OK, I'm starting to assemble a release and will send out another notice or two along the way, before a vote, but please let me know if you think we should not make a bugfix release, or you want to include something not on the current list of fixes:
* https://github.com/apache/lucene/pull/16559 (fixes reconnection of HNSW nodes on merge) * https://github.com/apache/lucene/pull/16537/ (hunspell: add cancellation checks to WordStorage) On Mon, Aug 31, 2026 at 11:18 AM Michael Sokolov <[email protected]> wrote: > > just saw this email in my spam (grr GMail!) -- I agree, we should do a > 10.5.2 release to fix this. I can be release manager. Is there > anything else we'd need to include? > > On Thu, Aug 27, 2026 at 12:25 PM Ethan Baker <[email protected]> wrote: > > > > Hi all, > > > > It seems that the changes introduced in 10.5.1 revealed a dormant bug that > > can silently regress KNN recall 5-7% (#16552 [1]), and I'm wondering if the > > community agrees this warrants a second bugfix release for 10.5. > > > > Some background on the bug: #15003 [2] added support for HNSW re-use across > > merges for segments with deletes in 10.4.0, but re-use was silently > > disabled under per-field codecs the whole time, until #16400 [3] fixed it > > in 10.5.1. The issue is that this 're-use with deletes' path that is now > > enabled had a latent bug, which skipped repairing nodes where connections > > deteriorated slowly over many merges. After many repeated merges on > > segments with low delete percents, connections continue to erode, and this > > bug ends up reducing out-degree 40+% and dropping recall by an observed > > 5-7%. > > > > The bug was fixed in #16559 [4], but this seems like a big drop in recall > > that should be resolved quickly. Assuming others agree it's needed, would > > anyone more experienced than me be willing to help release such a patch? > > > > Thanks, > > Ethan > > > > [1] https://github.com/apache/lucene/issues/16552 > > [2] https://github.com/apache/lucene/pull/15003 > > [3] https://github.com/apache/lucene/issues/16400 > > [4] https://github.com/apache/lucene/pull/16559 --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
