Today new version of JSON UDF functions: 0.3.2 was released. This is development release which contains new functionality. You can download functions from the MySQL Labs website.

What is new?

New function `JSON_COUNT` added. This function returns number of children of the key path specified. If no key path specified, number of children of the root element is returned. Bug #70580/17584692 ADD FUNCTION `JSON_COUNT` TO COUNT SIZE OF JSON DOCUMENT

mysql> select json_count('{"MySQL Central": ["conference", 2014]}') as 'root count',
    ­> json_count('{"MySQL Central": ["conference", 2014]}', 'MySQL Central') as 'first element count'\G     
                                                   
************************ 1. row ************************
         root count: 1
first element count: 2
1 row in set …

In this blog post we are going to talk about one of the features included since MySQL for Excel 1.3.0. 

Importing MySQL data into Excel is a common and important operation in MySQL for Excel. There may be times when you need to analyze the data stored in several MySQL tables or views, (possibly in an ExcelPivotTable which will be the subject of a future blog post), and to do it you need to dump the data into Excel as the first step. Starting with MySQL for Excel 1.3.0 we introduced a feature that allows you to import the data from multiple MySQL tables or views in a single operation.

Remember you can install the latest GA or maintenance version using the MySQL Installer or optionally you can download directly any GA or non-GA version from the  …

The biggest innovation in TokuDB v7.5 is Read Free Replication (RFR). I blogged a few days ago posting a benchmark showing how much additional throughput can be achieved on a replication slave, while at the same time lowering the read IO operations to almost zero. The official documentation on the feature is available here.

In this second blog I want to cover the requirements for RFR, as well as some interesting use-cases for the technology.

Recently I encountered a specific situation in which a customer was forced to stay with the MyISAM engine due to a legacy application using tables with over 1000 columns. Unfortunately InnoDB has a limit at this point. I did not expect to hear this argument for MyISAM. It is usually about full text search or spatial indexes functionality that were missing in InnoDB, and which were introduced in MySQL 5.6 and 5.7, respectively, to let people forget about MyISAM. In this case though, InnoDB still could not be used, so I gave the TokuDB a try.

I’ve created a simple bash script to generate a SQL file with …

September 25, 2014 By Severalnines

Coming up with a backup strategy that does not affect database performance or lock your tables can be tricky. How do you backup your production database cluster without affecting your applications? Should you use mysqldump or Percona Xtrabackup? When should you use incremental backups? Where do you store the backups? In this blog post, we will cover some of the common backup methods for Galera Cluster for MySQL/MariaDB, and how you can get the most out of these. 

Backup Method

There are various ways to backup your Galera Cluster data:

• xtrabackup (full physical backup)
• xtrabackup (incremental physical backup)
• mysqldump (logical backup)
• binary logging 
• replication slave

Xtrabackup (full backup)

Xtrabackup is an open-source MySQL hot …

The MySQL Development team is happy to announce our 5.7.5 development milestone release (DMR), now available for download at dev.mysql.com.  You can find the full list of changes and bug fixes in the 5.7.5 release notes.  Here are the highlights. Enjoy!

Scalability

Improve scalability by not using thr_lock locks for InnoDB tables (WL#6671) : This work by Dmitry Lenev improves InnoDB scalability by not using thr_lock locks for InnoDB tables. For InnoDB tables we now rely on MDL + InnoDB row locks. This patch shows good performance/scalability improvements in the single table Sysbench OLTP_RO/ POINT_SELECT tests for InnoDB on multi-core …

MySQL Fabric is a new product and some folks are running into issues when trying to deploy test instances that grow beyond a single server.

The Fabric documentation has an example GRANT statement illustrating the simple localhost use case:

CREATE USER 'fabric'@'localhost' IDENTIFIED BY 'secret';
GRANT ALL ON *.* TO 'fabric'@'localhost';

The example shown above belies the more complex way that Fabric uses the fabric login.

The Fabric config file has 3 sections that deal with user and password values, I will only focus on the [servers] section of the configuration file.  The user and password defined in this section is used by the mysqlfabric utility to connect to managed servers …

Percona Server and Percona XtraDB Cluster provide high-performance alternatives for MySQL users. We have also seen rapidly growing interest in these solutions in the OpenStack community where higher performance and high availability are crucial. Many OpenStack users are adopting these solutions but we’ve also seen demand from companies creating OpenStack distros. For example, Percona XtraDB Cluster is now certified for the RHEL OSP (OpenStack Platform) and is included in the Ubuntu 14.04 LTS release. …

The 5.7.5 DMR is now available, and we’ve made some changes to our build system in this one, so I wanted to spend some time discussing how you would now build MySQL.

When we released our April labs release, I wrote about building MySQL with Boost. Now that the first GIS work using Boost.Geometry has passed all the hurdles and landed in a development milestone release (DMR), it’s time to revisit the topic. From now on (5.7.5 and newer), MySQL needs Boost headers to compile. It’s not optional.

We got a few bug …

When ALTER TABLE crashes MySQL server it leaves orphaned records in InnoDB dictionary. It is annoying because next time you run the same ALTER TABLE query it will fail with error:

ERROR 1050 (42S01) at line 1: Table 'sakila/#sql-ib712' already exists

The post explains why it happens and how to fix it.

When you run ALTER table InnoDB follows the plan:

1. Block the original table
2. Create an empty temporary table with the new structure. The name of the new table is something like #sql-ib712.
3. Copy all records from the original table to the temporary one
4. Swap the temporary and original tables
5. Unblock the original table

The temporary table is a normal InnoDB table except it’s not visible to a user. InnoDB creates a record in the dictionary for the temporary table as for any other table.

If MySQL crashes in the middle of the …