I understand that CouchDB hashes the source of each design documents against the name of the index file. Whenever I change the source code, the index needs to be rebuild. Co
It is possible to set os_process_limit to an extra-low value (1 sec, for sample). This way you can detect which doc takes long to be indexed and optimize your map function for performance.
It is a known issue, but just in case: if you have gigabytes of docs, you can forget about reduce functions. Only build-in ones will work fast enough.