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Schema changes in MySQL for OpenStack Trove users

 | November 24, 2014 |  Posted In: MySQL, OpenStack

People using OpenStack Trove instances can hit a common issue in the MySQL world: how to perform schema change operations while minimizing the impact on the database server? Let’s explore the options that can allow online schema changes. Summary With MySQL 5.5, pt-online-schema-change from Percona Toolkit is your best option for large tables while regular […]

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Data inconsistencies on MySQL replicas: Beyond pt-table-checksum

 | November 4, 2014 |  Posted In: MySQL, Percona Toolkit

Percona Toolkit’s pt-table-checksum is a great tool to find data inconsistencies between a MySQL master and its replicas. However it is sometimes not enough to know that there are inconsistencies and let pt-table-sync fix the issue: you may want to know which exact rows are different to identify the statements that created the inconsistency. This […]

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MySQL ring replication: Why it is a bad option

 | October 7, 2014 |  Posted In: High-availability, Insight for DBAs, MySQL, Percona MySQL Consulting

I’ve recently worked with customers using replication rings with 4+ servers; several servers accepting writes. The idea behind this design is always the same: by having multiple servers, you get high availability and by having multiple writer nodes, you get write scalability. Alas, this is simply not true. Here is why. High Availability Having several […]

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HAProxy: Give me some logs on CentOS 6.5!

 | October 3, 2014 |  Posted In: Insight for DBAs, MySQL

HAProxy is frequently used as a load-balancer in front of a Galera cluster. While diagnosing an issue with HAProxy configuration, I realized that logging doesn’t work out of the box on CentOS 6.5. Here is a simple recipe to fix the issue. If you look at the top of /etc/haproxy/haproxy.cfg, you will see something like: […]

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Using MySQL 5.6 Global Transaction IDs (GTIDs) in production: Q&A

 | September 5, 2014 |  Posted In: MySQL, Percona MySQL Consulting, Technical Webinars

Thank you to all of you who attended my webinar last week about Global Transaction IDs (GTIDs), which were introduced in MySQL 5.6 to make the reconfiguration of replication straightforward. If you missed my webinar, you can still listen to the recording and download the sides (free). We had a lot of questions during the […]

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