July 10, 2014 By Severalnines

ClusterControl uses the Apache HTTP Server to serve its web interface, but it is also possible to use nginx. nginx + PHP fastcgi is well-known for its capabilities to run on a small memory footprint compared to standard Apache + PHP DSO.

In this post, we will show you how to run ClusterControl on nginx web server by swapping out the default Apache web server installed during the initial deployment. This blog post does not mean that we officially support nginx, it just an alternative way that a portion of our users have been interested in. For instance, Phil Bayfield wrote a blog on the same topic a while back.

Apache Configuration

Before we jump into nginx configurations, let’s look at how the …

Introduction

Human mistakes are inevitable. Wrong “DROP DATABASE” or “DROP TABLE” may destroy critical data on the MySQL server. Backups would help however they’re not always available. This situation is frightening but not hopeless. In many cases it is possible to recover almost all the data that was in the database or table.
Let’s look how we can do it. The recovery plan depends on whether InnoDB kept all data in a single ibdata1 or each table had its own tablespace . In this post we will consider the case innodb_file_per_table=OFF. This option assumes that all tables are stored in a common file, usually located at /var/lib/mysql/ibdata1.

Wrong action – table deletion

For our scenario we will use test database sakila that is shipped together with the tool.
Suppose we drop my mistake table actor:

mysql> SELECT * FROM actor LIMIT 10; …

With the majority of the clients where I perform server audits I find an issue where both the host server and MySQL are not configured with anything other than the default values for the open files limit. This can cause a system stalling event where users are not able to access the server. What do we do to keep this from happening? I'm glad you asked! But first a little background...

The open_files_limit configuration value is used to specify the number of open files a user is allowed to have at any one time. This is done both in the operating system, and in the MySQL configuraition. The reason that it matters to MySQL is that every table consists of multiple files. When the process user, typically mysql, is accessing tables for a query then really the user is accessing files. Since there can be hundreds of users at any one times the number of open files can quickly add up. With a default of 1024 open files …

While writing our TCP stream reassembly and MySQL protocol reverse-engineering algorithms, a few finer points of the MySQL protocol and internals came up. None of this is new information, but you may not have stumbled upon it before.

Prepared Statement IDs

Prepared statements are generated by the COM_STMT_PREPARE protocol command, with the statement text as an argument. The server prepares the statement, and assuming all goes well, returns a statement ID. This is a number that the client needs to remember for future executions of the prepared statement. The ID increments with each new prepared statement.

Statement Scope

The statement is scoped to the connection that created it. It's not visible or valid for any other connection. Statement IDs are private to the connection too, so server-wide you will not have uniqueness. Every connection can have its own statement numbered 32, and the server keeps …

We are using Percona Server + TokuDB engine extensively in Percona Cloud Tools and getting real usage operational experience with this engine. So I want to share some findings we came across, in hope it may help someone in their work with TokuDB.

So, one problem I faced is that SELECT * FROM INFORMATION_SCHEMA.TABLES is quite slow when I have thousands tables in TokuDB. How slow? For example…

select * from information_schema.tables limit 1000;
...
1000 rows in set (18 min 31.93 sec)

This is very similar to what InnoDB faced a couple years back. InnoDB solved it by adding variable …

A while back, I made some changes to the plugin interface for pt-online-schema-change which allows custom replication checks to be written. As I was adding this functionality, I also added the --plugin option to pt-table-checksum. This was released in Percona Toolkit 2.2.8.

With these additions, I spent some time writing a plugin that allows Percona Toolkit tools to use Tungsten Replicator to check for slave lag, you can find the code at https://github.com/grypyrg/percona-toolkit-plugin-tungsten-replicator

…

Hello all,

I hope you're doing well. After the successful event last year it's a no brainer to arrange another community dinner when we're all together again in London this November. We had a fantastic turn-out for the meal last year, seating over 100 MySQLers in a venue whom were expecting only 60. So this year join the MySQL community again for a bite to eat and a beverage or two and discuss life, love and data.

The When
Monday, November 3rd 2014

The Where 
Masala Zone, Covent Garden

The Why
We have a vibrant community surrounding the MySQL ecosystem. Whether you want to talk about the meaning of life with Colin Charles or find out how Facebook take their logical backups even quiz Shlomi Noach about where thinks up his latest and greatest MySQL tools; why not do it with a curry and a …

Taxonomy upgrade extras:  mysql performance monitor monitoring mpm maas performance monitor

FromDual has the pleasure to announce the release of the new version 0.9.3 of its popular Database Performance Monitor for MySQL, Galera Cluster, MariaDB and Percona Server mpm.

This release contains various minor bug fixes and improvements.

You can …

Anemometer is a MySQL slow query monitoring tool. It's used to analyze/visualize slow query log, collected from MySQL instance to identify the problematic queries. Also, makes it easier to figure out what to optimize and how to track performance over time.

Required:

• MySQL database to store query
• pt-query-digest from Percona
• slow query log from MySQL server
• Web server with php

Setup:

Configure, webserver with php, get aneommeter code from github and place into the document root of the webserver.

$ sudo git clone git://github.com/box/Anemometer.git anemometer 

OR, the below link can be used to get anemometer

$ sudo git clone git://github.com/box/Anemometer.git …

Anemometer is a MySQL slow query monitoring tool. It's used to analyze/visualize slow query log, collected from MySQL instance to identify the problematic queries. Also, makes it easier to figure out what to optimize and how to track performance over time.

Required:

• MySQL database to store query
• pt-query-digest from Percona
• slow query log from MySQL server
• Web server with php

Setup:

Configure, webserver with php, get aneommeter code from github and place into the document root of the webserver.

$ sudo git clone git://github.com/box/Anemometer.git anemometer 

OR, the below link can be used to get anemometer

$ sudo git clone git://github.com/box/Anemometer.git …