Stéphane Combaudon

Percona Toolkit is a set of tools that can help the DBA to perform tasks that are common but difficult to do manually. In this presentation, we will see how you can use some of the tools to solve typical problems: - Which queries should I try to optimize to get better response times (pt-query-digest)? - How can I efficiently purge data from my huge table without putting too much load on the server (pt-archiver)? - Someone has accidentally written to a replica, how can I check which tables are affected and fix the problems without rebuilding the replica (pt-table-checksum & pt-table-sync)? - How can I gather data for my performance problems that happen randomly and last only a few seconds (pt-stalk)? - How can I run ALTER TABLE on my largest tables without downtime (pt-online-schema-change)?

In many production systems, indexes are designed empirically and without instrumentation to check their efficiency, resulting in poor performance and increased hardware needs. Learn in this talk the fundamental ideas behind indexing, the errors you should avoid and the tools that can help you harness the full power of indexes. The following topics will be covered: - strengths and limitations of indexes in MySQL - performance degradation caused by bad indexes - guidelines to design efficient indexes - tools and methods to identify and remove unnecessary indexes.