Re: [PATCH] use fallocate to create table

Hi Sergei,

On 12/28/12 12:50, Sergei Golubchik wrote:
> Hi, Sveta!
>
> On Dec 27, Sveta Smirnova wrote:
>> Dear Toshikuni,
>>
>>>> I made a patch for MySQL 5.5.28 to speed up InnoDB table space
>>>> creation.  I noticed that there are slow I/Os (consisting of many
>>>> zero-fill writes and syncs) when creating tables.
>>>>
>>>> Linux kernels have the fallocate(2) system call, which guarantees
>>>> that a given file region is zeroed and yields a performance
>>>> improvement on supporting file systems.
>>>>
>>>> I measured a 10% speed up in table space creation in our
>>>> application.
>>>>
>>>> Could you please accept my patch? If there is anything further I
>>>> should do for this patch, please advise me.
>>
>> We evaluated this option internally and, unfortunately, results were not
>> conclusive, so we decided not to implement the patch.
>
> And why is that? What were the opinions? What were the arguments against
> this patch?

I am not sure how much can I say, because Oracle forbids its employees 
to distribute such discussions.

But in short: there are cases which this patch does not cover. Actual 
patch should be more complicated.

Sveta.

> Regards,
> Sergei

-- 
Sveta Smirnova, Principal Technical Support Engineer, Russia
MySQL @ Oracle, Moscow, Russia, www.oracle.com/mysql

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