Ever get called out for a MySQL issue only to realize that there was no issue?  It was a false alarm from the monitor.  We sure have and it’s frustrating, especially at 3:00 or 4:00 in the morning!

Many DBAs work in an environment where there is some sort of first level support that gets assigned tickets first.  Unfortunately, many of the times these groups are, shall we say, less than skilled in MySQL.  As a result, they quickly escalate the ticket onto the primary on-call DBA, even when there is really nothing wrong.

Much of the time, there are multiple types of MySQL topology in these environments: standalone, galera cluster, replication, etc.  Writing large runbooks with detailed test cases can be a daunting process and one that will cause many first-level support engineers to give up and simply escalate the issue anyway.

In an effort to avoid undue call outs, we developed a simple bash …

The MySQL server supports a variety of client connection methods. To summarize: you have TCP/IP (v4 and v6) on all OSes (with or without TLS/SSL encryption), Unix Domain Sockets on Unix/Linux, and Named Pipes and/or Shared Memory on Windows.

Each of these connection methods has its own set of pros and cons: speed, security, portability, and ease-of-use.…

Previous episodes:

• MySQL replication monitoring 101

MySQL replication in action - Part 1: GTID & CoMySQL replication in action - Part 2 - Fan-in topologyMySQL replication in action - Part 3 - All-masters P2P topologyMySQL replication in action - Part 4 - star and hybrid topologies
Parallel replication overviewOne …

In the theoretical part of this series, we have seen the basics of monitoring. In that article, though, we have barely mentioned the new tools available in MySQL 5.7 and MariaDB 10. Let’s start from something that has the potential of dramatically changing replication as we know it.
Crash-safe tables and Global transaction identifiers in MySQL 5.6 and 5.7Global transaction identifiers (GTID) is a feature that has been in my wish list for long time, since the times I was working with the MySQL team. By the time I left Oracle, this feature was not even in the plans.
When MySQL 5.6 was first disclosed, the biggest improvement for replication was the introduction of crash-safe tables (see Status persistence in …

Replication is the process that transfers data from an active master to a slave server, which reproduces the data stream to achieve, as best as possible, a faithful copy of the data in the master.

To check replication health, you may start with sampling the service, i.e. committing some Sentinel value in the master and retrieving it from the slave.

Sentinel data: Tap tap… Is this thing on?
If you want to make sure that replication is working, the easiest test is using replication itself to see if data is being copied across from the master to the slaves. The method is easy:

1. Make sure that the data you want to see is NOT in the master or in the slave. If you skip this step, you may think that replication is working, while in fact it may not.
2. Either create a table …

Performance Schema (PS) has been the subject of many, many recent discussions, presentations, and articles.  After its release in MySQL 5.7, PS has become the main actor for people who want to take the further steps in MySQL monitoring. At the same time, it has become clear that Oracle intends to make PS powerful with so many features and new instrumentation that old-style monitoring will begin to look like obsolete tools from the Stone Age.

This article will explain PS and provide guidance on what needs to be done in order to use it effectively.

What I am not going to do is to dig into specific performance issues or address polemics about what PS is and what, in a Utopian vision, it should be. I have seen too many presentations, articles and comments like this and they are not productive, nor are they in line with my target which is: keep people informed on how to do things EASILY.

For the scope of this …

Itchy Ninja Software is pleased to announce the release of Analyst for MySQL v1.1. Revolutionize the way you work and administrate MySQL, MariaDB, Galera, and Percona XtraDB installations.

Make More Efficient Use of Your Time

Gathering all of the metrics to diagnose a database installation is a very time consuming process, and many simply do not have the experience to know where to begin. With Analyst for MySQL, you will be able to get your hands on hundreds of metrics within moments. It really takes all of the guesswork, as well as tedious long sessions of writing queries out of managing a MySQL database server.

Cross-Platform

Not only can you run the program on Windows, Mac, or Linux, you can also generate server reports from each of those platforms as well! No need to install anything on the server at any time. All diagnostics are run from your laptop or desktop machine. The …

On servers that are into the swap file and have multiple processes running, I often wonder if it’s MySQL that is in the swap or some other process.  With Linux this is a fairly easy thing to figure out.  Below is the format of a command to do just that:

echo 0 $(cat /proc/`pidof process`/smaps | grep TYPE | awk '{print $2}' | sed 's#^#+#') | bc

In the above command, TYPE refers to what type of Memory you want to examine.  Below are some of the options for this value:

In my previous post, I talked about implementing multi-threaded replication (MTR) using Percona Server 5.6. The server pairs that are utilizing MTR are also exclusively using the TokuDB storage engine.

I find TokuDB to be a fascinating engine. I can tell I will need to re-watch our Dbhangops session where Tim Callaghan talked about the differences between B-Tree and Fractal Tree indexes. There’s also a session on how compression works in …

Some time back, when a client wanted us to setup MySQL Enterprise Monitor, we were surprised to find out that disk monitoring was not available! We worked hard to come up with a solution. Eventually, we decided to setup a custom agent to monitor the disk. Below is the result of that.

While this script may not work as-is for everyone, it should at least provide a basis for such a script. This script has been modified to send an email instead of plug directly into the MySQL Enterprise Monitor. But, it hopefully will get our creative juices flowing…

#!/bin/bash
#
# This script does a very simple test for checking disk space.
#
# Itchy Ninja Software: http://www.itchyninja.com
#

CHECKDISK=`df -h | awk '{print $5}' | grep % | grep -v Use | sort -n | tail -1 | cut -d "%" -f1 -`
ALERT_VALUE="80"
MAIL_USER="root@localhost.com"
MAIL_SUBJECT="Daily Disk Check"

if [ "$CHECKDISK" -ge "$ALERT_VALUE" ]; then
echo "At least one of my disks is nearly …