So I guess we have three algorithms :)
1. one-after-another (It will go to next partition only if the current
partition is full)
2. round-robin (if we implement as Reka explained above. It will always
select the next partition)
3. name-should-be-decided (this will work as Lahiru explained above. It
will always distribute the members in the partitions equally)
WDYT?
Thanks.
On Wed, Mar 4, 2015 at 12:01 AM, Reka Thirunavukkarasu <r...@wso2.com>
wrote:
> I think that if the selectedIndex is initial value as -1, then RR should
> traverse through all the partitions and find out who has the minimum
> instances and choose that partition as the selectedIndex in the first
> iteration(may be we can exc). Then from the second iteration onwards, it
> can increase the selectedIndex by 1 to choose the next adjacent partition.
> This will help in the stratos restart as we don't persist the
> selectedIndex. WDYT?
>
> On Tue, Mar 3, 2015 at 10:53 AM, Lahiru Sandaruwan <lahi...@wso2.com>
> wrote:
>
>>
>>
>> On Tue, Mar 3, 2015 at 11:15 PM, Rajkumar Rajaratnam <rajkum...@wso2.com>
>> wrote:
>>
>>> Problem is lowestInstanceCount is initially taking 0. Instead it should
>>> take the non terminated member count of 1st partition.
>>>
>>> To Fix,
>>>
>>> int selectedIndex = 0;
>>> int lowestInstanceCount =
>>> partitionContexts[0].getNonTerminatedMemberCount();
>>>
>>>
>> +1. I was thinking the same. We can start with first partition count.
>>
>> Thanks.
>>
>>> wdyt?
>>>
>>> Thanks.
>>>
>>> On Tue, Mar 3, 2015 at 10:57 PM, Rajkumar Rajaratnam <rajkum...@wso2.com
>>> > wrote:
>>>
>>>> Hi Lahiru,
>>>>
>>>> Actually, current logic is not working as your example. This logic only
>>>> uses the first partition. This will never use any other partitions. See my
>>>> comments within the following code.
>>>>
>>>> public PartitionContext
>>>> getNextScaleUpPartitionContext(PartitionContext[] partitionContexts) {
>>>>
>>>> int selectedIndex = 0;
>>>> int lowestInstanceCount = 0;
>>>>
>>>> for(int partitionIndex = 0; partitionIndex <
>>>> partitionContexts.length - 1; partitionIndex++) {
>>>>
>>>>
>>>> if(partitionContexts[partitionIndex].getNonTerminatedMemberCount() <
>>>> lowestInstanceCount) {
>>>>
>>>> *// this if condition is always false, because non terminated count is
>>>> always >=0*
>>>>
>>>> lowestInstanceCount =
>>>> partitionContexts[partitionIndex].getNonTerminatedMemberCount();
>>>> selectedIndex = partitionIndex;
>>>> }
>>>> }
>>>>
>>>> *// selected index is 0 always, so round-robin will always use first
>>>> partition*
>>>>
>>>> if(partitionContexts[selectedIndex].getNonTerminatedMemberCount() <
>>>> partitionContexts[selectedIndex].getMax()) {
>>>>
>>>> if(log.isDebugEnabled()){
>>>> log.debug(String.format("[round-robin algorithm]
>>>> [scale-up] [partition] %s has space to create members. " +
>>>> "[non terminated count] %s [max] %s"
>>>> ,
>>>> partitionContexts[selectedIndex].getPartitionId(),
>>>>
>>>> partitionContexts[selectedIndex].getNonTerminatedMemberCount(),
>>>> partitionContexts[selectedIndex].getMax()));
>>>> }
>>>> return partitionContexts[selectedIndex];
>>>> } else {
>>>>
>>>> return null;
>>>> }
>>>> }
>>>>
>>>> May be I am missing something here.
>>>>
>>>> Thanks.
>>>>
>>>> On Tue, Mar 3, 2015 at 10:42 PM, Lahiru Sandaruwan <lahi...@wso2.com>
>>>> wrote:
>>>>
>>>>> Hi Raj,
>>>>>
>>>>> Earlier in 4.0.0 release, we have been using the partition index. If
>>>>> that to be worked correctly we should persist the index for each cluster.
>>>>>
>>>>> IMO there is a better way to execute the round-robin method as follows,
>>>>>
>>>>> The intention of round robin algorithm is to distribute the members in
>>>>> the partitions equally. Current method works as per the following example.
>>>>>
>>>>> Say we have 3 partitions, p1, p2, and p3 and max of each partition is
>>>>> 2.
>>>>>
>>>>> So according to the algorithm, it will select the first partition who
>>>>> has the lowest member count.
>>>>>
>>>>> Iteration1: It will select p1.
>>>>> Iteration2: It will select p2.
>>>>> Iteration3: It will select p3.
>>>>> Iteration4: It will select p1.
>>>>> Iteration5: It will select p2.
>>>>> ....
>>>>>
>>>>> Thanks.
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Mar 3, 2015 at 10:22 PM, Rajkumar Rajaratnam <
>>>>> rajkum...@wso2.com> wrote:
>>>>>
>>>>>> Hi Devs,
>>>>>>
>>>>>> It seems to me that there is a bug in round-robin implementation of
>>>>>> partition algorithm.
>>>>>>
>>>>>>
>>>>>> https://github.com/apache/stratos/blob/0b7734f4c9f1444d064fec93bf9ac59a5883faf2/components/org.apache.stratos.autoscaler/src/main/java/org/apache/stratos/autoscaler/algorithm/RoundRobin.java#L43-L64
>>>>>>
>>>>>> Shouldn't it work based on current partition index? For example, if
>>>>>> the most recent instance was spin up in partition-1, the next instance
>>>>>> should be spin up in partition-2 and so on. According to current logic
>>>>>> what
>>>>>> is happening is, all the instance are spin up in partition-1.
>>>>>>
>>>>>> Please correct me If I am wrong.
>>>>>>
>>>>>> Thanks.
>>>>>>
>>>>>> --
>>>>>> Rajkumar Rajaratnam
>>>>>> Committer & PMC Member, Apache Stratos
>>>>>> Software Engineer, WSO2
>>>>>>
>>>>>> Mobile : +94777568639
>>>>>> Blog : rajkumarr.com
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> --
>>>>> Lahiru Sandaruwan
>>>>> Committer and PMC member, Apache Stratos,
>>>>> Senior Software Engineer,
>>>>> WSO2 Inc., http://wso2.com
>>>>> lean.enterprise.middleware
>>>>>
>>>>> email: lahi...@wso2.com blog: http://lahiruwrites.blogspot.com/
>>>>> linked-in: http://lk.linkedin.com/pub/lahiru-sandaruwan/16/153/146
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Rajkumar Rajaratnam
>>>> Committer & PMC Member, Apache Stratos
>>>> Software Engineer, WSO2
>>>>
>>>> Mobile : +94777568639
>>>> Blog : rajkumarr.com
>>>>
>>>
>>>
>>>
>>> --
>>> Rajkumar Rajaratnam
>>> Committer & PMC Member, Apache Stratos
>>> Software Engineer, WSO2
>>>
>>> Mobile : +94777568639
>>> Blog : rajkumarr.com
>>>
>>
>>
>>
>> --
>> --
>> Lahiru Sandaruwan
>> Committer and PMC member, Apache Stratos,
>> Senior Software Engineer,
>> WSO2 Inc., http://wso2.com
>> lean.enterprise.middleware
>>
>> email: lahi...@wso2.com blog: http://lahiruwrites.blogspot.com/
>> linked-in: http://lk.linkedin.com/pub/lahiru-sandaruwan/16/153/146
>>
>>
>
>
> --
> Reka Thirunavukkarasu
> Senior Software Engineer,
> WSO2, Inc.:http://wso2.com,
> Mobile: +94776442007
>
>
>
--
Rajkumar Rajaratnam
Committer & PMC Member, Apache Stratos
Software Engineer, WSO2
Mobile : +94777568639
Blog : rajkumarr.com
