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From jens.riemschnei...@icw.de
Subject Re: COUCHDB-161 Range Request support for attachments
Date Thu, 29 Oct 2009 09:14:06 GMT
Hi Jan,

I found some time to look into the code and I have a rough idea on how 
this can be implemented. As far as I understand, an attachment is stored 
in blocks and then contains data on where those blocks can be found on 
disk. The actual length of the block is stored on disk. Therefore, the 
attachment basically has a list of starting positions of the blocks. Only 
the lower level functions (such as pread_iolist) know the actual length of 
the blocks. Therefore, I will need to first determine the block lengths, 
then determine which blocks fall into the requested range and finally 
trigger the sending of those blocks. I could not find any way to get the 
block lengths yet, so I will have to implement this. Am I on the right 
track or do you think there is some other functionality in the current 
implementation that I could use for this?

Thanks,
Jens





Jan Lehnardt <jan@apache.org> 
27.10.2009 15:58
Please respond to
user@couchdb.apache.org


To
user@couchdb.apache.org
cc

Subject
Re: COUCHDB-161 Range Request support for attachments






Hi Jens,

http://svn.apache.org/viewvc/couchdb/trunk/src/couchdb/couch_httpd_db.erl?view=markup


line 857 ff.

Cheers
Jan
--

On 27 Oct 2009, at 15:32, jens.riemschneider@icw.de wrote:

> Hi Jan,
>
> I didn't check out the sources yet, so I can't promise anything. But 
> if
> you can point me to the right entry point in the code, I would 
> definitely
> have a look.
>
> Thanks,
> Jens
>
>
>
>
> Jan Lehnardt <jan@apache.org>
> 27.10.2009 15:22
> Please respond to
> user@couchdb.apache.org
>
>
> To
> user@couchdb.apache.org
> cc
>
> Subject
> Re: COUCHDB-161 Range Request support for attachments
>
>
>
>
>
>
>
> On 27 Oct 2009, at 15:10, jens.riemschneider@icw.de wrote:
>
>> Hi Jan,
>>
>> Thanks for the quick reply. I googled for the release notes and
>> ended up
>> at:
>>
> 
http://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12310780&styleName=Html&version=12313694

>
>> Guess that is just an automatic page generated from the Jira.
>> Anyway, are
>> there any plans to include this in the near future? I'm asking
>> because we
>> can work around this, but it would simplify our implementation if 
>> this
>> feature is available.
>
> I'd love to see it added too, but I don't know anyone who is currently
> taking this on. The patch shouldn't be too hard and would be perfect
> for a newcomer who is eager to dive into the CouchDB codebase.
>
> I'd be happy to do some guiding.
>
> Cheers
> Jan
> --
>
>
>
>>
>> Thanks,
>> Jens
>>
>>
>>
>>
>> Jan Lehnardt <jan@apache.org>
>> 27.10.2009 14:52
>> Please respond to
>> user@couchdb.apache.org
>>
>>
>> To
>> user@couchdb.apache.org
>> cc
>>
>> Subject
>> Re: COUCHDB-161 Range Request support for attachments
>>
>>
>>
>>
>>
>>
>> Hi,
>>
>> Range requests for attachments are not in 0.10. The release
>> notes don't include that information. I think the confusion stems
>> from that in JIRA, the issue is tagged 0.10. Note though that
>> the issue is still open.
>>
>> Cheers
>> Jan
>> --
>>
>> On 27 Oct 2009, at 14:38, jens.riemschneider@icw.de wrote:
>>
>>> Hi,
>>>
>>> I saw that the release notes of 0.10 include the feature request
>>> COUCHDB-161 "Range Request support for attachments". I tried using
>>> the
>>> http header "Range" when doing a normal Get request for an
>>> attachment.
>>> However, I always get the complete attachment. I configured the
>>> CouchDb
>>> log to output debug messages and it seems the header is received by
>>> CouchDb. Is there anything else I need to do?
>>>
>>> Thanks,
>>> Jens
>>>
>>> InterComponentWare AG:
>>> Vorstand: Dr. Lutz Kleinholz (Vors.), Dr. Georg Ralle, Jörg
>>> Stadler / Aufsichtsratsvors.: Prof. Dr. Christof Hettich
>>> Firmensitz: 69190 Walldorf, Industriestraße 41 / AG Mannheim HRB
>>> 351761 / USt.-IdNr.: DE 198388516
>>
>>
>>
>>
>>
>> InterComponentWare AG:
>> Vorstand: Dr. Lutz Kleinholz (Vors.), Dr. Georg Ralle, Jörg
>> Stadler / Aufsichtsratsvors.: Prof. Dr. Christof Hettich
>> Firmensitz: 69190 Walldorf, Industriestraße 41 / AG Mannheim HRB
>> 351761 / USt.-IdNr.: DE 198388516
>
>
>
>
> InterComponentWare AG:
> Vorstand: Dr. Lutz Kleinholz (Vors.), Dr. Georg Ralle, Jörg 
> Stadler / Aufsichtsratsvors.: Prof. Dr. Christof Hettich
> Firmensitz: 69190 Walldorf, Industriestraße 41 / AG Mannheim HRB 
> 351761 / USt.-IdNr.: DE 198388516





InterComponentWare AG:  
Vorstand: Dr. Lutz Kleinholz (Vors.), Dr. Georg Ralle, Jörg Stadler / Aufsichtsratsvors.:
Prof. Dr. Christof Hettich  
Firmensitz: 69190 Walldorf, Industriestraße 41 / AG Mannheim HRB 351761 / USt.-IdNr.: DE
198388516  
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