Search Results

Search found 243 results on 10 pages for 'couchdb'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 4/10 | < Previous Page | 1 2 3 4 5 6 7 8 9 10  | Next Page >

  • Can' get couchdb external http handlers to work.

    - by fuzzy lollipop
    following the instructions here http://wiki.apache.org/couchdb/ExternalProcesses this is what I get { * error: "{{badarg,[{erlang,port_command, [#Port<0.2056>, [123, [34,<<"info">>,34], 58, [123, [34,"db_name",34], 58, [34,<<"transfer_central">>,34], 44, [34,"doc_count",34], 58,"39441",44, [34,"doc_del_count",34], 58,"0",44, [34,"update_seq",34], 58,"56508",44, [34,"purge_seq",34], 58,"0",44, [34,"compact_running",34], 58,<<"false">>,44, [34,"disk_size",34], 58,"43593828",44, [34,"instance_start_time",34], 58, [34,<<"1272560477320483">>,34], 44, [34,"disk_format_version",34], 58,"5",125], 44, [34,<<"id">>,34], 58,<<"null">>,44, [34,<<"method">>,34], 58, [34,"GET",34], 44, [34,<<"path">>,34], 58, [91, [34,<<"transfer_central">>,34], 44, [34,<<"_test">>,34], 93], 44, [34,<<"query">>,34], 58,<<"{}">>,44, [34,<<"headers">>,34], 58, [123, [34,<<"Accept">>,34], 58, [34, <<"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8,application/json">>, 34], 44, [34,<<"Accept-Charset">>,34], 58, [34,<<"ISO-8859-1,utf-8;q=0.7,*;q=0.7">>,34], 44, [34,<<"Accept-Encoding">>,34], 58, [34,<<"gzip,deflate">>,34], 44, [34,<<"Accept-Language">>,34], 58, [34,<<"en-us,en;q=0.5">>,34], 44, [34,<<"Connection">>,34], 58, [34,<<"keep-alive">>,34], 44, [34,<<"Host">>,34], 58, [34,<<"127.0.0.1:5984">>,34], 44, [34,<<"Keep-Alive">>,34], 58, [34,<<"115">>,34], 44, [34,<<"User-Agent">>,34], 58, [34, <<"Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3">>, 34], 125], 44, [34,<<"body">>,34], 58, [34,"undefined",34], 44, [34,<<"peer">>,34], 58, [34,<<"127.0.0.1">>,34], 44, [34,<<"form">>,34], 58,<<"{}">>,44, [34,<<"cookie">>,34], 58,<<"{}">>,44, [34,<<"userCtx">>,34], 58, [123, [34,<<"db">>,34], 58, [34,<<"transfer_central">>,34], 44, [34,<<"name">>,34], 58,<<"null">>,44, [34,<<"roles">>,34], 58,<<"[]">>,125], 125,10]]}, {couch_os_process,writeline,2}, {couch_os_process,writejson,2}, {couch_os_process,handle_call,3}, {gen_server,handle_msg,5}, {proc_lib,init_p_do_apply,3}]}, {gen_server,call, [<0.110.0>, {prompt,{[{<<"info">>, {[{db_name,<<"transfer_central">>}, {doc_count,39441}, {doc_del_count,0}, {update_seq,56508}, {purge_seq,0}, {compact_running,false}, {disk_size,43593828}, {instance_start_time,<<"1272560477320483">>}, {disk_format_version,5}]}}, {<<"id">>,null}, {<<"method">>,'GET'}, {<<"path">>,[<<"transfer_central">>,<<"_test">>]}, {<<"query">>,{[]}}, {<<"headers">>, {[{<<"Accept">>, <<"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8,application/json">>}, {<<"Accept-Charset">>, <<"ISO-8859-1,utf-8;q=0.7,*;q=0.7">>}, {<<"Accept-Encoding">>,<<"gzip,deflate">>}, {<<"Accept-Language">>,<<"en-us,en;q=0.5">>}, {<<"Connection">>,<<"keep-alive">>}, {<<"Host">>,<<"127.0.0.1:5984">>}, {<<"Keep-Alive">>,<<"115">>}, {<<"User-Agent">>, <<"Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3">>}]}}, {<<"body">>,undefined}, {<<"peer">>,<<"127.0.0.1">>}, {<<"form">>,{[]}}, {<<"cookie">>,{[]}}, {<<"userCtx">>, {[{<<"db">>,<<"transfer_central">>}, {<<"name">>,null}, {<<"roles">>,[]}]}}]}}, infinity]}}" * reason: "{gen_server,call, [<0.109.0>, {execute,{[{<<"info">>, {[{db_name,<<"transfer_central">>}, {doc_count,39441}, {doc_del_count,0}, {update_seq,56508}, {purge_seq,0}, {compact_running,false}, {disk_size,43593828}, {instance_start_time,<<"1272560477320483">>}, {disk_format_version,5}]}}, {<<"id">>,null}, {<<"method">>,'GET'}, {<<"path">>,[<<"transfer_central">>,<<"_test">>]}, {<<"query">>,{[]}}, {<<"headers">>, {[{<<"Accept">>, <<"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8,application/json">>}, {<<"Accept-Charset">>, <<"ISO-8859-1,utf-8;q=0.7,*;q=0.7">>}, {<<"Accept-Encoding">>,<<"gzip,deflate">>}, {<<"Accept-Language">>,<<"en-us,en;q=0.5">>}, {<<"Connection">>,<<"keep-alive">>}, {<<"Host">>,<<"127.0.0.1:5984">>}, {<<"Keep-Alive">>,<<"115">>}, {<<"User-Agent">>, <<"Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3">>}]}}, {<<"body">>,undefined}, {<<"peer">>,<<"127.0.0.1">>}, {<<"form">>,{[]}}, {<<"cookie">>,{[]}}, {<<"userCtx">>, {[{<<"db">>,<<"transfer_central">>}, {<<"name">>,null}, {<<"roles">>,[]}]}}]}}, infinity]}" }

    Read the article

  • Is there any reason not to go directly from client-side Javascript to a database?

    - by Chris Smith
    So, let's say I'm going to build a Stack Exchange clone and I decide to use something like CouchDB as my backend store. If I use their built-in authentication and database-level authorization, is there any reason not to allow the client-side Javascript to write directly to the publicly available CouchDB server? Since this is basically a CRUD application and the business logic consists of "Only the author can edit their post" I don't see much of a need to have a layer between the client-side stuff and the database. I would simply use validation on the CouchDB side to make sure someone isn't putting in garbage data and make sure that permissions are set properly so that users can only read their own _user data. The rendering would be done client-side by something like AngularJS. In essence you could just have a CouchDB server and a bunch of "static" pages and you're good to go. You wouldn't need any kind of server-side processing, just something that could serve up the HTML pages. Opening my database up to the world seems wrong, but in this scenario I can't think of why as long as permissions are set properly. It goes against my instinct as a web developer, but I can't think of a good reason. So, why is this a bad idea? EDIT: Looks like there is a similar discussion here: Writing Web "server less" applications EDIT: Awesome discussion so far, and I appreciate everyone's feedback! I feel like I should add a few generic assumptions instead of calling out CouchDB and AngularJS specifically. So let's assume that: The database can authenticate users directly from its hidden store All database communication would happen over SSL Data validation can (but maybe shouldn't?) be handled by the database The only authorization we care about other than admin functions is someone only being allowed to edit their own post We're perfectly fine with everyone being able to read all data (EXCEPT user records which may contain password hashes) Administrative functions would be restricted by database authorization No one can add themselves to an administrator role The database is relatively easy to scale There is little to no true business logic; this is a basic CRUD app

    Read the article

  • multiple key ranges as parameters to a couchdb view

    - by kolosy
    is there a way to send multiple startKey/endKey pairs to a view, akin to the keys: [] array that can be posted for keys? the underlying problem - let's say my documents have "categories" and timestamps. if i want all documents in the "foo" category that have a timestamp that's within the last two hours, it's simple: function (doc) { emit([doc.category, doc.timestamp], null); } and then query as GET server:5894/.../myview?startKey=[foo, |now - 2 hours|]&endkey=[foo, |now|] the problem comes when i want something in categories foo or bar, within the last two hours. if i didn't care about time, i could just pull directly by key through the keys collection. unfortunately, i have no such option with ranges. what i ended up doing in the meantime is rounding the timestamp to two-hour blocks, and then multiplexing the query out: POST server:5894/.../myview keys=[[foo, 0 hours], [foo, 2 hours], [bar, 0 hours], [bar, 2 hours]] it works, but will get messy if i want to go back a large amount of time (in relationship to the blocksize)

    Read the article

  • Map/Reduce on an array of hashes in CouchDB

    - by sebastiangeiger
    Hello everyone, I am looking for a map/reduce function to calculate the status in a Design Document. Below you can see an example document from my current database. { "_id": "0238f1414f2f95a47266ca43709a6591", "_rev": "22-24a741981b4de71f33cc70c7e5744442", "status": "retrieved image urls", "term": "Lucas Winter", "urls": [ { "status": "retrieved", "url": "http://...." }, { "status": "retrieved", "url": "http://..." } ], "search_depth": 1, "possible_labels": { "gender": "male" }, "couchrest-type": "SearchTerm" } I'd like to get rid of the status key and rather calculate it from the statuses of the urls. My current by_status view looks like the following: function(doc) { if (doc['status']) { emit(doc['status'], null); } } I tried some things but nothing actually works. Right now my Map Function looks like this: function(doc) { if(doc.urls){ emit(doc._id, doc.urls) } } And my Reduce Function function(key, value, rereduce){ var reduced_status = "retrieved" for(var url in value){ if(url.status=="new"){ reduced_status = "new"; } } return reduced_status; } The result is that I get retrieved everywhere which is definitely not right. I tried to narrow down the problem and it seems to be that value is no array, when I use the following Reduce Function I get length 1 everywhere, which is impossible because I have 12 documents in my database, each containing between 20 to 200 urls function(key, value, rereduce){ return value.length; } What am I doing wrong? (I know I want you to write code for me and I'm feeling guilty, but right now I do the calculation of the statuses in ruby after getting the data from the database. It would be nice to already get the right data from the database)

    Read the article

  • CouchDB Map/Reduce raises execption in reduce function?

    - by fuzzy lollipop
    my view generates keys in this format ["job_id:1234567890", 1271430291000] where the first key element is a unique key and the second is a timestamp in milliseconds. I run my view with this elapsed_time?startkey=["123"]&endkey=["123",{}]&group=true&group_level=1 and here is my reduce function, the intention is to reduce the output to get the earliest and latest timestamps and return the difference between them and now function(keys,values,rereduce) { var now = new Date().valueOf(); var first = Number.MIN_VALUE; var last = Number.MAX_VALUE; if (rereduce) { first = Math.max(first,values[0].first); last = Math.min(last,values[0].last); } else { first = keys[0][0][1]; last = keys[keys.length-1][0][1]; } return {first:now - first, last:now - last}; } and when processing a query it constantly raises the following execption: function raised exception (new TypeError("keys has no properties", "", 1)) I am making sure not to reference keys inside my rereduce block. Why does this function constantly raise this exception?

    Read the article

  • problem with two key ranges in couchdb

    - by Duasto
    I'm having problem getting the right results in my coordinate system. To explain my system, I have this simple database that have x_axis, y_axis and name columns. I don't need to get all the data, I just need to display some part of it. For example, I have a coordinate system that have 10:10(meaning from x_axis -10 to 10 and from y_axis -10 to 10) and I want to display only 49 coordinates. In sql query I can do it something like this: "select * from coordinate where x_axis = -3 and x_axis <= 3 and y_axis = -3 y_axis <= 3" I tried this function but no success: "by_range": { "map": "function(doc) { emit([doc.x_axis, doc.y_axis], doc) }" } by_range?startkey=[-3,-3]&endkey=[3,3] I got a wrong results of: -3x-3 -3x-2 -3x-1 -3x0 -3x1 -3x2 -3x3 <-- should not display this part -- -3x4 -3x5 -3x6 -3x7 -3x8 -3x9 -3x10 <-- end of should not display this part -- ..... up to 3x3 to give you a better understanding of my project here is the screenshot of that I want to be made: Oops they don't allowed new poster to post an image img96(dot)imageshack(dot)us/img96/5382/coordinates(dot)jpg <<< just change the "(dot)" to "."

    Read the article

  • Best way to use Cradle with Express.js (CouchDB, Node.js)

    - by Costa
    I'm building my website ( http://tedxgramercy.jit.su ) with express.js and so far I've been using the http.request method in node to access couch, and that's been cool. I've learned lots about how http, couch, and node work, which is awesome. Anyways, I'm thinking of moving over to cradle now (Let me know if you have a strong opinion about this) and I'd like to know the "right" way to set this up. Should I... require() cradle and make a new connection to my db in each separate route? create my database connection once, and then just pass that connection by require()ing the connection in each route? (if so, how do I do that?) Thanks!!!

    Read the article

  • Which PHP library I should choose to work with CouchDB?

    - by Guss
    I want to try playing with CouchDB for a new project I'm writing (as a hobby, not part of my job). I'm well versed in PHP, but I haven't programmed with CouchDB at all, and also I have little experience with non-SQL databases. From looking at CouchDB's "Getting Started with PHP" document they recommend using a third-party library or writing your own client using their RESTful HTTP API. I think I'd rather not mess with writing protocol implementations myself at this point, but what is your experience with writing PHP to work with CouchDB? I haven't tested any of the alternatives yet, but I looked at: PHPillow : I'm interested in the way they implement ORM. I wasn't planning to do ORM, but my problem domain probably map well to that method. PHP Object Freezer: seems like a poor man's ORM - I can use it to implement an actual ORM, or just as an easy store/retrieve document API but it seems too primitive. PHP-on-Couch : Also a bit simple, but they have an interesting API for views and from the documentation it looks usable enough. PHP CouchDB Extension : From the listed options this looks like it has the best chance of making it into the PHP mainline itself, and also has the most complete API. Any opinion one wish to share on each library is welcome.

    Read the article

  • Should I go vor Arrays or Objects in PHP in a CouchDB/Ajax app?

    - by karlthorwald
    I find myself converting between array and object all the time in PHP application that uses couchDB and Ajax. Of course I am also converting objects to JSON and back (for sometimes couchdb but mostly Ajax), but this is not so much disturbing my workflow. At the present I have php objects that are returned by the CouchDB modules I use and on the other hand I have the old habbit to return arrays like array("error"="not found","data"=$dataObj) from my functions. This leads to a mixed occurence of real php objects and nested arrays and I cast with (object) or (array) if necessary. The worst thing is that I know more or less by heart what a function returns, but not what type (array or object), so I often run into type errors. My plan is now to always cast arrays to objects before returning from a function. Of course this implies a lot of refactoring. Is this the right way to go? What about the conversion overhead? Other ideas or tips? Edit: Kenaniah's answer suggests I should go the other way, this would mean I'd cast everything to arrays. And for all the Ajax / JSON stuff and also for CouchDB I would use $myarray = json_decode($json_data,$assoc = false) Even more work to change all the CouchDB and Ajax functions but in the end I have better code.

    Read the article

  • Is it really wrong to version documents using CouchDB's default behaviour?

    - by Tomas Sedovic
    This is one of those "I know I shouldn't do this but it's oh so convenient." questions. Sorry about that. I plan to use CouchDB for storing a bunch of documents and keeping their entire revision history. CouchDB does the versioning automatically, but it is strongly discouraged for programmer's use: "You cannot rely on document revisions for any other purpose than concurrency control." From what I've found on the CouchDB wiki, the versions can get deleted either during compaction or during replication. As far as I can tell, Compaction must always be triggered manually and Replication occurs only when there's more than one database server. The question is: if I won't run compaction and will use only single database instance for my documents, can I just use CouchDB's document versioning and expect it to work? What other problems I might run into? E.g. does not running compaction hurt the performance or consume significantly more disk space (than if I did handle the versioning manually)?

    Read the article

  • Should I go for Arrays or Objects in PHP in a CouchDB/Ajax app?

    - by karlthorwald
    I find myself converting between array and object all the time in PHP application that uses couchDB and Ajax. Of course I am also converting objects to JSON and back (for sometimes couchdb but mostly Ajax), but this is not so much disturbing my workflow. At the present I have php objects that are returned by the CouchDB modules I use and on the other hand I have the old habbit to return arrays like array("error"="not found","data"=$dataObj) from my functions. This leads to a mixed occurence of real php objects and nested arrays and I cast with (object) or (array) if necessary. The worst thing is that I know more or less by heart what a function returns, but not what type (array or object), so I often run into type errors. My plan is now to always cast arrays to objects before returning from a function. Of course this implies a lot of refactoring. Is this the right way to go? What about the conversion overhead? Other ideas or tips? Edit: Kenaniah's answer suggests I should go the other way, this would mean I'd cast everything to arrays. And for all the Ajax / JSON stuff and also for CouchDB I would use $myarray = json_decode($json_data,$assoc = true); //EDIT: changed to true, whcih is what I really meant Even more work to change all the CouchDB and Ajax functions but in the end I have better code.

    Read the article

  • Using ember-resource with couchdb - how can i save my documents?

    - by Thomas Herrmann
    I am implementing an application using ember.js and couchdb. I choose ember-resource as database access layer because it nicely supports nested JSON documents. Since couchdb uses the attribute _rev for optimistic locking in every document, this attribute has to be updated in my application after saving the data to the couchdb. My idea to implement this is to reload the data right after saving to the database and get the new _rev back with the rest of the document. Here is my code for this: // Since we use CouchDB, we have to make sure that we invalidate and re-fetch // every document right after saving it. CouchDB uses an optimistic locking // scheme based on the attribute "_rev" in the documents, so we reload it in // order to have the correct _rev value. didSave: function() { this._super.apply(this, arguments); this.forceReload(); }, // reload resource after save is done, expire to make reload really do something forceReload: function() { this.expire(); // Everything OK up to this location Ember.run.next(this, function() { this.fetch() // Sub-Document is reset here, and *not* refetched! .fail(function(error) { App.displayError(error); }) .done(function() { App.log("App.Resource.forceReload fetch done, got revision " + self.get('_rev')); }); }); } This works for most cases, but if i have a nested model, the sub-model is replaced with the old version of the data just before the fetch is executed! Interestingly enough, the correct (updated) data is stored in the database and the wrong (old) data is in the memory model after the fetch, although the _rev attribut is correct (as well as all attributes of the main object). Here is a part of my object definition: App.TaskDefinition = App.Resource.define({ url: App.dbPrefix + 'courseware', schema: { id: String, _rev: String, type: String, name: String, comment: String, task: { type: 'App.Task', nested: true } } }); App.Task = App.Resource.define({ schema: { id: String, title: String, description: String, startImmediate: Boolean, holdOnComment: Boolean, ..... // other attributes and sub-objects } }); Any ideas where the problem might be? Thank's a lot for any suggestion! Kind regards, Thomas

    Read the article

  • What data is actually stored in a B-tree database in CouchDB?

    - by Andrey Vlasovskikh
    I'm wondering what is actually stored in a CouchDB database B-tree? The CouchDB: The Definitive Guide tells that a database B-tree is used for append-only operations and that a database is stored in a single B-tree (besides per-view B-trees). So I guess the data items that are appended to the database file are revisions of documents, not the whole documents: +---------|### ... | | +------|###|------+ ... ---+ | | | | +------+ +------+ +------+ +------+ | doc1 | | doc2 | | doc1 | ... | doc1 | | rev1 | | rev1 | | rev2 | | rev7 | +------+ +------+ +------+ +------+ Is it true? If it is true, then how the current revision of a document is determined based on such a B-tree? Doesn't it mean, that CouchDB needs a separate "view" database for indexing current revisions of documents to preserve O(log n) access? Wouldn't it lead to race conditions while building such an index? (as far as I know, CouchDB uses no write locks).

    Read the article

  • Is it really wrong to version documents using CouchDB's behaviour?

    - by Tomas Sedovic
    This is one of those "I know I shouldn't do this but it's oh so convenient." questions. Sorry about that. I plan to use CouchDB for storing a bunch of documents and keeping their entire revision history. CouchDB does the versioning automatically, but it is strongly discouraged for programmer's use: "You cannot rely on document revisions for any other purpose than concurrency control." From what I've found on the CouchDB wiki, the versions can get deleted either during compaction or during replication. As far as I can tell, Compaction must always be triggered manually and Replication occurs only when there's more than one database server. The question is: if I won't run compaction and will use only single database instance for my documents, can I just use CouchDB's document versioning and expect it to work? What other problems I might run into? E.g. does not running compaction hurt the performance or consume significantly more disk space (than if I did handle the versioning manually)?

    Read the article

  • Any reason why I shouldn't use couchdb for message passing or realtime activity streams?

    - by Up
    While using ampq or xmpp (rabbitmq or ejabbered that could have couchdb as backends) seems like a good fit to deliver real time updates about friend state in a social gaming platform where updates are small but frequent, I can't help but think why wouldn't couchdb be a good platform to deliver such updates? The main advantage I could think of is its ability to filter updates based on friends and availability of changes api, which makes developing such an application and managing it (including replication) quite easy compared to ampq or xmpp where you have to think about how to manage the pubsub nodes and who is subscribed to them at any point in time. However, I can't help but think this is too good to be true, I can't find information on what couchdb's shortcomings are. Somehow, it feels like using MySQL for message passing which is why I am hesitant to using it. Anyone have any experience in using couchdb for such applications? would you recommend another platform to use?

    Read the article

  • Writing Web "server less" applications

    - by crodjer
    TL;DR What are the prospects of write applications which are completely based on a REST database server (CouchDB) and web applications which directly access the DB instead of having a web server in between? I recently started looking up some NoSQL databases. MongoDB seems to be a popular choices. I also liked the project. But I personally liked the REST interface of CouchDB. So what I wanted to know is if there was the possibility of applications (maybe cached apps in web browser, a chrome extension etc.) which could just just query the database directly with no requirement of a webserver in between. All the computational logic would reside in the client application and the database will do what it does, CRUD. Since mostly (I don't know which doesn't) client frameworks support REST quaries, it could be a good way writing applications well optimized for respective framework. These applications though won't be doing complicated computation, but still provide enough functionality which could replace lots of conventional applications. Are existing resources and projects which would help me move towards writing such applications and also the scope and moving towards developing in this way? Are their any technical/security issues with this? This post will help me decide to look into project like CouchDB (and maybe Dive into Erlang later) or stay with the conventional frameworks (like django) and SQL databases. Update A specific point of such apps I had in mind is creation of offline applications just by replicating couchdb data on client.

    Read the article

  • How does CouchDB perform for a regularly updated dataset?

    - by Ritesh M Nayak
    I am planning on using CouchDB on a project. But as the querying mechanism involves writing views (which are a lot like indexes on regular RDMBMS's) I was wondering, if the document database keeps getting updated a lot ( a write heavy database) would CouchDB perform well compared to a regular RDBMS? Or do we have to compact/re-index the system occasionally to make it perform faster?

    Read the article

  • NoSQL CouchDB Getting Stable with New Release

    <b>Database Journal:</b> "The open source Apache CouchDB database project hit a major milestone this week with the release of version 0.11. The release is an important one for the NoSQL database variant as it matures toward its 1.0 release."

    Read the article

  • CouchDB Moves to the Cloud With Couchio

    <b>Database Journal:</b> "According to its motto, the underlying premise behind the open source CouchDB NoSQL database is about helping developers "relax" -- chiefly by providing them with a simple, powerful database alternative."

    Read the article

  • How Should I Generate Trade Statistics For CouchDB/Rails3 Application?

    - by James
    My Problem: I am trying to developing a web application for currency traders. The application allows traders to enter or upload information about their trades and I want to calculate a wide variety of statistics based on what the user entered. Now, normally I would use a relational database for this, but I have two requirements that don't fit well with a relational database so I am attempting to use couchdb. Those two problems are: 1) Primarily, I have a companion desktop application that users will be able to work with and replicate to the site using couchdb's awesome replication feature and 2) I would like to allow users to be able to define their own custom things to track about trades and generate results based off of what they enter. The schema less nature of couch seems perfect here, but it may end up being harder than it sounds. (I already know couch requires you to define views in advance and such so I was just planning on sticking all the custom attributes in an array and then emitting the array in the view and further processing from there.) What I Am Doing: Right now I am just emitting each trade in couch keyed by each user's system and querying with the key of the system to get an array of trades per system. Simple. I am not using a reduce function currently to calculate any stats because I couldn't figure out how to get everything I need without getting a reduce overflow error. Here is an example of rows that are getting emitted from couch: {"total_rows":134,"offset":0,"rows":[ {"id":"5b1dcd47221e160d8721feee4ccc64be", "key":["80e40ba2fa43589d57ec3f1d19db41e6","2010/05/14 04:32:37 +0000"], null, "doc":{ "_id":"5b1dcd47221e160d8721feee4ccc64be", "_rev":"1-bc9fe763e2637694df47d6f5efb58e5b", "couchrest-type":"Trade", "system":"80e40ba2fa43589d57ec3f1d19db41e6", "pair":"EUR/USD", "direction":"Buy", "entry":12600, "exit":12700, "stop_loss":12500, "profit_target":12700, "status":"Closed", "slug":"101332132375", "custom_tracking": [{"name":"signal", "value":"Pin Bar"}] "updated_at":"2010/05/14 04:32:37 +0000", "created_at":"2010/05/14 04:32:37 +0000", "result":100}} ]} In my rails 3 controller I am basically just populating an array of trades such as the one above and then extracting out the relevant data into smaller arrays that I can compute my statistics on. Here is my show action for the page that I want to display the stats and all the trades: def show @trades = Trade.by_system(:startkey => [@system.id], :endkey => [@system.id, Time.now ]) @trades.each do |trade| if trade.result > 0 @winning_trades << trade.result elsif trade.result < 0 @losing_trades << trade.result else @breakeven_trades << trade.result end if trade.direction == "Buy" @long_trades << trade.result else @short_trades << trade.result end if trade["custom_tracking"] != nil @custom_tracking << {"result" => trade.result, "variables" => trade["custom_tracking"]} end end end I am omitting some other stuff that is going on, but that is the gist of what I am doing. Then I am calculating stuff in the view layer to produce some results: <% winning_long_trades = @long_trades.reject {|trade| trade <= 0 } %> <% winning_short_trades = @short_trades.reject {|trade| trade <= 0 } %> <ul> <li>Total Trades: <%= @trades.count %></li> <li>Winners: <%= @winning_trades.size %></li> <li>Biggest Winner (Pips): <%= @winning_trades.max %></li> <li>Average Win(Pips): <%= @winning_trades.sum/@winning_trades.size %></li> <li>Losers: <%= @losing_trades.size %></li> <li>Biggest Loser (Pips): <%= @losing_trades.min %></li> <li>Average Loss(Pips): <%= @losing_trades.sum/@losing_trades.size %></li> <li>Breakeven Trades: <%= @breakeven_trades.size %></li> <li>Long Trades: <%= @long_trades.size %></li> <li>Winning Long Trades: <%= winning_long_trades.size %></li> <li>Short Trades: <%= @short_trades.size %></li> <li>Winning Short Trades: <%= winning_short_trades.size %></li> <li>Total Pips: <%= @winning_trades.sum + @losing_trades.sum %></li> <li>Win Rate (%): <%= @winning_trades.size/@trades.count.to_f * 100 %></li> </ul> This produces the following results, which aside from a few things is exactly what I want: Total Trades: 134 Winners: 70 Biggest Winner (Pips): 1488 Average Win(Pips): 440 Losers: 58 Biggest Loser (Pips): -516 Average Loss(Pips): -225 Breakeven Trades: 6 Long Trades: 125 Winning Long Trades: 67 Short Trades: 9 Winning Short Trades: 3 Total Pips: 17819 Win Rate (%): 52.23880597014925 What I Am Wondering- Finally The Actual Questions: I am starting to get really skeptical of how well this method will work when a user has 5,000 trades instead of just 134 like in this example. I anticipate most users will only have somewhere under 200 per year, but some users may have a couple thousand trades per year. Probably no more than 5,000 per year. It seems to work ok now, but the page load times are already getting a tad high for my tastes. (About 800ms to generate the page according to rails logs with about a 250ms of that spent in the view layer.) I will end up caching this page I am sure, but I still need the regenerate the page each time a trade is updated and I can't afford to have this be too slow. Sooo..... Is doing something similar here possible with a straight couchdb reduce function? I am assuming handing this off to couch would possibly help with larger data sets. I couldn't figure out how, but I suppose that doesn't mean it isn't possible. If possible, any hints will be helpful. Could I use a list function if a reduce was not available due to reduce constraints? Are couchdb list functions suitable for this type of calculations? Anyone have any idea of whether or not list functions perform well? Any hints what one would look like for the type of calculations I am trying to achieve? I thought about other options such as running the calculations at the time each trade was saved or nightly if I had to and saving the results to a statistics doc that I could then query so that all the processing was done ahead of time. I would like this to be the last resort because then I can't really filter out trades by time periods dynamically like I would really like to. (I want to have a slider that a user can slide to only show trades from that time period using the startkey and endkey in couchdb if I can.) If I should continue running the calculations inside the rails app at the time of the page view, what can I do to improve my current implementation. I am new to rails, couch and programming in general. I am sure that I could be doing something better here. Do I need to create an array for each stat or is there a better way to do that. I guess I just would really like some advice on how to tackle this problem. I want to keep the page generation time minimal since I anticipate these being some of the highest trafficked pages. My gut is that I will need to offload the statistics calculation to either couch or run the stats in advance of when they are called, but I am not sure. Lastly: Like I mentioned above, one of the primary reasons for using couch is to allow users to define their own things to track per trade. Getting the data into couch is no problem, but how would I be able to take the custom_tracking array and find how many winning trades for each named tracking attribute. If anyone can give me any hints to the possibility of doing this that would be great. Thanks a bunch. Would really appreciate any help. Willing to fork out some $$$ if someone wants to take on the problem for me. (Don't know if that is allowed on stack overflow or not.)

    Read the article

  • In CouchDB, how to get documents limited on value in related document? In terms of SQL, how to make WHERE on JOINed table

    - by amorfis
    Crossposting from [email protected] Assume we have two kind of documents in CouchDB. Person and Car: Person: _id firstname surname position salary Car: _id person_id reg_number brand So there is one to many relationship. One person can have many cars. I can construct map function to get every person and his/her car next to each other. In such case key is array [person.id, 0] and [car.person_id, 1]. What I can't do, is limiting this view to owners of specific brand only, e.g. if I need salaries of owners of Ferrari.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 1 2 3 4 5 6 7 8 9 10  | Next Page >