Dear users, We recently migrated from Lucene9.7 to Lucene9.11. During the migration, we noticed that the Lucene9.11 has a longer warm up time for vector queries. The warm up time means: when the index just finishes building, the query time is high for the first few minutes.
The following figure shows the issue. The T=0 means the index just finishes building. The Madvise ON is vanilla Lucene9.11. The Madvise OFF is Lucene9.11 run with this JVM flag (--enable-native-access=NON_EXISTING_MODULE) which effectively disables the madvise change. Turning the Madvise off on Lucene9.11 brings the warm up time back to what Lucene9.7 is (Lucene9.7 does not have madvise). This reminds me of a possibly similar discussion in https://github.com/apache/lucene/issues/13920. Thanks! [image: image.png]
