Thanks for the quick reply, this is certainly good news. So just to clarify - doing a manual segment merge is optional when changing codecs, correct? I mean, I can just restart my application with a new codec config and let the regular, background merging task do the work of eventually converting all the data to the new format?
On Wed, May 15, 2013 at 2:30 PM, Uwe Schindler <u...@thetaphi.de> wrote: > Hi Vitaly, > > what you call an "index" is just a collection (a CompositeReader) of > atomic readers. They can be mixed regarding compression, just like you > could have a MultiReader with different indexes using different codecs. > Every atomic segment of an index can only have one stored fields format. > Once merging occurs, the uncompressed fields of e.g. an older atomic > segment gets merged into a new segment with compression enabled. The same > can happen in the other direction. The codec is responsible for encoding > the data on disk and this includes the compression. When merging segments, > the data is uncompressed and recompressed as needed. To improve > performance, there are shortcuts to copy the data directly if the codec > does not change while merging. > > With Lucene 4.x, you are free to open an IndexWriter with a different > codec configuration and e.g. use IndexUpgrader or do a force merge manually > to merge all "old" segments and "recompress" them to a different codec > config. This has nothing to do with "reindexing" as you are just changing > the encoding of the exact same data on disk. > > Uwe > > ----- > Uwe Schindler > H.-H.-Meier-Allee 63, D-28213 Bremen > http://www.thetaphi.de > eMail: u...@thetaphi.de > > > > -----Original Message----- > > From: Vitaly Funstein [mailto:vfunst...@gmail.com] > > Sent: Wednesday, May 15, 2013 10:38 PM > > To: java-user@lucene.apache.org > > Subject: Toggling compression for stored fields > > > > Is it possible to have a mix of compressed and uncompressed documents > > within a single index? That is, can I load an index created with Lucene > 4.0 into > > 4.1 and defer the decision of whether or not to use > > CompressingStoredFieldsFormat until a later time, or even go back and > forth > > between compressed and uncompressed codecs, if needed? I thought at > > first the answer would be an unequivocal "no", but then how would one > > migrate data from 4.0 to 4.1 without a full reindex? > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > >
