Why Query Rewrites?

Now that the cost model project is progressing, most of you are going to notice execution plan changes. In the vast majority of the cases, the changes will be for the better, and some bugs with a long history will finally be closed. In some cases, however, you will notice that your queries run slower. This is inevitable: even if the MySQL optimizer is doing a much better job with the information it has, it may still be the case that the information was incomplete and that the best plan was, in fact, found by not trusting that information! Normally, we would just say “add an optimizer hint” and be over with it. But sometimes you can’t do that. For instance your query could be auto-generated from an application that you have no control over. This is why you want to intervene right before the …

Now it's time to get serious about replicating to MariaDB from Oracle, and we are real close now, right? What I needed was a means of keeping track of what happens in a transaction, such as a LOG table of some kind, and then an idea of applying this log to MariaDB when there is a COMMIT in Oracle. And thing is, these two don't have to be related. So I can have a table which I write to and also have a Materialized View that is refreshed on COMMIT on, and I need a log table or something. And when the Materialized View is refreshed, as there is a COMMIT, then the log can be applied. From a schematic point-of-view, it looks something like this:
This looks more complex than it is, actually, all that is needed is some smart PL/SQL and this will work. I have not done much of any kind of testing, except checking that the basics …

In time for Oracle OpenWorld 2014, we released Connector/Python 2.0. We also released a labs release Connector/Python 2.1 and we have a new feature: a C Extension which uses Connector/C.

This C Extension is an optional, an alternative to the pure Python MySQL Client protocol implementation. One of the reasons to implement it was to improve performance in some situations, for example, when huge result sets are returned. Pure Python is still default, if C Extension is not available.

The following post will get your through downloading and installing the MySQL Connector/Python 2.1.0 labs release.

Requirements

• Windows users out of luck; the labs release only compiles on Linux, OSX …

In time for Oracle OpenWorld 2014, we released Connector/Python 2.0. We also released a labs release Connector/Python 2.1 and we have a new feature: a C Extension which uses Connector/C.

This C Extension is an optional, an alternative to the pure Python MySQL Client protocol implementation. One of the reasons to implement it was to improve performance in some situations, for example, when huge result sets are returned. Pure Python is still default, if C Extension is not available.

The following post will get your through downloading and installing the MySQL Connector/Python 2.1.0 labs release.

Requirements

• Windows users out of luck; the labs release only compiles on Linux, OSX and other …

Today SkySQL is changing its name to MariaDB Corporation. This is something that I had both anticipated and I think it's a great step for MariaDB.

I wanted here to to share my thoughts on how this change affects the MariaDB community.

The short version: As the MariaDB Corporation is the main driving force behind the development of the MariaDB server and the biggest support provider for it, it makes sense to give it a name that clearly communicates this fact.  The name change doesn't of course stop the company to continue it's excellent support for MySQL.

For MariaDB users and customers, the name change should not affect them in any way, except that it will make it easier for them to find more information about MariaDB as there is fewer names involved.

For the …

MySQL Fabric Support

MySQL Fabric servers can now be added to the Workbench home screen. When clicked, these connections will dynamically query the Fabric server and individual connections for all the managed MySQL servers will be created. You can then connect to each instance as usual. 

Metadata Lock Browser

MySQL uses metadata locking to manage access to objects (tables, triggers, and so forth). Sometimes that can be puzzling, as your query may block waiting on an object being manipulated by another connection from maybe another user. The Client Connections list was updated to take advantage of the metadata lock information provided in the performance_schema starting in MySQL 5.7.3, to show …

We have received a lot of requests from our user community regarding the ability to  truncate UNDO tablespaces (‘truncate’ here means that the size of the tablespace is reset back to what it was when it was first created). We are happy to say that we’ve now been able to implement this anticipated feature.

Introduction

The InnoDB UNDO tablespace(s) host rollback segments that hold rollback information related to database changes. This information is used to rollback a transaction and to retrieve the previous version of a record that has been updated or deleted for multi-version concurrency control (MVCC). Once a transaction is committed, InnoDB will discard the related UNDO log records. UNDO log records for updates or deletes will be kept around as long as there exists an open transaction that may access older versions of the records. When all such open transactions are committed then the associated UNDO log records can …

The multi master plugin for MySQL is here. MySQL Group Replication provides virtually synchronous updates on any node in a group of MySQL servers, with conflict handling and automatic group membership management and failure detection.

For a better understanding on how things work, we go under the hood in this post and will analyse the transaction life cycle on multi master and which components does it interact with. But before that we need to understand first what a group is.

Group Communication Toolkit

The multi master plugin is powered by a group communication toolkit. This is what decides which servers belong to the group, performs failure detection and orders server messages. Being the ordered messaging the magic thing that allows the data to be consistent across all nodes. You can check the details of the group communication toolkit at …

More MySQL releases than ever before. Check out the following that we just released:

– MySQL Connector Java 5.1.33 GA
– MySQL Fabric & MySQL Utilities 1.5.2 GA
– MySQL Connector Python 2.0.1 GA
– MySQL Fabric and Utilities 1.6.0 Alpha
– MySQL Connector C (Labs)
– MySQL Connector Python (Labs)
– MySQL Group Replication (Labs)
– MySQL HTTP Plugin (Labs)

Download from http://dev.mysql.com/downloads/ and http://dev.mysql.com/downloads/

Percona is pleased to announce the availability of Percona Toolkit 2.2.11.  Released on Sept. 25, Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or complex for DBAs to perform manually. Percona Toolkit, like all Percona software, is free and open source.

This release contains bug fixes for pt-query-digest, pt-mysql-summary, pt-stalk, as well as other tools and is the current GA (Generally Available) stable release in the 2.2 series. Downloads are available here and from the  …