Earlier this week we pushed to Github the ninth iteration of Twitter MySQL. Here are some of the highlights.

Bugs Fixed

• Bug#67718: InnoDB drastically under-fills pages in certain conditions [48996cad34] InnoDB's B+ tree page split algorithm that attempts to optimize for sequential inserts might end up causing poor space utilization depending on the distribution pattern of index key values throughout the index. For example, if an insert that causes a page to be split is inserting a key value that is an immediate successor or predecessor to the last inserted key value in the same page, the insertion point is used as the split point irrespective of the actual distribution of values in the page.
  
  The solution is to use the …

I have been preaching since 2003 that the default deployment of MySQL (where root can access without password) should be changed to something more sicure.

Yet, MySQL 5.6 still uses the same defaults.

$ mysql --no-defaults -u root --port=5000 -h 127.0.0.1
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.9-rc MySQL Community Server (GPL)

Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> set password=password('oh-come-on');
Query OK, 0 rows affected (0.00 sec)

mysql> exit
Bye

I have installed MySQL 5.6. Now I access as …

On 29 November last year, SkySQL and Monty Program jointly  announced the release of the so called "MariaDB Client Library for C Applications" and "Maria DB Client Library for Java Applications", which I will call C and JDBC connectors here. You can follow this link to read the press release from SkySQL.

Last week Baron Schwartz posted some findings re the C connector in his blog. Today, another post from Robert Hodges added few details and were looking for answers. I think I can help a bit in understanding what we have released and how the …

As 2013 begins, MySQL is way ahead for job openings in the data area. So perfect your MySQL database administration skills with the authentic MySQL for Database Administrator course.

In this 5 day course, you learn to install the MySQL Server, set up replication and security, perform database backups and performance tuning, and protect MySQL database.

You can take this course through one of the following delivery methods

• Training-on-Demand: Take the course at your pace from your own desk, following the instructor delivery of lecture material through streaming video and scheduling your lab exercises at a time that suits you.
• Live-Virtual: Follow a live event from your own desk - no travel …

MySQL Replication has a weak point: the master (primary) is a single point of failure. People ask frequently about client failover. Making a client library failover a client automatically from one server to another is simple. PECL/mysqlnd_ms can do it. Unfortunately, this is only the tip of the iceberg when using a primary copy (master-slave) database cluster. Among others, you may have to reconfigure clients. Below is one hint (no solution) for deploying PECL/mysqlnd_ms configuration files using MHA (Master High Availability Manager and tools for MySQL).

What’s the plural of dilemma?

If a server is unavailable a client may attempt to connect to another server given a list of alternatives. A client library can handle it entirely transparently and automatically if connection state is no …

A user of mysqlimport. Josh Baird, reminded me of a feature which I should have added from teh start, but which was forgotten about. The deal is that when you put a bunch of JSON objects in a file, you have a couple of options on how to do this.

The most obvious is maybe to export as a JSON array of objects, like this:
[
{"id":1, "name": "Geraint Watkins"},
{"id":2, "name": "Kim Wilson"}
]
But this is not what mysqljsoninport supported and this is not how, say, MongoDB exports JSON by default. The reason is that for large amount if data this is cumbersome, as what is in the file is actually one big JSON object containing all the data. This is difficult to parse, requires that a lot of data is read and that the object in whole is kept in memory, unless some clever processing is done. And if we are clever, this is still not effective. Rather, what was supported by mysqljsonimport and how MongoDB …

Download PDF Presentation

This presentation discusses the lessons learned about the issues of managing a large number of MySQL instances, Including experiences from multiple clients including supporting one billion+ requests statements per day (and 50+ billion SQL statements), and smaller users of LAMP stack, Microsoft stack and RDS configurations. Topics include:

• Monitoring and instrumentation are essential to manage cost
• Cost saving techniques
• How to automate installations, upgrades and deployments
• Traffic minimization techniques
• Creating HA with regions and zones
• Real-time traffic stats (aggregated every 5 seconds)
• AWS …

Apache Cassandra and BigTop updates. And more

For 451 Research clients: Kx Systems aims to slipstream the ‘big data’ bandwagon to expanded kdb+ adoption bit.ly/VxkYlC

— Matt Aslett (@maslett) January 3, 2013

For 451 Research clients: IBM sheds light on ‘big data’ integration and governance the Big Blue way bit.ly/ZTAZcw By Krishna Roy

— Matt Aslett (@maslett) January 2, 2013

The Apache Software Foundation Announces Apache Cassandra v1.2 bit.ly/UFGKFN

— Matt Aslett (@maslett) January …

In On learning InnoDB: A journey to the core, I introduced the innodb_diagrams project to document the InnoDB internals, which provides the diagrams used in this post. (Note that each image below is linked to a higher resolution version of the same image.)

The basic structure of the space and each page was described in The basics of InnoDB space file layout, so now we’ll expand on that to describe InnoDB’s structures related to management of pages and extents, and “free space” management, and how it tracks pages allocated to the many different purposes for which pages are used.

Extents and extent descriptors

As described previously, …

I got some very good comments/questions on my previous post on MariaDB global transaction ID, from Giuseppe and Robert (of Tungsten fame). I thought a follow-up post would be appropriate to answer and further elaborate on the comments, as the points they raise are very important and interesting.

(It also gives me the opportunity to explain more deeply a lot of interesting design decisions that I left out in the first post for the sake of brevity and clarity.)

On crash-safe slave

One of the things I really wanted to improve with global transaction ID is to make the replication slaves more crash safe with respect to their current replication state. This state is mostly persistently stored information about which event(s) were last executed on the slave, so that after a server restart the slave will know from which point in the master binlog(s) …