Tag - Optimizer

Why Optimization derived_merge can Break Your Queries

MySQL optimizer bugs

Lately, I worked on several queries which started returning wrong results after upgrading MySQL Server to version 5.7 The reason for the failure was derived merge optimization which is one of the default
optimizer_switch  options. Issues were solved, though at the price of performance, when we turned it
OFF . But, more importantly, we could […]

Read more

ANALYZE TABLE Is No Longer a Blocking Operation

analyze table

In this post, I’ll discuss the fix for lp:1704195 (migrated to PS-2503), which prevents
ANALYZE TABLE from blocking all subsequent queries on the same table.
In November 2017, Percona released a fix for lp:1704195 (migrated to PS-2503), created by Laurynas Biveinis. The fix, included with Percona Server for MySQL since versions 5.6.38-83.0 and 5.7.20-18, stops
ANALYZE TABLE from invalidating […]

Read more

Percona Live Featured Tutorial with Morgan Tocker — MySQL 8.0 Optimizer Guide

Percona Live Featured Tutorial

Welcome to another post in the series of Percona Live featured tutorial speakers blogs! In these blogs, we’ll highlight some of the tutorial speakers that will be at this year’s Percona Live conference. We’ll also discuss how these tutorials can help you improve your database environment. Make sure to read to the end to get a special […]

Read more

Percona Live Europe 2016: “MySQL 8.0: what’s new in Optimizer” with Manyi Lu

Percona Live Europe

Today was the first day of sessions at Percona Live Europe 2016, and it was packed with exciting talks and important information on open source databases. Some of the most anticipated talks are those that cover what to expect in MySQL 8.0.
One of those talks was given by Oracle’s Manyi Lu, Director of Software Development. […]

Read more

Introduction into storage engine troubleshooting: Q & A

Overlooked MySQL performance optimization

In this blog, I will provide answers to the Q & A for the “Introduction into storage engine troubleshooting” webinar.
First, I want to thank everybody for attending the July 14 webinar. The recording and slides for the webinar are available here. Below is the list of your questions that I wasn’t able to answer […]

Read more