Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Beyond spending time getting ready for Velocity and Open Source Summit Europe this week, there was some feature testing this week that compared MySQL and MariaDB. Naturally, a long report/blog is coming soon. Stay tuned.

Releases

I reckon a lot of folks are swamped after Percona Live Europe Dublin and Oracle OpenWorld, so the releases in the MySQL universe are a bit quieter.

• Percona Monitoring and Management 1.3.2. Fixes around Query Analytics
• …

What’s New in MariaDB Connector/ODBC 3.0 RalfGebhardt Fri, 10/13/2017 - 09:16

We are pleased to announce the general availability (GA) of MariaDB Connector/ODBC 3.0. MariaDB Connector/ODBC 3.0.2 is the newest version of MariaDB Connector/ODBC. This release is compatible with MariaDB Connector/ODBC 2.0 – no code changes necessary to upgrade.

MariaDB Connector/ODBC 3.0 is based on the new MariaDB Connector/C 3.0. It therefore takes advantage of the new security enhancements and plugins provided by MariaDB Connector/C.

Direct dependencies to functions of MariaDB Connector/C have been removed, only the functions provided by the documented API are used. This allows dynamic linking where preferred. Our own binaries still use the static linking.

New features

• Support of a new bulk load implementation (needs MariaDB …

The main objective of this post is to understand why innodb_fush_log_at_trx_commit variable is used? What are the applicable values for innodb_fush_log_at_trx_commit? How innodb_fush_log_at_trx_commit value will impact the MySQL performance and data safety?  How to change innodb_fush_log_at_trx_commit value? and How to change the frequency of InnoDB log flush?

Why innodb_fush_log_at_trx_commit?

In order to understand why we need innodb_fush_log_at_trx_commit variable, we should know about how InnoDB works. It is a huge and complex topic and it is not the scope of this article. I am trying to cover this topic in simple words and it is given below:

1. InnoDB performs most of its operations at the memory (InnoDB Buffer Pool)
2. It will write all changes from memory to the transaction log (InnoDB Log File)
3. From transaction log - it will flush (write) data to …

Prior to MySQL 5.7 client communications with a MySQL instance were unencrypted by default. This plaintext capability allowed for various tools including pt-query-digest to analyze TCP/IP traffic. Starting with MySQL 5.7 SSL is enabled by default and will be used in client communications if SSL is detected on the server.

We can detect and confirm this easily with the ngrep command.

Default client connection traffic (5.6)

On a MySQL 5.6 server we monitor the default MySQL port traffic.

mysql56$ sudo ngrep -d eth1 -wi -P ' ' -W single -l port 3306
interface: eth1 (192.168.42.0/255.255.255.0)
filter: ( port 3306 ) and ((ip || ip6) || (vlan && (ip || ip6)))
...

We connect to this server using TCP/IP.

host$ mysql -uexternal -p -h192.168.42.16
mysql56> select 'unencrypted';

We can observe the communication to and from the server (in this example 192.168.42.16) is …

In this blog, we’ll look at a mystery around setting the open_file_limit variable in MySQL and Percona Server for MySQL.

MySQL Server needs file descriptors to run. It uses them to open new connections, store tables in the cache, create temporary tables to resolve complicated queries and access persistent ones. If mysqld is not able to open new files when needed, it can stop functioning correctly. A common symptom of this issue is error 24: “Too many open files.”

The number of file descriptors

mysqld

 can open simultaneously is defined by the configuration

open_files_limit

 option. You would expect it to work like any other MySQL Server option: set in the configuration file, …

Notes/errata/updates for Chapter 6:
See the official book errata at http://tahaghoghi.com/LearningMySQL/errata.php – Chapter 6 includes pages 179 – 222.

Other notes:
At the end of the “Creating Tables” section (p.183-4), it says “We like using the underscore character to separate words, but that’s just a matter of style and taste; you could use underscores or dashes, or omit the word-separating formatting altogether.” While this is true, beware of using a dash, because MySQL will try to interpret “two-words”, thinking – is a minus sign. I recommend avoiding dashes for this reason (even though the book does this on page 215).

At the end of the “Collation and Character Sets” section (p.186), it says “When you’re creating a database, you can set the default character set and sort order for the database and its …

Join us for this training session where we discuss tools for backing up a MySQL database within Tungsten, and how Tungsten makes it easy to re-provision databases and recover a cluster. Tuesday, 10/17 at 9:00 am PT/12:00 pm ET. Sign up today at http://bit.ly/2hCkaPm

In this session we will cover:  Methods and tools for taking a backup Verifying the backup contains the last binary log position,

Percona announces the release of Percona Monitoring and Management 1.3.2. This release only contains bug fixes related to usability.

For install and upgrade instructions, see Deploying Percona Monitoring and Management.

Bug fixes

• PMM-1529: When the user selected “Today”, “This week”, “This month” or “This year” range in Metrics Monitor and clicked the Query Analytics button, the QAN page opened reporting no data for the selected range even if the data were available.
  
• PMM-1528: In some cases, the …

Instant ADD COLUMN for InnoDB Marko Mäkelä Wed, 10/11/2017 - 11:02

MariaDB Server 10.3.2 alpha was released this week. For InnoDB, the new features coming in MariaDB Server 10.3 include CREATE SEQUENCE which is a logical continuation of the Persistent AUTO_INCREMENT that appeared in MariaDB Server 10.2.

Perhaps one of the most important InnoDB changes coming in MariaDB Server 10.3 is Instant ADD COLUMN for InnoDB tables. The design was brainstormed in April by engineers from MariaDB Corporation, Alibaba and Tencent. A prototype was developed by Vin Chen (陈福荣) from the Tencent Game DBA Team.

What is …

Despite your very best efforts, as tables increase in size and more and more users come online, sluggish MySQL performance eventually rears its ugly head. When that happens, you may be tempted to shrug it off as part of doing business. Don’t. By understanding the mechanisms behind database slowdowns and by methodically attacking the problem, you can home in on the culprit(s) and remedy the issues in a timely manner, before your business suffers substantial losses as a result.

The purpose of this blog is to assist you in determining the cause(s) of MySQL database performance issues using a couple of built-in tools.

Why Database Performance Slows Down

It’s no secret that database performance tends to degrade over time. While it’s easy to point the finger at the number of concurrent users, table scans, and growing tables, the reality is more complex than that. The most common reason for slow database performance is …