Thanks, Erick, I had forgotten about that. I did find one short reference to it in the doc: "Be sure to run the Lucene IndexUpgrader included with Solr 4.10 if you might still have old 3x formatted segments in your index. Alternatively: fully optimize your index with Solr 4.10 to make sure it consists only of one up-to-date index segment."
See: https://cwiki.apache.org/confluence/display/solr/Major+Changes+from+Solr+4+to+Solr+5 Note to doc guys and committers: That section needs to be replaced with "Major Changes form Solr 5 to Solr 6". Also, that IU reference doesn't link to any doc, even the Lucene Javadoc: https://lucene.apache.org/core/5_5_0/core/org/apache/lucene/index/IndexUpgrader.html Feels like there should be some Solr doc as well. For example, can Solr be running, or does it (each node if SolrCloud) need to be shut down first. And note that it's needed for each collection. Presumably the collections can be upgraded in parallel since they are distinct directories. It would be nice to have a SolrIndexUpgrader to run in one shot and discover and upgrade all Solr collections. -- Jack Krupansky On Thu, Mar 24, 2016 at 12:16 PM, Erick Erickson <erickerick...@gmail.com> wrote: > There's always the IndexUpgrader, one could run the 5x version against > a 4x index and have a 5x-compatible index that would then be readable > by 6x OOB. > > A bit convoluted to be sure. > > Erick > > On Thu, Mar 24, 2016 at 8:49 AM, Yonik Seeley <ysee...@gmail.com> wrote: > > On Thu, Mar 24, 2016 at 11:45 AM, Yonik Seeley <ysee...@gmail.com> > wrote: > >>> I've been led to understand that 6.X (at least the Lucene part?) won't > >>> be backwards compatible with 4.X data. 5.5 at least works fine with > data > >>> files from 4.7, for instance. > > > > It really doesn't seem like much changed at the lucene index-format > > level from 5 to 6... > > it makes one wonder how much work would be involved in allowing Lucene > > 6 to directly read a newer 4.x index... maybe it's just down to > > version strings in the index and not much else? > > > > -Yonik >
