Percona Replication Manager (PRM) continues to evolve and improve, I want to introduce two new features: Slave resync and Async stop.

Slave resync

This behavior is for regular non-gtid replication.  When a master crashes and is no longer available, how do we make sure all the slaves are in a consistent state. It is easy to find the most up to date slave and promote it to be the new master based on the master execution position, the PRM agent already does that but how do we apply the missing transactions to the other slaves.

In order to solve that problem, I modified a tool originally written by Yelp, that outputs the MD5 sums of the payload (XID boundaries) and the commit positions of a binlog file. It produces an output like:

root@yves-desktop:/home/yves/src/PRM/percona-pacemaker-agents/tools/prm_binlog_parser# ./prm_binlog_parser.static.x86_64 /opt/prm/binlog.000382 | tail -n 5 …

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 fun places.

If you don’t want to present, do attend – …

We are pleased to inform you that the new Continuent Tungsten 2.0.3 is now available. This is a recommended release for all Continuent Tungsten clustering customers as it contains important updates and improvements to the stability of the manager component, specifically with respect to possible stalls and memory usage that would cause manager failures:

A number of fixes to the Manager

Martin Arrieta and I gave an online presentation last week on “Putting MySQL Fabric To Use.” If you missed it, you can find a recording and the slides here, and the vagrant environment we used plus a transcript of the commands we ran here (be sure to check out the ‘sharding’ branch, as that’s what we used during the webinar).

Thank you all for attending and asking interesting questions. We were unable to answer all of them in the scheduled time, so here are our replies to all the questions.

What is GTID? And how does it relate to MySQL Fabric?
GTID stands for Global …

The binary and source versions of MySQL Utilities/MySQL Fabric have now been made available at http://dev.mysql.com/downloads/utilities/.

This release contains bug fixes and minor enhancements – full details can be found in the MySQL Fabric/MySQL Utilities release notes.

I will be presenting two webinars in August:

• Aug 6, 10 a.m. PDT: Advanced Query Tuning in MySQL 5.6 and Beyond
• Aug 13, 10 a.m. PDT:  Using Performance Schema to Monitor and Troubleshoot MySQL 5.6

This Wednesday’s webinar on advanced MySQL query tuning will be focused on tuning the “usual suspects”: queries with “Group By”, “Order By” and subqueries; those query types are usually perform bad in MySQL and add an additional load as MySQL may need to create a temporary table(s) or perform a filesort. New this year: I will talk more about new MySQL …

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 "inside" the MariaDB. A daemon plugin can implement anything really, as long as it is …

To ensure that your MySQL Database works as efficiently as possible, it is important to know how to handle error messages and warnings.

Error messages have three components:

• A MySQL-specific error code, such as 1146
• A SQLSTATE error code. These codes are defined by standard SQL and the ODBC standard.
• A text message that describes the problem

MySQL Server generates a warning when it is not fully able to comply with a request or when an action has possibly unintended side effects. You can display these warnings with the SHOW WARNINGS statement.

To learn about handling error messages and warnings along with other developer topics, consider taking the MySQL for Developers training course.

The unDROP for InnoDB tool can be used to recover corrupt MySQL database. In this post we will show how to repair MySQL database if its files became corrupted and even innodb_force_recovery=6 doesn’t help.

The corruption of InnoDB tablespace may be caused by many reasons. A dying hard drive can write garbage, thus page checksum will be wrong. InnoDB then reports to the error log:

InnoDB: Database page corruption on disk or a failed
InnoDB: file read of page 4.

MySQL is well know for poor start-up script. A simple upgrade procedure may end up with two mysqld processes writing to the same tablespace. That leads to the corruption too. Sometimes power reset corrupts not only InnoDB files, but file system becomes unusable for the operating system.

InnoDB …

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...
/usr/lib64/mysql/plugin/ha_tokudb.so(_ZN7cleaner11run_cleaner...
/usr/lib64/mysql/plugin/ha_tokudb.so(+0xcfeee)[0x7fb25bed3eee] …