#DBHangOps 02/05/15 -- MySQL Event Scheduler, InnoDB IO Capacity, and more!

Hello everybody!

Join in #DBHangOps this Thursday, February, 5, 2015 at 11:00am pacific (18:00 GMT), to participate in the discussion about:

• Managing Multiple instance of MySQL

• MySQL Event Scheduler

  • What use cases do you have?
• What is everyone's understanding of innodb_io_capacity?

• Percona Live MySQL Conference and Expo 2015

  • What are you excited about?

You can check out the event page at https://plus.google.com/events/c50qple2vajgq6ltrutk1s3cfss on Thursday to participate.

As always, you can still watch the …

For some time already, FromDual's "Our Team" page lists me, and it even reveals that I joined in September, 2014. Also for some time, the list of FromDual blogs contains an entry "Jörg's Blog", but it doesn't lead to any entries. It is high time to fix this and create entries, starting with an introduction of myself.

Often, in such introductions people use the phrase of "the new kid on the block". I won't. If I am to use those words, I will arrange them as "the kid on the new block". The reason is that I don't feel as a new kid in the MySQL village (or is it a city?), let alone in DBMS country.

Ever since I left university (Technical University of Berlin, Germany), I have been involved in SQL DBMS development. After my previous product's team had been dissolved in Berlin and maintenance moved to Riga, Latvia, as a cost-cutting measure, I joined MySQL AB in 2004 as a member of the Build Team. Some of you will remember my name from …

A few days ago I wrote about MySQL performance implications of InnoDB isolation modes and I touched briefly upon the bizarre performance regression I found with InnoDB handling a large amount of versions for a single row. Today I wanted to look a bit deeper into the problem, which I also filed as a bug.

First I validated in which conditions the problem happens. It seems to happen only in REPEATABLE-READ isolation mode and only in case there is some hot rows which get many row versions during a benchmark run. For example the problem does NOT happen if I run sysbench with “uniform” distribution.

In terms of concurrent selects it also seems to require some very special conditions – you need to have the connection to let some …

On a recent consulting engagement, the PSCE team were charged with what can be considered a fairly common task of synchronising tables between master and slave in MySQL Replication. On this occasion the  schema contained both foreign key constraints and triggers, this post describes how we avoided the potential problems related to such an operation.

The process to synchronise tables in MySQL is to first identify the differences between tables and then execute queries which bring those tables into a consistent state. The first part of the process can be handled by the pt-table-checksum tool, which steps through the table analysing sets of rows (chunks) and recording a checksum value. Then taking advantage of replication, the same process occurs on each of the slaves and the checksums can then be compared. Once the entire table has been processed, a second tool pt-table-sync can be used …

Mon, 2015-01-19 10:46anatoliydimitrov

Nagios, one of the most popular hardware, network, and application monitoring tools, can also handle advanced MariaDB monitoring. With Nagios you can monitor the MariaDB server and its performance, as well as individual MariaDB databases and the information in them.

For this article I used the free Nagios Core, but the procedures I describe should be similar for the commercial version of Nagios and for Nagios derivatives such as Shinken.

Installation

To follow this article you should have some knowledge of Nagios and how it works. To get the most out of it you should have a Nagios server on which to practice. If you need help with getting started, check the …

Hi! Just to say I wrote this new post about only_full_group_by tricks, on the MySQL Server team's blog.

This is a story of intermittent 500 Internal Server errors from APIs, that ended up being caused by a hardcoded constant in Go’s database/sql package. I’ll mostly spare you the long-winded story, and get right to the problem and what we found to be the cause.

We noticed an increased number of 500 errors from specific API endpoints, and started to troubleshoot. We initially found something odd. When we retried a failed call, it would succeed sometimes. After a few minutes, we found that we could “fix” the problem pretty easily by simply CURL’ing a failed API call a couple of times. After that, it would succeed again and again.

This was puzzling for a moment, but then we realized that the call would fail again after leaving the API idle for a few moments. Meanwhile, another team member looked up the changes we’d made to that API at the time it started to fail. (We use …

Taxonomy upgrade extras: max_allowed_packetconnectionBackupRestoredump

We recently run into some troubles with max_allowed_packet size problems during backups with the FromDual Backup/Recovery Manager and thus I investigated a bit more in the symptoms of such problems.

Read more about: max_allowed_packet.

A general rule for …

MariaDB 10.1.2 was recently released, and is available for download here:

https://downloads.mariadb.org/mariadb/10.1.2/

This is the third alpha release of MariaDB 10.1, so there are still a lot of new changes, functionalities added, defaults changed, and many bugs fixed (I counted 117, which is *way* down from the 637 fixed in 10.1.1). Since it’s alpha, I’ll only cover the major changes and additions, and omit covering general bug fixes (feel free to browse them all here).

To me, these are the highlights of the new features:

• –mysql56-temporal-format option to use the MySQL-5.6 low level formats to store …

MariaDB 10.0.15 was recently released, and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.15/

This is the sixth GA release of MariaDB 10.0, and 16th overall release of MariaDB 10.0.

This release has an important InnoDB/XtraDB fix, a new addition, security enhancements (and improvement) – all related to yaSSL, so be sure to check out these fixes if you’re running MariaDB 10.0, and not up to 10.0.15 yet. (MariaDB 10.0 is the current stable series of MariaDB. It is an evolution of the MariaDB 5.5 with several entirely new features not found anywhere else and with backported and reimplemented features from MySQL 5.6.)

Here are the main items of note:

1. This release fixes a serious bug in InnoDB and XtraDB that sometimes could cause a hard lock up of the server ( …