November 28, 2014

How to move the InnoDB log sequence number (LSN) forward

This post focuses on the problem of the InnoDB log sequence number being in the future. Preface: What is an InnoDB log sequence number? The Log sequence number (LSN) is an important database parameter used by InnoDB in many places. The most important use is for crash recovery and buffer pool purge control. Internally, the InnoDB […]

MVCC: Transaction IDs, Log Sequence numbers and Snapshots

MySQL Storage Engines implementing Multi Version Concurrency Control have several internal identifiers related to MVCC. I see a lot of people being confused what they are and why they are needed so I decided to take a time to explain it a bit. This is general explanation, it does not corresponds to Innodb in particular […]

Trawling the binlog with FlexCDC and new FlexCDC plugins for MySQL

Swanhart-Tools includes FlexCDC, a change data capture tool for MySQL. FlexCDC follows a server’s binary log and usually writes “changelogs” that track the changes to tables in the database. I say usually because the latest version of Swanhart-Tools (only in github for now) supports FlexCDC plugins, which allow you to send the updates to a remote […]

Innodb redo log archiving

Percona Server 5.6.11-60.3 introduces a new “log archiving” feature. Percona XtraBackup 2.1.5 supports “apply archived logs.” What does it mean and how it can be used? Percona products propose three kinds of incremental backups. The first is full scan of data files and comparison the data with backup data to find some delta. This approach […]

Incremental backups with log archiving for XtraDB

Percona Server 5.6.11-60.3 has introduced a new feature called Log Archiving for XtraDB. This feature makes copies of the old log files before they are overwritten, thus saving all the redo log for a write workload. When log archiving is enabled, it duplicates all redo log writes in a separate set of files in addition […]

The relationship between Innodb Log checkpointing and dirty Buffer pool pages

This is a time-honored topic, and there’s no shortage of articles on the topic on this blog. I wanted to write a post trying to condense and clarify those posts, as it has taken me a while to really understand this relationship. Some basic facts Most of us know that writing into Innodb updates buffer […]

How to calculate a good InnoDB log file size

Peter wrote a post a while ago about choosing a good InnoDB log file size.  Not to pick on Peter, but the post actually kind of talks about a lot of things and then doesn’t tell you how to choose a good log file size!  So I thought I’d clarify it a little. The basic […]

Optimizing MySQL for Zabbix

This blog post was inspired by my visit at the annual Zabbix Conference in Riga, Latvia this year, where I gave a couple of talks on MySQL and beyond. It was a two day single-track event with some 200 participants, a number of interesting talks on Zabbix (and related technologies) and really well-organized evening activities. […]

Encrypted and incremental MySQL backups with Percona XtraBackup

We’ve recently received a number of questions on how to implement incremental MySQL backups alongside encryption with Percona XtraBackup. Some users thought it was not initially possible because with the default --encrypt options with XtraBackup, all files will be encrypted, but alas, that is not the case. This is where the option --extra-lsn-dir becomes useful, […]

Limited disk space? Compact backups with Percona Xtrabackup 2.1

One very interesting feature, “Compact Backup,” is introduced in Percona XtraBackup 2.1. You can run “compact backups” with the  –compact option, which is very useful for those who have limited disk space to keep the MySQL database backup. Now let’s first understand how it works. When we are using –compact option with Innobackupex, it will omit the […]