If you’ve used MySQL’s mysqlbinlog tool, you’ve probably seen something like the following in the output: “exec_time=0″ What is the exec_time? It seems to be the query’s execution time, but it is not.
Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the Percona documentation or forums. So I present to you what is now my newest Firefox toolbar bookmark: an option and [...]
Storing MySQL Binary logs on NFS Volume
July 30, 2010 By 19 Comments
There is a lot of discussions whenever running MySQL storing data on NFS is a good idea. There is a lot of things for and against this and this post is not about them. The fact is number of people run their databases on NetApp and other forms of NFS storage and this post is [...]
Estimating Replication Capacity
July 20, 2010 By 4 Comments
It is easy for MySQL replication to become bottleneck when Master server is not seriously loaded and the more cores and hard drives the get the larger the difference becomes, as long as replication remains single thread process. At the same time it is a lot easier to optimize your system when your replication runs [...]
Debugging problems with row based replication
May 6, 2010 By 12 Comments
MySQL 5.1 introduces row based binary logging. In fact, the default binary logging format in GA versions of MySQL 5.1 is ‘MIXED’ STATEMENT*; The binlog_format variable can still be changed per sessions which means it is possible that some of your binary log entries will be written in a row-based fashion instead of the [...]
How to know if you’re updating Slave you should not ?
April 11, 2010 By 8 Comments
When replication runs out of sync first question you often ask is if someone could be writing to the slave. Of course there is read_only setting which is good to set in the slave but it is not set always and also users with SUPER privilege bypass it. Looking into binary log is obvious choice [...]
Missleading Innodb message on recovery
February 15, 2010 By 2 Comments
As I wrote about 2 years ago the feature of Innodb to store copy of master’s position in Slave’s Innodb tablespace got broken. There is a lot of discussions at the corresponding bug report while outcome of the fix remained uncertain for me (the bug is market duplicate while the bugs it seems to be [...]
Mirrored Binlogs patch
October 25, 2008 By 3 Comments
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
September 29, 2008 By 10 Comments
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.
Recovery beyond data restore
August 2, 2008 By 11 Comments
Quite frequently I see customers looking at recovery as on ability to restore data from backup which can be far from being enough to restore the whole system to operating state, especially for complex systems. Instead of looking just at data restore process you better look at the whole process which is required to bring [...]
