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From Robert Dionne <dio...@dionne-associates.com>
Subject Re: multiview on github
Date Sun, 19 Sep 2010 11:21:00 GMT
I took another peek at this and I'm curious as to what it's doing. Is it just checking that
a given id participates in a view? So if it makes it around the ring it wins? Or is it actually
computing the result of passing the doc thru all the views?

If the answer is the former then would disjunction also be something one might want? I'm just
curious, I don't have a use case and I forget the original discussion around this. I sort
of think of views as a functional mapping from the database to some subset. That's not entirely
accurate given there's this reduce phase also. So I could imagine composing views in a functional
way, but the same thing can be had with just a different map function that is the composition.

Anyway if you have a brief description of this, with a use case,  it would help.

Cheers,

Bob




On Sep 17, 2010, at 11:32 PM, Norman Barker wrote:

> Chris, James
> 
> thanks for bumping this, we are using this internally at 'scale'
> (million+ keys). I want this to work for couchdb as we want to give
> back for such a great product and support this going forward, so any
> suggestions welcomed and we will test and add them to the local github
> account with the aim of getting this into trunk.
> 
> Norman
> 
> On Fri, Sep 17, 2010 at 7:00 PM, James Hayton <theboss@purplebulldog.com> wrote:
>> I want to use it!  I just haven't gotten around to it.  I was going to try
>> and test it out this weekend and if I am able, I will certainly report back
>> what I find.
>> 
>> James
>> 
>> On Fri, Sep 17, 2010 at 5:55 PM, Chris Anderson <jchris@apache.org> wrote:
>> 
>>> On Mon, Aug 30, 2010 at 10:58 AM, Norman Barker <norman.barker@gmail.com>
>>> wrote:
>>>> Bob,
>>>> 
>>>> I can and have been testing the multiview at this scale, it is ok
>>>> (fast enough), but I think being able to test inclusion of a document
>>>> id in a view without having to loop would be a considerable speed
>>>> improvement. If you have any ideas let me know.
>>>> 
>>> 
>>> I just want to bump this thread, as I think this is a useful feature.
>>> I don't expect to be able to test it in the coming weeks, but if I did
>>> I would. Is anyone besides Norman using this? Has anyone used it at
>>> scale?
>>> 
>>> Cheers,
>>> Chris
>>> 
>>>> thanks,
>>>> 
>>>> Norman
>>>> 
>>>> On Mon, Aug 30, 2010 at 10:49 AM, Robert Newson <robert.newson@gmail.com>
>>> wrote:
>>>>> I'm sorry, I've had no time to play with this at scale.
>>>>> 
>>>>> On Mon, Aug 30, 2010 at 5:35 PM, Norman Barker <norman.barker@gmail.com>
>>> wrote:
>>>>>> Hi,
>>>>>> 
>>>>>> are there any more comments on this, if not can you describe the
>>>>>> process (in particular how to obtain a wiki and jira account for
>>>>>> couchdb which I have been unable to do) and I will start documenting
>>>>>> this so we can put this into the trunk.
>>>>>> 
>>>>>> Bob, were you able to do any more testing with large views, are there
>>>>>> any suggestions on how to speed up the document id inclusion test
as
>>>>>> described below?
>>>>>> 
>>>>>> thanks,
>>>>>> 
>>>>>> Norman
>>>>>> 
>>>>>> On Mon, Aug 23, 2010 at 9:22 AM, Norman Barker <
>>> norman.barker@gmail.com> wrote:
>>>>>>> Bob,
>>>>>>> 
>>>>>>> thanks for the feedback and for taking a look at the code. Guidelines
>>>>>>> on when to use a supervisor within couchdb with a gen_server
would be
>>>>>>> appreciated, currently I have a supervisor and a gen_server,
but if
>>>>>>> couchdb has a supervision process I could remove that layer.
>>>>>>> 
>>>>>>> I think plugins is a great idea, however intersection of views
is such
>>>>>>> as common request, perhaps there needs to plugin system and if
a
>>>>>>> plugin is rated enough it goes into trunk as a core feature.
>>>>>>> 
>>>>>>> the four (or slightly more) summary is here
>>>>>>> 
>>>>>>> 
>>> http://github.com/normanb/couchdb/raw/trunk/src/couchdb/couch_query_ring.erl
>>>>>>> 
>>>>>>> %
>>>>>>> % send an id from the start list to the next node in the ring,
if the
>>>>>>> id is in adjacent node then the this node sends to the next ring
node
>>>>>>> ....
>>>>>>> % if the id gets all round the ring and back to the start node
then is
>>>>>>> has intersected all queries and should be included. The nodes
in the
>>>>>>> ring
>>>>>>> % should be sorted in size from small to large for this to be
>>> effective
>>>>>>> %
>>>>>>> % In addition send the initial id list round in parallel
>>>>>>> 
>>>>>>> it really needs some eyes from the core couchdb coders to see
how to
>>>>>>> speed up the inclusion testing, looping is bad even if it is
done in
>>>>>>> parallel.
>>>>>>> 
>>>>>>> Multiview is usable, I am using it with some pretty big mega-views
(as
>>>>>>> per the raindrop) model, I am also available to add features
to this
>>>>>>> as this is core part of our work and we want to give it to couch
as a
>>>>>>> contribution.
>>>>>>> 
>>>>>>> thanks,
>>>>>>> 
>>>>>>> Norman
>>>>>>> 
>>>>>>> On Mon, Aug 23, 2010 at 5:05 AM, Robert Dionne
>>>>>>> <dionne@dionne-associates.com> wrote:
>>>>>>>> Hi Norman,
>>>>>>>> 
>>>>>>>>  I took a peek at multiview. I haven't followed this too
closely on
>>> the mailing list but this is *view intersection*? Is there a 5 line summary
>>> of what this does somewhere?
>>>>>>>> 
>>>>>>>>  I'm curious as to why the daemon needs to be a supervisor,
most if
>>> not all of the other daemons are gen_servers. OTP allows this but I think
>>> this is a good area where some CouchDB guidelines on plugins would apply.
>>>>>>>> 
>>>>>>>>  It strikes me that views, the use of map/reduce, etc. are
one of the
>>> trickier aspects of using CouchDB, particularly for new users coming from
>>> the SQL world. People are also reporting issues with performance of views, I
>>> guess often because reduce functions go out of control.
>>>>>>>> 
>>>>>>>>  I think the project would be better served if features like
this
>>> were available as plugins. I would put GeoCouch in the same category. Its
>>> very neat and timely (given everyone wants to know where everyone else is
>>> using their telephone but without talking other than asynchronously), but a
>>> server plugin architecture that would allow this to be done cleanly should
>>> come first.
>>>>>>>> 
>>>>>>>>  This is just my opinion. I'd love to see some of the project
>>> founders and committers weigh in on this and set some direction.
>>>>>>>> 
>>>>>>>> Best regards,
>>>>>>>> 
>>>>>>>> Bob
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> On Aug 22, 2010, at 5:45 PM, Norman Barker wrote:
>>>>>>>> 
>>>>>>>>> I would like to take this multiview code and have it
added to trunk
>>> if
>>>>>>>>> possible, what are the next steps?
>>>>>>>>> 
>>>>>>>>> thanks,
>>>>>>>>> 
>>>>>>>>> Norman
>>>>>>>>> 
>>>>>>>>> On Wed, Aug 18, 2010 at 11:44 AM, Norman Barker <
>>> norman.barker@gmail.com> wrote:
>>>>>>>>>> I have made
>>>>>>>>>> 
>>>>>>>>>> http://github.com/normanb/couchdb
>>>>>>>>>> 
>>>>>>>>>> which is a fork of the latest couchdb trunk with
the multiview code
>>>>>>>>>> and tests added.
>>>>>>>>>> 
>>>>>>>>>> If geocouch is available then it can still be used.
>>>>>>>>>> 
>>>>>>>>>> There are a couple of questions about the multiview
on the user
>>> /dev
>>>>>>>>>> list so I will be adding some more test cases during
today.
>>>>>>>>>> 
>>>>>>>>>> thanks,
>>>>>>>>>> 
>>>>>>>>>> Norman
>>>>>>>>>> 
>>>>>>>>>> On Tue, Aug 17, 2010 at 9:23 PM, Norman Barker <
>>> norman.barker@gmail.com> wrote:
>>>>>>>>>>> this is possible, I forked geocouch since I use
it, but I have
>>> already
>>>>>>>>>>> separated the geocouch dependencies from the
trunk.
>>>>>>>>>>> 
>>>>>>>>>>> I can do this tomorrow, certainly be interested
in any feedback.
>>>>>>>>>>> 
>>>>>>>>>>> thanks,
>>>>>>>>>>> 
>>>>>>>>>>> Norman
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> On Tue, Aug 17, 2010 at 7:49 PM, Volker Mische
<
>>> volker.mische@gmail.com> wrote:
>>>>>>>>>>>> On 08/18/2010 03:26 AM, J Chris Anderson
wrote:
>>>>>>>>>>>>> 
>>>>>>>>>>>>> On Aug 16, 2010, at 4:38 PM, Norman Barker
wrote:
>>>>>>>>>>>>> 
>>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>>> 
>>>>>>>>>>>>>> I have made the changes as recommended,
adding a test case
>>>>>>>>>>>>>> multiview.js and also adding the
userCtx to open the db.
>>>>>>>>>>>>>> 
>>>>>>>>>>>>>> I have also forked geocouch and this
is available here
>>>>>>>>>>>>>> 
>>>>>>>>>>>>> 
>>>>>>>>>>>>> this patch seems important (especially
as people are already
>>> asking for
>>>>>>>>>>>>> help using it on user@)
>>>>>>>>>>>>> 
>>>>>>>>>>>>> to get it committed, it either must remove
the dependency on
>>> GeoCouch, or
>>>>>>>>>>>>> become part of CouchDB when (and if)
GeoCouch becomes part of
>>> CouchDB.
>>>>>>>>>>>>> 
>>>>>>>>>>>>> Is it possible / useful to make a version
that doesn't use
>>> GeoCouch? And
>>>>>>>>>>>>> then to make the GeoCouch capabilities
part GeoCouch for now?
>>>>>>>>>>>>> 
>>>>>>>>>>>>> Chris
>>>>>>>>>>>>> 
>>>>>>>>>>>> 
>>>>>>>>>>>> Hi Norman,
>>>>>>>>>>>> 
>>>>>>>>>>>> if the patch is ready for trunk, I'd be happy
to move the
>>> GeoCouch bits to
>>>>>>>>>>>> GeoCouch itself (as GeoCouch isn't ready
for trunk yet).
>>>>>>>>>>>> 
>>>>>>>>>>>> Lately I haven't been that responsive when
it comes to GeoCouch,
>>> but that
>>>>>>>>>>>> will change (in about a month) after holidays
and FOSS4G.
>>>>>>>>>>>> 
>>>>>>>>>>>> Cheers,
>>>>>>>>>>>>  Volker
>>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>> 
>>>> 
>>> 
>>> 
>>> 
>>> --
>>> Chris Anderson
>>> http://jchrisa.net
>>> http://couch.io
>>> 
>> 


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