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Eventual consistency  is a consistency model, which is used in many large distributed databases. Such databases require that all changes to a replicated piece of data eventually reach all affected replicas. Furthermore, the conflict resolution is not handled in these databases, and the responsibility is pushed up to the application authors in the event of conflicting updates. Eventual consistency is a specific form of weak consistency: the storage system guarantees that if no new updates are made to the object, eventually all accesses will return the last updated value . If no failures occur, the maximum size of the inconsistency window can be determined based on the factors such as communication delays, the load on the system, and the number of replicas involved in the replication scheme. We earlier in[Read more...]
The following sentence is brought to you by IBM Legal. The postings on this site are my own and don’t necessarily represent IBM’s positions, strategies or opinions.
Okay, now that is out of the way….
If you’re the kind of person who follows the MySQL bugs database closely or subscribes to the MySQL Internals mailing list, you may have worked out that I’ve spent a small amount of time poking at MySQL on modern POWER systems.
Unlike Intel CPUs, POWER CPUs require explicit memory barriers to synchronize memory state between[Read more...]
Today marks a milestone in terms of the MariaDB project – going forward, the MariaDB project plans to use Github and git for source code management. The migration happens from Launchpad and the bzr tool.
The 10.1 server development (under heavy development now) will happen on Github. You can check it out here: https://github.com/MariaDB/server. Feel free to watch, star or even fork the code, and send us contributions!
The project eventually wants to move the 10.0, 5.5, 5.3, 5.2, and[Read more...]
This week we discuss pt-table-checksum for keeping data in sync. Ear Candy is a rational look at why one company chose MySQL; At the Movies is using MySQL in a practical way for Big Data.
Episode 151, where we talked about Oracle toolsmysqldbcompare and mysqldiff
This week we discuss more Percona tools: pt-online-schema-change and pt-slave-find. Ear Candy is using the CONNECT storage engine to read GPX files, and At the Movies is Performance at Scale with TokuDB.
DB Hangops - every other Wednesay at noon Pacific time
Upcoming MySQL events (http://www.mysql.com/news-and-events/events/)
OSCon 2014 at the Oregon Convention Center in Portland, Oregon from Sunday July 20th through Thursday July 24th.
This is the blog of the MariaDB Foundation in particular and the MariaDB project in general. It is used to announce new MariaDB versions, for posts from MariaDB developers about new features, and for news from or about the MariaDB Foundation itself, among other things. For many this is the MariaDB blog, and on behalf of the MariaDB Foundation, welcome! We’re glad you’re here. Thanks for stopping by!
What you may not know is that there’s another MariaDB blog over at https://mariadb.com/blog run by the fine folks at SkySQL (full disclosure: I work for SkySQL, but my posts here are on behalf of the MariaDB project and the Foundation). This other MariaDB blog contains posts about SkySQL’s commercial MariaDB offerings (naturally) but also a lot of other[Read more...]
In January I wrote my first post about node.js and MariaDB . In February I continued with a second post about using jQuery and some GIS calculations. Now it is time for the third and this time the main focus is not so much on GIS functionality, but instead on the capabilities MariaDB has for handling piles of unstructured data. In this case I’ll be focusing on crunching a pile of XML files without importing the XML data itself.[Read more...]
Recently, MySQL 5.6 was added to the dotdeb repository. On the surface, this is a very harmless addition. MariaDB is a replacement for MySQL and it should be possible for applications designed for MySQL to easily switch to MariaDB. Therefore MariaDB also includes the libraries that applications using MySQL depend upon, such as libmysqlclient18 and mysql-common. The dpkg package manager looks at the MySQL 5.6 packages in dotdeb and assumes that 5.6 is a higher version than 5.5, which results in it removing or replacing libraries during normal apt-get installation and upgrade procedures.
The problems appear in the following scenarios:[Read more...]
The MariaDB Foundation is pleased to announce the releases of MariaDB C Client Library 2.0 and MariaDB JDBC Client 1.1.7
The MariaDB Client Library for C 2.0 is a major release which contains more than 70 bug fixes and a lot of new functions and features, e.g.
…and much more!
For a complete list of all new features please visit MariaDB Client Library for C 2.0.0 Release Notes
We are very proud for getting a tremendous amount of contributions: bug reports, ports, patches and suggestions which helped[Read more...]
The MariaDB project is pleased to announce MariaDB ODBC Driver Beta – the start of the public beta testing phase of MariaDB ODBC Driver
MariaDB ODBC Driver is a standarized database driver for Windows platforms. It supports ODBC Standard 3.5 and can be used as a drop-in replacement for MySQL Connector/ODBC.
Maria ODBC Driver is licensed under the LGPL license. It is compatible to MySQL Connector/ODBC and supports both Unicode and ANSI mode.
MariaDB ODBC Driver is build on top of the MariaDB LGPL C library and uses binary prepared statement protocol for client server communication.
For more information please visit the MariaDB ODBC Driver page
The MariaDB project is pleased to announce a special preview release of MariaDB 10.0.9 with significant performance gains on FusionIO devices. This is is a beta-quality preview release.
The latest work between MariaDB and FusionIO has focused on dramatically improving performance of MariaDB on the high-end SSD drives produced by Fusion-IO and at the same time delivering much better endurance for the drives themselves. Furthermore, FusionIO flash memory solutions increase transactional database performance. MariaDB includes specialized improvements for FusionIO devices, leveraging a feature of the NVMFS filesystem on these popular, high performance solid state disks. Using this feature, MariaDB 10 can[Read more...]
On Thursday MySQL technology saw a huge boost. It’s hard for anyone now to argue that MySQL isn’t in the game of extreme scalability and performance, which some NoSQL vendors have been using as a tagline for the last years. To see four of the largest MySQL and MariaDB users come together to bootstrap a branch of MySQL for extreme scaling needs is simply fantastic. The improvements done inside these companies will now be available to the rest of the community. In all fairness Facebook and Twitter, in particular, have been making their improvements publicly available also before. Google has also made some improvements available publicly over the years and have lately been active in the MariaDB project with code reviews, bug fixes and other patches. But broadening the public contributions further and combining it all, is new.
Engineering of MySQL technology happens in many places. Aside from[Read more...]
MariaDB 10 is nearing GA, and it makes sense to make sure that the test suite from MySQL 5.6 is merged into MariaDB 10. Svoj is doing a lot of this work, and then we like to look at features, especially ones that are deprecated upstream. We don’t do that on blogs, but on the maria-developers mailing list.
I bring to your attention: Intermediate status for test cases merge. We see that INSERT DELAYED and SHOW PROFILE for example are deprecated in MySQL 5.6. The only way for feedback to the MySQL team seems to be comments on Morgan’s blog. However with MariaDB, especially with the feedback plugin enabled, we[Read more...]
Eventual consistency is a consistency model used in many large distributed databases which requires that all changes to a replicated piece of data eventually reach all affected replicas; conflict resolution is not handled and responsibility is pushed up to the application author in the event of conflicting updates .
Eventual consistency is a specific form of weak consistency; the storage system guarantees that if no new updates are made to the object, eventually all accesses will return the last updated value . If no failures occur, the maximum size of the inconsistency window can be determined based on factors such as communication delays, the load on the system, and the number of replicas involved in the replication scheme .
A few examples of eventually consistent systems:
A MariaDB Howto authored by: Erkan Yanar.
This is a Howto about installing MariaDB Galera Cluster on Debian/Ubuntu. Because a lot of people were having problems installing MariaDB Galera Cluster, elenst from
#maria on freenode forced me to write this Howto
Installing MariaDB Galera Cluster is in fact quite easy and actually kind of boring in the end. This Howto is written for (and tested on) on Debian 7.1 (Wheezy) and Ubuntu 12.04 (Precise).
In our setup we assume 3 nodes (node01, node02, node03) with one interface each. We assume following IP addresses: 172.16.8.5, 172.16.8.6, and 172.16.8.4. We need three packages installed on all nodes:
As Galera[Read more...]
Lets start by considering a scenario where records are being inserted in a single auto-increment table via different nodes of a multi-master cluster. One issue that might arise is ‘collision’ of generated auto-increment values on different nodes, which is precisely the subject of this article.
As the cluster is multi-master, it allows writes on all master nodes. As a result of which a table might get same auto-incremented values on different nodes on INSERTs. This issue is discovered only after the writeset is replicated and that’s a problem!
Galera cluster suffers with the similar problem.
Lets try to emulate this on a 2-node Galera cluster :
1) On node #1: MariaDB [test]> CREATE TABLE t1(c1 INT AUTO_INCREMENT PRIMARY KEY, c2 INT)ENGINE=InnoDB; Query OK, 0 rows affected (0.07 sec) MariaDB [test]> START TRANSACTION; Query OK, 0[Read more...]
I’ve continued building on my MariaDB GIS and node.js example application that I wrote about two weeks back, https://blog.mariadb.org/node-js-mariadb-and-gis/. The application shows how to load GPX information into MariaDB, using some MariaDB GIS functionality, and making use of the node.js platform together with MariaDB’s non-blocking client.
With the GPX data converted into GIS points in the MariaDB database, I wanted to further expand a little on both the GIS aspect and also look at how some additional data could be shown in the application by using jQuery’s Ajax calls to update a piece of the web based application UI.
To start with, an interesting thing to do when you have a bunch of GIS[Read more...]
We rejoin our story with a lawsuit. While MySQL suing Progress NuSphere is not perhaps the first GPL lawsuit that comes to mind, it was the first time that the GPL was tested in court. Basically, the GEMINI storage engine was a proprietary storage engine bundled with a copy of MySQL. Guess what? The GPL was found to be valid and GEMINI was eventually GPLed, and it didn’t really go anywhere after that. Why? Probably some business reasons and also, InnoDB was actually rather good and there wasn’t a lawsuit to enforce the GPL there, making[Read more...]
Way back in May in the year 2000, a feature was added to MySQL that would keep many people employed for many years – replication. In 3.23.15 you could replicate from one MySQL instance to another. This is commonly cited as the results of two weeks of work by one developer. The idea is simple: create a log of all the SQL queries that modify the database and then replay them on a slave. Remember, this is[Read more...]
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