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Posted to users@kafka.apache.org by Stas Chizhov <sc...@gmail.com> on 2017/10/06 11:18:27 UTC

Serve interactive queries from standby replicas

Hi

Is there a way to serve read read requests from standby replicas?
StreamsMeatadata does not seem to provide standby end points as far as I
can see.

Thank you,
Stas

Re: Serve interactive queries from standby replicas

Posted by Damian Guy <da...@gmail.com>.
Hi,

No that isn't supported.

Thanks,
Damian

On Fri, 6 Oct 2017 at 04:18 Stas Chizhov <sc...@gmail.com> wrote:

> Hi
>
> Is there a way to serve read read requests from standby replicas?
> StreamsMeatadata does not seem to provide standby end points as far as I
> can see.
>
> Thank you,
> Stas
>

Re: Serve interactive queries from standby replicas

Posted by "Matthias J. Sax" <ma...@confluent.io>.
Thanks!

On 10/9/17 1:27 PM, Stas Chizhov wrote:
> Hi,
> 
> I have created a ticker: https://issues.apache.org/jira/browse/KAFKA-6031
> 
> Best regards,
> Stas.
> 
> 2017-10-06 23:39 GMT+02:00 Guozhang Wang <wa...@gmail.com>:
> 
>> Hi Stas,
>>
>> Would you mind creating a JIRA for this functionality request so that we
>> won't forget about it and drop on the floor?
>>
>>
>> Guozhang
>>
>> On Fri, Oct 6, 2017 at 1:10 PM, Stas Chizhov <sc...@gmail.com> wrote:
>>
>>> Thank you!
>>>
>>> I guess eventually consistent reads might be a reasonable trade off if
>> you
>>> can get ability to serve reads without downtime in some cases.
>>>
>>> By the way standby replicas are just extra consumers/processors of input
>>> topics? Or is there  some custom protocol for sinking the state?
>>>
>>>
>>>
>>> fre 6 okt. 2017 kl. 20:03 skrev Matthias J. Sax <ma...@confluent.io>:
>>>
>>>> No, that is not possible.
>>>>
>>>> Note: standby replicas might "lag" behind the active store, and thus,
>>>> you would get different results if querying standby replicas would be
>>>> supported.
>>>>
>>>> We might add this functionality at some point though -- but there are
>> no
>>>> concrete plans atm. Contributions are always welcome of course :)
>>>>
>>>>
>>>> -Matthias
>>>>
>>>> On 10/6/17 4:18 AM, Stas Chizhov wrote:
>>>>> Hi
>>>>>
>>>>> Is there a way to serve read read requests from standby replicas?
>>>>> StreamsMeatadata does not seem to provide standby end points as far
>> as
>>> I
>>>>> can see.
>>>>>
>>>>> Thank you,
>>>>> Stas
>>>>>
>>>>
>>>>
>>>
>>
>>
>>
>> --
>> -- Guozhang
>>
> 


Re: Serve interactive queries from standby replicas

Posted by Stas Chizhov <sc...@gmail.com>.
Hi,

I have created a ticker: https://issues.apache.org/jira/browse/KAFKA-6031

Best regards,
Stas.

2017-10-06 23:39 GMT+02:00 Guozhang Wang <wa...@gmail.com>:

> Hi Stas,
>
> Would you mind creating a JIRA for this functionality request so that we
> won't forget about it and drop on the floor?
>
>
> Guozhang
>
> On Fri, Oct 6, 2017 at 1:10 PM, Stas Chizhov <sc...@gmail.com> wrote:
>
> > Thank you!
> >
> > I guess eventually consistent reads might be a reasonable trade off if
> you
> > can get ability to serve reads without downtime in some cases.
> >
> > By the way standby replicas are just extra consumers/processors of input
> > topics? Or is there  some custom protocol for sinking the state?
> >
> >
> >
> > fre 6 okt. 2017 kl. 20:03 skrev Matthias J. Sax <ma...@confluent.io>:
> >
> > > No, that is not possible.
> > >
> > > Note: standby replicas might "lag" behind the active store, and thus,
> > > you would get different results if querying standby replicas would be
> > > supported.
> > >
> > > We might add this functionality at some point though -- but there are
> no
> > > concrete plans atm. Contributions are always welcome of course :)
> > >
> > >
> > > -Matthias
> > >
> > > On 10/6/17 4:18 AM, Stas Chizhov wrote:
> > > > Hi
> > > >
> > > > Is there a way to serve read read requests from standby replicas?
> > > > StreamsMeatadata does not seem to provide standby end points as far
> as
> > I
> > > > can see.
> > > >
> > > > Thank you,
> > > > Stas
> > > >
> > >
> > >
> >
>
>
>
> --
> -- Guozhang
>

Re: Serve interactive queries from standby replicas

Posted by Guozhang Wang <wa...@gmail.com>.
Hi Stas,

Would you mind creating a JIRA for this functionality request so that we
won't forget about it and drop on the floor?


Guozhang

On Fri, Oct 6, 2017 at 1:10 PM, Stas Chizhov <sc...@gmail.com> wrote:

> Thank you!
>
> I guess eventually consistent reads might be a reasonable trade off if you
> can get ability to serve reads without downtime in some cases.
>
> By the way standby replicas are just extra consumers/processors of input
> topics? Or is there  some custom protocol for sinking the state?
>
>
>
> fre 6 okt. 2017 kl. 20:03 skrev Matthias J. Sax <ma...@confluent.io>:
>
> > No, that is not possible.
> >
> > Note: standby replicas might "lag" behind the active store, and thus,
> > you would get different results if querying standby replicas would be
> > supported.
> >
> > We might add this functionality at some point though -- but there are no
> > concrete plans atm. Contributions are always welcome of course :)
> >
> >
> > -Matthias
> >
> > On 10/6/17 4:18 AM, Stas Chizhov wrote:
> > > Hi
> > >
> > > Is there a way to serve read read requests from standby replicas?
> > > StreamsMeatadata does not seem to provide standby end points as far as
> I
> > > can see.
> > >
> > > Thank you,
> > > Stas
> > >
> >
> >
>



-- 
-- Guozhang

Re: Serve interactive queries from standby replicas

Posted by Stas Chizhov <sc...@gmail.com>.
Ok I see. Thanks again!

fre 6 okt. 2017 kl. 22:13 skrev Matthias J. Sax <ma...@confluent.io>:

> >> I guess eventually consistent reads might be a reasonable trade off if
> you
> >> can get ability to serve reads without downtime in some cases.
>
> Agreed :)
>
> >> By the way standby replicas are just extra consumers/processors of input
> >> topics? Or is there  some custom protocol for sinking the state?
>
> We use a second consumer, that reads the changlog topic (that is written
> by the active store) to update the hot standby.
>
>
> -Matthias
>
> On 10/6/17 1:10 PM, Stas Chizhov wrote:
> > Thank you!
> >
> > I guess eventually consistent reads might be a reasonable trade off if
> you
> > can get ability to serve reads without downtime in some cases.
> >
> > By the way standby replicas are just extra consumers/processors of input
> > topics? Or is there  some custom protocol for sinking the state?
> >
> >
> >
> > fre 6 okt. 2017 kl. 20:03 skrev Matthias J. Sax <ma...@confluent.io>:
> >
> >> No, that is not possible.
> >>
> >> Note: standby replicas might "lag" behind the active store, and thus,
> >> you would get different results if querying standby replicas would be
> >> supported.
> >>
> >> We might add this functionality at some point though -- but there are no
> >> concrete plans atm. Contributions are always welcome of course :)
> >>
> >>
> >> -Matthias
> >>
> >> On 10/6/17 4:18 AM, Stas Chizhov wrote:
> >>> Hi
> >>>
> >>> Is there a way to serve read read requests from standby replicas?
> >>> StreamsMeatadata does not seem to provide standby end points as far as
> I
> >>> can see.
> >>>
> >>> Thank you,
> >>> Stas
> >>>
> >>
> >>
> >
>
>

Re: Serve interactive queries from standby replicas

Posted by "Matthias J. Sax" <ma...@confluent.io>.
>> I guess eventually consistent reads might be a reasonable trade off if you
>> can get ability to serve reads without downtime in some cases.

Agreed :)

>> By the way standby replicas are just extra consumers/processors of input
>> topics? Or is there  some custom protocol for sinking the state?

We use a second consumer, that reads the changlog topic (that is written
by the active store) to update the hot standby.


-Matthias

On 10/6/17 1:10 PM, Stas Chizhov wrote:
> Thank you!
> 
> I guess eventually consistent reads might be a reasonable trade off if you
> can get ability to serve reads without downtime in some cases.
> 
> By the way standby replicas are just extra consumers/processors of input
> topics? Or is there  some custom protocol for sinking the state?
> 
> 
> 
> fre 6 okt. 2017 kl. 20:03 skrev Matthias J. Sax <ma...@confluent.io>:
> 
>> No, that is not possible.
>>
>> Note: standby replicas might "lag" behind the active store, and thus,
>> you would get different results if querying standby replicas would be
>> supported.
>>
>> We might add this functionality at some point though -- but there are no
>> concrete plans atm. Contributions are always welcome of course :)
>>
>>
>> -Matthias
>>
>> On 10/6/17 4:18 AM, Stas Chizhov wrote:
>>> Hi
>>>
>>> Is there a way to serve read read requests from standby replicas?
>>> StreamsMeatadata does not seem to provide standby end points as far as I
>>> can see.
>>>
>>> Thank you,
>>> Stas
>>>
>>
>>
> 


Re: Serve interactive queries from standby replicas

Posted by Stas Chizhov <sc...@gmail.com>.
Thank you!

I guess eventually consistent reads might be a reasonable trade off if you
can get ability to serve reads without downtime in some cases.

By the way standby replicas are just extra consumers/processors of input
topics? Or is there  some custom protocol for sinking the state?



fre 6 okt. 2017 kl. 20:03 skrev Matthias J. Sax <ma...@confluent.io>:

> No, that is not possible.
>
> Note: standby replicas might "lag" behind the active store, and thus,
> you would get different results if querying standby replicas would be
> supported.
>
> We might add this functionality at some point though -- but there are no
> concrete plans atm. Contributions are always welcome of course :)
>
>
> -Matthias
>
> On 10/6/17 4:18 AM, Stas Chizhov wrote:
> > Hi
> >
> > Is there a way to serve read read requests from standby replicas?
> > StreamsMeatadata does not seem to provide standby end points as far as I
> > can see.
> >
> > Thank you,
> > Stas
> >
>
>

Re: Serve interactive queries from standby replicas

Posted by "Matthias J. Sax" <ma...@confluent.io>.
No, that is not possible.

Note: standby replicas might "lag" behind the active store, and thus,
you would get different results if querying standby replicas would be
supported.

We might add this functionality at some point though -- but there are no
concrete plans atm. Contributions are always welcome of course :)


-Matthias

On 10/6/17 4:18 AM, Stas Chizhov wrote:
> Hi
> 
> Is there a way to serve read read requests from standby replicas?
> StreamsMeatadata does not seem to provide standby end points as far as I
> can see.
> 
> Thank you,
> Stas
>