ProxySQL is a great tool. It’s one of the most recommended technologies in our Open Source Database practice.

Many of our clients are running it or are migrating towards it, but we’ve seen that it is pretty CPU-intensive. We’ve also seen strange behavior in the connection handling when reaching the CPU saturation point.

At this point, we noticed that the frontend_connections counter in the stats_mysql_users table was not decreasing even after the connections were no longer present at the network level. This counter is used to check the max_connections value in the mysql_users configuration table, causing frontend connections to receive a “Too many connections” error. So we determined that the key element here is to scale it properly. Obviously, all the major cloud providers can help us here as they all have features like auto-scaling groups.

Jervin Real of Percona has recently …

Just a reminder for the shows where you can find MySQL at this week, please find them below:

• GigaCon - OS Business, Warsaw, Poland, Jun 18, 2019

  • Vittorio Cioe, the Sr. MySQL Sales Consultant will talk about MySQL Enterprise during the shared slot with Linux/Cloud team. Talk is scheduled for 10:05-10:25 on Jun 18.
• OpenExpo Europe, Madrid, Spain, Jun 20, 2019
  • Find MySQL & Linux team at our shared booth at OpenExpo Europe as Gold sponsor.
  • Planned MySQL talk:
    • "MySQL 8.0: Highly Available, JSON , NoSQL & Document Store" by Keith Hollman, the MySQL Principal Sales Consultant. Time: 16:40-17:10.
  …

MySQL 8.0 introduces many new features. We will have a look at the exciting histogram  feature in MySQL 8.0

Histogram:

What is Histogram?

In General, a histogram is an accurate representation of the distribution of numerical data. In MySQL, It will be useful to collect data distribution for a specific column.

What problem it solves?

In general DB Optimizer gives us the best execution plan, But the stats make the execution plan better and better .The data distribution of values in columns can make good impact in optimiser in case of column with less distinct values.

We will see an example of how it helps optimizer in some cases. 

I have used a production case. MySQL version is 8.0.15 installed in ubuntu 18.04 (32GB RAM,8 core) with optimal configuration. Let us try to optimise a …

Welcome to our new blog series Benefits of SQL Diagnostic Manager for MySQL (formerly Monyog). This series will discuss the features of SQL Diagnostic Manager for MySQL designed to enable organizations to scale their existing resources for database administration. This week, we focus on the challenges associated with MySQL and MariaDB database systems.

The MySQL and MariaDB database systems are rapidly becoming the de-facto choice for traditional enterprises as well as pioneering Web 2.0 companies. Webyog has been consistently delivering powerful tools exclusively on the MySQL and MariaDB platform for the last 15 years.

While the adoption rate of MySQL and MariaDB continues to grow in momentum, it poses some unique challenges for traditional database administrators and their organizations. Some of these challenges are:

• Find problematic SQL queries
• Analyze MySQL and MariaDB performance data …

Archiving MariaDB Database with Mq and Tee filters

This whitepaper is about how to use MariaDB MaxScale filters for Archiving MariaDB database. We have considered two MariaDB / MySQL servers in this exercise, one is the MariaDB Production Database Server and other one for Archiving MariaDB Production Database Server . We have also accommodated RabbitMQ and MariaDB MaxScale servers in their respective Instances .

Our use case is a MariaDB Production Database Server and MariaDB archive Database Server where …

MySQL 8.0 : Error Logging
Here I would like to explain, How MySQL 8.0 server can be configured to log diagnosis messages inside the error log file. 
Generally, the error log contains:

• A record for mysqld service startup and shutdown.
• Diagnostic messages such as errors, warnings, and notes during mysqld server startup, running or shut down. 
• A stack trace if mysqld exits abnormally. 
• mysqld_safe writes once it finds mysqld exists abnormally and mysqld_safe invoke/start mysqld. 

Error Log Component Configuration MySQL 8.0 uses the MySQL error log component architecture that performs log event filtering and writing. These error log components can be configured using the …

The Question Recently, a customer asked us:

Why would heavy disk IO cause the Tungsten Manager and not MySQL to be starved of resources?

For example, we saw the following in the Manager log file tmsvc.log:

2019/06/03 00:50:30 | Pinging the JVM took 29 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 25 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 21 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 16 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 12 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 8 seconds to respond.

The Answer Why a Java application might be slow or freezing

The answer is that if a filesystem is busy being written to by another process, the background I/O will cause the Java JVM garbage collection (GC) to pause.

This problem is not specific to Continuent Tungsten …

So MySQL's group replication came out with MySQL 5.7. Now that is has been out a little while people are starting to ask more about it.

• https://dev.mysql.com/doc/refman/8.0/en/group-replication.html
• https://dev.mysql.com/doc/refman/8.0/en/group-replication-deploying-in-single-primary-mode.html

Below is an example of how to set this up and a few pain point examples as I poked around with it.
I am using three different servers,

 Server CENTOSA

mysql> INSTALL PLUGIN group_replication SONAME 'group_replication.so';
Query OK, 0 rows affected (0.02 sec)

vi my.cnf
…

SQL Right Join Tutorial With Example | Right Outer Join In SQL is today’s topic. We have already seen the Left Join, Full Outer Join, Cross Join, Self Join, and Inner Join in this blog. The RIGHT JOIN keyword returns all the records from a right table (table2), and the matched records from a left table (table1). The result is NULL from the left …

SQL Datatypes Tutorial With Example | Datatypes In SQL is today’s topic. Data types are used to represent a nature of a data that can be stored in the database. The data type is the set of representable values. It is also known as the attribute that specifies a type of data of the object. Each column, variable, and expression has the related data type in the SQL while creating the table. In the last tutorial, we have seen the SQL Date Time Functions. Now, let’s start our SQL Datatypes Tutorial.

#SQL Datatypes important points

1. Relational database vendors support not all data types. For example, the Oracle database doesn’t support a DATETIME, and MySQL doesn’t support a CLOB data type. So while designing the database schema and writing the SQL queries, make sure to check if the …