>>>>> "Sasha" == Sasha Pachev <sasha@stripped> writes:
Sasha> On Tuesday 21 August 2001 06:34, Andi Kleen wrote:
>> I noticed that the key cache in myisam 3.23.37 (mysys/mf_keycache.c) does
>> all IO under a global mutex when key caching is enabled. Isn't this a
>> scalability problem, as all the key IO will be single threaded?
Sasha> Yes, in some cases when there are a lot of keyblocks to examine to do a key
Sasha> lookup. This is being fixed in 4.0, and if I remember correctly, Monty
Sasha> already has finished most of the work. He will offer additional comments.
I have the new key cache 80 % coded (but not tested). I have however
had to delay this to get the new internal table structure ready for
4.0. I will continue to look at the key cache as soon as the new
table code is ready and we have released binary version of 4.0-alpha.
The plan is to release 4.0-alpha within 14 days.
There is two 'bad' mutex in MySQL. One when opening a table that is
not in the table cache and another in the key cache.
The new table structure will take care of the first mutex and the new
key cache should fix the second mutex.
For technical support contracts, goto https://order.mysql.com/
__ ___ ___ ____ __
/ |/ /_ __/ __/ __ \/ / Mr. Michael Widenius <monty@stripped>
/ /|_/ / // /\ \/ /_/ / /__ MySQL AB, CTO
/_/ /_/\_, /___/\___\_\___/ Helsinki, Finland