Search Results for: mysql log

Log rotate and the (deleted) MySQL log file mystery

Did your logging stop working after you set up logrotate? Then this post might be for you. Some time ago, Peter Boros wrote about Rotating MySQL Slow Logs safely, explaining the steps of a “best practice” log rotate/archive. This post will add more info about the topic. When running logrotate for MySQL (after proper setting […]

Be careful rotating MySQL logs

If you enable logging of all queries as “slow queries” using the patch or MySQL 5.1 you can get log file to grow huge. Same may happen with general log file. In some cases we’ve got log file sizes of 100G or more which may need to be cleaned up. Here is some danger waiting […]

Why base64-output=DECODE-ROWS does not print row events in MySQL binary logs

Lately I saw many cases when users specified option --base64-output=DECODE-ROWS  to print out a statement representation of row events in MySQL binary logs just to get nothing. Reason for this is obvious: option --base64-output=DECODE-ROWS  does not convert row events into its string representation, this is job of option --verbose . But why users mix these […]

Identifying useful info from MySQL row-based binary logs

As a MySQL DBA/consultant, it is part of my job to decode the MySQL binary logs – and there are a number of reasons for doing that. In this post, I’ll explain how you can get the important information about your write workload using MySQL row-based binary logs and a simple awk script. First, it […]

Logical MySQL backup tool mydumper 0.6.2 now available

We are pleased to announce the third release in the 0.6 series of mydumper, a tool for performing logical MySQL backups. In this release, we focused on simplifying compiling the code and added new features for making logical backups. These new features include enhancements to AWS RDS support and extending TokuDB support. Due to recent changes (or […]

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 […]

max_allowed_packet and binary log corruption in MySQL

The combination of max_allowed_packet variable and replication in MySQL is a common source of headaches. In a nutshell, max_allowed_packet is the maximum size of a MySQL network protocol packet that the server can create or read. It has a default value of 1MB (<= 5.6.5) or 4MB (>= 5.6.6) and a maximum size of 1GB. […]

7 Key MySQL clustering technologies – A joint webinar with 451 Research

I’m looking forward to Wednesday’s joint webinar on MySQL clustering technologies with Matt Aslett, research director of data management and analytics over at 451 Research. We’ll be participating in a live, in-depth discussion of MySQL Clustering for High Availability and Scalability. Matt will present an overview of the trends driving adoption of clustering technology. He’ll […]

How to log slow queries on Slave in MySQL 5.0 with pt-query-digest

Working as a Percona Support Engineer, every day we are seeing lots of issues related to MySQL replication. One very common issue is slave lagging. There are many reasons for slave lag but one common reason is that queries are taking more time on slave then master. How to check and log those long-running queries?  From […]

Tools and tips for analysis of MySQL’s Slow Query Log

MySQL has a nice feature, slow query log, which allows you to log all queries that exceed a predefined about of time to execute. Peter Zaitsev first wrote about this back in 2006 – there have been a few other posts here on the MySQL Performance Blog since then (check this and this, too) but […]