Comment by smallmancontrov
16 hours ago
I'm so glad git won the dvcs war. There was a solid decade where mercurial kept promoting itself as "faster than git*†‡" and every time I tried it wound up being dog slow (always) or broken (some of the time). Git is fugly but it's fast, reliable, and fugly, and I can work with that.
> I'm so glad git won the dvcs war. There was a solid decade where mercurial kept promoting itself as "faster than git".
It wasn't the Mercurial team saying it was faster than Git; that was Facebook after contributing a bunch of patches after testing Mercurial on their very large mono-repo in 2014 [1]:
For our repository, enabling Watchman integration has made Mercurial’s status command more than 5x faster than Git’s status command. Other commands that look for changed files–like diff, update, and commit—also became faster.
In fact they liked Mercurial so much they essentially cloned it to create their own dvcs, Sapling [2]. (An aside: Facebook did all of this because it was taking too long getting new engineers up to speed with Git. Shocker.)
Today, most of the core of Mercurial has been rewritten in Rust; when Facebook did their testing, Mercurial was nearly 100% Python. That's where the "Mercurial is slow" thing came from; launching a large Python 2.x app took a while back in the day.
I was messing with an old Mercurial repo recently… it was like a breath of fresh air. If I can push to GitHub using Mercurial… sign me up.
[1]: https://engineering.fb.com/2014/01/07/core-infra/scaling-mer...
[2]: https://sapling-scm.com/
You can push to GitHub using Sapling. I wish Sapling open source was given more love, as the experience for non-Facebookers is subpar. No bash completion outside the box, no distro packages, no good help pages, random issues interacting with a Git repo...
Sounds like what my teachers used to say: “a personal problem”. Literally nobody outside FB knows what they’re missing and until they fix that, literally nobody cares.
What is kind of funny here is that you're right locally. At the same time, the larger tech companies (Meta and Google, specifically) ended up building off of hg and not git because (at the time, especially) git cannot scale up to their use cases. So while the git CLI was super fast, and the hg CLI was slow, "performance" means more than just CLI speed.
I was never a fan of hg either, but now I can use jj, and get some of those benefits without actually using it directly.
>At the same time, the larger tech companies (Meta and Google, specifically) ended up building off of hg and not git because (at the time, especially) git cannot scale up to their use cases.
Fun story: I don't really know what Microsoft's server-side infra looked like when they migrated the OS repo to git (which, contrary to the name, contains more than just stuff related to the Windows OS), but after a few years they started to hit some object scaling limitations where the easiest solution was to just freeze the "os" repo and roll everyone over to "os2".
“roll everyone over to os2”
The IBM crowd may feel vindicated at last.
So 30 odd years later, MS went from working on OS/2 to working on OS2?
I guess what's old is new again.
I have heard that the Google monorepo is called google3 but I don't know why. Maybe those things are common...
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didn't msft write an ~entire new file system specifically to scale git to the windows code base?
I have fuzzy memories on reading about it.
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Small nit: Googles monorepo is based on Perforce.
I think what happened is Google bought a license for source code and customised it.
> Google bought a license for source code and customised it.
That makes sense because vanilla Perforce is unbearably slow and impossible to scale.
Last I checked, it was bought by Private Equity firms and actual product development had more or less stopped.
Yes, the server is based on Perforce, called Piper, but the CLI is based on mercurial. So locally you're doing hg and then when you create a CL, it translates it into what p4 needs.
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Right, and I'm glad there are projects serving The Cathedral, but I live in The Bazaar so I'm glad The Bazaar won.
The efforts to sell priest robes to fruit vendors were a little silly, but I'm glad they didn't catch on because if they had caught on they no longer would have been silly.
GNU Bazaar thoroughly lost, last release was 2016, Canonical retired it last year: https://en.wikipedia.org/wiki/GNU_Bazaar
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I might be the outlier, but am I the only one who doesn't care much about the speed of git? I've been using git since 2011 as my main vcs for personal and professional work as a freelancer contractor. Whenever I "wait" for git, it is either limited by the bandwidth (git clone) or by the amount of commit hooks that I implemented for linting, verification etc. The percentage of time actually spent in git internal execution must be a tiny fraction of my day to day usage. What IS affecting me (and my the teams I work in) is usability and UX experience. I.e. if people would screw up stuff (no matter if in git or mercurial) we spent far more time fixing this - I don't think the impmentation speed would matter here.
The only case I can imagine is when doing a full checkout of a big repo, but even there, there is --depth which is quite practical.
Isn't it kind of like how you don't care much about the oxygen content of the air around you, but you'd miss it if it was gone? I've done development with Mercurial, simple processes were irritatingly slow, particularly if you stray from the better-supported opinionated path.
I remember using darcs, but the repos I was using it with were so small as to performance really not mattering…
I remember darcs fondly but even with tiny repos (maybe 5-6 people working on it) we hit the "exponential merge" issues.
It worked just fine 99% of the time and then 1% it became completely unusable.
I definitely miss Darcs. I still use it very occasionally, but only with very small repos.
This matches my experience 100%. I was about to write a similar comment before I see yours.
Mercurial has a strictly superior API. The issue is solely that OG Mercurial was written in Python.
Git is super mid. It’s a shame that Git and GitHub are so dominant that VCS tooling has stagnated. It could be so so so much better!
Mercurial can't rebase without an extension, or force push. Are you using a definition of strictly superior that means it has fewer features?
When I ask for this people like to explain that these are bad features nobody should want.
Maybe forgejo has a shot?
It doesn't seem to support Mercurial though (not to imply that you were implying that it did). All I can find in this proxy/mirror thing to integrate it by presenting the Mercurial repo as a Git server: https://peterlavalle.github.io/post/forgejo-actions/
Unfortunatly out-of-the-box llm agents only focus on github support, creating friction.
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Whatever your opinion on one tool or another might be - it does seem weird that the "market" has been captured by what you are saying is a lesser product.
IOW, what do you know that nobody else does?
So far you've only gotten responses to "how can a worse product win?", and they are valid, but honestly the problem here is that Mercurial is not a better product in at least one very important way: branches.
You can visit any resource about git and branches will have a prominent role. Git is very good at branches. Mercurial fans will counter by explaining one of the several different branching options it has available and how it is better than the one git has. They may very well be right. It also doesn't matter, because the fact that there's a discussion about what branching method to use really just means Mercurial doesn't solve branches. For close to 20 years the Mercurial website contained a guide that explained only how to have "branches" by having multiple copies of the repository on your system. It looks like the website has now been updated: it doesn't have any explanation about branches at all that I can find. Instead it links to several different external resources that don't focus on branches either. One of them mentions "topic", introduced in 2015. Maybe that's the answer to Git's branching model. I don't care enough to look into it. By 2015 Git had long since won.
Mercurial is a cool toolbox of stuff. Some of them are almost certainly better than git. It's not a better product.
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GitHub had a business model where public repos were free. BitBucket didn’t.
That’s it. That’s why git won, you could put up open source libs with one for free and not the other.
Which is extra funny as the centralized service was the most important part of decentralized version control.
JWZ is still blocking traffic from HN so you can't click to read this but you can copy/paste it into a new tab or open it in a incognito window:
https://www.jwz.org/doc/worse-is-better.html
Worse products win all the time. Inertia is almost impossible to overcome. VHS vs Betamax is a classic. iPod wasn’t the best mp3 player but being a better mp3 player wasn’t enough to claw market share.
Google and Meta don’t use Git and GitHub. Sapling and Phabricator much much better (when supported by a massive internal team)
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Network effects and marketing can easily prevent better tools from winning.
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That worse is better, and some people don't know better or care.
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Welcome to VHS and Betamax. the superior product does not always win the market.
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> The issue is solely that OG Mercurial was written in Python.
Are we back to "programming language X is slow" assertions? I thought those had died long ago.
Better algorithms win over 'better' programming languages every single time. Git is really simple and efficient. You could reimplement it in Python and I doubt it would see any significant slowness. Heck, git was originally implemented as a handful of low level binaries stitched together with shell scripts.
> Are we back to "programming language X is slow" assertions? thought those had died long ago.
Yes we are? The slow paths of mercurial have been rewritten in C (and more recently in Rust) and improved the perf story substantially, without taking away from the wild modularity and extensibility hg always had.
Every time I've rewritten something from Python into Java, Scala, or Rust it has gotten around ~30x faster. Plus, now I can multithread too for even more speedups.
Python is absurdly slow - every method call is a string dict lookup (slots are way underused), everything is all dicts all the time, the bytecode doesn't specialize at all to observed types, it is a uniquely horrible slow language.
I love it, but python is almost uniquely a slow language.
Algorithms matter, but if you have good algorithms, or you're already linear time and just have a ton of data, rewriting something from a single-threaded Python program to a multithreaded rust program I've seen 500x speedups, where the algorithms were not improved at all.
It's the difference between a program running overnight vs. in 30 seconds. And if there are problems, the iteration speed from that is huge.
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I've rewritten a python tool in go, 1:1. And that turned something that was so slow that it was basically a toy, into something so fast that it became not just usable, but an essential asset.
Later on I also changed some of the algorithms to faster ones, but their impact was much lower than the language change.
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> git was originally implemented as a handful of low level binaries stitched together with shell scripts.
A bunch of low level binaries stitched together with shell scripts is a lot faster than python, so not really sure what the point of this comparison is.
Python is an extremely versatile language, but if what you're doing is computing hashes and diffs, and generally doing entirely CPU-bound work, then it's objectively the wrong tool, unless you can delegate that to a fast, native kernel, in which case you're not actually using Python anymore.
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> Better algorithms win over 'better' programming languages every single time.
That's often true, but not "every single time".
> You could reimplement it in Python and I doubt it would see any significant slowness
I doubt it wouldn't be significantly slower. I can't disprove it's possible to do this but it's totally possible for you to prove your claim, so I'd argue that the ball is in your court.
Python is by far the slowest programming language, an order of magnitude slower than other languages
One of the reason mercurial lost the dvcs battle is because of its performance - even the mercurial folks admitted that was at least in part because of python
You must belong to the club of folks who use hashmaps to store 100 objects. It's amazing how much we've brainwashed folks to focus on algorithms and lose sight of how to actually properly optimize code. Being aware of how your code interacts with cache is incredibly important. There are many cases of using slower algorithms to do work faster purely because it's more hardware friendly.
The reason that some more modern tools, like jj, really blow git out of the water in terms of performance is because they make good choices, such as doing a lot of transformations entirely in memory rather than via the filesystem. It's also because it's written in a language that can execute efficiently. Luckily, it's clear that modern tools like jj are heavily inspired by mercurial so we're not doomed to the ux and performance git binds us with.
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> I thought those had died long ago.
No, it's always been true. It's just that at some point people got bored and tired of pointing it out.
You barely have to try to have Python be noticeably slow. It's the only language I have ever used where I was even aware that a programming language could be slow.
They died because everyone knows that Python is infact very very slow. And that’s just totally fine for a vast number of glue operations.
It’s amusing you call Git fast. It’s notoriously problematic for large repos such that virtually every BigTech company has made a custom rewrite at some point or another!
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I just used it because I preferred the UX.
Git is not remotely fast for large projects.
Define "large"; I've never ran into serious performance issues during the ~15 years I've used Git, which either means the projects I've worked in aren't actually large large, or Git is fast enough for most use cases.