January 23, 2014 By Severalnines

Thanks to everyone who attended this week’s webinar; if you missed the sessions or would like to watch the webinar again and browse through the slides, they are now available online.

Special thanks to Seppo Jaakola from Codership, the creators of Galera Cluster, for walking us through the various scenarios of Galera recovery. 

Webinar topics discussed: 

• Redundancy models for Galera, NDB and MongoDB / TokuMX
• Failover & Recovery (Automatic vs Manual)
• Zooming into Galera recovery procedures
• Split brains in multi-datacenter setups

Watch the replay:

…

Todd Farmer’s MySQL 5.7 talk can been seen at http://www.youtube.com/user/sfmysql. For those few of you who did not stay up to watch Todd live, you get TWO slide decks in just over ninety minutes — it is almost the next best as being at the San Francisco Users Group in person.

I’ve covered some strange default behavior around nulls in MySQL. There’s another nuance to this issue: you can still insert rows without specifying values for not null columns. MySQL will helpfully give you a default value (this is not really helpful – true help would be a quick failure with a descriptive error message). Let’s walk through this example.

mysql> Create Table NullTable (a Int Not Null, b Int Not Null);
Query OK, 0 rows affected (0.01 sec)

Here’s a table with two not null columns.

mysql> Insert Into NullTable (a) Values (1);
Query OK, 1 row affected, 1 warning (0.01 sec)

We can totally insert, even though we didn’t specify a value for b and b is not null.

mysql> Show Warnings;
+---------+------+----------------------------------------+
| Level   | Code | Message …

In my previous post I wrote about how I achived a >40% speedup on sysbench read-only using profile-guided optimisation (PGO). While this is a preliminary result, I though it was so interesting that it deserved early mention. The fact that any benchmark can be improved that much shows clearly that PGO is something worth looking into. Even if we will probably not improve all workloads by 40%, it seems highly likely that we can obtain significant gains also for many real workloads.

I had one or two interesting comments on the post that raise valid concerns, so I wanted to write a follow-up here, explaining some of the points in more details and going deeper into the performance counter measurements. As I wrote before, actual observations and measurements are crucial to fully understand performance of complex code on modern CPUs. Intuition and …

This is the very first post in the series of Performance Schema Implementation Internals. This series is for MySQL Developers to understand implementation of Performance Schema. For user point of view of performance Schema, please refer to mysql documentation link : http://dev.mysql.com/doc/refman/5.7/en/performance-schema-quick-start.html

This post talks about the mechanism to register instruments in Performance Schema (referred as P_S from hereon) so that their statistics could be collected at runtime.

To understand this, lets first understand different instrument classes in P_S.

Instrument Classes in P_S:

An enum PFS_class_type is there to keep track of all possible classes of instruments.

enum PFS_class_type
{
…

FOSDEM is a free, yearly event that offers open source communities a place to meet, share ideas and collaborate. It takes place in Brussels, Belgium each February.

10 years ago now, the first MySQL devroom was organized there by David Axmark, marking the first time MySQL users got their own space to come together and discuss at the event. On this anniversary edition, Percona consultants will be present at the MySQL & Friends Community Booth, as well as giving talks in the devroom (full schedule):

* Frédéric Descamps at 12.35 with …

I confess I am a Galera fanboy. This post is going to present two slogans about Galera reminding you about Galera “limitations”. This is for the sake of user experience:)

Galera Phrases:

• One Cluster
• Replication

One Cluster

Think about Galera as One Cluster. As every transaction is committed virtually synchronously, the slowest node determines the (DML) speed of the cluster. This is true regarding the network too.

Replication

• Galera is still some kind of replication. So keep in mind to provide PK as for (ROW based) Replication. There is a Featurerequest of mine to have a PK option to enforce creating of Tables with a PK. Please vote for it:)

• With traditional MySQL Replication the slave might lag. This is …

Beware of bugs in the above code; I have only proved it correct, not tried it.
Donald Knuth

Bugs in software are a fact of life. MySQL, as part of Oracle, issues of Critical Patch Updates and Security Alerts notices. You may have seen Daniel van Eeden‘s blog on the January announcement.

Daniel’s summary:

For MySQL 5.6 you should upgrade to 5.6.15
For MySQL 5.5 you should upgrade to 5.5.35
For MySQL 5.1 you should upgrade to 5.1.73

But you probably missed the executive summary.

But how do YOU get this information when it become available? …

I’ve written a short course on MySQL backups. It’s really a MySQL backup starter kit, giving you the basics of what you need to make sure your system is protected. The real gem in this course is XtraBackup, which is a tool that allows you to backup your MySQL server without blocking other transactions. You see, MySQL doesn’t have that out of the box. You have to spend a bunch of money with Oracle to get that otherwise. Hot backups are pretty necessary if you care about uptime, so I’m excited about XtraBackup.

Here are the topics I cover:

Simple backups

Even though XtraBackup is a great tool, no MySQL user’s knowledge would be complete without knowing how to take a mysqldump. Simple backups are just useful for moving data from server to server, or perhaps migrating your data to, say, PostgreSQL.

Disaster Recovery Plans …

Early this month I spoke at linux.conf.au in Perth, Australia, where I presented “Past, Present and Future of MySQL and variants.”

Here’s my presentation in its entirety. Please let me know if you have any questions or comments. (linux.conf.au is widely regarded by delegates as one of the best community run Linux conferences worldwide.)

The post Past, present and future of MySQL and variants: linux.conf.au 2014 video appeared first on MySQL Performance Blog.