Until this feature is implemented we are planning to put memcached in
the middle, which supports a multi-key get. This will not help much
for hitting the views with startkey, etc, but for fetching multiple
docs by id, it would appear to do the trick (once the docs where cached)
-- troy
On Jul 9, 2008, at 8:07 AM, Bradford Winfrey wrote:
I'm going to wave the white flag on the multi-key search patch. If
anyone else is feeling saucy enough to tackle it, feel free to, I'm
completely un-qualified to do so. Thanks for all the input, but for
now I'm just going to have to execute the queries one at a time and
lump them together. I'd love to investigate it further, but time
just doesn't permit it at the moment. Maybe we could open a ticket
for it if enough people find it useful? That's my two cents.
Thanks again - especially Paul!
----- Original Message ----
From: Bradford Winfrey <[EMAIL PROTECTED]>
To: [email protected]
Sent: Tuesday, July 8, 2008 3:14:56 PM
Subject: Re: Views using JSON Arrays
Oy, I've got to be way off then as to where I'm looking (in
couch_view.erl, notably process_doc and view_insert_query_results).
But yes you are correct in saying:
"Where's the logic that's collecting json objects when they
match the view parameter `key` or is between `startkey` and `endkey`?"
I'm going to mull over this for a bit I think I finally made the
connection with your statement about how there is no real logical
"if-statement". Heh, again of course unless someone chimes in and
says otherwise.
Thanks again for the input.
Brad
----- Original Message ----
From: Paul Davis <[EMAIL PROTECTED]>
To: [email protected]
Sent: Tuesday, July 8, 2008 3:01:44 PM
Subject: Re: Views using JSON Arrays
When you say matching the key with what's being emitted, do you mean
to ask, "Where's the logic that's collecting json objects when they
match the view parameter `key` or is between `startkey` and `endkey`?"
If so, that's all in make_view_fold_fun. Specifically it's
PassedEndFun and how the result is used in [Neg|Pos]CountFun.
The basic idea is that you have `startkey` and `endkey` (When `key` is
provided `startkey` == `endkey` == `key`) and then you stream through
the nodes in the view index starting at `startkey` and stream until a
key is found that is beyond `endkey` which is the termination
condition. The key is to remember that all docs in the view are
ordered by key and that when you fold over them they are passed to the
functions in make_view_fold_fun in order. Hence why there's no logic
equivalent to "if record between start and end, add to results, else
skip" (which is why its freaky fast). Its slightly more complicated to
account for the reverse sorting, count, etc, parameters.
At least, I'm about 95% sure that's how its working. We'll see if
Damien laughs at me.
Paul
On Tue, Jul 8, 2008 at 2:25 PM, Bradford Winfrey <[EMAIL PROTECTED]
> wrote:
I'm trying to find the function that actually does the matching of
the key with what is being emitted, anyone have any insight where
that is? I have the multiple keys coming in, that was trivial, but
now I'm trying to see how in fact the view indexes can do multiple
lookups at once. I must admit, I'm operating on no more than maybe
2 days of looking at Erlang so any extra pointers are welcomed.
----- Original Message ----
From: Damien Katz <[EMAIL PROTECTED]>
To: [email protected]
Sent: Thursday, July 3, 2008 1:51:38 PM
Subject: Re: Views using JSON Arrays
On Jul 3, 2008, at 2:34 PM, Jan Lehnardt wrote:
On Jul 3, 2008, at 20:17, Jan Lehnardt wrote:
On Jul 3, 2008, at 20:07, Paul Bonser wrote:
On Thu, Jul 3, 2008 at 8:01 AM, Bradford Winfrey <[EMAIL PROTECTED]
wrote:
We would get back each one of our tags as a key, yea? Only if we
supplied one at a time. So how does one go about supplying a
range, array (not sure what we'd call it here) of keys to be
searched on? http://...?key=["octopus","hockey";] maybe? I'm
unsure of the plan of attack for such a thing. Maybe I'm just
going about it in the wrong direction. Any thoughts?
Hey everyone. I've pretty much just been watching the mailing list
here myself.
This is the second time somebody has asked about this since I've
started watching this mailing list. I could see it being a
valuable
feature.
Would it be valuable to add the ability to query a view with
multiple
keys, getting the results for each of those keys back? Something
like
http://...?key_list=["octopus","hockey";]
If I were interested in investigating how hard it would be to add
that
feature, where would I start looking in the code?
This simply doesn't fit the way views work. They are single indexes
that you
can use for single-key or or key-range lookups. if you need random
access
you'd basically need to query the view as many times as you have
keys
to search. No matter if you do that in front or behind the API.
Hey you smart-ass, on the one hand you are trying to recruit new
developers and on the other hand you discourage people from adding
useful features. Make up your mind man!
Paul, if you come up with a nice solution, we'd be happy to look at
integrating it. Please give it a try. To investigate the code it is
probably
best to start at src/couchdb/couch_http.erl as it defines the HTTP
API
and handles the requests you already know and just drill down from
there.
:)
The view indexes can indeed do multiple lookups at once. The only
thing is I don't think a GET with all the keys are URL args is the
way
to go as it can get really long and cause problems with proxies and
HTTP libs, a POST with the lookup keys as the body is probably
better.
Cheers
Jan
--
