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From "Markus Jelsma" <mar...@buyways.nl>
Subject Re: Weird document update conflict on delete
Date Mon, 11 Jan 2010 23:23:54 GMT
Michael,


You may want to read up this topic [1] for the sake of total clarity, the
authors have done a much better job in explaining everything all this. And
do not forget that CouchDB can only handle conflict management at the
single document level - something many of us have not understood
correctly.

Good luck with your Go client and do not forget to inform the mailing list
when all things turn out well :)


[1] http://books.couchdb.org/relax/reference/conflict-management


Cheers,


Michael Hoisie zei:
> Markus, thanks for the clarification and the examples -- the problem was
> a bug in the Go http library I use :)
>
> - Mike
>
> On Mon, Jan 11, 2010 at 2:22 PM, Markus Jelsma <markus@buyways.nl>
> wrote:
>> Hello Michael,
>>
>>
>> For as far as i know this is indeed normal behavior. When you add a
>> document and specifying a revision ID, CouchDB will increment the
>> revision ID rendering any actions following using the `old` ID
>> useless.
>>
>> If you add a document using a revision ID, you must use the new
>> revision ID for all modifying actions for that document.
>>
>> markus@relax:~$ curl -X PUT http://localhost:5984/bla
>> {"ok":true}
>>
>> markus@relax:~$ curl -X PUT
>> http://localhost:5984/bla/2b866715d560a2e62e11df4cfcf7258a -d
>> '{"_rev":"1-c7176253456a2d0378c55e597ed96ad3"}'
>> {"ok":true,"id":"2b866715d560a2e62e11df4cfcf7258a","rev":"2-ce5f1bb80a4b215d152444b303ecd73e"}
>>
>> Do you see the new revision ID? I cannot issue a delete using the
>> revision ID i specified during creation, let's see:
>>
>> markus@relax:~$ curl -X DELETE
>> http://localhost:5984/bla/2b866715d560a2e62e11df4cfcf7258a?rev=1-c7176253456a2d0378c55e597ed96ad3
>> {"error":"conflict","reason":"Document update conflict."}
>>
>> However, i can delete the document using the current revision ID,
>> check it out:
>>
>> markus@relax:~$ curl -X DELETE
>> http://localhost:5984/bla/2b866715d560a2e62e11df4cfcf7258a?rev=2-ce5f1bb80a4b215d152444b303ecd73e
>> {"ok":true,"id":"2b866715d560a2e62e11df4cfcf7258a","rev":"3-ba96b157226112e17db64f687416aafb"}
>>
>>
>> Next time, remember the following rule of thumb. Any operation
>> modifying an existing document without using the _current_ revision ID
>> will fire a conflict error! Therefore you must always use the current
>> revision ID.
>>
>> Of course, this can also return a conflict but that will be due to
>> another person or process that beat you to it
>>
>>
>> Cheers,
>>
>>
>>  Michael Hoisie zei:
>>> Hi,
>>>
>>> I'm writing a couchdb library for Go (
>>> http://github.com/hoisie/gocouch ) , and I'm running into this
>>> bizarre issue while testing the document delete method. This sequence
>>> of requests causes a document update conflict:
>>>
>>> 1. check if a database exists : HEAD http://127.0.0.1:5984/test123 2.
>>> create a new database: PUT http://127.0.0.1:5984/test123
>>> 3. add a document to the database POST http://127.0.0.1:5984/test123/
>>>   --> docid 2b866715d560a2e62e11df4cfcf7258a
>>>   --> revid 1-c7176253456a2d0378c55e597ed96ad3
>>> 4. delete the same document form the database:
>>> DELETE
>>> http://127.0.0.1:5984/test123/2b866715d560a2e62e11df4cfcf7258a?rev=1-c7176253456a2d0378c55e597ed96ad3
>>> --> {"error":"conflict","reason":"Document update conflict."}
>>>
>>> I believe this fairly simple sequence of events should work. Is there
>>> anything here that's not allowed? I believe both the POST and DELETE
>>> are run on the same http connection. Could that be causing problems?
>>>
>>> I'm running CouchDBX 0.8 ( couchdb 0.10.0) on mac os x 10.6.
>>>
>>> Thanks,
>>> Mike




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