Search Results for: use bad index order

Percona Toolkit Webinar followup Q&A

First, a thank you to everyone who attended the webinar Today, I appreciate your time and nice comments. As promised, here are answers to questions that couldn’t be answered during the talk:   Q: How do you install the tools? The manual has full details, but it’s important to know that the latest release for […]

When is MIN(DATE) != MIN(DATE) ?

Inspiration for this post is courtesy of a friend and former colleague of mine, Greg Youngblood, who pinged me last week with an interesting MySQL puzzle. He was running Percona Server 5.5.21 with a table structure that looks something like this:

When he ran this query:

The result came back as 2012-06-22 10:28:16. […]

A case for MariaDB’s Hash Joins

MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks […]

Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

This is the second blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is aimed at the optimizer enhancement Multi Range Read (MRR). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take a look at […]

Connecting orphaned .ibd files

There are two ways InnoDB can organize tablespaces. First is when all data, indexes and system buffers are stored in a single tablespace. This is typicaly one or several ibdata files. A well known innodb_file_per_table option brings the second one. Tables and system areas are split into different files. Usually system tablespace is located in […]

Pacemaker, please meet NDB Cluster or using Pacemaker/Heartbeat to start a NDB Cluster

Customers have always asked me to make NDB Cluster starts automatically upon startup of the servers. For the ones who know NDB Cluster, it is tricky to make it starts automatically. I know at least 2 sets of scripts to manage NDB startup, ndb-initializer and from Johan configurator www.severalnines.com. If all the nodes come up […]