mysql performance on freebsd 7

[Tomasz Pajor]

> > How the filesystem is relevant when tables are in memory?
> first, they somehow have to be put into the memory
> second, for consistency (yeah, this word is missing from toysql-users'
> vocabulary) it has to write the data to the disk. otherwise you'd lose
> anything on a crash

http://dev.mysql.com/doc/refman/5.1/en/memory-storage-engine.html

"As indicated by the name, MEMORY tables are stored in memory. They use hash indexes by default, which makes them very fast, and very useful for creating temporary tables. However, when the server shuts down, all rows stored in MEMORY tables are lost. The tables themselves continue to exist because their definitions are stored in .frm files on disk, but they are empty when the server restarts."

so only the structure is in file not data