Here's a nice story - Twitter has open sourced some of their enhancements to MySQL. http://www.theregist..._sources_mysql_code/
Code the company has released includes what it calls:
- Add additional status variables, particularly from the internals of InnoDB. This allows us to monitor our systems more effectively and understand their behavior better when handling production workloads.
- Optimize memory allocation on large NUMA systems: Allocate InnoDB's buffer pool fully on startup, fail fast if memory is not available, ensure performance over time even when server is under memory pressure.
- Reduce unnecessary work through improved server-side statement timeout support. This allows the server to proactively cancel queries that run longer than a millisecond-granularity timeout.
- Export and restore InnoDB buffer pool in using a safe and lightweight method. This enables us to build tools to support rolling restarts of our services with minimal pain.
- Optimize MySQL for SSD-based machines, including page-flushing behavior and reduction in writes to disk to improve lifespan.
+1 for Twitter there!