CouchDB Map / Reduce to Array

Question

I have a few docs that look like this:

{userId: 123, msg:{ timestamp:123456, event:"actionA"} }

{userId: 123, msg:{ timestamp:123466, event:"actionB"} }

etc...

Fn map:

emit(doc.userId, [doc.msg])

Decrease fn:

return [].concat.apply([], vs)

These functions seem to do what I expect, so I thought I would see output like:

Key: 123, Value: [{timestamp:123456, event:"actionA"}, {timestamp:123466, event:"actionB"}, ...etc...]

But I get an overflow error while shrinking: "Slow performance should shrink faster." Indeed, couchdb docs say that "typically, the reduction function should come down to a single scalar value" .... "CouchDB will give you a warning if you try to use the" wrong path ".

So, I assume I'm using Couch MR in the “wrong way”. What will be the “right path” for such a calculation?

Answer 1

. CouchDB , . , , , , .

userId, . ?key=123. Id .

( JSON, ), .

Answer 2

, - . JSON, , .