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From Jan Lehnardt <...@apache.org>
Subject Re: Deleted documents and revs_info=true
Date Fri, 08 May 2009 14:57:31 GMT

On 8 May 2009, at 16:32, Jaap van der Plas wrote:

> The use I am intending for this is providing a change log of sorts
> tell the user which changes were made recently, and in the case of
> document deletion it would be helpful to retrieve the document that
> was deleted to provide info about which document got deleted.

That is a case of relying on CouchDB's revision system to power
the application and you shouldn't do that. If you need to record
an action (change ro deletion of a data item) you want to create
a separate document for that action.


> I have been seeing some messages in the svn log about a _changes api,
> is that made with this sort of use in mind?

the _changes API will replace / augment the db update notification
system. You can query CouchDB with long-polling HTTP requests to
get notified for events in a DB. This might tie in with your use-case.

Cheers
Jan
==


>
> Jaap
>
> On Fri, May 8, 2009 at 15:37, Jan Lehnardt <jan@apache.org> wrote:
>>
>> On 8 May 2009, at 13:52, Jaap van der Plas wrote:
>>
>>> for that reason (that the revision before deletion may be gone) it
>>> would be helpful to have access to _revs_info, as it specifies which
>>> revisions are still available.
>>
>> No, _rev ids are kept around forever*. Only the content gets removed
>> on compaction. Everything that is not the latest version of a  
>> document
>> must be considered "gone" by the application.
>>
>> * up to the revision stemming threshold.
>>
>> Cheers
>> Jan
>> --
>>
>>
>>>
>>> Jaap
>>>
>>> On Fri, May 8, 2009 at 11:31, Nicholas Orr  
>>> <nicholas.orr@zxgen.net> wrote:
>>>>
>>>> Keep in mind that _rev != git like revisions. _rev is for the  
>>>> replication
>>>> and conflict resolution.
>>>> Read more here: http://wiki.apache.org/couchdb/Document_revisions
>>>>
>>>> <http://wiki.apache.org/couchdb/Document_revisions>As for your  
>>>> exact
>>>> issue I
>>>> don't know anything about that. I was pointed in the direction ^  
>>>> above
>>>> and
>>>> thought I'd pass that along as maybe you might not know about it  
>>>> yet
>>>> either
>>>> :)
>>>>
>>>> Nick
>>>>
>>>> On Fri, May 8, 2009 at 7:20 PM, Jaap van der Plas  
>>>> <jaap@brightin.nl>
>>>> wrote:
>>>>
>>>>> Greetings,
>>>>>
>>>>> I am working on code to retrieve a deleted document from a  
>>>>> database,
>>>>> and have got as far as to retrieve the revision in which a  
>>>>> document
>>>>> gets deleted. If I pass "revs=true" I do get an array with  
>>>>> revision
>>>>> numbers (not complete ones though for some reason, they lack the
>>>>> 'human-readable' revision number prefix.) However, "rev_info=true"
>>>>> does not seem to have any effect here. Working as intended? (I am
>>>>> using the 0.9.0 stable release btw.)
>>>>>
>>>>> Jaap
>>>>>
>>>>
>>>
>>
>>
>


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