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Performance Schema: Measure Multi-Threaded Slave Activity

 | December 18, 2015 |  Posted In: MySQL, Performance Schema

multi-threaded slave

Performance Schema In many types of database workloads, using a multi-threaded slave from 5.6+ helps improve replication performance. I’ve had a number of users enable this feature, but have not seen anyone ask how each thread is performing. Here’s a quick way with Performance_Schema to measure the amount of multi-threaded slave activity on each thread (after you […]

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How Big Can Your Galera Transactions Be

 | October 26, 2015 |  Posted In: Percona XtraDB Cluster

While we should be aiming for small and fast transactions with Galera, it is always possible at some point you might want a single large transaction, but what is involved? First, this is supposed to be controlled by two settings, wsrep_max_ws_rows  and wsrep_max_ws_size . The first variable is not yet enforced and has no effect – see […]

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Profiling MySQL queries from Performance Schema

 | April 16, 2015 |  Posted In: MySQL

When optimizing queries and investigating performance issues, MySQL comes with built in support for profiling queries aka SET profiling = 1; . This is already awesome and simple to use, but why the PERFORMANCE_SCHEMA alternative? Because profiling will be removed soon (already deprecated on MySQL 5.6 ad 5.7); the built-in profiling capability can only be enabled per session. This […]

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Recover orphaned InnoDB partition tablespaces in MySQL

 | October 14, 2014 |  Posted In: InnoDB, MySQL

A few months back, Michael wrote about reconnecting orphaned *.ibd files using MySQL 5.6. I will show you the same procedure, this time for partitioned tables. An InnoDB partition is also a self-contained tablespace in itself so you can use the same method described in the previous post. To begin with, I have an example […]

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Syncing MySQL slave table with pt-online-schema-change

 | September 17, 2014 |  Posted In: Insight for DBAs, MySQL, Percona Toolkit

I recently encountered a situation in which after running Percona Toolkit’s pt-table-checksum on a customer system, 95% of the table on the MySQL master was different on the MySQL slave. Although this table was not a critical part of the infrastructure, from time to time, writes to the table from the master would break replication. […]

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High Availability with mysqlnd_ms on Percona XtraDB Cluster

 | July 16, 2014 |  Posted In: High-availability, Insight for Developers, MySQL, Percona XtraDB Cluster

This is the second part of my series on High Availability with mysqlnd_ms. In my first post, “Simple MySQL Master HA with mysqlnd_ms,” I showed a simple HA solution using asynchronous MySQL replication. This time we will see how to leverage an all-primary cluster where you can write to all nodes. In this post I used […]

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Simple MySQL Master HA with mysqlnd_ms

 | July 14, 2014 |  Posted In: Insight for Developers, MySQL

I had the pleasure of presenting to the PHP Users Group Philippines a few days ago about mysqlnd_ms. The mysqlnd plugin, MySQL Master Slave, is a transparent layer on top of mysqlnd extension. This allows you to do read-write splitting and slave reads load balancing without needing to change anything from your application. But do […]

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Encrypted and incremental MySQL backups with Percona XtraBackup

 | April 24, 2014 |  Posted In: MySQL, Percona MySQL Consulting, Percona MySQL Support, Percona Software, Percona XtraBackup

We’ve recently received a number of questions on how to implement incremental MySQL backups alongside encryption with Percona XtraBackup. Some users thought it was not initially possible because with the default --encrypt options with XtraBackup, all files will be encrypted, but alas, that is not the case. This is where the option --extra-lsn-dir becomes useful, […]

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