September 2, 2014

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 […]

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 […]

Why MySQL’s binlog-do-db option is dangerous

I see a lot of people filtering replication with binlog-do-db, binlog-ignore-db, replicate-do-db, and replicate-ignore-db. Although there are uses for these, they are dangerous and in my opinion, they are overused. For many cases, there’s a safer alternative.

Impact of logging on MySQL’s performance

Introduction When people think about Percona’s microslow patch immediately a question arises how much logging impacts on performance. When we do performance audit often we log every query to find not only slow queries. A query may take less than a second to execute, but a huge number of such queries may significantly load a […]

Beware: ext3 and sync-binlog do not play well together

One of our customers reported strange problem with MySQL having extremely poor performance when sync-binlog=1 is enabled, even though the system with RAID and BBU were expected to have much better performance. The problem could be repeated with SysBench as follows:

Mirrored Binlogs patch

Google patches V1 contain interesting patch to mirror binary log on slave. Although Google is preparing GlobalTransactionId patch, which going to be replacement for MirroredBinlogs, we still think mirroring binary logs is very useful for: Backup of binary logs in real time High availability, to switch master load to slave with mirrored binary logs By […]

Why audit logging with triggers in MySQL is bad for replication

Recently I was tasked with investigating slippage between master and slave in a standard replication setup. The client was using Maatkit’s mk-table-checksum to check his slave data was indeed a fair copy of that of the master.

Troubleshooting Relay Log Corruption in MySQL

Have you ever seen the replication stopped with message like this: Last_Error: Could not parse relay log event entry. The possible reasons are: the master’s binary log is corrupted (you can check this by running ‘mysqlbinlog’ on the binary log), the slave’s relay log is corrupted (you can check this by running ‘mysqlbinlog’ on the […]

Monty unviels Maria and starts Blogging

This weekend we’re hearing great news from Michael “Monty” Widenius – one of the Fathers of MySQL. Monty finally found a time to create his own blog with very descriptive name Monty Says. At the same time Monty finally announces Maria – the MyISAM successor storage engine he has been working for last few years. […]

Rebuilding MySQL Binary

Running RPM based or other packaged MySQL Binary you may have a problem if you would like to rebuild binary for some reason – change some build settings, apply some third party patches or simply try latest snapshot (This time I was both applying patches for Innodb scalability and Vadim’s patches to get proper slow […]