MySQL replication isn’t perfect and sometimes our data gets out of sync, either by a failure in replication or human intervention. We are all familiar with Percona Toolkit’s pt-table-checksum and pt-table-sync to help us check and fix data inconsistencies – but imagine the following scenario where we mix regular replication with the Tungsten Replicator:

We have regular replication going from master (db1) to 4 slaves (db2, db3, db4 and db5), but also we find that db3 is also master of db4 and db5 using Tungsten replication for 1 database called test. This setup is currently working this way because it was deployed some time ago when multi-source replication was not possible using regular MySQL replication. This is now a working feature in …

An idea for a benchmark based on the “arrival request” rate that I wrote about in a post headlined “Introducing new type of benchmark” back in 2012 was implemented in Sysbench. However, Sysbench provides only a simple workload, so to be able to compare InnoDB with TokuDB, and later MongoDB with Percona TokuMX, I wanted to use more complicated scenarios. (Both TokuDB and TokuMX are part of Percona’s product line, in the case you missed Tokutek now part of the Percona family.)

Thanks to Facebook – they provide LinkBench, a benchmark that emulates the social graph …

Download MariaDB 5.5.43

Release Notes Changelog What is MariaDB 5.5?

MariaDB APT and YUM Repository Configuration Generator

The MariaDB project is pleased to announce the immediate availability of MariaDB 5.5.43. This is a Stable (GA) release.

See the Release Notes and …

This article is a part of our Rockstar DBA initiative, a platform for thought leaders to share their knowledge and make a positive contribution towards the database management community.

Manojit Paul, with more than 19 years of professional DBA experience in enterprise database solutions, especially Sybase product set and database infrastructure is our first Rockstar DBA.

Let’s hear from Manojit about how he manages MySQL databases, why he loves MONyog, his advice to young DBA’s and more.

How do you manage your MySQL databases?
We presently have 9 MySQL servers in production trading environment, all being managed via a host of automated scripts which I’ve created and manual intervention when issues are reported. We deploy MONyog for managing 5 of these critical MySQL instances. …

There are tools like pt-kill from the percona tool kit that may print/kill the long running transactions at MariaDB, MySQL or at Percona data instances, but a lot of backup scripts are just some simple bash lines.
So checking for long running transactions before the backup to be executed seems to be a step that is missed a lot.

Here is one line that might be just added in every bash script before the backup to be executed
Variant 1. Just log all the processlist entries and calculate which ones were running longer than TIMELIMIT:

$ export TIMELIMIT=70 && echo "$(date) : check for long runnig queries start:" >> /tmp/processlist.list.to.kill && mysql -BN -e 'show processlist;' | tee -a /tmp/processlist.list.to.kill | awk -vlongtime=${TIMELIMIT} '($6>longtime){print "kill "$1";"}' | tee -a /tmp/processlist.list.to.kill

Variant 2: Log all the processlist, calculate the calculate which processes are …

In version MySQL 5.7.7 Oracle presented a new promising feature: optimizer hints. However it did not publish any documentation about the hints. The only note which I found in the user manual about the hints is:

• It is now possible to provide hints to the optimizer by including /*+ ... */ comments following the SELECT, INSERT, REPLACE, …

Today, oCERT published advisory 2015-003 describing a TLS vulnerability in MySQL and derivative products.  The content isn’t exactly news – it is documented legacy behavior and the subject of an earlier blog post describing how MySQL Server 5.7 solves the problem.  That said, the efforts of Duo Security are certainly appreciated and welcomed – it provides a meaningful context to discuss how to properly harden existing MySQL 5.5 and 5.6 deployments, as well as frame a discussion on potential changes in these versions to increase security.

Vulnerability

The vulnerability described in the advisory relies on the legacy behavior of the client …

A few days ago I wrote up my thoughts about the Percona acquisition of Tokutek with respect to TokuDB. In this blog I'm going to do the same for TokuMX and TokuMXse. And in a few days I'll wrap up this trilogy by sharing my thoughts about Fractal Tree Indexes.

Again, when I'm writing up something that I was very involved with in the past I think it's important to disclose that I worked at Tokutek for 3.5 years (08/2011 - 01/2015) as VP/Engineering and I do not have any equity in Tokutek or Percona.

Since much of the MySQL crowd might be hearing about Tokutek's "other products" for the first time I'll provide a little history of both of the products before I dive in deeper.

TokuMX is a fork of MongoDB …

About 2 weeks ago Oracle published the MySQL 5.7.7-labs-json version which includes a very interesting feature called “Generated columns” (also know as Virtual or Computed columns). MariaDB has a similar feature as well: Virtual (Computed) Columns.

The idea is very simple: if we store a column

`FlightDate` date

in our table we may want to filter or group by year(FlightDate), month(FlightDate) or even dayofweek(FlightDate). The “brute-force” approach: use the above Date and Time MySQL functions in the query; however it will prevent MySQL from using an index (see below). Generated columns will allow you to declare a “Virtual”, non-stored column …

Introduction

Systemd is a management and configuration platform available in all major Linux distributions. It provides infrastructure for service start, stop, restart and several other novel functionalities to manage services. Systemd replaces SysV and upstart initialization systems and is the default init system in most modern Linux distributions including Red Hat Enterprise Linux, Oracle Linux, Debian, Ubuntu, Fedora, SLES and openSUSE.

Preliminary support for systemd was introduced in earlier versions of MySQL. However, it had the following limitations and disadvantages:

1. Use of ping tricks to check whether mysqld is ready to serve client connections.
2. Though systemd had superior process control for automatic restarts, mysqld_safe was still used to identify abnormal mysqld termination and do automatic restarts.
…