mikemccand commented on issue #13867: URL: https://github.com/apache/lucene/issues/13867#issuecomment-2400966177
> I am struggling to create the 9.10.0 `int8_hnsw.9.10.0.zip` -- we did not yet have `TestInt8HnswBackwardsCompatibility.java` in 9.10.0 ... @benwtrent do you remember how you generated this BWC index? And I now see why we name them `int8` ... in 9.10.0, 8 bit quantization was the only option. Then in 9.11.0, we allowed 4, 7, 8 bits, and made the default 7 bits (but didn't rename the bwc index `.zip` files to match). OK scratch that -- it looks like in 9.10.0 it was also (hardwired) 7 bit quantization back then. I will rename the bwc indices to `int7` ... Also, curiously, even after I regenerated the 9.10.0 bwc index (so that it correctly actually used scalar quantization), it did not cause any failures in the 9.12.x bwc test ... digging a bit I see it's because in [`Lucene99ScalarQuantizedVectorsReader#FieldEntry`](https://github.com/apache/lucene/blob/e4092396d55064009de51d00a9b0c9f03a07ad83/lucene/core/src/java/org/apache/lucene/codecs/lucene99/Lucene99ScalarQuantizedVectorsReader.java#L370-L371) we implement the back compat case by setting `compress=false` and `bits=7`, so it sidesteps the bug. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
