For complete clarity..."minVersion" for a SegmentInfo is the min of the minVersions of all segments involved in the merge which resulted in this segment. If it is a "pure" segment, then minVersion=version.
On Sat, Apr 19, 2025 at 10:35 PM Rahul Goswami <rahul196...@gmail.com> wrote: > Ankit, > "I guess the SegmentInfo "minVersion" is the min across all segments > during the merge process?" > > That is correct > > I am wondering if there is any way to end up in the 2nd scenario, without > having deleted all the documents first? > > Consider the following sequence of events... > an index with 2 segments (seg1 and seg2) originally created in Lucene > 8.x. ==> Upgrade to 9.x ==> index few documents and commit ==> seg3 gets > created with version 9.x, but merge doesn't kick in ==> documents in seg1 > and seg2 get deleted followed by commit.==> You are left with seg3 in 9.x > but indexCreatedVersionMajor as 8.x ==> Upgrade to Lucene 10.x fails. > > -Rahul > > On Sat, Apr 19, 2025 at 1:01 PM Ankit Jain <jain.ank...@gmail.com> wrote: > >> Hi Rahul, >> >> Thanks for starting this interesting discussion. I was initially thinking >> that this API potentially allows upgrading "indexCreatedVersionMajor" via >> the merge process after rewriting all the segments, but I guess the >> SegmentInfo "minVersion" is the min across all segments during the merge >> process? >> >> So, I am wondering if there is any way to end up in the 2nd scenario, >> without having deleted all the documents first? >> >> >> Thanks >> Ankit >> >> On Sat, Apr 19, 2025 at 9:17 AM Rahul Goswami <rahul196...@gmail.com> >> wrote: >> >>> Hello, >>> Today even after all documents in an index are deleted via an API call, >>> reindexing still doesn't change the "indexCreatedVersionMajor" property >>> value in SegmentInfos. Hence even after complete reindexing, an upgrade >>> path X--> X+1 --> X+2 is still not possible as we end up with an >>> IndexFormatTooOldException. >>> >>> Requesting an API (on IndexWriter?) which can reset this property (upon >>> a new commit) to the current Lucene version if: >>> 1) No more live docs present >>> OR >>> 2) If all SegmentInfo in the index have a "minVersion" AND "version" >>> stamp of the latest version , but SegmentInfos has an older >>> "indexCreatedVersionMajor". >>> >>> This will help users a LOT since they can now interact with the index >>> purely via API without needing manual deletion and also help open up a >>> legitimate path to upgrade when an index doesn't HAVE to be repopulated >>> from the source. >>> >>> If there is agreement, I am happy to pick this up and submit a PR. >>> >>> Thanks, >>> Rahul Goswami >>> >>> >>>
