In MySQL 5.1 there was the
--with-fast-mutexes configure flag used almost everywhere in custom builds.
Currently, the documentation for MySQL 5.5 (here) says nothing about WITH_FAST_MUTEXES, but
cmake . -LAH reports it to be there and disabled by default:
// Compile with fast mutexes WITH_FAST_MUTEXES:BOOL=OFF
So, my question: what's the fate and the importance of WITH_FAST_MUTEXES in MySQL 5.5? Is it just a hidden option that could be enabled? does it add any performance improvements? or is it just a zombie option good for nothing/ignored?