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From Mudit Verma <mudit.f2004...@gmail.com>
Subject Re: Asynchronous API's and monotonicity
Date Wed, 11 Jun 2014 13:34:46 GMT
Thanks Rakesh,

Does bookeeper also offer C APIs? I couldn't find them.

Thanks
Mudit


On Sat, Jun 7, 2014 at 7:08 AM, Rakesh Radhakrishnan <
rakeshr.apache@gmail.com> wrote:

> Hi Mudit,
>
> Thanks Flavio for showing BookKeeper. Yeah this is another option you can
> explore in your free time:)
>
>
> I'd like to introduce it briefly to you, please have a look if you are
> interested.
>
> Documentation available at
> http://zookeeper.apache.org/bookkeeper/docs/r4.2.2/
>
> Basic terminologies:-
>
>  - servers called as"bookies",
>  - log are "ledgers",
>  - and each unit of a log (aka record) is a "ledger entry"
>
> Bookie server uses filesystem to store the ledgers and their entries(Since
> it uses filesystem, message size won't be a constraint I guess). Also, it
> uses ZK for storing the ledger metadata information.
>
> Basic operations:-
> 1) Open a bookkeeper client.
> 2) Create a ledger -
> Here it will internally generate id for this ledger and it will be unique.
>  Like ZooKeeper sequential znodes it internally maintains sequence to
> generate the ids.
> Upon creating a ledger, a BookKeeper client writes metadata about the
> ledger to ZK.
> 3) Write to the ledger - User can add entries(user data) to the ledger. BK
> guarantees single writer.
> 4) After write close the ledger.
>
> Assume user has created four ledgers, now ledger id looks like L00001,
> L00002, L00003, L00004. When user tries to create a new ledger, then id
> will be incremented L00005.
>
> Ledger metadata in ZK:
> /ledgers/L00001
> /ledgers/L00002
> /ledgers/L00003
> /ledgers/L00004
> /ledgers/L00005
>
> Now using this sequential ledger znodes present in ZK, one can write the
> logic of distributed queue.
>
> Any queries feel free to ping us happy to help you:)
> You can reach us bookkeeper-dev@zookeeper.apache.org or user mailing id.
>
> Regards,
> Rakesh
>
>
> On Sat, Jun 7, 2014 at 2:32 AM, Flavio Junqueira <
> fpjunqueira@yahoo.com.invalid> wrote:
>
>> You may want to have a look at BookKeeper.
>>
>> -Flavio
>>
>> On 05 Jun 2014, at 16:32, Mudit Verma <mudit.f2004912@gmail.com> wrote:
>>
>> > Hi Zookeeper Users,
>> >
>> > Lately, I have been working on a research project where I want to use
>> zookeeper as a distributed logging service.
>> >
>> > I want to build a queue on top of zookeeper (also provided in recipes).
>> >
>> > What for:
>> > Intention is to insert some operations performed by different clients
>> in a distributed queue, and process them lazily at some later point of
>> time.  And I want some ordering between these operations.
>> >
>> > Setup:
>> > 5 physical  zookeeper servers
>> >
>> > The problem is:
>> > In my current setup, I am observing a latency of about 13 ms per
>> enqueue operation (using synchronous create APIs with sequential flags). I
>> want to significantly reduce this time. The other way could be to use
>> asynchronous zookeeper calls  but I am not sure what can be the side
>> effects. Would it still be monotonous when used with SEQUENTIAL flag?
>> >
>> > For example, a  client X created a SEQUENTIAL node Z1 at time t1 using
>> async create, same client created another SEQUENTIAL node Z2 at time t2
>> where t2 > t1. Would the monotonic number associated with Z1 be lesser than
>> that of Z2?
>> >
>> > Your help is much appreciated.
>> >
>> > Thanks
>> > Mudit
>> >
>>
>>
>

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