The latest from the MySQL community

Locking is important in many scenarios to prevent other sessions from modifying tables during periods when a session requires exclusive access to them. for example altering table definition online or any kind of table definition changes. Mysql provides an option to lock table/s with different types of locks, depends on need.

syntax for lock table:

LOCK TABLES
    tbl_name [[AS] alias] lock_type
    [, tbl_name [[AS] alias] lock_type] ...

lock_type:
    READ [LOCAL]
  | [LOW_PRIORITY] WRITE

UNLOCK TABLES

Following are the examples for READ and WRITE LOCK:

READ LOCK:

session1> create table t1( c1 int);
Query OK, 0 rows affected (0.06 sec)

session1> insert …

While I previously blogged about installing Netbeans 8, some of my students would prefer to use the Eclipse IDE. This post shows how to install and configure Eclipse IDE, include the mysql-connector-java.jar, and write Java to access the MySQL.

You can download Eclipse IDE and then open it in Fedora’s Archive Manager. You can use the Archive Manager to Extract the Eclipse IDE to a directory of your choice. I opted to extract it into my student user’s home directory, which is /home/student.

After extracting the Eclipse IDE, you can check the contents of the eclipse directory with the following command:

ls -al eclipse

You should see the following:

While our engineering team is working on finalizing the TokuMXse storage engine, I want to provide an experimental build that you can try and test MongoDB 3.0 with our storage engine.

It is available here
percona.com/downloads/TESTING/Percona-TokuMXse-rc5/percona-tokumxse-3.0.3pre-rc5.tar.gz

To start MongoDB with TokuMXse storage engine use:

mongod --storageEngine=tokuft

I am looking for your feedback!

The post MongoDB with Percona TokuMXse – experimental build RC5 is available! appeared first on MySQL Performance Blog.

We discussed in an earlier post how to design indexes for many types of queries using a single table. Here is a real-world example of the challenges you will face when trying to optimize queries: two similar queries, but one is performing a full table scan while the other one is using the index we specially created for these queries. Bug or expected behavior? Read on!

Our two similar queries

# Q1
mysql> explain select col1, col2 from t where ts >= '2015-04-30 00:00:00';
+----+-------------+---------------+------+---------------+------+---------+------+---------+-------------+
| id | select_type | table         | type | possible_keys | key  | key_len | ref  | rows    | Extra       |
+----+-------------+---------------+------+---------------+------+---------+------+---------+-------------+
|  1 | SIMPLE      | t …

Download MariaDB 10.0.18

Release Notes Changelog What is MariaDB 10.0?

MariaDB APT and YUM Repository Configuration Generator

The MariaDB project is pleased to announce the immediate availability of MariaDB 10.0.18. This is a Stable (GA) release.

See the Release Notes and …

In MySQL 5.7.6 we’ve done some major spring cleaning within the GIS function namespace. We have deprecated 66 function names and added 13 new aliases. Please see the release notes for a complete list of all the changes. But why have we done this, and what impact does this have for you?

Standardization

GIS is a growing area, and to keep MySQL up to speed we have made the GIS namespace more SQL/MM compliant. …

The MariaDB Foundation Board has been meeting monthly since February and on Monday this week had the third meeting of the year. Here is an update on a couple of things from the meeting.

We’re happy to announce that Booking.com has renewed their support to the foundation. As a major corporate sponsor Booking.com has been offered a seat on the Foundation board. Booking.com nominated Eric Herman.  Eric has a history with MySQL dating from 2004 where he joined MySQL working on the server and tools.  In 2010, Eric joined Booking.com where he works on database scaling challenges and BigData. As a community member, he has contributed to the perl MySQL client driver, the perl interpreter, and other Free Software.  To represent community and industry interests in line with the Foundation mission, Eric Herman has joined the Board.

In the MySQL Labs version of MySQL version 5.7, there is a new HTTP plugin. The HTTP plugin documentation from the labs site provides this information (from MySQL Labs):

The HTTP Plugin for MySQL adds HTTP(S) interfaces to MySQL. Clients can use the HTTP respectively HTTPS (SSL) protocol to query data stored in MySQL. The query language is SQL but other, simpler interfaces exist. All data is serialized as JSON. This version of MySQL Server HTTP Plugin is a Labs release, which means it’s at an early development stage. It contains several known bugs and limitation, and is meant primarily to give you a rough idea how this plugin will look some day. Likewise, the user API is anything but finalized. Be aware it will change in many respects.

In …

Being schemaless is one of the key features of MongoDB. On the bright side this allows developers to easily modify the schema of their collections without waiting for the database to be ready to accept a new schema. However schemaless is not free and one of the drawbacks is write amplification. Let’s focus on that topic.

Write amplification?

The link between schema and write amplification is not obvious at first sight. So let’s first look at a table in the relational world:

mysql> SELECT * FROM user LIMIT 2;
+----+-------+------------+-----------+-----------+----------------------------------+---------+-----------------------------------+------------+------------+
| id | login | first_name | last_name | city      | country                          | zipcode | address                           | password   | birth_year | …

Incremental backups in MySQL were always a tricky exercise. Logical backup tools like mysqldump or mydumper don’t support incremental backups, although it’s possible to emulate them with binary logs. And with snapshot-based backup tools it’s close to impossible to take incremental copies.

Percona’s XtraBackup does support incremental backups, but you have to understand well how it works under the hood and be familiar with command line options. That’s not so easy and it’s getting worse when it comes to restoring the database from an incremental copy. Some shops even ditch incremental backups due to complexity in scripting backup and restore procedures.

With TwinDB incremental backups are easy. In this post I will show how to configure MySQL incremental backups for a replication …