Arjen posted a
good note about MyISAM concurrent-insert
features, though I should mention
concurrent-insert can be cause of
scalablity and peformance problems on SMP boxes, especially on
queries processing range-queries. The reason of problems is POSIX
read-write locks, which are used to protect key_buffer from
concurrent changes and called for each processed row. More info
you can get from my UC2006 talk, in short on main platforms
(Linux, Solaris, Windows) rw-locks have a bad implementation and
too many calls cause waste of CPU in user-space (Solaris) or
kernel-space (Linux).
Some results for MyISAM table, query SELECT id FROM sbtest
WHERE id BETWEEN N AND N+20000, id - primary …