Search Results for: define primary key mysql

What stopped MySQL? Tracing back signals sent to MySQL

Have you ever had a case where you needed to find a process which sent a HUP/KILL/TERM or other signal to your database? Let me rephrase. Did you ever have to find which process messed up your night? ūüėČ If so, you might want to read on. I’m going to tell you how you can […]

‘Indexing’ JSON documents for efficient MySQL queries over JSON data

MySQL meets NoSQL with JSON UDF I recently got back from FOSDEM, in Brussels, Belgium. While I was there I got to see a great talk by Sveta Smirnova, about her MySQL 5.7 Labs release JSON UDF functions. It is important to note that while the UDF come in a 5.7 release it is absolutely […]

InnoDB crash recovery speed in MySQL 5.6

It has been a while since I have looked at InnoDB crash recovery. A lot has change in the last few years – we have serious crash recovery performance improvements in MySQL 5.5 and MySQL 5.6, we have solid state drives raising as typical high performance IO subsystem and we also have the ability to […]

How to avoid hash collisions when using MySQL’s CRC32 function

Percona Toolkit’s¬† pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master – and the tool pt-table-sync synchronizes data efficiently between MySQL tables. The tools by default use the¬†CRC32. Other good choices include¬†MD5¬†and¬†SHA1. If you have installed the¬†FNV_64¬†user-defined function,¬†pt-table-sync¬†will […]

Managing shards of MySQL databases with MySQL Fabric

This is the fourth post in our MySQL Fabric series. In case you’re joining us now, we started with an¬†introductory¬†post, and then discussed High Availability (HA) using MySQL Fabric here (Part 1) and here (Part 2). Today we will¬†talk about how MySQL Fabric can help you scale out MySQL databases with sharding. Introduction At the […]

Q&A: Common (but deadly) MySQL Development Mistakes

On Wednesday I gave a presentation on ‚ÄúHow to Avoid Common (but Deadly) MySQL Development Mistakes‚ÄĚ for Percona MySQL Webinars. If you missed it, you can still¬†register¬†to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions. I answered as many as we had time […]

How to monitor ALTER TABLE progress in MySQL

While working on a recent support issue as a¬†Percona Support Engineer,¬† I got one question from a customer asking how to monitor ALTER TABLE progress. Actually, for¬†MySQL 5.5¬†and prior versions,¬†it’s quite difficult to ALTER the table in a running production environment especially for large tables (with millions records).¬†Because it will rebuild and lock the table […]

InnoDB scalability issues due to tables without primary keys

Each day there is probably work done to improve performance of the InnoDB storage engine and remove bottlenecks and scalability issues. Hence there was another one I wanted to highlight: Scalability issues due to tables without primary keys This scalability issue is caused by the usage of tables without primary keys. This issue typically shows […]

Introduction to Percona XtraBackup 2.1 (MySQL webinar & more)

Percona XtraBackup 2.1 has been in GA now for a little over four months and has some impressive new features to improve backup performance, security, and storage requirements. When used with Percona Server, additional features are enabled that can provide even more dramatic performance improvements. Percona XtraBackup is open source, free MySQL hot backup software […]

Advanced MySQL Query Tuning: Webinar followup Q&A

Thanks to all who attended my “MySQL Query Tuning” webinar on July 24. ¬†If you missed it, you can you can download the slides and also watch the recorded video. Thank you for the excellent questions after the webinar as well. Query tuning is a big topic and, due to the limited time, I had […]