You can use an update handler. It works with non-existent docs. It's a very clean way to do it that I use.
On Mon, Nov 5, 2012 at 11:45 AM, Robert Newson <[email protected]> wrote: > Easiest to just create the document, you'll get a 409 response to indicate > that it already existed. If your documents don't have user assigned id's, > then I don't see how you could check for existence before writing anyway. > > > On 5 November 2012 19:40, Kevin Burton <[email protected]> wrote: > > > I am mainly using it the context of initially populating a database. So > > there isn't any danger of a race because there is only one user. > > > > On Nov 5, 2012, at 12:47 PM, Jens Alfke <[email protected]> wrote: > > > > > > > > On Nov 5, 2012, at 10:22 AM, Kevin Burton <[email protected]> > > wrote: > > > > > >> I am calling CreateDocument<Document>() but I suspect that testing if > > the document exists first may perform better in the long run. I am using > > DreamSeat for my driver but I suspect other drivers have a similar > "test". > > My problem is that I don't know what to test for and I am unfamiliar with > > the available methods. Any one successfully use such a pattern > (preferably > > with DreamSeat) that tests for existence then creates if the document > > doesn't exist? Keep in mind I don't initially have an id. Thank you. > > > > > > I don’t know anything about that particular API, but in general, > > check-then-create doesn’t work well in a concurrent environment. It’s > prone > > to race conditions where something else creates the resource in between > > your check call and your create call. (The canonical example is checking > > whether a file exists, then creating the file, which is a classic old > > security hole in privileged Unix tools.) > > > > > > —Jens > > >
