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Showing entries 1 to 10 of 867 10 Older Entries

Displaying posts with tag: mariadb (reset)

Creating JSON documents with MariaDB
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You probably know about two MariaDB great features: Dynamic Columns and Virtual Colums. I don’t think that we already found all possible use cases for them: more ideas will come in the future, and hopefully someone will write about them. Here, I will describe a use case which involves both Virtual Columns and Dynamic Columns.

Now, suppose that we have relational data in MariaDB, and we want to …

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Multi-source Replication with Galera Cluster for MySQL
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November 20, 2014 By Severalnines

Multi-source replication means that one server can have multiple masters from which it replicates. Why multi-source? One good reason is to consolidate databases (e.g. merge your shards) for analytical reporting or as a centralized backup server. MariaDB 10 already has this feature, and MySQL 5.7 will also support it. 

It is possible to set up your Galera Cluster as an aggregator of your masters in a multi-source replication setup, we’ll walk you through the steps in this blog. Note that the howto is for Galera Cluster for MySQL (Codership) and Percona XtraDB Cluster. In a separate post, …

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Improving InnoDB index statistics
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The MySQL/MariaDB optimiser likes to know things like the cardinality of an index – that is, the number of distinct values the index holds. For a PRIMARY KEY, which only has unique values, the number is the same as the number of rows.  For an indexed column that is boolean (such as yes/no) the cardinality would be 2.

There’s more to it than that, but the point is that the optimiser needs some statistics from indexes in order to try and make somewhat sane decisions about which index to use for a particular query. The statistics also need to be updated when a significant number of rows have been added, deleted, or modified.

In MyISAM, …

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New ClusterControl User Guide for MySQL based Clusters
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November 19, 2014 By Severalnines

Following the release of ClusterControl 1.2.8 with a range of cool new features, we have now also published a new ClusterControl User Guide that provides all the steps, tips & tricks to follow in order to successfully deploy, monitor, manage and scale database clusters.  

This user guide predominantly covers ClusterControl with MySQL-based clusters, namely:

  • Percona XtraDB Cluster
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Optimising multi-threaded replication
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Multi-threaded replication is a new feature introduced in MySQL 5.6 and MariaDB 10.0. In traditional single-threaded replication, the slaves have a disadvantage as they have to process in sequence what a master executed in parallel. This, plus the fact that slaves usually have a lot of read-only connections to deal with as well, can easily create performance problems. That is, a single-threaded slave …

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MMUG9: Madrid MySQL Users Group meeting to take place on 20th Noevember 2014
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Madrid MySQL Users Group will have its next meeting on the 20th of November. Details can be found on the group’s Meetup page.

We plan to talk about pstop, which I’ve announced earlier and also the latest changes in MariaDB and MySQL since our last meeting.  The meeting will be in Spanish. I hope to see you there.

La próxima reunión de Madrid MySQL Users Group tendrá lugar el jueves 20 de noviembre. Se puede encontrar más detalles en la  …

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9 DevOps Tips for Going in Production with Galera Cluster for MySQL - Webinar Replay & Slides
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November 14, 2014 By Severalnines

Thanks to everyone who attended and participated in this week's webinar on '9 DevOps Tips for Going in Production with Galera Cluster for MySQL'. If you missed the sessions or would like to watch the webinar again & browse through the slides, they are now available online.

 

In this webinar, Severalnines CTO Johan Andersson discussed 9 key aspects to consider before taking Galera Cluster for MySQL into production:

  • 101 Sanity Check
  • Operating System
  • Backup Strategies
  • Galera Recovery
  • Query …
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Log rotate and the (deleted) MySQL log file mystery
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Did your logging stop working after you set up logrotate? Then this post might be for you.

Archive your log files!

Some time ago, Peter Boros wrote about Rotating MySQL Slow Logs safely, explaining the steps of a “best practice” log rotate/archive. This post will add more info about the topic.

When running logrotate for MySQL (after proper setting the /etc/logrotate.d/mysql conf file) from anacron, there’s a situation that you might potentially face if the user and password used to execute the …

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Discussing the innodb_log_block_size variable
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Not a ground-breaking post here, but if you are interested in knowing more about the innodb_log_block_size variable, or if you use SSD cards and/or large InnoDB log files on ext4, then this is for you.

I’d read about it before briefly before, but didn’t give it too much thought until I ran across the following entry in an error log the other day:

InnoDB: Warning: innodb_log_block_size has been changed
from default value 512. (###EXPERIMENTAL### operation)

This got me wanting to know more.

Basically, this variable changes the size of transaction log records. Generally, the default of 512 is a good value. However, …

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Dynamic compound statements in MariaDB
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A long-ago-discussed and much-requested feature, "dynamic compound statements", is working at last.

It's been eleven years since the original discussion of dynamic compound statements for MySQL, as you can see by looking at the worklog task on the wayback machine. (As usual, you have to click the "high level architecture" box to see the meat of the specification.) The essential idea is that one can directly enter compound statements like BEGIN ... END and conditional statements like "IF ... END IF" and looping statements …

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Showing entries 1 to 10 of 867 10 Older Entries

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