Robert, I have not heard from you (or anyone) an argument against System property based configurability (as I described in Option 4 via a System property). Uwe notes wisely some care must be taken to ensure it actually works. Sure, of course. What concerns do you have with this?
~ David Smiley Apache Lucene/Solr Search Developer http://www.linkedin.com/in/davidwsmiley On Tue, May 16, 2023 at 9:50 PM Robert Muir <rcm...@gmail.com> wrote: > by the way, i agree with the idea to MOVE THE LIMIT UNCHANGED to the > hsnw-specific code. > > This way, someone can write alternative codec with vectors using some > other completely different approach that incorporates a different more > appropriate limit (maybe lower, maybe higher) depending upon their > tradeoffs. We should encourage this as I think it is the "only true fix" to > the scalability issues: use a scalable algorithm! Also, alternative codecs > don't force the project into many years of index backwards compatibility, > which is really my penultimate concern. We can lock ourselves into a truly > bad place and become irrelevant (especially with scalar code implementing > all this vector stuff, it is really senseless). In the meantime I suggest > we try to reduce pain for the default codec with the current implementation > if possible. If it is not possible, we need a new codec that performs. > > On Tue, May 16, 2023 at 8:53 PM Robert Muir <rcm...@gmail.com> wrote: > >> Gus, I think i explained myself multiple times on issues and in this >> thread. the performance is unacceptable, everyone knows it, but nobody is >> talking about. >> I don't need to explain myself time and time again here. >> You don't seem to understand the technical issues (at least you sure as >> fuck don't know how service loading works or you wouldnt have opened >> https://github.com/apache/lucene/issues/12300 😂) >> >> I'm just the only one here completely unconstrained by any of silicon >> valley's influences to speak my true mind, without any repercussions, so I >> do it. Don't give any fucks about ChatGPT. >> >> I'm standing by my technical veto. If you bypass it, I'll revert the >> offending commit. >> >> As far as fixing the technical performance, I just opened an issue with >> some ideas to at least improve cpu usage by a factor of N. It does not help >> with the crazy heap memory usage or other issues of KNN implementation >> causing shit like OOM on merge. But it is one step: >> https://github.com/apache/lucene/issues/12302 >> >> >> >> On Tue, May 16, 2023 at 7:45 AM Gus Heck <gus.h...@gmail.com> wrote: >> >>> Robert, >>> >>> Can you explain in clear technical terms the standard that must be met >>> for performance? A benchmark that must run in X time on Y hardware for >>> example (and why that test is suitable)? Or some other reproducible >>> criteria? So far I've heard you give an *opinion* that it's unusable, but >>> that's not a technical criteria, others may have a different concept of >>> what is usable to them. >>> >>> Forgive me if I misunderstand, but the essence of your argument has >>> seemed to be >>> >>> "Performance isn't good enough, therefore we should force anyone who >>> wants to experiment with something bigger to fork the code base to do it" >>> >>> Thus, it is necessary to have a clear unambiguous standard that anyone >>> can verify for "good enough". A clear standard would also focus efforts at >>> improvement. >>> >>> Where are the goal posts? >>> >>> FWIW I'm +1 on any of 2-4 since I believe the existence of a hard limit >>> is fundamentally counterproductive in an open source setting, as it will >>> lead to *fewer people* pushing the limits. Extremely few people are >>> going to get into the nitty-gritty of optimizing things unless they are >>> staring at code that they can prove does something interesting, but doesn't >>> run fast enough for their purposes. If people hit a hard limit, more of >>> them give up and never develop the code that will motivate them to look for >>> optimizations. >>> >>> -Gus >>> >>> On Tue, May 16, 2023 at 6:04 AM Robert Muir <rcm...@gmail.com> wrote: >>> >>>> i still feel -1 (veto) on increasing this limit. sending more emails >>>> does not change the technical facts or make the veto go away. >>>> >>>> On Tue, May 16, 2023 at 4:50 AM Alessandro Benedetti < >>>> a.benede...@sease.io> wrote: >>>> >>>>> Hi all, >>>>> we have finalized all the options proposed by the community and we are >>>>> ready to vote for the preferred one and then proceed with the >>>>> implementation. >>>>> >>>>> *Option 1* >>>>> Keep it as it is (dimension limit hardcoded to 1024) >>>>> *Motivation*: >>>>> We are close to improving on many fronts. Given the criticality of >>>>> Lucene in computing infrastructure and the concerns raised by one of the >>>>> most active stewards of the project, I think we should keep working toward >>>>> improving the feature as is and move to up the limit after we can >>>>> demonstrate improvement unambiguously. >>>>> >>>>> *Option 2* >>>>> make the limit configurable, for example through a system property >>>>> *Motivation*: >>>>> The system administrator can enforce a limit its users need to respect >>>>> that it's in line with whatever the admin decided to be acceptable for >>>>> them. >>>>> The default can stay the current one. >>>>> This should open the doors for Apache Solr, Elasticsearch, OpenSearch, >>>>> and any sort of plugin development >>>>> >>>>> *Option 3* >>>>> Move the max dimension limit lower level to a HNSW specific >>>>> implementation. Once there, this limit would not bind any other potential >>>>> vector engine alternative/evolution. >>>>> *Motivation:* There seem to be contradictory performance >>>>> interpretations about the current HNSW implementation. Some consider its >>>>> performance ok, some not, and it depends on the target data set and use >>>>> case. Increasing the max dimension limit where it is currently (in top >>>>> level FloatVectorValues) would not allow potential alternatives (e.g. for >>>>> other use-cases) to be based on a lower limit. >>>>> >>>>> *Option 4* >>>>> Make it configurable and move it to an appropriate place. >>>>> In particular, a >>>>> simple Integer.getInteger("lucene.hnsw.maxDimensions", 1024) should be >>>>> enough. >>>>> *Motivation*: >>>>> Both are good and not mutually exclusive and could happen in any order. >>>>> Someone suggested to perfect what the _default_ limit should be, but >>>>> I've not seen an argument _against_ configurability. Especially in this >>>>> way -- a toggle that doesn't bind Lucene's APIs in any way. >>>>> >>>>> I'll keep this [VOTE] open for a week and then proceed to the >>>>> implementation. >>>>> -------------------------- >>>>> *Alessandro Benedetti* >>>>> Director @ Sease Ltd. >>>>> *Apache Lucene/Solr Committer* >>>>> *Apache Solr PMC Member* >>>>> >>>>> e-mail: a.benede...@sease.io >>>>> >>>>> >>>>> *Sease* - Information Retrieval Applied >>>>> Consulting | Training | Open Source >>>>> >>>>> Website: Sease.io <http://sease.io/> >>>>> LinkedIn <https://linkedin.com/company/sease-ltd> | Twitter >>>>> <https://twitter.com/seaseltd> | Youtube >>>>> <https://www.youtube.com/channel/UCDx86ZKLYNpI3gzMercM7BQ> | Github >>>>> <https://github.com/seaseltd> >>>>> >>>> >>> >>> -- >>> http://www.needhamsoftware.com (work) >>> http://www.the111shift.com (play) >>> >>
