Search Results for: small is better

How small changes impact complex systems – MySQL example

If you’ve been studying complex systems you know what minor changes might cause consequences of much greater proportions, sometimes causing some effects that are not easily explained at first. I recently ran across a great illustration of such behavior while doing MySQL benchmarks which I thought would be interesting to share. I’m using a very […]

Wanted: Better memory profiling for MySQL

Quite frequently I would log in to customers system and find MySQL using too much memory. I would look at memory consumed by Innodb (it is often higher than innodb_buffer_pool_size) substract memory used by other global buffers such as query_cache_size and key_buffer and will in many cases see some mysterous memory which I can’t really […]

Are larger buffers always better ?

Sometimes I see people thinking about buffers as “larger is always better” so if “large” MySQL sample configuration is designed for 2GB and they happen to have 16, they would simply multiply all/most values by 10 and hope it will work well. Obviously it does not. The least problem would be wasting memory, allocating a […]

Indexing 101: Optimizing MySQL queries on a single table

I have recently seen several cases when performance for MySQL queries on a single table was terrible. The reason was simple: the wrong indexes were added and so the execution plan was poor. Here are guidelines to help you optimize various kinds of single-table queries. Disclaimer: I will be presenting general guidelines and I do […]

InnoDB locks and deadlocks with or without index for different isolation level

Recently, I was working on one of the issue related to locks and deadlocks with InnoDB tables and I found very interesting details about how InnoDB locks and deadlocks works with or without index for different Isolation levels. Here, I would like to describe a small test case about how SELECT ..FOR UPDATE (with and without limit) behave […]

The value of MySQL Support

Years ago when I worked for the MySQL Support organization at the original MySQL AB, we spoke about MySQL Support as insurance and focused on a value proposition similar to that of car insurance. For your car to be fully covered, you must purchase car insurance before the incident happens – in fact most places […]

Calling all MySQL DBAs: How do you use Percona Toolkit?

Percona Toolkit is one of our most mature open source applications. Derived from Maatkit and Aspersa, Percona Toolkit has evolved significantly over the years. The software now contains 32 tools, over 4,000 tests, and has been downloaded over 250,000 times. Anyone who manages a database – from DBAs to system administrators to even software developers […]