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Showing entries 1 to 30 of 32833 Next 30 Older Entries
Troubleshooting TokuDB Corruption
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I recently ran across some TokuDB table corruption, which was not easily identifiable at first, and the error log entry was not too verbose either, so I wanted to share that experience here.

Basically, TokuDB crashed, and then mysqld had problems restarting afterward. Just for reference, the error log had the following in the stack trace:

  [Read more...]
Troubleshooting TokuDB ERROR 1126 – API Version Mismatch or bitmap_free
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When setting up TokuDB, you may encounter error 1126.

I’ve seen 2 recent invocations of it, so I wanted to share them both here in case you run into this issue:

MariaDB [(none)]> install soname 'ha_tokudb';
ERROR 1126 (HY000): Can't open shared library
'/usr/lib/mysql/plugin/ha_tokudb.so' (errno: 2, undefined symbol: bitmap_free)
MariaDB [(none)]> install soname 'ha_tokudb';
ERROR 1126 (HY000): Can't open shared library 'ha_tokudb.so'
(errno: 8, API version for STORAGE ENGINE plugin TokuDB not
supported by this version of the server)

The latter is a bit more descriptive, but the former is fairly cryptic.

Given the latter, as you may have guessed it, if you run into either of these, you have the wrong version of ha_tokudb.so in your plugin directory – that is, it is not the correct version

  [Read more...]
Disabling Transparent Hugepages for TokuDB
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If you want to use TokuDB with MariaDB, MySQL, or Percona Server, you will need to disable support for transparent hugepages in Linux.

Fortunately, this is very easy to check, and to change.

An easy way to check is with:

cat /sys/kernel/mm/transparent_hugepage/enabled

This will return something like:

[always] madvise never

Note the word surrounded by “[]” is what this option is set to. So the above is set to “always”. To disable it, we want it set to “never”.

I’ve found the easiest way to change/set this is to add the below to your /etc/rc.local file (and then reboot your system):

if test -f /sys/kernel/mm/transparent_hugepage/enabled; then
   echo never >
  [Read more...]
Enabling TokuDB in MariaDB is a Breeze
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TokuDB is gaining more and more popularity and many people are finding it very helpful for certain cases.

Using/enabling it in some distributions can be quite a pain, but enabling it in MariaDB is easy as 1-2-…, well, only 1-2, since that’s all there is to it!

1. Ensure you have the correct MariaDB version:

  • MariaDB 5.5.36+
  • MariaDB 10.0.9+
  • Note: Linux 64-bit systems only – specific packages include: Ubuntu, Debian, Fedora, CentOS, Red Hat
  • Note: If using the Linux tarball – it must be the version built with glibc 2.14+

2. Run this command:

INSTALL SONAME 'ha_tokudb';

or update my.cnf file with:


There is one requirement from

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Upgrade MySQL to a new version with a fresh installation & use shell scripts and mysqldump to reload your data
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There are several ways to upgrade MySQL (http://mysql.com). In this post, we will use a combination of shell scripts and the mysqldump application to export our MySQL (http://mysql.com) data, and then re-import it back into the upgraded version of MySQL (http://mysql.com).

In this example, we will be doing a minor version upgrade. We will be going from 5.6.17 to 5.6.19. This method may not work if you are upgrading from one major release to another – from 5.1 to 5.5, or 5.5 to 5.6. You will want to check each version and review the new features/functions and also what features/functions have been deprecated. We are also assuming that no one will be using the database during the time it takes

  [Read more...]
MySQL 5.5.39 Overview and Highlights
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MySQL 5.5.39 was recently released (it is the latest MySQL 5.5, is GA), and is available for download here:


This release, similar to the last 5.5 release, is mostly uneventful.

There were two “Functionality Added or Changed” and 24 bugs fixed.

The “Functionality Added or Changed” changes are:

  • CMake support was updated to handle CMake version 3.
  • The timed_mutexes system variable has no effect and is deprecated.

Out of the 24 bugs, most seemed rather minor or obscure, but here are the ones I think are worth noting (crashing, security, wrong results, deadlock):

  • InnoDB: Opening a parent table that has thousands of child tables could
  [Read more...]
New! MySQL Utilities release-1.4.4 GA
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The MySQL Utilities Team is pleased to announce the latest GA release of MySQL Utilities, release-1.4.4. This release includes improvements in terms of usability, stability, security and an overall improvement regarding the comprehensibility of the provided error messages.


The following highlights a few of the more significant improvements.

  • mysqlrpladmin errant transactions for switchover have been improved. Note : The errant transactions check requires all servers in the topology to have GTID’s enabled.
  • Failed MySQL server connection error messages now display the actual error returned from the failed connection.
  • Error messages that occur during automatic slave discovery (–discover-slaves-login) have been improved. Now the –verbose option generates specific information for each slave, including their
  [Read more...]
OurSQL Episode 195: Common Schema, part 5
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This week we complete our series on Common Schema by talking about QueryScript. Special guest co-host Jon Day of SkySQL joins us. Ear Candy is some MySQL security tips and At the Movies is a humorous look at value chain mapping.

MySQL Connector/Python on GitHub
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Last week we released Connector/Python v2.0 (alpha); today we publish the source on GitHub. Yes, we are using Git internally and are now able to push it out on each release. Previous versions are still available through LaunchPad.

Here is the full process to get Connector/Python installed in a virtual environment. You’ll need Git installed of course.

shell> git clone https://github.com/oracle/mysql-connector-python.git cpy
shell> virtualenv ENVCPY
shell> source ENVCPY/bin/activate
(ENVCPY)shell> cd cpy
(ENVCPY)shell> python setup.py install
(ENVCPY)shell> python
>>> import
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Basic Windows MySQL Installation Without Installer
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It dawned on me that most folks are using the Installer these days.

As I need quick access to every MySQL version,  using an Installer is never an option.
And for folks wanting 100% control over their setups, they may not want an installer doing things.

So this shows how to setup an instance manually.
  • download non-installer .zip version from dev.mysql.com
  • create a directory c:\mysql and c:\mysql\tmp
  • unzip the .zip into c:\mysql
  • move the data directory into c:\mysql for easier future upgrades
  • create a basic my.ini
  • install the service
  • start the service

  • Here I'll show each step with more detail.   I purposely leave out things like post-installation security, to keep it simple.

    1.  Create a directory.

    Decide where you will put the installation and

      [Read more...]
    Paris OpenStack Summit Voting – Percona Submits 16 MySQL Talks
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    MySQL plays a critical role in OpenStack. It serves as the host database supporting most components such as Nova, Glance, and Keystone and is the most mature guest database in Trove. Many OpenStack operators use Percona open source software including the MySQL drop-in compatible Percona Server and Galera-based Percona XtraDB Cluster as well as tools such as Percona XtraBackup and 

      [Read more...]
    MariaDB: Selective binary logs events
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    In the first post in a series on MariaDB features we find interesting, we begin with selectively skipping replication of binlog events. This feature is available on MariaDB 5.5 and 10.

    By default when using MySQL’s standard replication, all events are logged in the binary log and those binary log events are replicated to all slaves (it’s possible to filter out some schema). But with this feature, it’s also possible to bypass some events to be replicated on the slave(s) even if they are written in the binary log. Having those event in the binary logs is always useful for point-in-time recovery.

    Indeed, usually when we need to not replicate an

      [Read more...]
    Percona Server 5.1.73-14.12 is now available
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    Percona Server version 5.1.73-14.12

    Percona is glad to announce the release of Percona Server 5.1.73-14.12 on July 31st, 2014 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.1.73, including all the bug fixes in it, Percona Server 5.1.73-14.12 is now the current stable release in

      [Read more...]
    Testing MySQL repository packages: how we make sure they work for you
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    Around nine months ago, we launched the MySQL yum repositories for Enterprise Linux and Fedora, followed by apt repos for Debian and Ubuntu back in May. We’re extremely happy that the repos have proved to be a big hit with the community: the monthly number of downloads hit 100K recently and it is still growing […]
    Testing that all projects need
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    Today, I was reminded of a Jim Starkey quote on the Random Query Generator:

    “The Colonoscopy of Database Software”
    - Jim Starkey

    If your project does not have something that you can adapt that quote to, odds are your testing is inadequate.

    MySQL Community Server 5.6
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    MySQL Community Server 5.6 (5.6.20 GA, published on Thursday, 31 Jul 2014)
    Connector/C++ 1.1
    +2 Vote Up -0Vote Down
    Connector/C++ 1.1 (1.1.4 GA, published on Thursday, 31 Jul 2014)
    MySQL Installer 5.5
    +1 Vote Up -0Vote Down
    MySQL Installer 5.5 (5.5.39 GA, published on Thursday, 31 Jul 2014)
    MySQL Utilities 1.4
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    MySQL Utilities 1.4 (1.4.4 GA, published on Thursday, 31 Jul 2014)
    Compare and Synchronize with Updated Database Tools!
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    We are happy to announce the update of comparison tools for Oracle and MySQL databases. Each of them has its own features that our team implemented to let you feel a professional in comparing and synchronizing databases. Choose the right product that is suited for you and enjoy your work.

    Compare and Synchronize with Updated Database Tools!
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    We are happy to announce the update of comparison tools for Oracle and MySQL databases. Each of them has its own features that our team implemented to let you feel a professional in comparing and synchronizing databases. Choose the right product that is suited for you and enjoy your work.

    Beyond the FRM: ideas for a native MySQL Data Dictionary
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    The frm file has provided long service since the earliest days of MySQL. Now, it is time to replace it with a native InnoDB-based Data Dictionary.

    This is a change that has been on our wish list for a long time, as well as others in the MySQL development community:

      [Read more...]
    Resetting advanced options to defaults in MySQL for Excel
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    Welcome to another blog post from the MySQL for Excel Team. Today we're going to talk about a new feature included since 1.3.0, remember you can always install the latest GA or maintenance version using the MySQL Installer also you can download directly any GA or non-GA version from the MySQL Developer Zone.

    In this post we will learn how to reset several advanced options to their default values.

    Remember that your feedback is very important for us, please drop us a message with your comments, suggestions for this or other

      [Read more...]
    Examining the TokuDB MySQL storage engine file structure
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    As we know different storage engines in MySQL have different file structures. Every table in MySQL 5.6 must have a .frm file in the database directory matching the table name. But where the rest of the data resides depends on the storage engine.

    For MyISAM we have .MYI and .MYD files in the database directory (unless special settings are in place); for InnoDB we might have data stored in the single table space (typically ibdata1 in the database directory) or as file per table (or better said file per partition) producing a single file with .ibd extension for each table/partition. TokuDB as of this version (7.1.7) has its own innovative approach to storing the table contents.

    I have created the table in the database test having the following

      [Read more...]
    Chicago MySQL Meetup August 4th
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    High Availability With MySQL – Jay Janssen of Percona

    Monday, August 4, 2014
    6:00 PM

    111 W. Washington St.
    Suite 2100
    Chicago, IL

    Come join Jay Janssen, Principal Consultant at Percona as he speaks about High Availability with MySQL. Jay has been with Percona since 2011. Before that, spent 7 years working for Yahoo in a variety of fields including High Availability architectures, MySQL training, tool building, global server load balancing, multi-datacenter environments, operationalization, and monitoring.

    Pizza and beverages will be provided.

      [Read more...]
    Using innodb_large_prefix to avoid ERROR 1071
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    If you've ever tried to add an index that includes a long varchar column to an InnoDB table in MySQL, you may have seen this error:

    ERROR 1071 (42000): Specified key was too long; max key length is 767 bytes

    The character limit depends on the character set you use. For example if you use latin1 then the largest column you can index is varchar(767), but if you use utf8 then the limit is varchar(255). There is also a separate 3072 byte limit per index. The 767 byte limit is per column, so you can include multiple columns (each 767 bytes or smaller) up to 3072 total bytes per index, but no column longer than 767 bytes. (MyISAM is a little different. It has a 1000 byte index length limit, but no separate column length limit within that).

    One workaround for these limits is to

      [Read more...]
    Early Bird Pricing for MySQL Central @ Oracle Open World Extended to August 1st
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    Register before August 1st for early bird pricing!

    Millions of organizations around the world trust MySQL to power their business-critical web, cloud, and embedded applications. Want to learn best practices to develop next-generation applications with MySQL? Joins us at MySQL Central @ OpenWorld.

    Learn new skills
    Share and network with the global MySQL community
    Hear about new MySQL features directly from Oracle
    Get insight on product roadmaps
    Have fun

    OSCON 2014: Wrap Up
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    Tue, 2014-07-29 19:36Marc Sherwood

    Another OSCON has been wrapped up. While these year was slightly smaller than last year it was still an amazing event. The interesting part was that MySQL and MariaDB seemed to be bigger topics than in years gone by.

    Now that I have been back in the office for a few days, I am getting caught up on my overloaded inbox, and have had some time to reflect on the event.

    The first thing that comes to mind is that MariaDB adoption rate is growing rapidly, and we hear about more amazing deployments at each event we attend. This year we met with a number of people who have made the switch from MySQL to MariaDB for their corporate use, as well as a good number of hosting companies who have migrated to MariaDB. We are working on getting some of these stories ready to share so stay tuned for more on that!

    We aim to have fun in the MariaDB booth - how else could we

      [Read more...]
    Prevent MySQL downtime: Set max_user_connections
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    One of the common causes of downtime with MySQL is running out of connections. Have you ever seen this error? “ERROR 1040 (00000): Too many connections.” If you’re working with MySQL long enough you surely have. This is quite a nasty error as it might cause complete downtime… transient errors with successful transactions mixed with failing ones as well as only some processes stopping to run properly causing various kinds of effects if not monitored properly.

    There are number of causes for running out of connections, the most common ones involving when the Web/App server is creating unexpectedly large numbers of connections due to a miss-configuration or some script/application leaking connections or creating too many connections in error.

    The solution I see some people employ is just to increase

      [Read more...]
    MySQL Cluster latest developments – webinar replay + Q&A
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    I recently hosted hosting a webinar which explained what MySQL Clusrter is, what it can deliver and what the latest developments were. The “Discover the latest MySQL Cluster Developments” webinar is now available to view here (http://www.mysql.com/news-and-events/web-seminars/discover-the-latest-mysql-cluster-developments/" target="_blank). At the end of this article you’ll find a full transcript of the Q&A from the live session.


    View this webinar to learn how MySQL Cluster 7.3, the latest GA release, enables developer agility by

      [Read more...]
    Showing entries 1 to 30 of 32833 Next 30 Older Entries

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