[HN Gopher] Machine learning saves us $1.7M a year on document p...
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       Machine learning saves us $1.7M a year on document previews
        
       Author : wsuen
       Score  : 67 points
       Date   : 2021-01-27 20:10 UTC (2 hours ago)
        
 (HTM) web link (dropbox.tech)
 (TXT) w3m dump (dropbox.tech)
        
       | mehrdada wrote:
       | The technical details are interesting but the emphasis on "1.7M
       | savings" screams misdirection of resources, considering the
       | salaries of SWEs/ML engineers and more importantly opportunity
       | cost of them to deploy to an optimization task.
        
         | jeffbee wrote:
         | It does sound like it would barely have broken even when
         | considering the opportunity cost of the highly-compensated
         | developers who had to write it, which they ignore in the
         | article. It goes against the "rules of thumb" i learned at
         | Google, which suggest that an engineer would break even if they
         | saved [redacted but huge number] CPUs per year, and should only
         | choose problems that promise to save 10x that or better.
        
         | bagels wrote:
         | Was totally going to point this out as well. It's entirely
         | possible that their ML team cost nearly this much to begin
         | with.
        
         | laluser wrote:
         | We're looking at this from a very narrow lens. A few of these
         | wins a year in a small team will end up paying for itself
         | fairly quickly.
        
         | piyh wrote:
         | Let's say X engineers making 200k a year work on this. This is
         | a 5x return on your money in 5 years if it took 8 people
         | working the full year to complete it. Sounds like a solid
         | business case to me.
        
           | dheera wrote:
           | You also need to subtract the value those 8 people could
           | create if they worked on something else.
        
             | Closi wrote:
             | You don't - If you do that you are double counting the cost
             | of the engineers (If they were working on something else,
             | you wouldn't account their salary against this
             | optimisation).
        
             | arthurcolle wrote:
             | This is unknowable
        
           | X6S1x6Okd1st wrote:
           | That makes sense if all engineers are fungable, and you are
           | never limited by engineering capacity.
        
         | wsuen wrote:
         | Hi mehrdada. In the article, we discuss how to evaluate
         | tradeoffs of ML projects. One of these tradeoffs is cost of
         | development and deployment vs. cost of not developing a
         | solution. In our particular case, the tradeoff made sense.
        
       | RcouF1uZ4gsC wrote:
       | > We used the "percentage-rejected" metric minus the false
       | negatives to ballpark the $1.7 million total annual savings.
       | 
       | I think this may too sanguine for the false negatives in that it
       | ignore latency sensitivity. Generally, batch processing (like
       | preview generation during pre-warming) is cheaper than latency
       | sensitive processing (like preview generation when the user is
       | waiting for it). If you don't take that into account, you can be
       | misled by your cost metrics.
        
       | joosters wrote:
       | Is the cost saving really measuring the right thing? Instead of
       | comparing against the cost of pre-generating and caching every
       | file preview, shouldn't they be comparing against he cost of
       | adding enough infrastructure (or just optimising their preview
       | code) to make on-the-fly preview generation acceptably fast?
        
       | mushufasa wrote:
       | FYI there's also the off-the-shelf https://filepreviews.io for
       | this
        
         | appleflaxen wrote:
         | cool product, but the blog hasn't seen a post since 2017. is it
         | active?
        
       | wsuen wrote:
       | Hi folks, author here. I am very excited to share this post about
       | how we use machine learning at Dropbox to optimize our document
       | preview generation process. Enjoy!
       | 
       | I'll be online for the next hour or so; happy to answer any
       | questions about ML at Dropbox.
        
         | wsuen wrote:
         | I've gotta run, I'll take a look later if other questions come
         | in!
        
         | setib wrote:
         | I work in an innovation ML-oriented lab, and we have a hard
         | time identifying use cases with real added values.
         | 
         | So I wondered: who had the initiative to use ML in riviera, the
         | riviera team or the ML team? How do you collabore between the
         | two teams/worlds (production team and data science team)?
        
           | wsuen wrote:
           | Hi setib, great question. The original idea to use heuristics
           | for preview cost reduction came out of a Hack Week project.
           | This led to an initial brainstorm meeting between the ML team
           | and the Previews team about what this might look like as a
           | full-fledged ML product.
           | 
           | From the beginning the ML team's focus was on providing
           | measurable impact to our Previews stakeholders. One thing
           | that helped us collaborate effectively was being transparent
           | about the process and unknowns of ML (which are different
           | from the constraints of non-ML software engineering). We
           | openly shared our process and results, including experimental
           | outcomes that did not work as well as planned and that we did
           | not roll into production. We also worked closely with
           | Previews to define rollout, monitoring, and maintenance
           | processes that would reduce ops load on their side and
           | provide clear escalation paths should something unexpected
           | happen. Consistent and clear communication helps build trust.
           | 
           | On their side, the Previews team has been an amazing ML
           | partner, and it was a joy to work with them.
        
           | andy99 wrote:
           | I'm curious to know the answer to this question as well. I
           | have done a fair bit of work working with organizations to
           | identify ML use cases. When we looked at it from a business
           | process perspective, honestly it didn't go very well. Trying
           | to find company process specific interventions, especially in
           | the format of building a funnel to priortize which to move
           | forward, rarely surfaces unique or game changing ideas. We
           | usually ended up generating a list of things where either ML
           | played a minimal role, something more simple would have been
           | better, or you'd need AGI.
           | 
           | What I've seen work better is a product approach, where ML is
           | incorporated as a feature (rarely but possible the
           | centerpiece) of a full solution for an industry that provides
           | a new way of doing something and the value that comes with
           | it. The caveat is that this is hard and takes up front R&D
           | and product market fit research that any product would. It
           | doesn't happen in a series of workshops with representatives
           | from the business.
           | 
           | This Dropbox story is an obvious counterexample, and really
           | looks like the mythical "low hanging fruit" that we always
           | want to identify in ideation workshops. But I'd be careful
           | trying to generalize a process for identifying ML use cases
           | from it.
        
             | Jugurtha wrote:
             | @andy99, @setib: we're a boutique that helps large
             | organization in different sectors and industries with
             | machine learning. Energy, banking, telcos, retail,
             | transportation, etc. These organizations have different
             | maturity levels and their functions expect different
             | deliverables.
             | 
             | The organizations range on the maturity level from "We want
             | to use AI, can you help us?" to "We have an internal
             | machine learning and data science team that's overbooked,
             | can you help?" to "We have an internal team, but you worked
             | on [domain] for one of your project and we'd like your
             | expertise".
             | 
             | For the expectations, you can deal with an extremely
             | technical team that tells you: I want something that spits
             | JSON. I'll send your service this payload and I expect this
             | payload. So that's a tiny part.
             | 
             | Sometimes, you have to build everything: data acquisition,
             | develop and train models, make a web application for their
             | domain experts with all the bells and whistles, admin,
             | roles, data management, etc. I wrote about some of the
             | problems we hit here[0].
             | 
             | The point is that, finding these problems is an effort that
             | requires a certain skill/process and goodwill from the
             | clients. We worked on a variety of problems.
             | 
             | - [0]: https://news.ycombinator.com/item?id=25871632
        
             | mlthoughts2018 wrote:
             | I've worked on ML across several large e-commerce firms,
             | and two patterns I have seen along the lines of your
             | comment:
             | 
             | 1. many organizations dismiss ML solutions without actually
             | trying them. Rather, if one hack week style prototype
             | doesn't work on the first try, it's chalked up to "over
             | hyped AI" and never sees the light of day. Organizations
             | that succeed with ML don't do it that way. Instead they
             | ensure the success criteria are stated up front and
             | measured throughout, so you can see _why_ it didn't work
             | and iterate for v2 and v3. "We spent a bunch of R &D
             | expense on magic bullet v0 and it didn't succeed
             | immediately" is a leadership and culture problem - you
             | probably can't succeed with ML until you fix that.
             | 
             | 2. Many companies have no idea how to staff and support ML
             | teams, and go through various cycles of either taking
             | statistical researchers and bogging them down with devops
             | or taking pure backend engineers and letting them do
             | unprofessional hackery with no clarifying product quality
             | ML expert in the loop.
             | 
             | You need a foundation of ML operations / infra support that
             | cleanly separates the responsibilities of devops away from
             | the responsibilities of model research, and you must invest
             | in clear data platform tools that facilitate getting data
             | to these teams.
             | 
             | If an org just figures they can throw an ML team sink or
             | swim into an existing devops environment or they can
             | require an ML team to sort out their own data access, it's
             | setting ML up for disaster - and again you'll get a lot of
             | cynics rushing to say it's failing because ML is just hype,
             | when actually it's failing due to poor leadership, poor
             | team structure and poor resourcing.
        
       | junippor wrote:
       | Haven't read the doc. But is it just me or does that seem tiny,
       | considering how large dropbox is?
        
         | heipei wrote:
         | It does seem tiny, and my first thought was "how many dollars
         | did they burn to save those $1.7M", but that was one of the
         | first things they evaluated, and both the research phase and
         | operational burden of running the service seem to be relatively
         | small so that the investment definitely paid off. It's great
         | that they're talking real numbers, loved the post in general!
        
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       (page generated 2021-01-27 23:00 UTC)