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10 Newer Entries Showing entries 61 to 70 of 852 10 Older Entries

Displaying posts with tag: mariadb (reset)

Percona Live London Call for Presentations
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Europe traditionally doesn’t have many MySQL-dedicated conferences, which is why I personally enjoy Percona Live London, now in its 2014 Edition. This year it happens November 3-4, and the call for presentations is still open — till August 17th.

The topic list is growing as the MySQL ecosystem matures: DevOps, cloud, security, case studies and what’s new are things you don’t often see. Tutorials are also welcome, of course.

Location-wise, London can’t be beat. And happening at Gloucester Road, you’re on the District/Circle/Picadilly lines to go to many

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What is HandlerSocket? And why would you use it? Part 1
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HandlerSocket is included with MariaDB and acts like a simple NoSQL interface to InnoDB, XtraDB and Spider and I will describe it a bit more in this and a few upcoming blogs.

So, what is HandlerSocket? Adam Donnison wrote a great blog on how to get started with it, but if you are developing MariaDB applications using C, C++, PHP or Java what good does HandlerSocket do you?

HandlerSocket in itself is a MariaDB plugin, of a type that is not that common as is is a daemon plugin. Adam shows in his blog how to enable it and install it, so I will not cover that here. Instead I will describe what it does, and doesn't do.

A daemon plugin is a process that runs





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MariaDB and Stored Procedures: errata & repository
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In the article How MariaDB makes Stored Procedures usable I explained how to use the MariaDB CONNECT Storage Engine to workaround Stored Procedures limitations. Please read that article, if you didn’t, for details.

Since the technique to workaround such limitations is verbose and error-proof, I also proposed a procedure which makes it easy and convenient. Even thought this is a simple country blog, I have immediately received positive feedback after that article. But then, people started to write me: “Hey, doesn’t work!”. The reason is… MariaDB/MySQL bugs. While investigating these problems, I was able to report

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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:

/usr/lib64/mysql/plugin/ha_tokudb.so(+0x71c48)[0x7fb25be75c48]
/usr/lib64/mysql/plugin/ha_tokudb.so(+0x71cbd)[0x7fb25be75cbd]
/usr/lib64/mysql/plugin/ha_tokudb.so(_Z29toku_deserialize_bp_from_disk...
/usr/lib64/mysql/plugin/ha_tokudb.so(_Z23toku_ftnode_pf_callback...
/usr/lib64/mysql/plugin/ha_tokudb.so(_Z30toku_cachetable_pf_pinned_pair..
/usr/lib64/mysql/plugin/ha_tokudb.so(_Z24toku_ft_flush_some_child...
/usr/lib64/mysql/plugin/ha_tokudb.so(_Z28toku_ftnode_cleaner_callback...
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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

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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 >
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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:

[mysqld]
plugin-load=ha_tokudb

There is one requirement from

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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:

http://downloads.skysql.com/archive/index/p/mysql/v/5.5.39

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
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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

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Galera Cluster using GTID: MySQL vs. MariaDB
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Using GTID to attach an asynchronous Slave sounds promising. Lets have a look at the two existing GTID implementations and their integration with Galera.

GTID@MariaDB

There is one GTID used by the cluster and every node increments the common seqno by itself. This works well as long all transactions are replicated by Galera (simplified InnoDB). Because Galera takes care of the Commit Order of the transactions on all nodes. So having identical GTID/seqno from the start there are no problems.

  node1> show global variables like 'gtid_binlog_pos';
  +-----------------+---------+
  | Variable_name   | Value   |
  +-----------------+---------+
  | gtid_binlog_pos | 0-1-504 |
  +-----------------+---------+

  node2> show global variables like 'gtid_binlog_pos';
  +-----------------+---------+
  |
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10 Newer Entries Showing entries 61 to 70 of 852 10 Older Entries

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