Welcome to the first Percona Live Europe featured talk with Percona Live Europe 2016: Amsterdam speakers! In this series of blogs, we’ll highlight some of the speakers that will be at this year’s conference. We’ll also discuss the technologies and outlooks of the speakers themselves. Make sure to read to the end to get a special Percona Live Europe registration bonus!

In this Percona Live Europe featured talk, we’ll meet Krzysztof Książek, Senior Support Engineer at Severalnines AB. His talk will be on MySQL Load Balancers – MaxScale, ProxySQL, HAProxy, MySQL Router & nginx: a close up …

Introduction

This is part three of a five part blog series to explore InnoDB internals by looking at the related tunable system variables. In part 2 we covered variables that had the greatest impact on the file structure of InnoDB as well as how data is written to logs. In this section we will continue looking at I/O but more specifically looking at the mechanics on how data gets written to table files as well as how background threads read from them.

Just like in part two, I would like to emphasize something that was written in part one of this blog post series.

“I should note that while tuning recommendations are provided, this objective of this blog post series was NOT meant to be a tuning primer, but instead to explore the mechanics that each variable interacts with. As such I would …

Introducing PostgreSQL Day at Percona Live Europe, Amsterdam 2016.

As modern open source database deployments change, often including more than just a single open source database, Percona Live has also changed. We changed our model from being a purely MySQL-focused conference (with variants) to include a significant amount of MongoDB content. We’ve also expanded our overview of the open source database landscape and included introductory talks on many other technologies. These included practices we commonly see used in the world, and new up and coming solutions we think show promise.

In getting Percona Live Europe 2016 ready, something unexpected happened: we noticed the PostgreSQL …

Welcome to this week’s Planets9s, covering all the latest resources and technologies we create around automation and management of open source database infrastructures.

Ever wanted to just look at QPS in real time while logged into your server?

Well here’s a little command line hackery to do it quick and dirty.

[user@yourserver ~] $ LASTVAL=0; while true; do CURVAL=`mysql --batch -N -e "show status like 'Quer%';" | awk '{print $2}'`; QPS=`expr $CURVAL - $LASTVAL`; if [ $LASTVAL -ne 0 ]; then echo "$CURVAL $QPS"; fi; LASTVAL=$CURVAL; sleep 1; done

The output looks like this:

65549603430 2439
65549605421 1991
65549606912 1491
65549611219 4307
65549614186 2967
65549618048 3862
65549620853 2805

The first column is just the Query counter value. The second column is the QPS.

This script requires a .my.cnf to exist in your home directory (or that you do something nastily insecure and supply -u user -ppassword to the mysql command in the example above).

This only works if you’re using innodb_file_per_table.

Purpose: import this csv quickly into google sheets (or other spreadsheet) and compare MySQL’s internal data size to the container size on disk to determine tables needing to be optimized (or “null altered”) to reclaim disk space and maybe increase performance due to defragmentation. Rule of thumb is probably something like >=10% difference may warrant action.

I wrote this loop as a one-liner dynamically / ad-hoc on the command line a couple weeks ago but made it into a configurable, yet quick-and-dirty shell script, below.

Add -u and -p arguments to MySQL CLI command if you need to, or just place a .my.cnf in your home directory and use the script as-is.

#!/bin/bash

DATADIR="/path/to/datadir" # ex: /var/lib/mysql
SCHEMANAME="yourschema"

for x in `mysql --batch -n -e "select concat(concat(table_name,'.ibd'),',',(data_length + index_length)) as …

Today we had a very interesting phenomena at a customer. He complained that MySQL always get some errors of the following type:

[ERROR] mysqld: Sort aborted: Error writing file '/tmp/MYGbBrpA' (Errcode: 28 - No space left on device)

After a first investigation we found that df -h /tmp shows from time to time a full disk but we could not see any file with ls -la /tmp/MY*.

After some more investigation we found even the query from the Slow Query Log which was producing the same problem. It looked similar to this query:

SELECT * FROM test ORDER BY field5, field4, field3, field2, field1;

Now we were capable to simulate the problem at will with the following table:

CREATE TABLE `test` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `data` varchar(64) DEFAULT NULL,
  `ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE …

The MySQL development team recently made a new labs release of the Group Replication plugin for MySQL Server. This is a preview of a new plugin that adds virtually synchronous replication with support for multi-master or active/active update-anywhere replication groups to the already strong lineup of native replication options in MySQL. Docker is a great […]

This article shows the essential parts of the configuration for a quick console application using the .NET Core command-line (CLI) tool. The application will show how to create an EF Core model and some basic operations that can easily be done in Windows, Linux or OSx.

1. Requirements

Install the sdk, framework and tools:

Windows:
Install
– .NET Core SDK for Windows direct link here
– Visual Studio 2015 Update 3* here’s the publication page with more information about the update.
– .NET Core 1.0 tooling for Visual Studio direct link here

Linux:
An …

Learn how to set up and use Percona's clustercheck script in a MySQL Galera Cluster.

The post Percona’s Clustercheck Script for MySQL Galera appeared first on Datavail.