It is the third day I try to find mysqlnd plugin use cases for the Succeed with Plugins webinar on October, 26th. Not being innovative or creative today, I looked into a classic: client fail over. As a trained and talented reader, you won’t be shocked to see 54 lines of PECL/mysqlnd_uh hacking today.

class __mysqlnd_conn_failover extends MysqlndUhConnection {
        
 private $fail_over_errno = array(
  2002 => "Can't connect to local MySQL server through socket '%s' (%d)",
  2003 => "Can't connect to MySQL server on '%s' (%d)",
  2004 => "Unknown MySQL server host '%s' (%d)",
  2006 => "MySQL server has gone away",
  2013 => "Lost connection to MySQL server during query"
 );
 private $fail_over_servers = array(
  array("host" => …

I have been working with a few customer cases and one interesting case popped up. The customer was facing a peculiar problem where the rows column in the EXPLAIN output of the query was totally off. The actual number of rows was 18 times more than the number of rows reported by MySQL in the output of EXPLAIN. Now this can be a real pain as MySQL uses “the number of rows” estimation to pick and choose indexes and it could really be picking up a wrong index simply because of the wrong estimate.

The customer reported that he changed the value of innodb_stats_sample_pages from 8 to 256 but with no effect, however I think innodb_stats_sample_pages really would have no effect on the “number of rows estimation”, because page sampling is used to generate index cardinality estimates which are then in turn used by MySQL to pick and choose indexes and hence is irrelevant to this problem.

Next, I proceeded to test using MySQL 5.1.58 and …

Are you a developer who wishes to create applications using MySQL? You can reach this goal by taking the MySQL for Developers course. This 5 day, instructor led class is the foundation course for MySQL developers. This course covers essential SQL statements for data design, querying, and programming.

Admittedly MySQL Cluster have some way to go before monitoring becomes best in class. But, we are progressing!
In 7.1 we introduced NDBINFO, which is an infrastructure that enables presenting information from within the cluster in SQL format.
And here are a 4 new tables that are currently brewing
ndbinfo.transactions and ndbinfo.operations

mysql> select COLUMN_NAME, DATA_TYPE, COLUMN_COMMENT from information_schema.columns where TABLE_NAME = 'ndb$transactions';
+----------------+-----------+---------------------------------+
| COLUMN_NAME    | DATA_TYPE | COLUMN_COMMENT                  |
+----------------+-----------+---------------------------------+
| node_id        | int       | node id                         |
| block_instance | int       | TC instance no                  |
| objid          | int       | Object id of transaction object |
| apiref         | int       | API reference …

This blog post shows how you can use the Severalnines Configurator for MySQL Replication to deploy a Multi-master replication setup, and install ClusterControl.
You can also watch videos showing what is described below or read an even more detailed tutorial.

When the deployment is finished you have a set of tools to manage and monitor replication, as well as to add new slaves, and to perform failover.
You can choose:

• The number of slaves you wish to connect to the …

MySQL with InnoDB has been proven to be the world’s best transactional database for web and enterprise. SchoonerSQL with parallel appliers has a unique approach to provide highly synchronous replication for your MySQL-InnoDB environment.
Schooner SQL is 100% compatible with MySQL and InnoDB.

Join the webinar on Tuesday, October 18 2011, 10:00 AM - 11:00 AM PDT
to learn more
https://www3.gotomeeting.com/register/963942046

This webinar discusses various replication solutions and explains why SchoonerSQL offers the best and the only synchronous replication solution with five 9s for MySQL-InnoDB

In this webinar, you will learn:
* Design and pros/cons of asynchronous, semi-synchronous, and synchronous replication
* Schooner’s synchronous replication to Read Masters
* How Schooner delivers zero data loss and no slave lag
* Schooner performance and throughput …

I’ll be presenting a free one-hour webinar on preventing downtime in production MySQL servers, in conjunction with the ODTUG. It is scheduled on Thursday, November 10, 2011 3:00 PM – 4:00 PM EST, and you can register for free. Here’s an abstract of what you’ll learn: Everyone wants to prevent database downtime by being proactive, but how effective are the common measures such as inspecting logs and analyzing SQL? To be truly proactive, one must prevent problems, which requires studying and understanding the reasons for downtime.

The Issue
I haven't blogged in a while an I have a long TODO list of things to publish: The repository for the SNMP Agent, video and slides of my OSCON talk and a quick overview of MHA master-master support. In the meantime, here's a little fact that I didn't know from MySQL CREATE VIEW documentation:

Although it is possible to create a view with a nonexistent DEFINER account, an error occurs when the view is referenced if the SQL SECURITY value is DEFINER but the definer account does not exist.How can this be possible?
The ProblemFor a number of reasons we don't have the same user accounts on the master than we have on the slaves (ie: developers shouldn't be querying the master). Our configuration files include the following line:

replicate-ignore-table=mysql.user

So if …

A few people have asked me how it’s going, so I thought I’d just share it with everyone. Things are going great. I’m writing much more quickly than I thought I would be, and as a result I’m finding I have time to do more changes than I thought I could, which makes me happy. I should be finished drafting the chapters by the end of the year.

In particular, the faster than expected pace is giving me a chance to address one of the big weaknesses of the second edition. In many places, the second edition is a collection of facts and experiences. It says what and why, but it doesn’t convey a process or method, and it doesn’t teach you how to think about things and apply the results to situations beyond what the book covers. I’m finding a number of key areas to remedy that: performance optimization, profiling, indexing, high availability, scalability, and so on. I’m adding an explanation of the principles and consequences, and …

SkySQL today announced that it will begin reselling Severalnines' ClusterControl™ product, which enables customers to set-up a production-ready, MySQL® Cluster configuration. The latest addition to the SkySQL™ Reference Architecture - SkySQL's framework for reducing the cost and complexity of deploying some of the most common MySQL data infrastructure applications - ClusterControl™ provides a virtual DBA assistant that frees the developer from the complexity and typical learning curves associated with database clusters, and provides assistance throughout the database lifecycle.

Kaj Arnö, EVP of products at SkySQL, and Vinay Joosery, CEO of Severalnines, will give an overview of the ClusterControl™ solution in a live webinar, on November 8th at 4PM CET/10AM ET. Register for this webinar.

To learn more about this partnership, read today's …