On 18 Nov 2010, at 02:56, Chad George wrote: > I guess I was more wondering if its possible for two calls to the update > function to "see" the same revision of the document. Or if it was possible > for another call to document API to successfully update a document *while* > the update handler is processing? > > Are you saying that all the processing of HTTP calls and related javascript > calls are all effectively serialized so this can't happen? > > It seemed by Jan's comments that a _rev collision can occur with update > handlers. > > And maybe most importantly, when an update handler fails to write the > document what happens? I didn't see any tests for this in > update_documents.js but maybe I missed something.
You get the regular 412 response as if you would provide no or an out of date _rev. Cheers Jan -- > > > On Wed, Nov 17, 2010 at 8:14 PM, Randall Leeds <[email protected]>wrote: > >> On Wed, Nov 17, 2010 at 16:15, Chad George <[email protected]> wrote: >>> I've been wondering about this for a while, when two update requests for >> the >>> same document come to couchdb nearly simultaneously what exactly happens? >>> >>> Is it possible for both requests to get the same revision of the document >> to >>> update or is there some mechanism to force the updates to occur in >> series? >>> >> >> There is a mechanism. The message passing within the Erlang runtime >> guarantee an ordering of messages to the update process. >> It is impossible for both updates to occur. >>
