas as long as you stick to statements that do not modify data, right?
Not quite. Issue I was asked to investigate can be described as follows:
The DBA created two tables connected using a foreign key relationship:

CREATE TABLE `employee` (
  `e_id` int(11) NOT …