Ah, sorry for the misdirection, thanks for the correction, Erick. That does jibe with what I now remember having heard before. I guess we reserve the right to create index data structures in the future for which we did not save sufficient data in the past.
On Fri, Nov 20, 2020 at 9:15 AM Erick Erickson <erickerick...@gmail.com> wrote: > > The IndexUpgraderTool does a forceMerge(1). If you have a large index, > that has its own problems, but will work. The threshold for the issues is > 5G. See: https://lucidworks.com/post/solr-and-optimizing-your-index-take-ii/ > I should emphasize that if you have a very large single segment as a > result, it’ll eventually shrink if it accumulated deleted (or updated) > documents, > it’ll just require a bunch of I/O amortized over time. > > IndexUpgraderTool will _not_ allow you to take an index originally created > with > 7x to be used in 9x. (Uwe, I’ve been telling people this for a long time, if > I’ve > been lying please let me know!). Starting with Lucene 6, a version is written > into > each segment. Upon merge, the lowest version stamp is preserved. Lucene > will refuse to open an index where _any_ segment has a version stamp X-2 or > older. > > Best, > Erick > > > On Nov 20, 2020, at 7:57 AM, Michael Sokolov <msoko...@gmail.com> wrote: > > > > I think running the upgrade tool would also be necessary to set you up for > > the next upgrade, when 9.0 comes along. > > > > On Fri, Nov 20, 2020, 4:25 AM Uwe Schindler <u...@thetaphi.de> wrote: > > > >> Hi, > >> > >>> Currently I am using Lucene 7.3, I want to upgrade to lucene 8.5.1. > >> Should > >>> I do reindexing in this case ? > >> > >> No, you don't need that. > >> > >>> Can I make use of backward codec jar without a reindex? > >> > >> Yes, just add the JAR file to your classpath and it can read the indexes. > >> Updates written to the index will use the new codecs. To force a full > >> upgrade (rewrite all segments), invoke the IndexUpgrader class either from > >> your code or using the command line. But this is not needed, it just makes > >> sure that you can get rid of the backwards-codecs jar. > >> > >> Uwe > >> > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > >> For additional commands, e-mail: java-user-h...@lucene.apache.org > >> > >> > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
