couchdb - startkey endkey doesn't filter records with key arrays as expected - mapreduce

Question

I have Couch-DB map-reduce view which outputs this;
{
rows: [
{
key: [
"2014-08-20",
2,
"registration"
],
value: 2
},
{
key: [
"2014-08-20",
2,
"search"
],
value: 3
},
{
key: [
"2014-08-21",
2,
"registration"
],
value: 3
},
{
key: [
"2014-08-21",
2,
"search"
],
value: 4
}
]
}
I need to query all the records that has between 2014-08-20 and 2014-08-21 Also the same time I need the integer value in the middle to be 2 and the last value to be "registration".
My curl request URL looks like this
BASE_URL?group=true&startkey=["2014-08-20",1,"registration"]
&endkey=["2014-08-21",1,"registration"]
This filters out the date but none of the other elements (the integer value and the string). Anyone got an idea whats happening?
Any help would be appreciated.
UPDATE
My Document structure looks something like this
[
{
platform_version: 2,
UDID: "EWHSJeNp20sBFuzqcorkKVVi",
session: {
timestamp: "2014-08-20T00:00:00.000Z",
session_id: "kOnNIhCNQ31LlkpEPQ7XnN1D",
ip: "202.150.213.66",
location: "1.30324,103.5498"
},
events: [
{
event_type: "search",
timestamp: "2014-08-21T00:00:00.000Z",
location: "1.30354,103.5301",
attributes: {
}
}
]
},
{
platform_version: 2,
UDID: "EWHSJeNp20sBFuzqcorkKVVi",
session: {
timestamp: "2014-08-21T00:00:00.000Z",
session_id: "kOnNIhCNQ31LlkpEPQ7XnN1D",
ip: "202.150.213.66",
location: "1.30324,103.5498"
},
events: [
{
event_type: "search",
timestamp: "2014-08-21T00:00:00.000Z",
location: "1.30354,103.5301",
attributes: {
}
}
]
},
{
platform_version: 2,
UDID: "EWHSJeNp20sBFuzqcorkKVVi",
session: {
timestamp: "2014-08-20T00:00:00.000Z",
session_id: "kOnNIhCNQ31LlkpEPQ7XnN1D",
ip: "202.150.213.66",
location: "1.30324,103.5498"
},
events: [
{
event_type: "click",
timestamp: "2014-08-21T00:00:00.000Z",
location: "1.30354,103.5301",
attributes: {
}
}
]
}
]
and the map reduce function looks like this.
function(doc) {
date = doc.session.timestamp.split("T")[0];
eventArray = doc.events;
for (i = 0; i < eventArray.length; i++) {
emit([doc.app_version,eventArray[i].event_type,date],1);
}
}
It started working after I change the order of the keys. but still, I can't use a wildcard to query all the event types.

Answer 1

You are getting documents with different second array item different then 1 because in the CouchDB the limits (startkey and endkey) are compared to map keys using lexicographical order. In the lexicographical order [1,1] < [1,2] < [2,1] < [2,2].
What you need is either multidimensional queries (which are not supported by CouchDB), additional client-side filtering (which may increase data transferred between CouchDB and your app) or additional server-side filtering with list function (which increase processing time of queries).
If your app needs filtering using range only on the first element of key array (just like in your example query), you would solve your problem easily by placing the item at the last position of array, eg. emitting [1, "registration", "2014-08-21"] instead of ["2014-08-21", 1, "registration"].