Q&A: Multi-threaded Replication in MySQL 5.6 and MySQL 5.7

My webinar “Multi-threaded Replication in MySQL 5.6 and 5.7″ on February 25 generated several excellent questions following the presentation (available here for playback along with the slides). I didn’t have time to answer many of the questions during the session and so in this post I answer all of them. Thanks to everyone who attended! Q: […]

Emulating MySQL roles with the Percona PAM plugin and proxy users

From time to time people wonder how to implement roles in MySQL. This can be useful for companies having to deal with many user accounts or for companies with tight security requirements (PCI or HIPAA for instance). Roles do not exist in regular MySQL but here is an example on how to emulate them using […]

More on MySQL 5.6 multi-threaded replication and GTIDs (and Feb. 25 webinar)

In a previous post, titled “Multi-threaded replication with MySQL 5.6: Use GTIDs,” I explained that using GTID replication is almost a requirement when using MySQL 5.6 MTS. Let’s see now how to perform the day-to-day operations when MTS and GTIDs are both enabled. (I’ll also be presenting a related webinar next week titled “Multi-threaded Replication […]

Percona XtraDB Cluster 5.6: a tale of 2 GTIDs

Say you have a cluster with 3 nodes using Percona XtraDB Cluster (PXC) 5.6 and one asynchronous replica connected to node1. If asynchronous replication is using GTIDs, moving the replica so that it is connected to node2 is trivial, right? Actually replication can easily break for reasons that may not be obvious at first sight. […]

Online GTID rollout now available in Percona Server 5.6

Global Transaction IDs (GTIDs) are one of my favorite features of MySQL 5.6. The main limitation is that you must stop all the servers at the same time to allow GTID-replication. Not everyone can afford to take a downtime so this requirement has been a showstopper for many people. Starting with Percona Server 5.6.22-72.0 enabling […]

Multi-threaded replication with MySQL 5.6: Use GTIDs!

MySQL 5.6 allows you to execute replicated events in parallel as long as data is split across several databases. This feature is named “Multi-Threaded Slave” (MTS) and it is easy to enable by setting slave_parallel_workers to a > 1 value. However if you decide to use MTS without GTIDs, you may run into annoying issues. […]

Diagnosing SST errors with Percona XtraDB Cluster for MySQL

State Snapshot Transfer (SST) is used in Percona XtraDB Cluster (PXC) when a new node joins the cluster or to resync a failed node if Incremental State Transfer (IST) is no longer available. SST is triggered automatically but there is no magic: If it is not configured properly, it will not work and new nodes […]

Making HAProxy 1.5 replication lag aware in MySQL

HAProxy is frequently used as a software load balancer in the MySQL world. Peter Boros, in a past post, explained how to set it up with Percona XtraDB Cluster (PXC) so that it only sends queries to available nodes. The same approach can be used in a regular master-slaves setup to spread the read load across […]

Faster restarts for MySQL and Percona Server 5.6.21+

By default in MySQL 5.6, each time MySQL is started (regular start or crash recovery), it iterates through all the binlog files when GTIDs are not enabled. This can take a very long time if you have a large number of binary log files. MySQL and Percona Server 5.6.21+ have a fix with the simplified-binlog-gtid-recovery […]

Schema changes in MySQL for OpenStack Trove users

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 […]