Dear MySQL users,

MySQL Connector/ODBC 5.3.14, a new version of the ODBC driver for the
MySQL database management system, has been released.

The available downloads include both a Unicode driver and an ANSI
driver based on the same modern codebase. Please select the driver
type you need based on the type of your application – Unicode or ANSI.
Server-side prepared statements are enabled by default. It is suitable
for use with any MySQL version from 5.6.

This is the sixth release of the MySQL ODBC driver conforming to the
ODBC 3.8 specification. It contains implementations of key 3.8
features, including self-identification as a ODBC 3.8 driver,
streaming of output parameters (supported for binary types only), and
support of the SQL_ATTR_RESET_CONNECTION connection attribute (for the
Unicode driver only).

The release is now available in …

In MySQL 8.0.18 there is a new feature called Hash Joins, and I wanted to see how it works and in which situations it can help us. Here you can find a nice detailed explanation about how it works under the hood.

The high-level basics are the following: if there is a join, it will create an in-memory hash table based on one of the tables and will read the other table row by row, calculate a hash, and do a lookup on the in-memory hash table.

Great, but does this give us any performance benefits?

First of all, this only works on fields that are not indexed, so that is an immediate table scan and we usually do not recommend doing joins without indexes because it is slow. Here is …

Maintenance of databases or servers is quite often performed by database administrators at night. But these routines sometimes get blocked by long-running queries or applications that hang onto locks much longer than expected. Regularly, priority is given to the application and maintenance routines are often canceled in order not to interfere with the application. But […]

The post How to kill certain connections to a MySQL database appeared first on blog.

We are fueled and energized by the inquisitiveness and eagerness of Database Administrators as a community, reminding us of conducting the next edition of Mydbops Database Meetup. The regular attendees are now looking forward to this quarterly meetup organized by Mydbops, for the benefit of its participants, with the latest hands-on knowledge being shared by the practitioners themselves.

This time we are back in to Diamond District as the venue for this edition of 5th Mydbops Database Meetup, even though, the place of the meeting will be in a different Tower within the same campus at Gojek Tech, Diamond District, 4th Floor, Tower ‘B’, HAL Road, Bangalore – 560 008.

Mydbops Database Meetup

Bangalore, IN
175 Members

Let us meet together at Mydbops Database Conference. This …

Fedora 31 is out today; another rev on one of the most popular community Linux distros out there. As usual, we support the latest Fedora from day one, and we have added the following MySQL products to our official MySQL yum repos: MySQL Server (8.0.18 and 5.7.28) Connector C++ 8.0.18 Connector Python 8.0.18 Connector ODBC […]

From time to time you may have experienced that MySQL was not able to find the best execution plan for a query. You felt the query should have been faster. You felt that something didn’t work, but you didn’t realize exactly what.

Maybe some of you did tests and discovered there was a better execution plan that MySQL wasn’t able to find (forcing the order of the tables with STRAIGHT_JOIN for example).

In this article, we’ll see a new interesting feature available on MySQL 8.0 as well as Percona Server for MySQL 8.0: the histogram-based statistics.

Today, we’ll see what a histogram is, how you can create and manage it, and how MySQL’s optimizer can use it.

Just for completeness, histogram statistics have been available on MariaDB since version 10.0.2, with a slightly different …

Codership is pleased to announce a new Generally Available (GA) release of Galera Cluster for MySQL 5.6 and 5.7, consisting of MySQL-wsrep 5.6.46 (release notes, download) and MySQL-wsrep 5.7.28 (release notes, download). There is no Galera replication library release this time, so please continue using the 3.28 version, implementing wsrep API version 25.

This release incorporates all changes to MySQL 5.6.46 and 5.7.28 respectively and can be considered an updated rebased version. It is worth noting that …

Introduction In this article, we are going to see how a deadlock can occur in a relational database system, and how Oracle, SQL Server, PostgreSQL, or MySQL recover from a deadlock situation. Database locking Relational database systems use various locks to guarantee transaction ACID properties. For instance, no matter what relational database system you are using, locks will always be acquired when modifying (e.g., UPDATE or DELETE) a certain table record. Without locking a row that was modified by a currently running transaction, Atomicity would be compromised. Using locking for controlling access... Read More

The post A beginner’s guide to database deadlock appeared first on Vlad Mihalcea.

This article is an update of a previous post explaining how to setup a second cluster on a second data center to be used as disaster recovery (or to run some off site queries, like long reports, etc..).

This new article covers also the CLONE plugin. Before you ask, CLONE plugin and Replication Channel Based Filters are only available in MySQL 8.0 ! It’s time to upgrade, MySQL 8 is Great !

Also, for DR only, a single MySQL instance acting as asynchronous replica is enough. But if for any reason you want to also have a HA cluster in the second data …

In MySQL 8.0.18 there is a new feature called Explain Analyze when for many years we mostly had only the traditional Explain. I know there are different formats, but those based on the same information just show it in a different format with some extra details.

But Explain Analyze is a different concept. It is actually going to run the query and measure execution time by using the new iterator executor for each step. That topic itself deserves its own blog post on how the new iterator executor works, and I will write a post about that as well. But if you cannot wait and you would like to read up, here are some links to some additional information: Iterator executor analytics …