Connector/NET 6.7 provides replication & load balancing configuration that allows to connect to master/slaves environments and at the same time balancing the request over all the available server in this scenario. This post will show you how to configure and use these new features on a console application.

DBTA roundtable: Building a Geo-Distributed Database for Your Global Applications

THURSDAY, DECEMBER 5, 2013

11:00am PT / 2:00pm ET

In today's global economy, more and more businesses have employees,

Binding threads to CPUs in the MySQL Cluster data nodes can have great benefits. So what about hyperthreading, should we use all CPU threads, or only 1 CPU thread per CPU core? The recommendation differs actually. For the most part it is beneficial to use hyperthreading. In most thread types it gives about 40% higher performance with 2 CPUs using hyperthreading compared to 1 CPU not using hyperthreading. There are a few cases where it might be beneficial to not use hyperthreading though.

The first example is for LDM threads. Using hyperthreading means we will increase the number of partitions of a table by a factor of two. In many cases this isn't beneficial, particularly when the number of LDM threads is high. I tried with using 24 LDM threads with hyperthreading on 12 CPU cores and compared it to 12 LDM threads on 12 CPU cores. This case didn't benefit from using hyperthreading of LDM threads. However if the number of LDM threads …

Thank you to the Drupal User Group Toronto for hosting me last night. My slides are now available online:

In response to some discussions:

• There is a new ‘tree-like’ EXPLAIN format in MySQL 5.6 called FORMAT=JSON. You can see an example in this post.
• innodb_buffer_pool_size is the in memory setting for how much of your data+indexes can be in RAM, and defaults to 128MB (far too small for most production environments). innodb_flush_method=O_DIRECT is the option to disable filesystem caching. Both are mentioned in my what to tune after installation guide.

Thanks …

(No, this is not a duplicate of the previous blog post I wrote. It's for another position!)

As MySQL is thriving and growing, we're looking for an experienced technical writer located in the UK or Ireland to join the MySQL documentation team.

For this job, we need the best and most dedicated people around. You will be part of a geographically distributed documentation team responsible for the technical documentation of all MySQL products. Team members are expected to work independently, requiring discipline and excellent time-management skills as well as the technical facilities and experience to communicate across the Internet.

Candidates should be prepared to work intensively with our engineers and support personnel. The overall team is highly distributed across different geographies and time zones. Our source format is DocBook XML. We're not just writing documentation, but also handling …

The first selection in selecting run-time environment is done by selecting the binary. The original NDB run-time environment was a single-threaded environment where we executed everything except IO threads in a single thread. This environment actually still exists and is selected by running with the binary ndbd. The new multithreaded environment is selected by running with the binary ndbmtd. The ndbmtd can clearly scale far beyond ndbd, but ndbd can still have advantages in environments which has a low load and needs optimisation on latency. Since ndbd does receive on socket, execution of signals and send of signals in the same thread it can have shorter latency at the cost of scalability. Most of the rest of this description discusses ndbmtd configuration. The ThreadConfig variable doesn't apply to running with ndbd since ndbd uses hard-coded thread configuation consisting of 1 main thread.

When configuring the MySQL Cluster run-time …

The run-time environment in MySQL Cluster have always been geared towards high throughput, but also at having many features providing real-time access to the data in MySQL Cluster. Real-time features have included the possibility to lock the memory such that no swapping occurs. It has also included the ability to control placement of the many threads introduced in the MySQL Cluster 7.x series.

In the latest version of MySQL Cluster 7.x we have improved these real-time features and enabled a higher level of control over how those features are configured in the MySQL Cluster data nodes.

Given the high flexibility of configuring MySQL Cluster 7.x we have moved away from global config variables affecting all threads and instead moved towards using the ThreadConfig variable to specify the configured behavior of MySQL Cluster data nodes. The global variables are still in use, but they only set the default value, this value …

What does it mean if MySQL returns the ‘Incorrect key file for table’ error for one of my queries? The answer is complicated and depends on which storage engine is returning the error. We have debugged two cases which we describe here.

File system out of space

When running the random query generator, one of the queries failed.

Query: SELECT * FROM (mysql . general_log AS table1 INNER JOIN INFORMATION_SCHEMA . INNODB_BUFFER_PAGE AS table2 
ON ( table2 . SPACE = table1 . user_host ) ) ORDER BY table1 . thread_id LIMIT 168 
failed: 126 Incorrect key file for table '/data/mysql7/performance_schema_vardir/tmp/#sql_6b8_17.MYI'; 
try to repair it

Since this query requires a sort, MySQL creates a hidden temporary table called ‘#sql_6b8_17.MYI’ to hold the intermediate results. While the query was executing, some operation performed on the MyISAM table returned an error. What could it be?

MySQL maps the …

The MySQL Insights Survey 2013 was conducted during September 2013. Over 200 international respondents, who are followers of SkySQL and MariaDB Twitter and Facebook pages, took part. The aim was to provide insight into their experiences and opinions about the future of open source databases. We have five key findings below.

read more

November 19, 2013 By Severalnines

The Severalnines team is pleased to announce the release of ClusterControl 1.2.4. This release contains key new features along with performance improvements and bug fixes.

We have outlined some of the key features below. For additional details about the release:

• 1.2.4 ChangeLog
• Documentation
• Upgrade instructions
  • Manual upgrade instructions
  • …