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Showing entries 1 to 10 of 33112 10 Older Entries
How to start Percona Xtradb Cluster on CentOS 7
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Normally, when we want to start PXC (Percona XtraDB Cluster) on RHEL/CentOS 6 or older then that, we can simply start with init.d script or service command. i.e shell> /etc/init.d/mysql start OR shell> /etc/init.d/mysql bootstrap-pxc shell> service mysql start. But, Continue reading →   [Read more...]
Downgrading from MySQL 5.6 to MySQL 5.5
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Last week I had to downgrade from MySQL 5.6 to 5.5. The reason for this was that the application used a very old Connector/J and that's incompatible with MySQL 5.6 because the removal of SET OPTION syntax.

We're now planning to upgrade Connector/J to be able to upgrade to 5.6 again.

There are two methods of downgrading:
  • Dump/Restore with mysqldump. This is easy and reliable, but can take more time.
  • In place (replace binaries, don't change data). This fast, but won't work if file formats have changed.
As expected this is documented in the MySQL Reference Manual.

I went for the in place method. I expected this to work without many issues as this database was not using the fancy new features like fulltext indexes for






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CIS Oracle MySQL 5.6 Security Benchmark
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I've been working on the CIS security benchmark for Oracle MySQL 5.6. There already is a benchmark document for earlier versions of MySQL.

The benchmark document helps you to ensure you have a secure configuration for MySQL.

Center for Internet Security (CIS) is a nonprofit organization.

The Call For Participation is now open.

If you are already a CIS member then you can download the document here. If you don't have an account you can register for free.
What part of NoSQL don't you understand?
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In the word "NoSQL", the letters "No" are an acronym so the meaning is "Not Only SQL" rather than "No SQL". True or false?

Historically, it's false

The first NoSQL product was a classic DBMS which didn't happen to use SQL for a query language, featured in Linux Journal in 1999. Its current web page has a traffic-sign symbol of the word SQL with a bar through it, and a title "NoSQL: a non-SQL RDBMS".

For a meetup in June 2009 about "open source, distributed, non-relational databases" the question came up "What's a good name?" Eric Evans of Rackspace suggested NoSQL, a suggestion which

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MySQL Performance: More in depth with LinkBench Workload on MySQL 5.7, MariaDB 10.1 and also Percona Server 5.6
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This is the next chapter of the story started in my previous article and related to the updated results on LinkBench workload published by MariaDB..

Keeping in mind that the obtained results are completely opposite from both sides, I've started to investigate then the same LinkBench-150GB 64 concurrent users workload from the "most favorable" possible test conditions on the same 40cores-HT server as in my previous article:

  • InnoDB Buffer Pool (BP) = 150G (so, all the data may remain in memory)



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Oracle OpenWorld 2014 – Bloggers Meetup
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Guess what? You all know that it’s coming, when it’s coming and where… That’s right! The Annual Oracle Bloggers Meetup, one of your top favourite events of OpenWorld, is happening at usual place and time.

What: Oracle Bloggers Meetup 2014

When: Wed, 1-Oct-2014, 5:30pm

Where: Main Dining Room, Jillian’s Billiards @ Metreon, 101 Fourth Street, San Francisco, CA 94103 (

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MySQL upgrade best practices
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MySQL upgrades are necessary tasks and we field a variety of questions here at Percona Support regarding MySQL upgrade best practices. This post highlights recommended ways to upgrade MySQL in different scenarios.

Why are MySQL upgrades needed? The reasons are many and include: Access to new features, performance benefits, bug fixes…. However, MySQL upgrades can be risky if not tested extensively beforehand with your application because the process might break it, prevent the application from functioning properly – or performance issues could arise following the upgrade. Moreover, I suggest keeping an eye on

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Some current MySQL Architecture writings
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So, I’ve been looking around for a while (and a few times now) for any good resources that cover a bunch of MySQL architecture and technical details aimed towards the technically proficient but not MySQL literate audience. I haven’t really found anything. I mean, there’s the (huge and very detailed) MySQL manual, there’s the MySQL Internals manual (which is sometimes only 10 years out of date) and there’s various blog entries around the place. So I thought I’d write something explaining roughly how it all fits together and what it does to your system (processes, threads, IO etc).(Basically, I’ve found myself explaining this enough times in the past few years that I should really write it down and just point people to my blog).

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MySQL 5.6.20 on POWER
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It’s been a little while since I blogged on MySQL on POWER (last time was thinking that new releases would be much better for running on POWER). Well, I recently grabbed the MySQL 5.6.20 source tarball and had a go with it on a POWER8 system in the lab. There is good news: I now only need one patch to have it function pretty flawlessly (no crashes). Unfortunately, there’s still a bit of an odd thing with some of the InnoDB mutex code (bug filed at some point soon).

But, with this one patch applied, I was getting okay sysbench results and things are looking good.

Now just to hope the MySQL team applies my other patches that improve things on POWER. To be honest, I’m a bit disappointed many of them have sat there for this long… it doesn’t help build a

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Lessons from Deploying MySQL GTID at Scale
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by Evan Elias and Santosh Praneeth Banda


Global Transaction ID (GTID) is one of the most compelling new features of MySQL 5.6. It provides major benefits in failover, point-in-time backup recovery, and hierarchical replication, and it's a prerequisite for crash-safe multi-threaded replication. Over the course of the last few months, we enabled GTID on every production MySQL instance at Facebook. In the process, we learned a great deal about deployment and operational use of the feature. We plan to open source many of our server-side fixes via WebScaleSQL, as we believe others in the scale community can



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Showing entries 1 to 10 of 33112 10 Older Entries

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