頭昏腦脹的小小MIS記錄資料

Limited number of ports

Windows systems have about 4,000 ports available for client
connections, and after a connection on a port closes, it takes
two to four minutes before the port can be reused. In
situations where clients connect to and disconnect from the
server at a high rate, it is possible for all available ports
to be used up before closed ports become available again. If
this happens, the MySQL server appears to be unresponsive even
though it is running. Note that ports may be used by other
applications running on the machine as well, in which case the
number of ports available to MySQL is lower.

For more information about this problem, see
http://support.microsoft.com/default.aspx?scid=kb;en-us;196271.

Concurrent reads

MySQL depends on the pread() and
pwrite() system calls to be able to mix
INSERT and
SELECT. Currently, we use
mutexes to emulate pread() and
pwrite(). We intend to replace the file
level interface with a virtual interface in the future so that
we can use the
readfile()/writefile()
interface to get more speed. The current implementation limits
the number of open files that MySQL 5.1 can use
to 2,048, which means that you cannot run as many concurrent
threads on Windows as on Unix.