Re: IgniteAtomicSequence

[Pavel Vinokurov <vi...@gmail.com>]

IgniteAtomicLong shows poor results in case of non zero backups.
But IgniteAtomicSequence incremented 1M by ~0.4 second in the attached
example.

ср, 28 окт. 2020 г. в 13:45, narges saleh <sn...@gmail.com>:

> Thanks Pavel for the replies.
>
> I did a quick/basic benchmark of IgniteAtomicLong, and IgniteAtomicLong,
> with only two ignite nodes, with 1,000,000 iterations. Unless, I am doing
> something wrong, the result was very disappointing.
> With IgniteAtomicSequence, the iterations took about 30 seconds.
> With IgniteAtomicLong, it took over 3 minutes. I repeated the test 5 times.
>
> On Wed, Oct 28, 2020 at 5:33 AM Pavel Vinokurov <vi...@gmail.com>
> wrote:
>
>> The atomic sequence/long could be persisted if the default data region is
>> persistent[1].
>> One of the use cases for IgniteAtomicSequence is to generate unique IDs.
>> You could estimate the volume implicitly by getting metrics from the
>> default data region[2].
>>
>> [1]
>> https://ignite.apache.org/docs/latest/persistence/native-persistence#enabling-persistent-storage
>> [2]
>> https://apacheignite.readme.io/v2.8.0/docs/memory-metrics#getting-metrics
>>
>> вт, 27 окт. 2020 г. в 21:50, narges saleh <sn...@gmail.com>:
>>
>>> Questions:
>>> I know I should take into account the cluster size and the data volume,
>>> but how bad is the overhead of IgniteAtomicLong? Any benchmarking?
>>> What are the use cases for IgniteAtomicSequence if it does not
>>> guarantee ordering?
>>>
>>> thanks.
>>>
>>> On Tue, Oct 27, 2020 at 10:27 AM narges saleh <sn...@gmail.com>
>>> wrote:
>>>
>>>> Thank you Pavel, for the information.
>>>>
>>>> What happens to the atomic sequence/long value in case of a system
>>>> restart? Do I need to persist the value somewhere and pass it as the
>>>> initial value, across cluster restarts?
>>>>
>>>> On Tue, Oct 27, 2020 at 1:13 AM Pavel Vinokurov <
>>>> vinokurov.pasha@gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> In case of rebalance the reserves aren't recalculated. So the next
>>>>> values will be in the range  [1001,1000+reserveSize].
>>>>> After the local reserve exceeds, the node reserves a new range
>>>>> starting from the global last sequence number.
>>>>> The main idea IgniteAtomicSequence is to generate unique numbers but
>>>>> it doesn't guarantee ordering.
>>>>> If you need ordering you could set the reserve size to 1 or use
>>>>> IgniteAtomicLong.
>>>>>
>>>>> Thanks,
>>>>> Pavel
>>>>>
>>>>> вс, 25 окт. 2020 г. в 05:00, narges saleh <sn...@gmail.com>:
>>>>>
>>>>>> Hi All,
>>>>>> What is the consequence of data rebalancing across nodes as far as
>>>>>> IgniteAtomicSequence and the reserve on each node is concerned? For
>>>>>> example, if the last sequence number is 6000 in one node and the record
>>>>>> moves to a node whose last sequence number is 1000? Do the reserves on both
>>>>>> nodes get recalculated?
>>>>>>
>>>>>> Are there best practices for generating and using these sequences?
>>>>>>
>>>>>> Is IgniteAtomicSequence the right approach if I want to keep track of
>>>>>> the records on each node for a partitioned cache?
>>>>>>
>>>>>> thanks.
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> Regards
>>>>>
>>>>> Pavel Vinokurov
>>>>>
>>>>
>>
>> --
>>
>> Regards
>>
>> Pavel Vinokurov
>>
>

-- 

Regards

Pavel Vinokurov