Some notes about
MyISAM file handling:
If a table is never updated, MySQL will never touch the table files, so it would never be marked as closed or corrupted.
If a table is marked readonly by the OS, it will only be opened in readonly mode. Any updates to it will fail.
When a normal table is opened for reading by a
SELECT, MySQL will open it in read/write
mode, but will not write anything to it.
A table can be closed during one of the following events:
Out of space in table cache
Someone executed flush tables
MySQL was shut down
flush_time expired (which causes an automatic flush-tables to be executed)
When MySQL opens a table, it checks if the table is clean.
If it isn't and the server was started with the
--myisam-recover option, check the table
and try to recover it if it's crashed. (The safest automatic
recover option is probably