In a previous post I showed how to implement multi-source round-robin replication in pure SQL using the tables that are needed for crash-safe replication. I also outlined a revised version of this approach in the Replication Tips & Tricks presentation I gave at MySQL Connect. This was, however, before the GTID (Global Transaction ID) implementation was done. Now that they are introduced, multi-source replication is even easier since you no longer have to keep track of the positions.

Figure 1. Tables for storing information about masters

CREATE TABLE my_masters (
    idx INT AUTO_INCREMENT,
    host CHAR(50) NOT NULL,
    port INT NOT NULL DEFAULT …

Parallel Universe is released in x86-64bit binaries for CentOS 5.x and Red Hat Enterprise Linux 5.x OS.

Available at www.ParallelUniverse-inc.com/Download2.shtml .

Solid State Drive (SSD) have made it big and have made their way not only in desktop computing but also in mission-critical servers. SSDs have proved to be a break-through in IO performance and leave HDD far far behind in terms of Random IO performance. Random IO is what most of the database administrators would be concerned about as that is 90% of the IO pattern visible on database servers like MySQL. I have found Intel 520-series and Intel 910-series to be quite popular and they do give very good numbers in terms of Random IOPS. However, its not just performance that you should be concerned about, failure predictions and health gauges are also very important, as loss of data is a big NO-NO. There is a great deal of misconception about the endurance level of SSD, as its mostly compared to rotating disks even when measuring endurance levels, however, there is a big difference in how both SSD and HDD work, and that has a direct impact on the endurance …

Following the tremendous success of MySQL Connect, you can now watch some of the keynotes online:

The State of the Dolphin – by Oracle Chief Corporate Architect Edward Screven and MySQL Vice President of Engineering Tomas Ulin

MySQL Perspectives – featuring power users of MySQL who share their experiences and perspectives:

• Jeremy Cole, DBA Team Manager, Twitter
• Daniel Austin, Chief Architect, PayPal
• Ash Kanagat, IT Director; and Shivinder Singh, Database Architect, Verizon Wireless

You can also access slides from a number of MySQL Connect presentations in the Content Catalog. Missing ones will be added shortly (provided the speakers consented …

Today, one of the MySQL database server response time has been increased within the pool of servers and noticed it was returning the query in 0.20 secs (randomly) as opposed[...]

Mark Leith writes that it’s time to say goodbye to SHOW PROCESSLIST in MySQL 5.6, and use the Performance Schema replacement for it instead, because the older tools cause some blocking, and the Performance Schema replacement is completely non-blocking. On the face of it that’s a good thing, but I wonder whether we’ll want to keep some blocking functionality around anyway. Inspecting systems that are doing concurrent work can be hard unless you can see a variety of views on them.

USE mysql;

SHOW FULL TABLES WHERE table_type = ‘base table’;
/* returns
…
innodb_index_stats BASE TABLE
innodb_table_stats BASE TABLE
…
*/

SELECT * from innodb_table_stats;
/* returns
Error CODE: 1146
TABLE ‘mysql.innodb_table_stats’ doesn’t exist
*/

SHOW CREATE TABLE innodb_table_stats;
/* returns
Error CODE: 1146
TABLE ‘mysql.innodb_table_stats’ doesn’t exist
*/

Well .. the table exists and also does not exist at the same time. There is a free choice from the shelf! But what is happening?  I am not sure yet.  It was reported to this bug report by a Linux user, and it is reproducible for me on Windows. Miguel (the MySQL supporter, who is on it) cannot reproduce  - not yet at least.

First of all this …

 One of those exciting Bugs that hang up your database and leave you stranded.  At 6:30 and the workload hang up on the databases, every query local or remote hangs up with no outcome. 

Examination of MySQL error log reveled the following cool error messages:

InnoDB: Warning: a long semaphore wait:
--Thread 140178284349184 has waited at dict0dict.c line 747 for 262.00 seconds the semaphore:
Mutex at 0x2c6dc9e8 '&dict_sys->mutex', lock var 1
waiters flag 1
InnoDB: Warning: a long semaphore wait:
--Thread 140178284054272 has waited at dict0dict.c line 747 for 257.00 seconds the semaphore:
Mutex at 0x2c6dc9e8 '&dict_sys->mutex', lock var 1
waiters flag 1
InnoDB: Warning: a long semaphore wait:
--Thread 140178283759360 has waited at dict0dict.c line 747 for 256.00 seconds the semaphore:
Mutex at 0x2c6dc9e8 …

Virtual Hosting With vsftpd And MySQL On Ubuntu 12.04

Vsftpd is one of the most secure and fastest FTP servers for Linux. Usually vsftpd is configured to work with system users. This document describes how to install a vsftpd server that uses virtual users from a MySQL database instead of real system users. This is much more performant and allows to have thousands of ftp users on a single machine.

There’s a lot happening in the world of MySQL and it’s really vital to be up-to-date with the latest advancements in this field to stay ahead of the game. Reminds me of this quote by Albert Einstein “Once you stop learning, you start dying.” The easiest way to stay updated is by reading blogs. There are loads of blogs talking about MySQL, and even more for databases in general, so which of these really matter and are worth your time and attention?

We’ve handpicked the best MySQL community/ experts blogs and grouped them into various categories. You can also add these great blogs to your RSS reader to get all industry news, tips that you will ever need all in one place. If you prefer the micro blogging platform twitter for real time updates/ news can subscribe to all of them on our twitter list.

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