The latest from the MySQL community

http://www.percona.com/live/london-2014/sessions/mysql-cluster-101

We will be attending and participating in the OmniTI Surge Conference September 25 and 26. Stop by our booth and let us give you a demo of our product.

Owen Zanzal and Baron Schwartz will also be presenting: The GoLang Effect: How Go Changed Operations at VividCortex.

The session is Thursday 2:30 PM. Hope to see you there. If you cannot attend but would like to know more about Go, consider this webinar.

Here is a bit about the presenters:

Owen Zanzal

Twitter Handle: @AgentO3

Owen Zanzal is a developer at VividCortex, where he is on the operations team putting …

I was asked some questions on IRC last night about how the query example in libAttachSQL's code base works. For those who missed previous posts, libAttachSQL is a lightweight, non-blocking, Apache 2.0 licensed C connector for MySQL servers which I am developing for HP's Advanced Technology Group.

In this blog post I'm going to break down a basic query example and explain what is happening at each step. It is possible that this syntax may change slightly by the time we hit GA but it will be similar to this.

#include <libattachsql-1.0/attachsql.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>

Only one include is needed for the library itself, libattachsql-1.0/attachsql.h. The others are used for other functions in the code. …

It's been almost a year now since the initial release of MySQL Fabric. It is maturing and reached a GA state earlier this year as part of MySQL Utilities 1.4. Developers and architects are evaluating it for their applications, learning the capabilities of the system, and providing feedback for future features and usability enhancements. Connector/J has supported Fabric from the very beginning and continues to support the latest features. This blog post is an introductory level guide to using Fabric for high-availability from Java applications. Sharding features and Java APIs will be covered in a later post. The commands shown and feature descriptions are current for Fabric 1.5.1. In addition, Connector/J 5.1.32 and later support only Fabric 1.5 due to communication protocol differences from Fabric 1.4.

High-availability is a core concept in Fabric and is implemented by HA groups. An HA group is a set of servers configured with MySQL …

New to TokuDB® v7.5 is a feature we’re calling “Read Free Replication” (RFR). RFR allows TokuDB replication slaves to process insert, update, and delete statements with almost no read IO. As a result, the slave can easily keep up with the master (no lag) as well as brings all the read IO capacity of the slave for read-scaling your workload.

The goal of this blog is two-fold: (1) to cover why RFR is important and how RFR works and (2) to run a simple before/after benchmark showing the impact of RFR on a well known workload. Later this week I’ll post another blog showing other interesting use-cases for RFR beyond this first benchmark.

Read Free Replication: The Why and How

In MySQL, a replication slave does less work than the master because there is no need for a slave to execute SELECT statements (only INSERT, UPDATE, and DELETE). However, a MYSQL slave can struggle to keep up with the master because replication is …

Choosing the right backup solution is most important for any database. People always choose a backup solution that has the below qualities

 a) Minimal Downtime
 b) Consistent data
 c) Less restoration time

There are several backup solutions like mysqldump, mysqlhottcopy, Xtrabackup, raw copy using cp/rsync/scp (and of course MySQL Enterprise backup. we are not going to talk about it here) etc.., I always prefer mysqldump when the data size is small(few GBs) even if it locks the tables. But what if the data size is huge in TB's, you cannot bring down the DB for a whole day. No client is comfortable with this, they need minimal or no downtime. Percona's Xtrabackup actually comes in handy in such situations. Xtrabackup locks the tables only when dumping the meta data.

                But what we are really interested here is LVM …

Below are 10 common replication problems :

1)Session binlog :

Setting sql_log_bin = 0 will disable binary logging for the session. So any DML/DDL query executed within that session on the master will not be replicated to slave

Example:

Turn off binary logging on master :

mysql> set sql_log_bin = 0 ;
Query OK, 0 rows affected (0.00 sec)

Create table in reptest database ( on master )

mysql> create table reptest(ID int) ;
Query OK, 0 rows affected (0.01 sec)

mysql> show tables ;
+-------------------+
| Tables_in_reptest |
+-------------------+
| reptest           |
+-------------------+
1 row in set (0.00 sec)

Validate to see that table is not created on slave :

mysql> use reptest ;
Database changed
mysql> show tables ;
Empty set (0.00 sec)

2) Updating slave directly

Master and slave will get out of …

libAttachSQL Query Example

I was asked some questions on IRC last night about how the query example in libAttachSQL’s code base works. For those who missed previous posts, libAttachSQL is a lightweight, non-blocking, Apache 2.0 licensed C connector for MySQL servers which I am developing for HP’s Advanced Technology Group.

In this blog post I’m going to break down a basic query example and explain what is happening at each step. It is possible that this syntax may change slightly by the time we hit GA but it will be similar to this.

#include <libattachsql-1.0/attachsql.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>

Only one include is needed for the library itself, libattachsql-1.0/attachsql.h. The others are …

Mon, 2014-09-22 12:19hartmut

The question seemed easy enough:

We've dropped a user, now we want to change the DEFINER on all database objects that currently have it set to this dropped user?

This should be possible by checking the INFORMATION_SCHEMA tables of the appropriate object types (routines, triggers, views and events) and performing an ALTER on each of them that just modifies the DEFINER but nothing else, right?

Unfortunately it isn't that easy, or at least not yet (see http://bugs.mysql.com/73894 and https://mariadb.atlassian.net/browse/MDEV-6731 ).

Events are closest to this as ALTER EVENT does support changing the definer, but it also requires that at least one other event attribute gets changed at the same time, e.g.:

ALTER …

We will be joining Percona Live UK again in November! Please come and meet Galera developers and experts at our keynote, sessions and booth!

Percona Live London Keynote:

Synchronous Revelation (by Alexey Yurchenko) 4 November 9:40am – 10:05am

What is synchronous replication? For many it is just the same as asynchronous, only safer and slower. But is it all that is to that? (At this point you’re probably guessing “no?”) In this talk Alex will ponder eternal questions: what is “synchronous”? is it “replication”? and how new MySQL server UUIDs are relevant to that?

http://www.percona.com/live/london-2014/sessions/synchronous-revelation

Percona Live London session:

Galera Cluster New Features (by Seppo Jaakola) 4 November 3:10pm – 4:00pm @ …