The latest from the MySQL community

How InnoDB initializes AUTO_INCREMENT counters is actually not a bug, but a documented mechanism. There were some complaints and even people who lost data over this. To initialize an auto-increment counter after a server restart, InnoDB executes the equivalent of the following statement on the first insert into a table containing an AUTO_INCREMENT column. SELECT MAX(ai_col) FROM table_name FOR

On the MySQL Bugs website there are some tide stats available. These show rate of bug creation.

I've put them in a graph:

I made these with this IPython Notebook. There are more detailed graphs per version in the notebook.

Update: The version in the notebook now uses the same range for the Y axis and has a marker for the GA dates of each release.

A question which would come sometimes to mind when starting with MySQL is whether I should use DATETIME or TIMESTAMP data type since both appear to store same date and time component.


Similarities between datetime and timestamp:
1. Values contain both date and time parts.
2. Format of retrieval and display is "YYYY-MM-DD HH:MM:SS".
3. Can include a trailing fractional seconds part in up to microseconds (6 digits) precision.
4. With the fractional part included, the format for these values is "YYYY-MM-DD HH:MM:SS[.fraction]".
5. Both the TIMESTAMP and (as of MySQL 5.6.5) DATETIME offer automatic initialization and updating to the current …

In this post, we’ll look at MySQL CDC, streaming binary logs and asynchronous triggers.

What is Change Data Capture and why do we need it?

Change Data Capture (CDC) tracks data changes (usually close to realtime). In MySQL, the easiest and probably most efficient way to track data changes is to use binary logs. However, other approaches exist. For example:

• General log or Audit Log Plugin (which logs all queries, not just the changes)
• MySQL triggers (not recommended, as it can slow down the application — more below)

One of the first implementations of CDC for …

This blog post discusses ProxySQL and MHA integration, and how they work together.

MHA (Master High Availability Manager and tools for MySQL) is almost fully integrated with the ProxySQL process. This means you can count on the MHA standard feature to manage failover, and ProxySQL to manage the traffic and shift from one server to another.

This is one of the main differences between MHA and VIP, and MHA and ProxySQL: with MHA/ProxySQL, there is no need to move IPs or re-define DNS.

The following is an example of an MHA configuration file for use 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 …

Coinciding with the new native data dictionary in MySQL 8.0, we have made a number of useful enhancements to our INFORMATION_SCHEMA subsystem design in MySQL 8.0. In this post I will first go through our legacy implementation as it has stood since MySQL 5.1, and then cover what’s changed.…

This blog post explains benefits, features and limitations of the improved semi-sync replication in MySQL 5.7

The post Improved Semi-Sync Replication in MySQL 5.7 appeared first on Datavail.

When it comes to the query tuning, EXPLAIN is one the most important tools in the DBA’s arsenal. Why is a given query slow, what does the execution plan look like, how will JOINs be processed, is the query using the correct indexes, or is it creating a temporary table?

You can now sign up for the webinar, which takes place at the end of this month on September 27th. We’ll look at the EXPLAIN command and see how it can help us answer these questions.

We will also look into how to use database indexes to speed up queries. More specifically, we’ll cover the different index types such as B-Tree, Fulltext and Hash, deepdive into B-Tree indexes, and discuss the indexes for MyISAM vs. InnoDB tables as well as some gotchas.

MySQL Query Tuning Trilogy: Indexing and …

Invisible indexes are a new feature in MySQL 8.0 that provide the ability to mark an index as unavailable for use by the Optimizer. This means that the index will still be maintained and kept up-to-date as data is modified, but no queries will be permitted to make use of the index (even if the query uses a FORCE INDEX hint).…

In this blog post, I will discuss the CVE-2016-6662 vulnerability, how to tell if it affects you, and how to prevent the vulnerability from affecting you if you have an older version of MySQL.

I’ll also list which MySQL versions include the vulnerability fixes.

As we announced in a previous post, there are certain scenarios in Percona Server (and MySQL) that can allow a remote root code execution (CVE-2016-6662).

Vulnerability approach

The website legalhackers.com contains the full, current explanation of the …