On Thu, Dec 9, 2010 at 7:51 AM, Jan Lehnardt <j...@apache.org> wrote: > Hi Huw, > > > On 9 Dec 2010, at 13:32, Huw Selley wrote: > >> Hi, >> >> I read on http://guide.couchdb.org/draft/performance.html that >> >> "Views load a batch of updates from disk, pass them through the view engine, >> and then write the view rows out. Each batch is a few hundred documents, so >> the writer can take advantage of the bulk efficiencies we see in the next >> section." >> >> Is there a method to change the batch size? I would like to try measure the >> impact of using smaller and larger batches. > > Thanks for helping to profile things. You may want to take this to > d...@couchdb.apache.org as it is the development-related mailing list. > > For tuning these values, see src/couchdb/couch_view_updater.erl > > The `update()` function has these lines: > > {ok, MapQueue} = couch_work_queue:new(100000, 500), > {ok, WriteQueue} = couch_work_queue:new(100000, 500), > > They set up a queue for mapping and writing each. The parameters are > > couch_work_queue:new(MaxSize, MaxItems) > > If either maximum is hit, the queue is deemed full. > > Note: This is from about 30 seconds of looking at the source, so I > might miss a subtlety or three. > > Cheers > Jan > -- > > >
The only real subtlety is that we don't wait for a minimum amount to be inserted into the queue. Playing with larger or smaller queues on either side might be an interesting bit. Also, for testing it might not be a bad idea to add config values for these values. Paul
