CouchDB manages a pool of couchjs processes, any one of which is capable of evaluating Javascript map/reduce functions.
A single view group (all views in the same ddoc) is indexed serially using a single couchjs process (aka, there is no parallelism here). In CouchDB 2.0, of course, a database can, and typically does, consist of multiple shards, introducing parallelism to view builds among other effects. B. On 14 Jul 2014, at 05:54, Stanley Iriele <[email protected]> wrote: > firstly..Thanks for the,I answer appreciate that. I was in a hurry while > writing the past email > > To be slightly clearer. I know that the _changes feed is generated from > some bookkeeping mechanism internal to the database. When I said > "Calculated for a particular set of entries" I mean the actual javascript > view server that is evaluating your map function because the doc(s) have > been fed to it and it must response with the emitted results. I ..could > have phrased that better. > > My questions revolve around how CouchDB utilizes the view server...and if > there is only one of them running at a given time on a box.The docs suggest > that CouchDB talks to a view server with a line bases protocol, but I don't > know there can be more than one view server executing map functions at a > time...and if so...is that a configurable thing? > > > On Sun, Jul 13, 2014 at 9:33 PM, Jens Alfke <[email protected]> wrote: > >> I am no expert on the implementation of CouchDB, but I don’t believe your >> question makes sense in the form that you asked it. The changes feed isn’t >> related to views at all. Rather, there’s an underlying by-sequence index in >> the main database that’s scanned to generate that feed. And it doesn’t >> “calculate” docs; it just returns existing doc IDs and revision IDs. >> >> If that’s not what you were actually asking, you’ll need to rephrase your >> question more clearly. >> >> —Jens >> >> On Jul 13, 2014, at 8:49 PM, Stanley Iriele <[email protected]> wrote: >> >>> any thoughts on this?...Its not a blocker..I'd just really like to know >>> >>> >>> On Thu, Jul 10, 2014 at 3:44 PM, Stanley Iriele <[email protected]> >>> wrote: >>> >>>> When a doc needs to be calculated for a particular set of entries from >> the >>>> changes feed...are docs sent one at a time or in batches?... And is >> there >>>> just one view server doing all of the computation. >>>> >>>> Lastly...is there a way to configure or control any of the settings that >>>> would dictate the above?..like number of view servers.. Or batch size >> for >>>> docs.... Etc... And if not should there be?.. But I've been very curious >>>> about this for a while... I looked a few view server implementations.. >>>> But...meh >>>> >> >>
