Search Results for: database replica master slave mysql

Checking table definition consistency with mysqldiff

Data inconsistencies in replication environments are a pretty common. There are lots of posts that explain how to fix those using pt-table-checksum and pt-table-sync. Usually we only care about the data but from time to time we receive this question in support: How can I check the table definition consistency between servers? Replication also allow […]

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: […]

5 free handy tools for monitoring and managing MySQL replication

MySQL Replication is very simple to set up. In this post I’ll discuss its importance and five handy tools for monitoring and managing MySQL replication. What is MySQL Replication? It’s the process of copying the (real-time events) data from one master instance to another slave instance and maintaining the redundant consistent data in a different […]

How to setup a PXC cluster with GTIDs (and have async slaves replicating from it!)

This past week was marked by a series of personal findings related to the use of Global Transaction IDs (GTIDs) on Galera-based clusters such as Percona XtraDB Cluster (PXC). The main one being the fact that transactions touching MyISAM tables (and FLUSH PRIVILEGES!) issued on a giving node of the cluster are recorded on a GTID set […]

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. […]

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 […]

Avoiding MySQL ALTER table downtime

MySQL table alterations can interrupt production traffic causing bad customer experience or in worst cases, loss of revenue. Not all DBAs, developers, syadmins know MySQL well enough to avoid this pitfall. DBAs usually encounter these kinds of production interruptions when working with upgrade scripts that touch both application and database or if an inexperienced admin/dev […]

Facebook MySQL database engineers ready for Percona Live London 2014

With 1.28 billion active users, Facebook MySQL database engineers are active and extremely valuable contributors to the global MySQL community. So naturally they are also active participants of Percona Live MySQL conferences! And next week’s Percona Live London 2014 (Nov. 3-4) is no exception. (Register now and use the promotional code “Facebook” to save £30!) […]

How to avoid hash collisions when using MySQL’s CRC32 function

Percona Toolkit’s  pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master – and the tool pt-table-sync synchronizes data efficiently between MySQL tables. The tools by default use the CRC32. Other good choices include MD5 and SHA1. If you have installed the FNV_64 user-defined function, pt-table-sync will […]

MySQL Replication: ‘Got fatal error 1236′ causes and cures

MySQL replication is a core process for maintaining multiple copies of data – and replication is a very important aspect in database administration. In order to synchronize data between master and slaves you need to make sure that data transfers smoothly, and to do so you need to act promptly regarding replication errors to continue […]