[erlang-questions] trouble with erlang or erlang is a ghetto

Ulf Wiger ulf.wiger@REDACTED
Wed Jul 27 22:23:17 CEST 2011

On 27 Jul 2011, at 18:58, Richard Bucker wrote:

> There is nothing in the language or VM that makes it's sigma rating any better or worse than any other language or framework.

Erlang doesn't pretend to have a sigma rating. What language does (except perhaps in some very narrow context)?

Erlang has been used to build systems with better than 5-nines availability, according the rules for measuring In-Service Performance (ISP) in Telecoms. That's what it was made for.

> Indeed Mnesia and Mnesia's replication cannot add to it's rating as it fails all the time. And hello-world is not an acceptable app to test or rate.

As it happens the system responsible for the 99.99999% availability figure floating around [1], did in fact use mnesia. Klarna uses mnesia, and has best-in-class availability among online factoring services in Scandinavia (I believe - I have no hard data, but their CTO was pretty confident at the last Erlang Factory in London). There are other examples, and just about every database used in anger has its share of horror stories too. Perhaps you shouldn't believe everything you read in the blogosphere? ;-)

[1] That was a real data point, made official by British Telecom - which is why it could be used by Joe in a talk at MIT. The average ISP reported from all our deployments was lower, but consistently better than 99.999% while I was keeping track. I cannot give you the exact numbers.

> Erlang solves some interesting problems and creates some new ones. It's more of a "religion of functionalism" than anything else. And for the same reasons it's a little dangerous and risky.

I'm not sure what you base that on. Erlang's history has clearly been driven by pragmatism, and has made it this far mainly because it proved excellent for solving the problems it was designed for.

But I admit - Erlang has gone through some different phases: 
* from being young and hyped, 
* to being banned, bashed and nearly killed,
* to seeing some kind of truce, where it was tolerated, as long as its proponents didn't try to make a big deal out of it,
* to wooing part of the Open Source crowd and seeing some hype again (and some bashing too, for good measure).

Having experienced all of those, I have long since given up on trying to convince anyone who doesn't want to be convinced. For the purpose of the list, I will try to comment on things that I find incorrect, and share my experience when asked.

If you don't see anything special about Erlang, and consider using it a risk, I'd assume the sensible thing is not to use it. Are you willing to entertain the possibility that other people reach a very different conclusion, without being blinded by religious fervour?

Ulf W

Ulf Wiger, CTO, Erlang Solutions, Ltd.

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