So far most of the benchmarks posted about MySQL 5.6 use the sysbench OLTP workload. I wanted to test a set of queries which, unlike sysbench, utilize joins. I also wanted an easily reproducible set of data which is more rich than the simple sysbench table. The Star Schema Benchmark (SSB) seems ideal for this. [...]
Recovery deleted ibdata1
August 10, 2012 By 9 Comments
Recently I had a case when a customer deleted the InnoDB main table space – ibdata1 – and redo logs – ib_logfile*. MySQL keeps InnoDB files open all the time. The following recovery technique is based on this fact and it allowed to salvage the database. Actually, the files were deleted long time ago – [...]
Comparing Percona XtraDB Cluster with Semi-Sync replication Cross-WAN
June 14, 2012 By 7 Comments
I have a customer who is considering Percona XtraDB Cluster (PXC) in a two colo WAN environment. They wanted me to do a test comparing PXC against semi-synchronous replication to see how they stack up against each other. Test Environment The test environment included AWS EC2 nodes in US-East and US-West (Oregon). The ping RTT latency [...]
How to recover deleted rows from an InnoDB Tablespace
February 20, 2012 By 4 Comments
In my previous post I explained how it could be possible to recover, on some specific cases, a single table from a full backup in order to save time and make the recovery process more straightforward. Now the scenario is worse because we don’t have a backup or the backup restore process doesn’t work. How [...]
Recovering Linux software RAID, RAID5 Array
August 27, 2011 By 2 Comments
Dealing with MySQL you might need to deal with RAID recovery every so often. Sometimes because of client lacking the proper backup or sometimes because recovering RAID might improve recovery, for example you might get point in time recovery while backup setup only takes you to the point where last binary log was backed up. [...]
MySQL performance on EC2/EBS versus RDS
August 4, 2011 By 11 Comments
A while ago I started a series of posts showing benchmark results on Amazon EC2 servers with RAID’ed EBS volumes and MySQL, versus RDS machines. For reasons that won’t add anything to this discussion, I got sidetracked, and then time passed, and I no longer think it’s a good idea to publish those blog posts [...]
Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
In the first part of this article I have showed how I align IO, now I want to share results of the benchmark that I have been running to see how much benefit can we get from a proper IO alignment on a 4-disk RAID1+0 with 64k stripe element. I haven’t been running any benchmarks [...]
How InnoDB handles REDO logging
February 3, 2011 By 19 Comments
Xaprb (Baron) recently blogged about how InnoDB performs a checkpoint , I thought it might be useful to explain another important mechanism that affects both response time and throughput – The transaction log.
How innodb_open_files affects performance
November 18, 2009 By 4 Comments
Recently I looked at table_cache sizing which showed larger table cache does not always provides the best performance. So I decided to look at yet another similar variable – innodb_open_files which defines how many files Innodb will keep open while working in innodb_file_per_table mode. Unlike MyISAM Innodb does not have to keep open file descriptor [...]
table_cache negative scalability
November 16, 2009 By 23 Comments
Couple of months ago there was a post by FreshBooks on getting great performance improvements by lowering table_cache variable. So I decided to investigate what is really happening here. The “common sense” approach to tuning caches is to get them as large as you can if you have enough resources (such as memory). With MySQL [...]
