Notes from Google + InnoDB Scalability Talk
– It seems the biggest scalability issue in InnoDB has to do with its excessive use of inefficient mutexes to protect data structures. Turning down innodb_thread_concurrency should actually help performance on multi-core boxes.
– The performance problems really start to hit at about eight core. Four core is just fine but still feels a performance hit.
– Google implemented their mutexes using X86-specific compare and swap. Apparently, Monty is working on a CAS portability library. An audit of the room 99% of the people running on X86 anyway so this might not be an issue.
– If you’re having CPU issues not upgrade to > 5.0.30. There’s another fix in > 5.0.54 which is interesting.
– Google has also replaced the innodb malloc heap with a scalable malloc library (tcmalloc). For larger buffer pools this might make a big difference.
– MySQL 6 separates threds from connections. Google will backport this patch… (Awesome)