ProxySQL and MHA integration
MHA (Master High Availability Manager and tools for MySQL), is almost fully integrated with the ProxySQL process.

What it means is that you can count on the MHA standard feature to manage the failover, and on ProxySQL to manage the traffic and shift from one server.

This is one of the main difference between using MHA and VIP vs MHA and ProxySQL.

There is no need to move IPs or re-define DNS.

The following is an example of configuration file for MHA in case you use it with ProxySQL:

[server default]
    user=mha
    password=mha
    ssh_user=root
    repl_password=replica
    manager_log=/tmp/mha.log
    manager_workdir=/tmp
    remote_workdir=/tmp
    master_binlog_dir=/opt/mysql_instances/mha1/logs
    client_bindir=/opt/mysql_templates/mysql-57/bin
    client_libdir=/opt/mysql_templates/mysql-57/lib …

ProxySQL and MHA integration
MHA (Master High Availability Manager and tools for MySQL), is almost fully integrated with the ProxySQL process.

What it means is that you can count on the MHA standard feature to manage the failover, and on ProxySQL to manage the traffic and shift from one server.

This is one of the main difference between using MHA and VIP vs MHA and ProxySQL.

There is no need to move IPs or re-define DNS.

The following is an example of configuration file for MHA in case you use it with ProxySQL:

[server default]
    user=mha
    password=mha
    ssh_user=root
    repl_password=replica
    manager_log=/tmp/mha.log
    manager_workdir=/tmp
    remote_workdir=/tmp
    master_binlog_dir=/opt/mysql_instances/mha1/logs
    client_bindir=/opt/mysql_templates/mysql-57/bin
    client_libdir=/opt/mysql_templates/mysql-57/lib …

This blog post discussed the advantages of SSDs over HDDs for database environments.

For years now, I’ve been telling audiences for my MySQL Performance talk the following: if you are running an I/O-intensive database on spinning disks you’re doing it wrong. But there are still a surprising number of laggards who aren’t embracing SSD storage (whether it’s for cost or reliability reasons).

Let’s look at cost first. As I write this now (September 2016), high-performance server-grade spinning hard drives run for about $240 for 600GB (or $0.40 per GB).  Of course, you can get an 8TB archive drive at about same price …

I recently had the opportunity to test out Ansible’s ability to interact with docker containers. Some might ask why we would want Ansible to connect to running containers. Afterall, we can build the containers to our liking using ansible-container, or even mundane tools such as Docker’s Dockerfile. Also, we can link configuration files at runtime to override the container’s settings where appropriate.

The point, though, is to leverage Ansible’s capability as an orchestration tool.

As a very basic example, assume that you have plays for your non-docker environment to ensure MySQL users exist. How do you do that with Docker containers?

You have a few options:

1. Assume you have users with appropriate privileges that can connect remotely, you can execute the Ansible plays locally to connect to MySQL over the …

In this blog post, we’ll look at some of the basic housekeeping steps for MySQL indexes.

We all know that indexes can be the difference between a high-performance database and a bad/slow/painful query ride. It’s a critical part that needs deserves some housekeeping once in a while. So, what should you check? In no particular order, here are some things to look at:

1. Unused indexes

With sys schema, is pretty easy to find unused indexes: use the schema_unused_indexes view.

mysql> select * from sys.schema_unused_indexes;
+---------------+-----------------+-------------+
| object_schema | object_name     | index_name  |
+---------------+-----------------+-------------+
| world         | City …

In this blog, I will provide answers to the Q & A for the MySQL Replication Troubleshooting webinar.

First, I want to thank everybody for attending the August 25 webinar. The recording and slides for the webinar are available here. Below is the list of your questions that I wasn’t able to answer during the webinar, with responses:

Q: Hi Sveta. One question: how is it possible to get N previous events using the SHOW BINLOG EVENTS command? For example, the position is 999 and I want to analyze the previous five events. Is it possible?

A: Not, there is no such option. You cannot get the previous five events using

SHOW BINLOG EVENTS

. …

Disclaimer: this post takes into consideration that strict mode is enabled on the server

VARCHAR  and  CHAR  are used to store strings. VARCHAR stores varying length and CHAR always use the same exact size no matter the size of the string. For example, CHAR(4) will always store 4 bytes, whereas VARCHAR(4) will store up to 5 bytes. See documentation.

When we create a table like this one:

We put inside the parentheses the length of the field in characters for the VARCHAR field. However, the maximum size in bytes of the field will depend on the CHARSET and COLLATION of the table. You can also specify a different collation for a column.

For instance:

• latin1: 1 to 2 bytes per …

Dear MySQL users,

MySQL Connector/Net 7.0.5 is the second development release that expands cross-platform support to Linux and OS X when using Microsoft’s .NET Core framework. Now, .NET developers can use the X DevAPI with .NET Core and Entity Framework Core (EF Core) 1.0 to create server applications that run on Windows, Linux and OS X. We are very excited about this change and really look forward to your feedback on it!

MySQL Connector/Net 7.0.5 is also the fourth development release of MySQL Connector/Net to add support for the new X DevAPI.  The X DevAPI enables application developers to write code that combines the strengths of the relational and document models using a modern, NoSQL-like syntax that does not assume previous experience writing traditional SQL.

To learn more about how to write applications using the X DevAPI, see …

There is not yet an equivalent to GROUP_CONCAT that produces a JSON array. (There is in MySQL 8, but that's not GA yet.) Until then, you can hack it together with string functions:

SELECT * FROM t;
+------+--------+
| id   | data   |
+------+--------+
|    1 | First  |
|    2 | Second |
+------+--------+

SELECT CONCAT('[', GROUP_CONCAT(JSON_OBJECT('id', id, 'value', data) SEPARATOR ', '), ']') AS j FROM t;
+-------------------------------------------------------------+
| j                                                           |
+-------------------------------------------------------------+
| [{"id": 1, "value": "First"}, {"id": 2, "value": "Second"}] |
+-------------------------------------------------------------+

Or you can use all JSON functions but hack the grouping:

SELECT j FROM (
       SELECT
         @c := …

I’m happy to speak at Percona Live Europe Amsterdam 2016 again this year (just look at the awesome schedule). On my agenda:

• Monday Oct 3 Tutorial: Best Practices of MySQL High Availability
• Monday Oct 3 Tutorial: The Complete MariaDB Tutorial
• Wednesday Oct 5 Talk: Securing your MySQL/MariaDB data with my friend, Ronald Bradford.
• Wednesday Oct 5 Talk: …