> > > >2.I see a lot of "problems" when Searching and Updating on the same index. May be is >just me, but what i discovered is: > a)It is not possible "update" a document, it is possible just delete and re-add, >that mean open a Reader, do a delete, close the reader, open a writer, add the >document, optimize , close the writer. >So it is possible move the "delete" method from the IndexReader to the IndexWriter? >Or it is impossible for tech. reasons? In this way we open just the Writer to do >update,delete and add documents. This is useful when the index needs to be updated >often. > b)There is no way to update just a field in a document,you need to update the entire >document, so a field update will be good,may be this is hard to do. > The (a) and maybe the (b) is also on my wish/todo list. The approach I was thinking of taking was to make these "transactional", so that both changes are done on an IndexWriter and they take effect when the writer closes. The old document in an older segment gets "shadowed" by the new one until the optimization. Once optimized, the old document is gone for good. I think this will solve the issue of updates being combersome and will also make a lot of the concurrency headaches go away.
Another feature on my list is reduction in the number of open files. This is especially a problem in cases where many indexes are in use at the same time. The approach I'm thinking of here is to merge all files of a given segment into a single file after that segment is closed. Since the segment is never written to after it's first created (besides the deleted file?), there should be no problem with fragmentation and growth. This can be done as part of the segment merge, so that the output of a merge is this new single-file segment rather then the existing multi-file one. For extra credit, we can add support for having 1 to n file handles allocated to this one-file segment, in case OS will be able to do better optimization of non-contegious reads when multiple file handles are used. Does anyone know? Dmitry. -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
