There is much excitement today at the launch of MySQL 5.4, so I will relate my story about a project I contributed to this new version.
When we started looking at performance improvements for MySQL, we were interested in "low hanging fruit", or fixes and changes that could reap measurable benefits for users in the short term.
An obvious candidate at that time was the now well-known Google SMP patch. I had seen Mark Callaghan present on this at the MySQL User Conference in 2008, and was interested to investigate.
I was pretty new to InnoDB at that time, and was soon to discover that InnoDB was possibly experiencing poor scalability around its mutexes and read-write locks because InnoDB had a private implementation of adaptive mutexes and …
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