Hello everybody

I would like to know if the asynchronous operations of the client API
are often used in applications that use Zookeeper.
In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
Service, Katta and the Yahoo! Message Broker). However, I do not find if
they use the synchronous or asynchronous operations.

The big question I am trying to answer is : is it relevant to consider a
closed-loop model in order to benchmark replicated services (Zookeeper
being a good candidate to build replicated services)? Can you give me
any clue on that?

Thanks in advance
Pierre Louis Aublin

[1] ZooKeeper: Wait-free Coordination for Internet-scale Systems,
Patrick Hunt and Mahadev Konar, /Yahoo! Grid;/ Flavio P. Junqueira and
Benjamin Reed, /Yahoo! Research/

On 02/08/2012 11:09 PM, Pierre Louis Aublin wrote:
> Hello everybody
>
> I would like to know if the asynchronous operations of the client API
> are often used in applications that use Zookeeper.
> In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
> Service, Katta and the Yahoo! Message Broker). However, I do not find
> if they use the synchronous or asynchronous operations.
>
> The big question I am trying to answer is : is it relevant to consider
> a closed-loop model in order to benchmark replicated services
> (Zookeeper being a good candidate to build replicated services)? Can
> you give me any clue on that?
One must read open-loop model, not closed-loop.
Sorry for that mistake.

the yahoo services mention use asynchronous operations a lot. during
startup and reconfig they would have to modify a bunch of znodes. by
shooting off the modifications asynchronously, they were able to
drastically reduce the startup and reconfig time.

ben

On Wed, Feb 8, 2012 at 2:09 PM, Pierre Louis Aublin
<[EMAIL PROTECTED]> wrote:
> Hello everybody
>
> I would like to know if the asynchronous operations of the client API are
> often used in applications that use Zookeeper.
> In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
> Service, Katta and the Yahoo! Message Broker). However, I do not find if
> they use the synchronous or asynchronous operations.
>
> The big question I am trying to answer is : is it relevant to consider a
> closed-loop model in order to benchmark replicated services (Zookeeper being
> a good candidate to build replicated services)? Can you give me any clue on
> that?
>
> Thanks in advance
> Pierre Louis Aublin
>
> [1] ZooKeeper: Wait-free Coordination for Internet-scale Systems, Patrick
> Hunt and Mahadev Konar, /Yahoo! Grid;/ Flavio P. Junqueira and Benjamin
> Reed, /Yahoo! Research/

Some of the Curator recipes use async. For instance, adding a entry into
the DistributedQueue is done in the background as there's no reason for
the foreground process to wait for this.

-JZ

On 2/8/12 2:09 PM, "Pierre Louis Aublin" <[EMAIL PROTECTED]>
wrote:

>Hello everybody
>
>I would like to know if the asynchronous operations of the client API
>are often used in applications that use Zookeeper.
>In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
>Service, Katta and the Yahoo! Message Broker). However, I do not find if
>they use the synchronous or asynchronous operations.
>
>The big question I am trying to answer is : is it relevant to consider a
>closed-loop model in order to benchmark replicated services (Zookeeper
>being a good candidate to build replicated services)? Can you give me
>any clue on that?
>
>Thanks in advance
>Pierre Louis Aublin
>
>[1] ZooKeeper: Wait-free Coordination for Internet-scale Systems,
>Patrick Hunt and Mahadev Konar, /Yahoo! Grid;/ Flavio P. Junqueira and
>Benjamin Reed, /Yahoo! Research/

Thank you for your replies.
On 02/09/2012 12:46 AM, Benjamin Reed wrote:
> the yahoo services mention use asynchronous operations a lot. during
> startup and reconfig they would have to modify a bunch of znodes. by
> shooting off the modifications asynchronously, they were able to
> drastically reduce the startup and reconfig time.
>
> ben

On 02/09/2012 12:48 AM, Jordan Zimmerman wrote:
> Some of the Curator recipes use async. For instance, adding a entry into
> the DistributedQueue is done in the background as there's no reason for
> the foreground process to wait for this.
>
> -JZ
>
> On 2/8/12 2:09 PM, "Pierre Louis Aublin"<[EMAIL PROTECTED]>
> wrote:
>
> On Wed, Feb 8, 2012 at 2:09 PM, Pierre Louis Aublin
> <[EMAIL PROTECTED]>  wrote:
>> Hello everybody
>>
>> I would like to know if the asynchronous operations of the client API are
>> often used in applications that use Zookeeper.
>> In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
>> Service, Katta and the Yahoo! Message Broker). However, I do not find if
>> they use the synchronous or asynchronous operations.
>>
>> The big question I am trying to answer is : is it relevant to consider a
>> closed-loop model in order to benchmark replicated services (Zookeeper being
>> a good candidate to build replicated services)? Can you give me any clue on
>> that?
>>
>> Thanks in advance
>> Pierre Louis Aublin
>>
>> [1] ZooKeeper: Wait-free Coordination for Internet-scale Systems, Patrick
>> Hunt and Mahadev Konar, /Yahoo! Grid;/ Flavio P. Junqueira and Benjamin
>> Reed, /Yahoo! Research/

Almost all my zk agents use asynchronous api; mainly because all services
are intrinsically asynchronous.
In fact I've wrapped the Zookeeper client to hide synchronous methods; so
anyone who want to develop new agents should think asynchronously.
It could be hard at first but one you are used to it, the resulting code is
cleaner than with sync api, and more easy to understand and maintain by
other developers.

/César.
On Thu, Feb 9, 2012 at 10:32 AM, Pierre Louis Aublin <
[EMAIL PROTECTED]> wrote:

> Thank you for your replies.
>
>
>
> On 02/09/2012 12:46 AM, Benjamin Reed wrote:
>
>> the yahoo services mention use asynchronous operations a lot. during
>> startup and reconfig they would have to modify a bunch of znodes. by
>> shooting off the modifications asynchronously, they were able to
>> drastically reduce the startup and reconfig time.
>>
>> ben
>>
>
> On 02/09/2012 12:48 AM, Jordan Zimmerman wrote:
>
>> Some of the Curator recipes use async. For instance, adding a entry into
>> the DistributedQueue is done in the background as there's no reason for
>> the foreground process to wait for this.
>>
>> -JZ
>>
>> On 2/8/12 2:09 PM, "Pierre Louis Aublin"<pierre-louis.aublin@**inria.fr<[EMAIL PROTECTED]>
>> >
>> wrote:
>>
>>
>
>  On Wed, Feb 8, 2012 at 2:09 PM, Pierre Louis Aublin
>> <[EMAIL PROTECTED]>  wrote:
>>
>>> Hello everybody
>>>
>>> I would like to know if the asynchronous operations of the client API are
>>> often used in applications that use Zookeeper.
>>> In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
>>> Service, Katta and the Yahoo! Message Broker). However, I do not find if
>>> they use the synchronous or asynchronous operations.
>>>
>>> The big question I am trying to answer is : is it relevant to consider a
>>> closed-loop model in order to benchmark replicated services (Zookeeper
>>> being
>>> a good candidate to build replicated services)? Can you give me any clue
>>> on
>>> that?
>>>
>>> Thanks in advance
>>> Pierre Louis Aublin
>>>
>>> [1] ZooKeeper: Wait-free Coordination for Internet-scale Systems, Patrick
>>> Hunt and Mahadev Konar, /Yahoo! Grid;/ Flavio P. Junqueira and Benjamin
>>> Reed, /Yahoo! Research/
>>>
>>
>

Hello

On 02/09/2012 11:22 AM, César Álvarez Núñez wrote:
> Almost all my zk agents use asynchronous api; mainly because all services
> are intrinsically asynchronous.
Can you give me more details about these services? Can I found details
about them on the web?

> In fact I've wrapped the Zookeeper client to hide synchronous methods; so
> anyone who want to develop new agents should think asynchronously.
> It could be hard at first but one you are used to it, the resulting code is
> cleaner than with sync api, and more easy to understand and maintain by
> other developers.
I also imagine that in some scenarios event-based applications (i.e.
that rely on the async api) provide better performance than applications
that use the sync api.

Thanks
Pierre Louis
> On Thu, Feb 9, 2012 at 10:32 AM, Pierre Louis Aublin<
> [EMAIL PROTECTED]>  wrote:
>
>> Thank you for your replies.
>>
>>
>>
>> On 02/09/2012 12:46 AM, Benjamin Reed wrote:
>>
>>> the yahoo services mention use asynchronous operations a lot. during
>>> startup and reconfig they would have to modify a bunch of znodes. by
>>> shooting off the modifications asynchronously, they were able to
>>> drastically reduce the startup and reconfig time.
>>>
>>> ben
>>>
>> On 02/09/2012 12:48 AM, Jordan Zimmerman wrote:
>>
>>> Some of the Curator recipes use async. For instance, adding a entry into
>>> the DistributedQueue is done in the background as there's no reason for
>>> the foreground process to wait for this.
>>>
>>> -JZ
>>>
>>> On 2/8/12 2:09 PM, "Pierre Louis Aublin"<pierre-louis.aublin@**inria.fr<[EMAIL PROTECTED]>
>>> wrote:
>>>
>>>
>>   On Wed, Feb 8, 2012 at 2:09 PM, Pierre Louis Aublin
>>> <[EMAIL PROTECTED]>   wrote:
>>>
>>>> Hello everybody
>>>>
>>>> I would like to know if the asynchronous operations of the client API are
>>>> often used in applications that use Zookeeper.
>>>> In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
>>>> Service, Katta and the Yahoo! Message Broker). However, I do not find if
>>>> they use the synchronous or asynchronous operations.
>>>>
>>>> The big question I am trying to answer is : is it relevant to consider a
>>>> closed-loop model in order to benchmark replicated services (Zookeeper
>>>> being
>>>> a good candidate to build replicated services)? Can you give me any clue
>>>> on
>>>> that?
>>>>
>>>> Thanks in advance
>>>> Pierre Louis Aublin
>>>>
>>>> [1] ZooKeeper: Wait-free Coordination for Internet-scale Systems, Patrick
>>>> Hunt and Mahadev Konar, /Yahoo! Grid;/ Flavio P. Junqueira and Benjamin
>>>> Reed, /Yahoo! Research/
>>>>

Hi,

I use both. I use the async API when I want to reuse a single thread to
multiplex multiple processes using a single thread or send a batch of
requests to avoid waiting on round trip time. You can create an async
callback that is a future makes batching requests easy.

I try to use the synchronous API where possible to make the code read
sequentialy without nesting. That usually means a dedicated thread that
manages the process wide view of state coordinated in ZK for a given
subsystem or process.

If doing the work synchronously is an option that is my preference because
it involves less code, less indentation, and serializes interactions with
ZK (especially if you have a single actor).

Regards,
Ariel

On Thu, Feb 9, 2012 at 1:12 PM, Pierre Louis Aublin <
[EMAIL PROTECTED]> wrote:

> Hello
>
>
> On 02/09/2012 11:22 AM, César Álvarez Núñez wrote:
>
>> Almost all my zk agents use asynchronous api; mainly because all services
>> are intrinsically asynchronous.
>>
> Can you give me more details about these services? Can I found details
> about them on the web?
>
>
>  In fact I've wrapped the Zookeeper client to hide synchronous methods; so
>> anyone who want to develop new agents should think asynchronously.
>> It could be hard at first but one you are used to it, the resulting code
>> is
>> cleaner than with sync api, and more easy to understand and maintain by
>> other developers.
>>
> I also imagine that in some scenarios event-based applications (i.e. that
> rely on the async api) provide better performance than applications that
> use the sync api.
>
> Thanks
> Pierre Louis
>
>
>
>  On Thu, Feb 9, 2012 at 10:32 AM, Pierre Louis Aublin<
>> [EMAIL PROTECTED]>  wrote:
>>
>>  Thank you for your replies.
>>>
>>>
>>>
>>> On 02/09/2012 12:46 AM, Benjamin Reed wrote:
>>>
>>>  the yahoo services mention use asynchronous operations a lot. during
>>>> startup and reconfig they would have to modify a bunch of znodes. by
>>>> shooting off the modifications asynchronously, they were able to
>>>> drastically reduce the startup and reconfig time.
>>>>
>>>> ben
>>>>
>>>>  On 02/09/2012 12:48 AM, Jordan Zimmerman wrote:
>>>
>>>  Some of the Curator recipes use async. For instance, adding a entry into
>>>> the DistributedQueue is done in the background as there's no reason for
>>>> the foreground process to wait for this.
>>>>
>>>> -JZ
>>>>
>>>> On 2/8/12 2:09 PM, "Pierre Louis Aublin"<pierre-louis.aublin@****
>>>> inria.fr <http://inria.fr><pierre-louis.aublin@**inria.fr<[EMAIL PROTECTED]>
>>>> >
>>>> wrote:
>>>>
>>>>
>>>>   On Wed, Feb 8, 2012 at 2:09 PM, Pierre Louis Aublin
>>>
>>>> <[EMAIL PROTECTED]>   wrote:
>>>>
>>>>  Hello everybody
>>>>>
>>>>> I would like to know if the asynchronous operations of the client API
>>>>> are
>>>>> often used in applications that use Zookeeper.
>>>>> In [1] I found 3 applications built on Zookeeper (the Yahoo! Fetching
>>>>> Service, Katta and the Yahoo! Message Broker). However, I do not find
>>>>> if
>>>>> they use the synchronous or asynchronous operations.
>>>>>
>>>>> The big question I am trying to answer is : is it relevant to consider
>>>>> a
>>>>> closed-loop model in order to benchmark replicated services (Zookeeper
>>>>> being
>>>>> a good candidate to build replicated services)? Can you give me any
>>>>> clue
>>>>> on
>>>>> that?
>>>>>
>>>>> Thanks in advance
>>>>> Pierre Louis Aublin
>>>>>
>>>>> [1] ZooKeeper: Wait-free Coordination for Internet-scale Systems,
>>>>> Patrick
>>>>> Hunt and Mahadev Konar, /Yahoo! Grid;/ Flavio P. Junqueira and Benjamin
>>>>> Reed, /Yahoo! Research/
>>>>>
>>>>>
>