It’s been almost 4.5 years since, during some code refactoring, it was decided (or accidentally changed?) that sql_log_bin should become a GLOBAL variable as well as a SESSION one. Almost 2 years ago, during MySQL 5.5 upgrades at Twitter, I filed MySQL Bug 67433 describing in detail how stupid and dangerous this change was, and asking for a reversal.

Nothing has been changed or reversed, so SET GLOBAL sql_log_bin continues to be allowed. I continue to directly see, and hear about damage caused by incorrect use of SET GLOBAL sql_log_bin. So, let me describe just how stupid and dangerous it really is.

What really happens when you run SET GLOBAL sql_log_bin?

If you have a master-slave replication configuration, your master will have binary logging enabled (log_bin) and be recording each transaction to its local binary logs, which the slaves read (more or …

I’m using Redmine to manage projects and bug reports, I was needing a daily report with spent time by user on each project, nothing complicated, but I wanted a cross-reference result like Excel dynamic tables. As we know, MySQL doesn’t support dynamic cross-reference queries but I make an approach:

1. Write the main query with rows: project identifier, task subject and total hours in a date range.

SELECT p.identifier, 
        e.issue_id, i.subject, round(SUM(e.hours),2) AS total_hours
        FROM redmine_nsp.time_entries e
        INNER JOIN redmine_nsp.issues i ON e.issue_id = i.id
        INNER JOIN redmine_nsp.projects p ON e.project_id = p.id
        WHERE e.spent_on BETWEEN '2014-07-01' AND '2014-07-07'
 GROUP BY p.identifier,e.issue_id;

+------------+----------+----------------------------+-------------+
| identifier | issue_id | subject                    | total_hours | …

I have been meaning to update some systems to MariaDB 10.0 and finally had a bit of time to get around to that.  The documentation of specifics of what’s needed to go from MariaDB 5.5 to 10.0 can be found here and while it’s not very long it seems there’s little to actually do. Having already … Continue reading MariaDB 10.0 upgrade goes smoothly

The MySQL replication and load balancing plugin for PHP, PECL/mysqlnd_ms, aims to make using a cluster of MySQL servers instead of a single server as transparent as possible. Should you ever want to migrate your PHP app from a single MySQL server to any kind of MySQL cluster, install PECL/mysqlnd_ms and see how much breaks. A simple app, might need no code changes at all. Your APIs connect call remains unchanged, your query execution calls remain the same: one connection handle transparently switched to an appropriate cluster node (read-write splitting, weighted load balancing, …).

/* Or, …

As businesses head into the cloud, it is tempting to reach for the first product that offers to make database operation as simple as punching a few buttons on a menu.  However, there’s a big difference between firing up cloud database services such as Amazon RDS for testing or development and finding a solution that can handle hundreds of millions of transactions daily. This webinar-on-demand

This Tuesday Markus Winand will talk at the MySQL User Group NL meetup about "Indexes: The neglected performance all-rounder".
Markus is known for the http://use-the-index-luke.com website and the SQL Performance Explained book.

Date: Tuesday August 12
Location: Marktplaats/eBay Office Amsterdam
Registration: http://www.meetup.com/MySQL-User-Group-NL/events/196440532/

MySQL for Visual Studio is a product that includes all of the Visual Studio integration functionality to create and manage MySQL databases when developing .NET applications. The 1.2.3 version is a General Availability release of this product which is feature complete and is suitable for production environments.

In this blog post we are going to talk about one of the features included since MySQL for Excel 1.3.0, MySQL for Excel has always let you create new schemas and tables in a MySQL database, in versions lower than 1.3.0 these were created with the default character set and collation defined in the MySQL server. Starting with version 1.3.0 we introduced several features regarding collations:

• New drop-downs were added that let you to override the default collation for new MySQL schemas and tables.
• Default collations for each schema can be shownin the schemas list below the schema names.
• The SQL queries for schemas creation can be previewed or displayed (depending on its global setting).

Remember you can install the latest GA or maintenance version using the  …

It is not clear for many MySQL users that Percona XtraDB Cluster (PXC) and MariaDB Galera Cluster depend on the same Galera library i.e used in Galera Cluster for MySQL which is provided by Codership team:

• Galera Cluster: MySQL Server (by Oracle) + Galera library.
• Percona XtraDB Cluster: Percona Server + Galera library.
• MariaDB Galera Cluster: MariaDB Server + Galera library.

But the question is, are there any performance differences between the three of them ?

Let's discover that by doing some simple benchmark to test …

Over the last several months we’ve designed and built an events dashboard that lets you inspect very large amounts of system event data quickly (interactively). This feature was driven by customer requests and feedback. The initial proof of concept established its usefulness right away, when customers began remarking that they’d diagnosed server issues by noticing events such as database restarts, replication failures, and configuration changes. At least one customer told us this saved them a long wild-goose chase.

The key concept is that event data is loaded fully into the browser and then you can thin-slice and drill down without reloading any events. And it’s fast. Really fast – it remains responsive even with hundreds of thousands of events. Here’s what the last 30 days of fine-grained events looks like on our own systems:

The skyline along the top shows events by count over time. The left-hand pane lets you …