Finding documents with a time-range which intersect a given time-range - couchdb

Question

There is a list of documents P having two timestamps representing the time range [ P ] in which the document is valid. An index over these intervals was created:
function (doc) {
emit([doc.start, doc.end], someStuff(doc));
}
We want to receive documents P wich start before some end timestamp E and stop after some start timestamp S:
P(S, E) = { P | P_s <= E && P_e >= S }
For instance, in a picture like this
<-- TIME -->
..------------------S-------------------------------------E----------------------..
.. P0 ][ P1 ][ P2 ][ P3 ][ P4 ][ P5 ][ P6 ..
we expected the subset {P1, P2, P3, P4} as the result. We try to get the desired result using the following key-range
_view/range?descending=false&startkey=[0,S]&endkey=[E,{}]
The result P(A, E) = {P0, P1, P2, P3, P4} is wrong which makes sense when checking the following example for S=17 and E=30:
key startkey endkey accept
_________________________________________________________________________
[10,15] [0,17] <= [10,15] <= [30, {}] -> True <- This is wrong
[15,25] [0,17] <= [15,25] <= [30, {}] -> True OK
[25,30] [0,17] <= [25,30] <= [30, {}] -> True OK
[25,50] [0,17] <= [25,50] <= [30, {}] -> True OK
[35,50] [0,17] <= [35,50] <= [30, {}] -> False OK
Is it possible to define a range such that we get the desired result?

Answer 1

This is much easier to achieve using the POST /db/_find endpoint. You can express your query as a selector:
{
"selector": {
"start": { "$lt": 100 },
"end": { "$gt": 300 }
}
"sort": ["start"]
}
This is the equivalent to the SQL SELECT * FROM db WHERE start<100 AND end > 300 SORY BY start.
You will almost certainly need an index on "start" too to speed things up.