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 [...]
I got a serendipitous call (thanks!) yesterday asking what would be needed to tune a database for better performance. It is a question that I hear often, but I never thought about answering it in public. Here’s a consolidated version of what I explained during our conversation.
There are two ways InnoDB can organize tablespaces. First is when all data, indexes and system buffers are stored in a single tablespace. This is typicaly one or several ibdata files. A well known innodb_file_per_table option brings the second one. Tables and system areas are split into different files. Usually system tablespace is located in [...]
In a recent blog post, I wrote about four fundamental metrics for system performance analysis. These are throughput, residence time, “weighted time” (the sum of all residence times in the observation period — the terminology is mine for lack of a better name), and concurrency. I derived all of these metrics from two “even more [...]
I decided to try a series of blog posts keeping people informed about what’s happening in Percona Server and Percona XtraBackup once a week. I’ll try to digest things, but it turns out to be hard — I want to provide details and links for everything, but then it isn’t really a digest anymore, so [...]
I have a 5G mysqldump which takes 30 minutes to restore from backup.Â That means that when the database reaches 50G, it should take 30×10=5 hours to restore.Â Right?Â Wrong.
This is the third in a series on whatâ€™s seriously limiting MySQL in certain circumstances (links: part 1, 2). This post is about subqueries, which in some cases execute outside-in instead of inside-out as users expect.
Few days ago I was working on a case where we needed to modify a lot of data before pushing it to sphinx – MySQL did not have a function to do the thing so I thought I’ll write MySQL Stored Function and we’ll be good to go. It worked! But not so well really [...]
When examining MySQL configuration, we quite often want to know how various buffer sizes are used. This matters because some buffers (sort_buffer_size for example) are allocated to their full size immediately as soon as they are needed, but others are effectively a “max size” and the corresponding buffers are allocated only as big as needed [...]
So you’re running MySQL With innodb_file_per_table option but your ibdata1 file which holds main (or system) tablespace have grown dramatically from its starting 10MB size. What could be the reason of this growth and what you can do about it ? There are few things which are always stored in main tablespace – these are [...]