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From J Chris Anderson <jch...@gmail.com>
Subject Re: _changes/Filter detecting new documents
Date Sat, 29 May 2010 17:20:49 GMT

On May 28, 2010, at 11:28 PM, Sebastian Cohnen wrote:

> I'm not sure that this is working properly, when replication is involved. As far as I
understood the _changes API it is only guaranteed to get the latest change to a document,
not every single one. When replication is involved it is possible to miss a newly created
document and only see an updated one (first part of the MVCC token >1), when it's being
replicated to the node where the _changes feed is consumed from.
> 

that's true. if you have a few edits rapidly in a row, you might not see a doc in the changes
feed until a later revision (even on a single node), as the _changes feed only shows the latest
edit of a doc.

if you want to process a doc the first time it shows up at a node, you can use filtered changes
to only see docs that don't have doc.markedAsProcessed == true, and then process those docs,
and add the corresponding field.

Chris


> 
> On 29.05.2010, at 05:04, Pavan Kumar wrote:
> 
>> Thanks guys, will go the rev id split way as of now.
>> 
>> On Fri, May 28, 2010 at 10:42 PM, J Chris Anderson <jchris@gmail.com> wrote:
>> 
>>> 
>>> On May 28, 2010, at 8:54 AM, Zachary Zolton wrote:
>>> 
>>>> I was just thinking on this problem the other day....
>>>> 
>>>> The only thing I can think of is looking at the _rev of the document.
>>>> Unfortunately, the format of the _rev has changed in the past, and it
>>>> may change in the future. So I think we're supposed to treat it as an
>>>> opaque token.
>>>> 
>>>> Hmm... Hopefully someone else has a better solution.
>>>> 
>>> 
>>> I've started to write code that depends on the fact that the rev is
>>> structured like "3-abcdefabcedef" (eg I've got some code that splits by "-",
>>> etc).
>>> 
>>> So you could look for docs with a rev that starts with 1. I'm not sure how
>>> good an idea it is to do that...
>>> 
>>>> --Zach
>>>> 
>>>> On Fri, May 28, 2010 at 4:33 AM, Pavan Kumar <tvpavan@gmail.com> wrote:
>>>>> Hi ,
>>>>> 
>>>>> using _changes API with filters, can i detect if the document is a
>>> newly
>>>>> Created one or Modified one ? What i understand now is that for both
of
>>> the
>>>>> scenarios ( new documents added or existing document changed ) _changes
>>> API
>>>>> will give a reply back.
>>>>> 
>>>>> Is there a way to differentiate ?
>>>>> 
>>>>> Thanks,
>>>>> Pavan
>>>>> 
>>> 
>>> 
> 


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