Showing entries 151 to 160 of 36944
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MySQL Cluster 7.5 is GA, best cluster release ever

I have been fairly quiet on my blog for some time. We've been very busy
developing new features for MySQL Cluster 7.5 and ensuring that the
quality is improved even further.

We're now very pleased to release a new version of MySQL Cluster.

MySQL Cluster 7.5 contains a number of new things that makes MySQL
Cluster even better.
1) You can declare a table as a READ_BACKUP table. This means that
the updating transactions will receive the commit acknowledge
a little bit later to ensure that we can always use any of the
replicas for reading. We will use the nearest replica for
committed reads, for locking reads we will still use the primary
replica to avoid deadlocks.

For applications that are mostly read-focused one can make it easier
to set this variable by setting the ndb-read-backup config variable
to 1 in the MySQL Server …

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Designing Euclid to Make Uber Engineering Marketing Savvy

In this article, we take a look at Euclid, Uber Engineering's Hadoop and Spark-based in-house marketing platform.

The post Designing Euclid to Make Uber Engineering Marketing Savvy appeared first on Uber Engineering Blog.

Make MyRocks 2X less slow

Fixing mutex contention has been good for my career. I had the workload, an RDBMS that needed a few improvements and support from a great team. Usually someone else found the bugs and I got to fix many of them. Sometimes I got too much credit because a good bug report is as valuable as the bug fix. These days I don't see many mutex contention bugs but I have begun to see more bugs from memory contention. My perf debugging skills need refreshing. They are far from modern. Thankfully we have Brendan Gregg.

For someone who debugs performance, shared_ptr is a gift. Mistakenly passing shared_ptr by value means the reference count will be changed too much and that is not good on a concurrent workload. I have encountered that at least twice in RocksDB and MyRocks. I even encountered it in MongoDB with …

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Three Things to Consider When Thinking About Containers

Containers like Docker and Rocket are getting more popular every day. In my conversations with customers, they consistently ask what containers are and how they can use them in their environment. If you’re as curious as most people, read on. . .

How did this happen?

From what I understand, containers grew out of Google’s (and others’) need for massive horizontal scale. Now, this is hardly a unique problem. At the time there were several different solutions out there that could help deploy and orchestrate the applications and infrastructure necessary to scale — namely virtual machines (VMs) and their orchestration services (like Vmware’s vCenter). At the uber-massive scale that companies like Google were pushing, however, server virtualization had some serious drawbacks. Enter containers. . .

What is a container?

Essentially, the main difference between a container and a virtual …

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MySQL Connector/J 6.0.5 m4 Development Release has been released

Dear MySQL users,

MySQL Connector/J 6.0.5 m4 Development Release is a developer milestone
release for the 6.0.x series.
This release includes the following new features and changes, also described
in more detail on

As always, we recommend that you check the “CHANGES” file in the download
archive to be aware of changes in behavior that might affect your application.

To download MySQL Connector/J 6.0.5 M4, see the “Development
Releases” tab at


Changes in MySQL Connector/J 6.0.5 (2016-10-19, Milestone 4)

Version 6.0.5 Milestone is the forth development …

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Database Cluster Management - Manual vs Automation via ClusterControl

In a previous blog, we looked at the efficiency gains when automating the deployment of a Galera cluster for MySQL. In this post, we are going to dive into cluster management. Should we manage our cluster manually, or does it make sense to automate the procedures ? What do we gain with automation?

Cluster management involves a number of tasks:

  • Node management:
    • Restart service (per node or rolling restart)
    • Bootstrap cluster
    • Stop cluster
    • Reboot server
    • Rebuild node
    • Recover cluster/node
    • Find most advanced node (i.e. node with latest data)
  • Configuration management:
    • Centrally manage configuration files
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Optimizing and repairing MySQL databases with mysqlcheck

In this post, we will talk about mysqlcheck which is a maintenance command line tool that allows you to check, analyze, repair, and optimize MySQL/MariaDB tables and databases. Check one table in the database The following command will check the table posts in the database blog: $ mysqlcheck -c blog posts blog.posts OK If your database is protected by a password add -u root -p at the end of the command: $ mysqlcheck -c blog posts -u root -p Enter password: blog.posts OK Analyze all tables in a database The following command will check the table posts in the database […]

Install cx_Oracle for Python

This shows you how to install the cx_Oracle library for Python 2.7 on Fedora Linux. If Fedora has it on the server you can download it with the following yum command:

yum install -y cx_Oracle-5.2.1-11g-py27-1.x86_64.rpm

Currently, you’ll get the following failure because it’s not available in the Fedora repository:

Loaded plugins: langpacks, refresh-packagekit
mysql-connectors-community                                      | 2.5 kB  00:00:00     
mysql-tools-community                                           | 2.5 kB  00:00:00     
mysql56-community                                               | 2.5 kB  00:00:00     
pgdg93                                                          | 3.6 kB  00:00:00     
updates/20/x86_64/metalink                                      | 2.3 kB  00:00:00     
No package …
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Upgrading to MySQL 5.7? Beware of the new STRICT mode

This blog post discusses the ramifications of STRICT mode in MySQL 5.7.

In short

By default, MySQL 5.7 is much “stricter” than older versions of MySQL. That can make your application fail. To temporarily fix this, change the




 (same as in MySQL 5.6):


MySQL 5.7, dates and default values

The default


 in MySQL 5.7 is:


That makes MySQL operate in “strict” mode for transactional tables.

“Strict …

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MySQL Downgrade Caveats

In this blog, we’ll discuss things to watch out for during a MySQL downgrade.

Previously, I wrote the blog MySQL upgrade best practices. Besides upgrading your MySQL version, sometimes you need to downgrade. When it comes to downgrading MySQL, there are two types of downgrade methods supported:

  1. In-Place Downgrade: In this method, you use the existing data directory and replace MySQL binaries, followed by a
     execution. This type of downgrade is supported within the same release series. For example, in-place downgrades are supported when moving from 5.7.12 to 5.7.10.
  2. SQL Dump Downgrade: An SQL dump is another …
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