[Gluster-devel] Query regarding dictionary logic

Mohit Agrawal moagrawa at redhat.com
Tue Apr 30 08:59:06 UTC 2019


Thanks, Amar for sharing the patch, I will test and share the result.

On Tue, Apr 30, 2019 at 2:23 PM Amar Tumballi Suryanarayan <
atumball at redhat.com> wrote:

> Shreyas/Kevin tried to address it some time back using
> https://bugzilla.redhat.com/show_bug.cgi?id=1428049 (
> https://review.gluster.org/16830)
>
> I vaguely remember the reason to keep the hash value 1 was done during the
> time when we had dictionary itself sent as on wire protocol, and in most
> other places, number of entries in dictionary was on an avg, 3. So, we
> felt, saving on a bit of memory for optimization was better at that time.
>
> -Amar
>
> On Tue, Apr 30, 2019 at 12:02 PM Mohit Agrawal <moagrawa at redhat.com>
> wrote:
>
>> sure Vijay, I will try and update.
>>
>> Regards,
>> Mohit Agrawal
>>
>> On Tue, Apr 30, 2019 at 11:44 AM Vijay Bellur <vbellur at redhat.com> wrote:
>>
>>> Hi Mohit,
>>>
>>> On Mon, Apr 29, 2019 at 7:15 AM Mohit Agrawal <moagrawa at redhat.com>
>>> wrote:
>>>
>>>> Hi All,
>>>>
>>>>   I was just looking at the code of dict, I have one query current
>>>> dictionary logic.
>>>>   I am not able to understand why we use hash_size is 1 for a
>>>> dictionary.IMO with the
>>>>   hash_size of 1 dictionary always work like a list, not a hash, for
>>>> every lookup
>>>>   in dictionary complexity is O(n).
>>>>
>>>>   Before optimizing the code I just want to know what was the exact
>>>> reason to define
>>>>   hash_size is 1?
>>>>
>>>
>>> This is a good question. I looked up the source in gluster's historic
>>> repo [1] and hash_size is 1 even there. So, this could have been the case
>>> since the first version of the dictionary code.
>>>
>>> Would you be able to run some tests with a larger hash_size and share
>>> your observations?
>>>
>>> Thanks,
>>> Vijay
>>>
>>> [1]
>>> https://github.com/gluster/historic/blob/master/libglusterfs/src/dict.c
>>>
>>>
>>>
>>>>
>>>>   Please share your view on the same.
>>>>
>>>> Thanks,
>>>> Mohit Agrawal
>>>> _______________________________________________
>>>> Gluster-devel mailing list
>>>> Gluster-devel at gluster.org
>>>> https://lists.gluster.org/mailman/listinfo/gluster-devel
>>>
>>> _______________________________________________
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>
>
>
> --
> Amar Tumballi (amarts)
>
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