maria-developers team mailing list archive

[Michael Widenius <monty@xxxxxxxxxxxx>]

Hi!

>>>>> "MARK" == MARK CALLAGHAN <mdcallag@xxxxxxxxx> writes:

MARK> On Mon, Oct 19, 2009 at 5:52 AM, Sergei Golubchik <sergii@xxxxxxxxx> wrote:
>> Hi, Monty!
>> 
>> On Oct 19, Michael Widenius wrote:
>>> 
>>> I just finished applying / modifying / rewriting the userstats patch
>>> to MariaDB 5.2 and will commit this in a moment.
>> 
>> I wonder if anybody cares to monitor mutex usage in MySQL.
>> 
>> This patch adds few new global mutexes that are locked at least once per
>> statement (or more).
>> 
>> Without benchmark results one can only speculate whether it will affect
>> users or not.

MARK> I am willing to bet that Monty's patch makes sysbench readonly much
MARK> slower with high concurrency on an 8-core server. But those problems
MARK> have been fixed in recent versions of the patch.

One should note that I changed the patch so that there is minimal
overhead (in the order of 4 if) if the userstat is not enabled (ie,
the userstat variable is not set)

Where can I find that newer version of the patch or can you describe
what changes needs to be done ?

One obvious one is to not update the user stats for every query, but
only every minute (for the user and client stats at least). That would
give some notable improvements.

MARK> Is MySQL or MariaDB going to run and publish performance regression
MARK> results for each release/feature? I would love for that to happen, but
MARK> then I will have less to write about.

Yes, we plan to add that as part of buildbot.

In this case, we need to run an explicite benchmark with and without
userstat enabled and publish the results.

Hakan, can you put this on your todo?

Regards,
Monty