In terms of the impact upon the index, there is no difference, they do the same thing - mark the previous doc deleted and insert another. As jack says, maybe atomic updates are easier for you from an application perspective.
Note Solr/lucene are heavily optimised towards reading - writing is a relatively heavy operation. Upayavira On Fri, Mar 8, 2013, at 10:41 PM, Mingfeng Yang wrote: > Then what's the difference between adding a new document vs. > replacing/overwriting a document? > > Ming- > > > On Fri, Mar 8, 2013 at 2:07 PM, Upayavira <u...@odoko.co.uk> wrote: > > > With an atomic update, you need to retrieve the stored fields in order > > to build up the full document to insert back. > > > > In either case, you'll have to locate the previous version and mark it > > deleted before you can insert the new version. > > > > I bet that the amount of time spent retrieving stored fields is matched > > by the time saved by not having to transmit those fields over the wire, > > although I'd be very curious to see someone actually test that. > > > > Upayavira > > > > On Fri, Mar 8, 2013, at 09:51 PM, Mingfeng Yang wrote: > > > Generally speaking, which has better performance for Solr? > > > 1. updating some fields or adding new fields into a document. > > > or > > > 2. replacing the whole document. > > > > > > As I understand, update fields need to search for the corresponding doc > > > first, and then replace field values. While replacing the whole document > > > is just like adding new document. Is it right? > >
