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From Dmitry Unkovsky <>
Subject Re: View Performance (was Re: The 1.0 Thread)
Date Thu, 09 Jul 2009 09:12:22 GMT
Can please someone give a very brief outline, how do I build erlview?
Or just a  pointer to somewhere on internets to read for it.

I'm no expert in erlang (well, yet), and running make in src gives
some arity error that i'm not capable to deal with for now.
This refers to checked out from git://
master branch (that is at 3e49de6998... "added cheesy helper

Sorry for disturbing, probably I'd better go reading more docs, but as
they say "all work and no play makes Jack a dull boy", if it's
question of a few lines then I'll ask and you please forgive noob ;)

Best, Dmitry.

2009/7/7 Michael McDaniel <>:
> On Tue, Jul 07, 2009 at 12:29:08PM -0700, Scott Shumaker wrote:
>> The erlang view server does sound like it would be a big performance
>> win - although I think it will make CouchDB meet with more resistance
>> to mass-adoption if it becomes the preferred view path - simply
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>  Though someone could write a parse transformer so that
>  scripts entered via, e.g. Futon, could be closer to the
>  default javascript syntax, even when using an Erlang
>  view server (e.g. erlview).
>  Or even write wrappers which used more generally-familiar
>  syntax.  I started to do that with erlview, write wrappers
>  which helped simplify view writing.
> ~Michael
>> because Erlang is a much less common language than, say, Javascript -
>> and Javascript is a more natural fit to deal with JSON data.  Right
>> now, I don't have to train my team up on a new language to merely be
>> clients of CouchDB - and Javascript is far less intimidating and well
>> documented to the novice.  For us, there's additional benefits since
>> most of our codebase is in Javascript anyway - so our views can
>> leverage functionality by including code from our app.  But if the
>> erlang view server performance turns out to be significantly better,
>> we'll probably have to bite the bullet and rewrite all of our views.
>> Still, I'm pretty convinced that you could make optimizations to make
>> the javascript view server nearly as fast as the erlang one -
>> especially since, when you really think about it - data comes into
>> CouchDB as JSON, gets run through a Javascript view server, and gets
>> returned to the client as JSON.  With JSON in and out (which is barely
>> touched by CouchDB - other than _id and _rev), it does seem like you
>> could avoid most of the conversion overhead.  And you could certainly
>> re-architect couchjs to have a more efficient communication path.
>> I know the standard response is 'you want it - well, patches are
>> welcome!' but I'm speaking as a client of CouchDB - one that is very
>> busy trying to get a product launched (and not blessed with enough
>> free time at the present moment to really learn Erlang, let alone
>> contribute significant amounts of code).  So I'm just trying to be an
>> advocate for the many developers who would love to use (or are using)
>> CouchDB as a 'better SQL' - a persistent storage backend that makes a
>> lot more sense for storing and dealing with the kinds of data most web
>> apps face.  I think there are lot more people like me out there, too -
>> and tons more who are waiting with bated breath to see how CouchDB
>> develops.
>> On Mon, Jul 6, 2009 at 1:53 AM, Brian Candler<> wrote:
>> > On Sat, Jul 04, 2009 at 03:26:23PM -0700, Scott Shumaker wrote:
>> >> 53K docs apparently take 68s to be converted to JSON, and received by
>> >> the dummy server (with no docs emitted) - or about 780 docs/second.
>> >> couchjs is slower than bork.rb in this case (unsurprising -  bork.rb
>> >> not really parsing the data)
>> >> filtering on the couch side is an enormous win for our test case.
>> >>
>> >> K/V inserts - (5*53K in (200-68)s) = ~2000 per second
>> >>
>> >> This is a pretty big difference from Brian's results (8000/sec),
>> >> although we're dealing with many more docs, and without comparing
>> >> hardware specs, it's difficult to draw conclusions.
>> >
>> > Hmm, my hardware is pretty lame (Thinkpad X30 laptop, P3-M 1.2GHz, 1GB RAM,
>> > 2.5" IDE drive). Maybe it's because you're using a substantially larger
>> > dataset than mine, e.g. more Btree nodes to update or more flushes to disk
>> > or something. I'll try increasing the size of my benchmark test, but
>> > annoyingly RestClient inherits Net::HTTP's 60-second request timeout, and
>> > the high-level RestClient.get / RestClient.put API doesn't allow it to be
>> > overridden. I'll probably monkey-patch Net::HTTP for simplicity.
>> >
>> > Regards,
>> >
>> > Brian.
>> >
> --
> Michael McDaniel
> Portland, Oregon, USA

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