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To: user@couchdb.apache.org
Subject: Re: COUCHDB-161 Range Request support for attachments
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Date: Thu, 29 Oct 2009 10:14:06 +0100
From: jens.riemschneider@icw.de
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Hi Jan,

I found some time to look into the code and I have a rough idea on how=20
this can be implemented. As far as I understand, an attachment is stored=20
in blocks and then contains data on where those blocks can be found on=20
disk. The actual length of the block is stored on disk. Therefore, the=20
attachment basically has a list of starting positions of the blocks. Only=20
the lower level functions (such as pread=5Fiolist) know the actual length o=
f=20
the blocks. Therefore, I will need to first determine the block lengths,=20
then determine which blocks fall into the requested range and finally=20
trigger the sending of those blocks. I could not find any way to get the=20
block lengths yet, so I will have to implement this. Am I on the right=20
track or do you think there is some other functionality in the current=20
implementation that I could use for this?

Thanks,
Jens


Jan Lehnardt <jan@apache.org>=20
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=5Fhttpd=5Fdb.e=
rl?view=3Dmarkup


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=20
> if
> you can point me to the right entry point in the code, I would=20
> 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:
>>
>=20
http://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=3D12310780&=
styleName=3DHtml&version=3D12313694

>
>> 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=20
>> 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, J=F6rg
>>> Stadler / Aufsichtsratsvors.: Prof. Dr. Christof Hettich
>>> Firmensitz: 69190 Walldorf, Industriestra=DFe 41 / AG Mannheim HRB
>>> 351761 / USt.-IdNr.: DE 198388516
>>
>>
>>
>>
>>
>> InterComponentWare AG:
>> Vorstand: Dr. Lutz Kleinholz (Vors.), Dr. Georg Ralle, J=F6rg
>> Stadler / Aufsichtsratsvors.: Prof. Dr. Christof Hettich
>> Firmensitz: 69190 Walldorf, Industriestra=DFe 41 / AG Mannheim HRB
>> 351761 / USt.-IdNr.: DE 198388516
>
>
>
>
> InterComponentWare AG:
> Vorstand: Dr. Lutz Kleinholz (Vors.), Dr. Georg Ralle, J=F6rg=20
> Stadler / Aufsichtsratsvors.: Prof. Dr. Christof Hettich
> Firmensitz: 69190 Walldorf, Industriestra=DFe 41 / AG Mannheim HRB=20
> 351761 / USt.-IdNr.: DE 198388516


InterComponentWare AG: =20
Vorstand: Dr. Lutz Kleinholz (Vors.), Dr. Georg Ralle, J=F6rg Stadler / Auf=
sichtsratsvors.: Prof. Dr. Christof Hettich =20
Firmensitz: 69190 Walldorf, Industriestra=DFe 41 / AG Mannheim HRB 351761 /=
 USt.-IdNr.: DE 198388516  =
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