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From Jan Lehnardt <...@apache.org>
Subject Re: Cluster aware _local_seq in a view?
Date Sat, 07 Jan 2017 18:53:48 GMT
Robert, gotcha. Your global view result should include a update_seq you can use for that purpose
*except* in 2.x _changes _can_ include duplicates and may return results prior to the seq.
The only guarantee is that you do get all _changes after that update_seq, so you need to keep
track of things outside of CouchDB.

Hope this helps.

Best
Jan
--




> On 7 Jan 2017, at 19:49, Robert Payne <robertpayne@me.com> wrote:
> 
> Hi Jan,
> 
> Just to simplify it as much as possible we have a view like:
> 
> function (doc) {
>   emit(doc._local_seq, null);
> }
> 
> In CouchDB 1.x _local_seq is global for the entire database and as far as we ever noticed
we'd never have a duplicate value for a single db. What we are doing is syncing all documents
from that view and then starting the _changes feed from the last _local_seq we got.
> 
> In CouchDB 2.x _local_seq seems to be local to the database/shard as they are all integer
values and even then we have duplicates because I'm presuming each shard has it's own _local_seq.
What we'd need is the cluster aware seq that you pass back to _changes for this to work.
> 
> Cheers,
> Robert
> 
> 
>> On 8/01/2017, at 7:43 AM, Jan Lehnardt <jan@apache.org> wrote:
>> 
>> I know we fixed this for _all_docs: https://issues.apache.org/jira/browse/COUCHDB-2849
>> 
>> Didn’t this make it into regular views as well?
>> 
>> Robert, can you show an example of what you are doing in 1.x and what that returns
for 2.x?
>> 
>> Best
>> Jan
>> --
>> 
>>> On 7 Jan 2017, at 19:32, Robert Payne <robertpayne@me.com> wrote:
>>> 
>>> Hey All,
>>> 
>>> Would anyone still by chance have an idea on this? Or a adequate alternative
that is performant?
>>> 
>>> Cheers,
>>> Robert
>>> 
>>>> On 19/12/2016, at 5:07 PM, Robert Payne <robertpayne@me.com> wrote:
>>>> 
>>>> Hey All,
>>>> 
>>>> In CouchDB 1.x we used a view with the "local_seq" option and then used emitted
_local_seq's to determine where to kick off a change feed starting point. If there any way
to emit a cluster aware local seq in CouchDB 2.0? I can't seem to find any way to get the
node/shard suffixed sequence when using a view.
>>>> 
>>>> Cheers,
>>>> Robert
>>> 
>> 
>> -- 
>> Professional Support for Apache CouchDB:
>> https://neighbourhood.ie/couchdb-support/
>> 
> 

-- 
Professional Support for Apache CouchDB:
https://neighbourhood.ie/couchdb-support/


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