Emergency

Search Results for: how mysql works

The MySQL Query Cache: How it works, plus workload impacts (good and bad)

Query caching is one of the prominent features in MySQL and a vital part of query optimization. It is important to know how it works as it has the potential to cause significant performance improvements – …


How to scale big data applications using MySQL sharding frameworks

This Wednesday I’ll be discussing two common types of big data: machine-generated data and user-generated content. These types of big data are amenable to sharding, a commonly used technique for spreading data over more than …


MySQL Workshops: Chicago & London this April

Percona will be in Chicago and London the week of April 8th delivering two 2-day MySQL workshops. For our MPB readers, we are offering a 15% discount. Just use MPB15A when purchasing your tickets to …


How MySQL Query Cache works with Transactions

As MySQL Manual Says Query Cache works with transactions with Innodb tables but it does not tell you how and with which restrictions. According to my tests it works but it is very restricted and …


Multi-source replication in MySQL 5.7 vs Tungsten Replicator

MySQL 5.7 comes with a new set of features and multi-source replication is one of them. In few words this means that one slave can replicate from different masters simultaneously. During the last couple of …


MySQL QA Episode 5: Preparing Your QA Run with pquery

Welcome to MySQL QA Episode #5! In this episode we’ll be setting up and running pquery for the first time… and I’ll also trigger some actual bugs (fun guaranteed)! I’ll also introduce you to mtr_to_sql.sh …


Getting EXPLAIN information from already running queries in MySQL 5.7

When a new version of MySQL is about to be released we read a lot of blog posts about the performance and scalability improvements. That’s good but sometimes we miss some small features that can …


Optimizer hints in MySQL 5.7.7 – The missed manual

In version MySQL 5.7.7 Oracle presented a new promising feature: optimizer hints. However it did not publish any documentation about the hints. The only note which I found in the user manual about the hints …


Yelp IT! A talk with 3 Yelp MySQL DBAs on Percona Live & more

Founded in 2004 to help people find great local businesses, Yelp has some 135 million monthly unique visitors. With those traffic volumes Yelp’s 300+ engineers are constantly working to keep things moving smoothly – and …


Easy query metrics with MySQL Performance Schema

The MySQL Performance Schema exposes so much data that it’s not trivial to learn, configure, and use. With recently released Percona Agent 1.0.11 you can get query metrics – like min, max, and average query execution time …