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 @ …

Codership will have booth E21 at OpenStack Summit 3-5  November in Paris. Come and meet Galera expert and talk your OpenStack Galera plans.

Galera presentation Wednesday 5th, 11.30 on Demotheater stage: Designing for Scale: Data Storage in OpenStack and Galera Cluster By Jay Pipes,  Mirantis

If you’re going to build a house, you don’t start by finding a plot of quicksand to build on. A good house requires a good foundation. Same goes for your OpenStack deployments. The foundation of your OpenStack deployment is composed of the data stores you use for the various types of data that flow through the OpenStack componentry.

Before you deploy OpenStack, spend some time thinking about how to build on a good foundation. In this session, we will analyze the numerous OpenStack components with an eye for how the data each component produces and consumes is stored in …

September 22, 2014 By Severalnines

Need to add phone and SMS alerting to ClusterControl? ClusterControl 1.2.8 introduces support for PagerDuty, an alerting service for Ops teams to schedule on-calls and add phone and SMS notifications to IT tools. By integrating PagerDuty with ClusterControl, you can start receiving phone, SMS and email notifications for all important database events as monitored by ClusterControl. Alerts go directly to the right person who can solve the issue.

This integration is possible thanks to a new plugin interface, that takes ClusterControl alarms in JSON format and outputs to an external system via plugins. Plugins can be either scripts or executable binaries.

We have built a few example …

Normally, when we want to start PXC (Percona XtraDB Cluster) on RHEL/CentOS 6 or older then that, we can simply start with init.d script or service command. i.e

shell> /etc/init.d/mysql start 
OR 
shell> /etc/init.d/mysql bootstrap-pxc

shell> service mysql start.

But, the way is changed from CentOS 7. Because systemd integration with RHEL/CentOS 7 is now available for Percona XtraDB Cluster (#1342223).

So now, we have to start mysql with systemctl command i.e

shell> systemctl start mysql

For boostrap,

shell> systemctl start mysql@bootstrap.service

I would also suggest to read one very informative post by Przemek for recovering PXC cluster. …

This is a story of using low-level kernel interfaces to optimize an edge case one of our agents encountered in some servers. The TL;DR version is that accessing /proc/ can be very expensive if there are a lot of network connections, and the Netlink interface between userspace and kernel space is a much more efficient method.

Background

VividCortex runs several agents, each specialized to a set of tasks. There’s one for gathering operating system metrics, called vc-os-metrics. We capture per-process metrics in the same high resolution as all of our metrics, because in many cases a performance problem is due to a process causing collateral damage to another process by hogging resources. In addition to per-process metrics, we gather a lot of other things, like the usual memory, CPU, and disk metrics.

One of these global metrics is a variety of IPv4/6 socket statistics. Knowing what sockets are …

Last week I had to downgrade from MySQL 5.6 to 5.5. The reason for this was that the application used a very old Connector/J and that's incompatible with MySQL 5.6 because the removal of SET OPTION syntax.

We're now planning to upgrade Connector/J to be able to upgrade to 5.6 again.

There are two methods of downgrading:

• Dump/Restore with mysqldump. This is easy and reliable, but can take more time.

• In place (replace binaries, don't change data). This fast, but won't work if file formats have changed.

As expected this is documented in the MySQL Reference Manual.

I went for the in place method. I expected this to work without many issues as this database was not using the fancy new features like fulltext indexes for InnoDB. All tables used …

I've been working on the CIS security benchmark for Oracle MySQL 5.6. There already is a benchmark document for earlier versions of MySQL.

The benchmark document helps you to ensure you have a secure configuration for MySQL.

Center for Internet Security (CIS) is a nonprofit organization.

The Call For Participation is now open.

If you are already a CIS member then you can download the document here. If you don't have an account you can register for free.

This is another big step forward for doing high QoS OLTP. Thanks for contributing it.

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Mark,

Yes, we can do many interesting things on top of the infrastructure that threadpool provides. The idea we are toying with is to have two staged processing. At first stage, when a socket becomes readable, we read the packet and do some initial parsing e.g.: figure out request type etc. Once we have that information we can then queue/process the request appropriately by applying different rules. For example, give highest priority to COMMIT and ROLLBACKS, limit number of certain type of queries, control queries from a given user account etc.

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