Thanks Mike, this is useful information. Then I'll try to reproduce this benchmark to better understand what is happening.
On Thu, Jun 19, 2025 at 8:16 PM Michael Sokolov <msoko...@gmail.com> wrote: > We've recently been comparing Lucene's HNSW w/FAISS' and there is not > a 2x difference there. FAISS does seem to be around 10-15% faster I > think? The 2x difference is roughly what I was seeing in comparisons > w/hnswlib prior to the dot-product improvements we made in Lucene. > > On Thu, Jun 19, 2025 at 2:12 PM Adrien Grand <jpou...@gmail.com> wrote: > > > > Chris, > > > > FWIW I was looking at luceneknn ( > https://github.com/erikbern/ann-benchmarks/blob/f402b2cc17b980d7cd45241ab5a7a4cc0f965e55/ann_benchmarks/algorithms/luceneknn/Dockerfile#L15) > which is on 9.7, though I don't know if it enabled the incubating vector > API at runtime? > > > > I hope that mentioning ANN benchmarks did not add noise to this thread, > I was mostly looking at whether I could find another benchmark that > suggests that Lucene is significantly slower in similar conditions. Does it > align with other people's experience that Lucene is 2x slower or more > compared with other good HNSW implementations? > > > > Adrien > > > > Le jeu. 19 juin 2025, 18:44, Chris Hegarty > <christopher.hega...@elastic.co.invalid> a écrit : > >> > >> Hi Adrien, > >> > >> > Even though it uses Elasticsearch to run the benchmark, it really > benchmarks Lucene functionality, > >> > >> Agreed. > >> > >> > This seems consistent with results from > https://ann-benchmarks.com/index.html though I don't know if the cause of > the performance difference is the same or not. > >> > >> On ann-benchmarks specifically. Unless I’m looking in the wrong place, > then they’re using Elasticsearch 8.7.0 [1], which predates our usage of the > Panama Vector API for vector search. We added support for that in Lucene > 9.7.0 -> Elasticsearch 8.9.0. So those benchmarks are wildly out of date, > no ? > >> > >> -Chris. > >> > >> [1] > https://github.com/erikbern/ann-benchmarks/blob/f402b2cc17b980d7cd45241ab5a7a4cc0f965e55/ann_benchmarks/algorithms/elasticsearch/Dockerfile#L2 > >> > >> > >> > On 19 Jun 2025, at 16:39, Adrien Grand <jpou...@gmail.com> wrote: > >> > > >> > Hello all, > >> > > >> > I have been looking at this benchmark against Vespa recently: > https://blog.vespa.ai/elasticsearch-vs-vespa-performance-comparison/. > (The report is behind an annoying email wall, but I'm copying relevant data > below, so hopefully you don't need to download the report.) Even though it > uses Elasticsearch to run the benchmark, it really benchmarks Lucene > functionality, I don't believe that Elasticsearch does anything that > meaningfully alters the results that you would get if you were to run > Lucene directly. > >> > > >> > The benchmark seems designed to highlight the benefits of Vespa's > realtime design, that's fair game I guess. But it also runs some queries in > read-only scenarios when I was expecting Lucene to perform better. > >> > > >> > One thing that got me curious is that it reports about 2x worse > latency and throughput for pure unfiltered vector search on a force-merged > index (so single segment/graph). Does anybody know why Lucene's HNSW may > perform slower than Vespa's HNSW? This seems consistent with results from > https://ann-benchmarks.com/index.html though I don't know if the cause of > the performance difference is the same or not. > >> > > >> > For reference, here are details that apply to both Lucene and Vespa's > vector search: > >> > - HNSW, > >> > - float32 vectors, no quantization, > >> > - embeddings generated using Snowflake's Arctic-embed-xs model > >> > - 1M docs > >> > - 384 dimensions, > >> > - dot product, > >> > - m = 16, > >> > - max connections = 200, > >> > - search for top 10 hits, > >> > - no filter, > >> > - single client, so no search concurrency, > >> > - purple column is force-merged, so single segment/graph like Vespa. > >> > > >> > I never seriously looked at Lucene's vector search performance, so > I'm very happy to be educated if I'm making naive assumptions! > >> > > >> > Somewhat related, is this the reason why I'm seeing many threads > around bringing 3rd party implementations into Lucene, including ones that > are very similar to Lucene on paper? To speed up vector search? > >> > > >> > -- > >> > Adrien > >> > <vespa-vs-es-screenshot.png> > >> > --------------------------------------------------------------------- > >> > To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org > >> > For additional commands, e-mail: dev-h...@lucene.apache.org > >> > >> > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org > >> For additional commands, e-mail: dev-h...@lucene.apache.org > >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org > For additional commands, e-mail: dev-h...@lucene.apache.org > > -- Adrien
