Hi,
2016-09-01 12:22 GMT+02:00 Giridhar Addepalli <[email protected]>:
> Hi,
>
> Function declaration for reduce functions look like
>
> function(keys, values, rereduce) {
> }
>
> My doubt is regarding the 'keys' parameter.
> Can multiple keys be passed to single invocation of custom reduce function
> ?
>
Yes. Each key corresponds to the value of the same index.
The keys could be same but could also differ if the view was queried with a
grouplevel.
e.g. you have 3 documents, the view emits the keys:
[1,2,3]
[1,2,4]
[1,3,5]
if you call the view with "group_level" = 1, reduce will be called once¹
and keys² will be:
[
[[1,2,3], documentid],
[[1,2,4], documentid],
[[1,3,5], documentid]
]
the result is assigned to "[1]"
if you call the view with "group_level" = 2, reduce will be called twice¹
and keys² will be:
[
[[1,2,3], documentid],
[[1,2,4], documentid]
]
this result is assigned to "[1,2]"
and
[
[[1,3,5], documentid]
]
this result is assigned to "[1,3]"
Hope this helps,
Stefan
[1]: ignoring rereduce
[2]: CouchDB 1.6.1 here
