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