High memory usage scenarios may sometimes be trivial to troubleshoot e.g. when memory parameters are explicitly set too high. Investigations into such issues may also prove to be very difficult when memory pressure is a result of specific workload patterns or better yet, engine bugs.
Advanced memory troubleshooting in MySQL was never easy but thanks to performance_schema memory instrumentation in MySQL 5.7, we finally have some tools to work with. There are still situations when performance schema will not be sufficient:

1. On servers running MyQL <5.7 (well... vast majority),
2. When the component you're interested in is not instrumented,
3. When you don't fancy reading cryptic names of performance schema instruments. While I do love performance schema, this is no joke: OS-level heap profiles are much …

Next article from the MySQL 5.7 Performance stories (if missed, see 1.6M SQL Query/sec (QPS) with MySQL 5.7, 1M SQL Query/sec on mixed OLTP_RO , true Point-Selects performance and over 100K Connect/sec Rate -- all with MySQL 5.7)..

The today's article will be about re:visited MyISAM -vs- InnoDB performance comparison within MySQL 5.7 -- in fact the main and detailed article …

I lost count of the number of times I had customers come to me for a regular MySQL performance check-up saying “no, we don’t have any performance problems right now”, just to find they do actually have them, they’re just not aware of it. It’s no big surprise this happens when you’re not using your system as actively as your users are.

So let me share with you one trick I’m using to quickly check if the system I’m on has any problems that need troubleshooting. Actually, it’s dead simple. And no, it’s not a slow query log, it’s Threads_running. Let me show you.

Wait, what’s wrong with the slow query log?

Nothing at all. MySQL’s slow query log is a great tool when you’re looking for slow queries. Or when you’re fishing for things to optimize – either to reduce the resource consumption, or to increase speed for queries you didn’t know are slow.

And it’s …

This week, the Log Buffer Edition digs deep into the world of Oracle, SQL Server and MySQL and brings you some of the best blog posts around.

Oracle:

• Regardless of what type of industry or business you are involved in, the bottom-line goal is to optimize sales; and that involves replacing any archaic tech processes with cutting-edge technology and substituting any existing chaos with results-driven clarity.
• Oracle Private Cloud Appliance 2.1.1 Released.
• Every version of the optimizer enhances existing mechanisms and introduces new features, while 12c …

At the end of my talk “Troubleshooting MySQL Performance” at the LinuxPiter conference, a user asked me a question: “What does the EXPLAIN ‘filtered’ field mean, and how do I use it?” I explained that this is the percentage of rows that were actually needed, against the equal or bigger number of resolved rows. While the user was happy with the answer, I’d like to better illustrate this. And I can do it with help of EXPLAIN FORMAT=JSON and its

rows_examined_per_scan, rows_produced_per_join

  statistics.

Let’s take a simple query that searches information about the …

Secure communications is a core component of a robust security policy, and MySQL Server 5.7.10 – the first maintenance release of MySQL Server 5.7 – introduces needed improvements in this area.  Support for TLS has been expanded from TLSv1.0 to include TLSv1.1 and TLSv1.2, default ciphers have been updated, and controls have been implemented allowing both server and client-side configuration of acceptable TLS protocol versions.  This blog post will describe the changes, the context in which these changes were made, note important differences in capabilities between Community and Enterprise versions, and outline future plans.

Context

SSL (Secure Sockets Layer)  was superseded by TLS ( …

The MariaDB project is pleased to announce the immediate availability of MariaDB 5.5.47, MariaDB Connector/C 2.2.2, and MariaDB Connector/J 1.3.3. See the release notes and changelogs for details on each release. Download MariaDB 5.5.47 Release Notes Changelog What is MariaDB 5.5? MariaDB APT and YUM Repository Configuration Generator Download MariaDB Connector/C 2.2.2 Release Notes Changelog […]

The post MariaDB 5.5.47 and updated connectors now available appeared first on MariaDB.org.

We just announced availability of MySQL Cluster Manager 1.4.0! In this post we’ll highlight some details of the MCM 1.4.0 release.

Based on MySQL 5.6 MySQL Cluster Manager is part of the commercial MySQL Cluster offering from Oracle. MCM 1.4.0 is now based on the tried and tested MySQL 5.6 release.…

I posted earlier in the year how to configure a Fedora instance to test PHP code on a local VM. However, I’ve got a few questions on how to find those posts. Here’s a consolidation with links on those steps:

1. Go to this blog post and install the httpd and php libraries with the yum installer.
2. In the same blog post as step 1 (you can put the sample PHP code into the /var/www/html directory for testing), connect to the yum shell and remove the php-mysql library and then install the mysqlnd library.
3. Go to this blog …

When you work with complicated queries, especially ones which contain subqueries, it is easy to make a typo or misinterpret column name. While in many cases you will receive a 

column not found

 error, sometimes you can get strange results instead.

Like finding 4079 countries in Antarctica:

mysql> select count(*) from City where CountryCode in (select CountryCode from Country where Continent = 'Antarctica');
+----------+
| count(*) |
+----------+
|     4079 |
+----------+
1 row in set (0.05 sec)

Or not finding any cities in Georgia:

mysql> select Name, Language from City join CountryLanguage using (CountryCode) where CountryCode in (select Code from Country where District='Georgia' and Continent='Asia');
Empty set (0.18 sec)

I used a standard …