You can take down a MySQL database in multiple ways. Some obvious ways are to shut down the host, pull out the power cable, or hard kill the mysqld process with SIGKILL to simulate an unclean MySQL shutdown behaviour. But there are also less subtle ways to deliberately crash your MySQL server, and then see what kind of chain reaction it triggers. Why would you want to do this? Failure and recovery can have many corner cases, and understanding them can help reduce the element of surprise when things happen in production. Ideally, you would want to simulate failures in a controlled environment, and then design and test database failover procedures.

There are several areas in MySQL that we can tackle, depending on how you want it to fail or crash. You can corrupt the tablespace, overflow the MySQL buffers and caches, limit the resources to starve the server, and also mess around with permissions. In this blog post, we are going to show you some …

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

So we have announced the call for presentations for Percona Live Santa Clara 2018. Please send your submissions in!

As you probably already know, we have been expanding the content to be more than just MySQL and MongoDB. It really does include more open source databases: the whole of 2016 had a “time series” theme to it, and we of course love to have more PostgreSQL content (there have been tracks dedicated to PostgreSQL for sometime now). I found this one comment interesting recently, from John Arundel, “If you’re going to learn one database really well, make it Postgres.” I have been noticing newer developers jump on the …

Happy Thanksgiving!

We know everyone likes spending quality time with their family at the holidays. That’s why we thought you might like to start using SQLyog MySQL GUI as you try to accomplish more work in less time.

Get flat 30% off on SQLyog purchases and renewals. Use coupon code: TG30

Upgrade your SQLyog community edition to the commercial version to save tons of time on a daily basis. Purchase here.

If you’re an existing customer and want to extend your license – head right away to Customer Area.

Hurry up, this offer is valid until 23rd November, 23:59 PST.

Cheers,
Team SQLyog

Index dives are performed during the optimization phase to help decide which index to use. Currently when user specifies FORCE INDEX, optimizer still always calculates cost using index dives. Under some circumstances it is possible to avoid the index dives and this could speed up execution.…

Dear MySQL users,

The MySQL developer tools team announces 6.3.10 as our GA release for
MySQL Workbench 6.3.

For the full list of changes in this revision, visit
http://dev.mysql.com/doc/relnotes/workbench/en/changes-6-3.html

For discussion, join the MySQL Workbench Forums:
http://forums.mysql.com/index.php?152

Download MySQL Workbench 6.3.10 GA now, for Windows, macOS 10.11+,
Oracle Linux 7, Fedora 26 and 27, Ubuntu 16.04 and 17.10
or sources, from:

http://dev.mysql.com/downloads/tools/workbench/

Enjoy!

Changes in MySQL Workbench 6.3.10 (2017-11-15)
Bugs Fixed

* Performance information within the Administration –
Dashboard tab demonstrated a slow rate of refresh on
hosts running macOS High Sierra. (Bug #26921498)

* Tooltips within the Administration – Dashboard tab did
not display when the mouse pointer …

With MySQL 8.0, one key feature is the new Data Dictionary.

The system tables that were previously in MyISAM are now replaced by new protected ones in the DD.

My friend Giuseppe already explained how you could see those tables using sandbox  and he also warned you that you should not mess up with them in this post too.

I’ll explain you how you can see those tables and their actual content. But will also explain why we decided to protect them and why it should stay like that.

DD protected internal tables list

The easiest way …

With Halloween all but a distant memory, the time has come to turn our attention to the upcoming holiday season. First, Thanksgiving, then Black Friday and Cyber Monday, culminating in the Christmas/boxing week shopping bonanza. For business owners, this time of the year marks the long-awaited year’s end profit taking. For some DBA’s, it brings fear, trepidation, and even sleepless nights toiling away to bring systems back online.

Thankfully, this need not be the case. With a little proactive tweaking of MySQL performance variables, you can insulate your database server(s) against the onslaught of increased demand that the shopping season brings.

Tip #1: Determine the Maximum Number of MySQL Connections

A good starting estimate for the maximum number connections on MySQL is one for every five requests to your web server. A few of those five requests to your web server will be for resources like CSS style sheets, …

These are the slides for my MySQL 8.0 Preview: What is coming? At PHPWorld 2017.

Abstract:

Yes, you read it correctly, we are jumping from 5.7 to 8.0 (that sounds familiar, doesn’t it?). The new version doesn’t only change the number but also changes how you write SQL. Recursive queries will allow you to generate series and work with hierarchical data. New JSON functions and performance improvements were also added to 8.0 to help you work on non-relational data. Expect to see what is new and improved in this talk to power up your application even more.

Please share your feedback at Joind.in: https://joind.in/talk/0e88f

I would like to thank Digital Ocean for enabling my research for this talk …

In a clustering environment, we often see a node that needs to be taken down for maintenance. For a node to rejoin, it should re-sync with the cluster state. In PXC (Percona XtraDB Cluster), there are 2 ways for the rejoining node to re-sync: State Snapshot Transfer (SST) and Incremental State Transfer (IST). SST involves a full data transfer (which could be time consuming). IST is an incremental data transfer whereby only missing write-sets are donated by a DONOR to the rejoining node (aka as JOINER).

In this article I will try to show how a DONOR for the IST process is selected.

Selecting an IST DONOR

First, a word about gcache. Each node retains some write-sets in its cache known as gcache. Once this gcache is full it is purged to make room for new write-sets. Based on gcache configuration, each node may retain a different span of write-sets. The wider the span, the greater the probability of the node acting as …

This new release of SQLyog primarily addresses a long-time concern by corporate users preferring to do a ‘silent installation’ over the corporate network. Even though ‘silent installation’ already was possible, every instance still had to be registered interactively from the workstation by every user. Now registration details can be applied on the command-line as well when doing a ‘silent install’. In addition to command-line this has been tested with a number of 3rd party softwares used by corporations for managing a centralized software repository and for centralized software management.

Changes as compared to MySQL GUI 12.4.3 include:

Features:

* Added command-line syntax for applying registration details when doing a ‘silent install’. You may refer …