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From:Dmitry Lenev Date:December 16 2010 11:50am
Subject:Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054
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Hello Davi!

* Davi Arnaut <davi.arnaut@stripped> [10/12/16 14:39]:
>>>> Also I have found the following article claiming that using gethrtime
>>>> gives boost to MySQL performance even on Solaris 10:
>>>>
>>>> http://developers.sun.com/solaris/articles/mysql_perf_tune.html
>>>
>>> I find this article highly suspicious since this hack exist at least
>>> since July of 2007. Also, obviously, the explanation there is simply
>>> wrong as we _can't_ use gethrtime for timing.
>>
>> Well, it is not very clear when this article was written.
>>
>> But it seems to be focused on MySQL 5.0 which AFAICS doesn't
>> include this particular hack. This can explain its results.
>>
>> I agree that explanation is somewhat confusing. But in the end
>> I think the suggestion in article boils down to using time()
>> implementation which is based on gethrtime() similarly to
>> hack in out code. This is achieved by linking MySQL with
>> -lfasttime library described at
>> http://developers.sun.com/solaris/articles/time_stamp.html.
>
> Similar in the sense that it has the same bug and is not thread safe --  
> the MySQL one is wrapper inside a mutex.
>
> How about we ask the benchmark team to actually measure this patch?

Good idea! Could you please do this?

>
>>>
>>>> And finally please note that for 5.1 we still support Solaris 8 and 9:
>>>>
>>>> http://www.mysql.com/support/supportedplatforms/database.html
>>>>
>>>
>>> What is your point?
>>
>> My point was that if, for example, time() became fast only starting from
>> Solaris 10, we could not simply remove this hack from 5.1, as it would make
>> MySQL 5.1 slower on one of its supported platforms.
>>
>
> Yes, but we still need to fix the bug, don't we? The hack is wrong.
> Also, in the worst case, we could simply use gettimeofday.

Absolutely. I just have tried to point out that we should be careful
when choosing approach to fixing this problem.

-- 
Dmitry Lenev, Software Developer
Oracle Development SPB/MySQL, www.mysql.com

Are you MySQL certified?  http://www.mysql.com/certification
Thread
bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Davi Arnaut14 Dec
Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Magne Mæhre15 Dec
Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Dmitry Lenev16 Dec
  • Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Davi Arnaut16 Dec
    • Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Dmitry Lenev16 Dec
      • Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Davi Arnaut16 Dec
        • Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Dmitry Lenev16 Dec
          • Re: bzr commit into mysql-5.1-bugteam branch (davi:3520) Bug#42054Davi Arnaut16 Dec