Generally speaking, there are many levels of “if you know what you are doing.”

- The system warns about unsafe usage at either compile time or runtime, and you ignore at your peril.

- The system does not warn, but official documentation is consistently verbose about what is required for safety.

- Official documentation isn’t consistently helpful and can be downright dangerous, but the community picks up the slack.

- The company gaslights the community into believing it is possible for a non-core-team member to “know what they are doing” from one of the above levels when Jepsen provides written evidence that this is not true.

I’m fine with things that are the third level from the top. I like to live dangerously. But I don’t think anyone can look at that last level and say “people are giving informed consent to this.”

The problem is that if you know what you are doing (I.e. you configure MongoDB to be safe) you may lose all reason to use it (no longer has the same performance, of course)

That comment wasn't yesterday, it was a month ago. It was actually after that comment that Jepsen decided to retest MongoDB and write this new article

Ah, good to know. I saw it when someone I follow retweeted it yesterday.

Firstly let me point out that this response is neither intended as a defence of MongoDB defaults which are atrocious, or of the company, who are arguably duplicitous.

However I can _quite easily_ see how a non-native English speaker could use the phrase “if you know what you are doing” to mean “if you are careful”.

Even so, they're just implicitly admitting to the very accusations that they are defending. If "running it right" is so insufficiently defined that jespen cannot figure out how to set it up, maybe your product just doesn't actually offer consistency. Sure, you're conceding at a different abstraction level, but it still means that you're failing to solve the problem of consistency for businesses that that want to solve it with your product.

He just replaced "cannot consistently synchronize data" with "cannot consistently deploy a system that can consistently synchronize data". But what's the difference between those statements to people that need to solve that problem? None.

Perhaps, but the point is, if you're working in DevRel and you think your role is to defend the product from criticism, and you do it by placing the onus on the developer to figure out how to use your product safely, you've totally lost the plot.

Also, if you're a DevRel, maybe you should have strong verbal and written communication skills in the language of your users? Just an idea

I think personally it's an abusive tactic on their part, lots of devs are concerned with being smart, by saying if you know what you're doing you can get the insecure ones to shut up.

But obviously it is a tactic of the doomed.

"If you are careful you might not lose all your data" doesn't sound very reassuring, either.

> I can _quite easily_ see how a non-native English speaker could use the phrase “if you know what you are doing” to mean “if you are careful”.

This kind of thing is a scourge. I had a Chinese friend respond to something I said once by saying "that's nice". It looks so innocent... but it's really hard to overlook the fact that "that's nice" is a serious insult coming from a native speaker. I had to ask them to please never use that phrase to me again.

Wow! Where are you from that you consider it a "fact" that "that's nice" is a "serious insult"? (I'm genuinely curious... I assume not the US based on the time this was posted?)

To my ear (American who grew up in the South, lives in the Midwest, and works with people largely from the Mountain West), "that's nice" could definitely be used dismissively or sarcastically, but there's any number of ways to say it that are actually sincere and genuine, and I can't imagine a situation in which it would be a "serious insult".

I mean, I can imagine that in a professional setting, if the coworker was saying it with a sarcastic tone or being showily bored or dismissive when saying it, that their behavior might be insulting. But anything can be insulting if it's delivered in an insulting way. "That's nice" has no particular edge to it to my ear.

So I have to assume you aren't American, or that this is a regional thing that I don't have experience with. In any case, your reaction to "that's nice" reminds me of an American friend of mine who moved to London and when her coworkers would ask her if she had a preference about where to get lunch, she would reply "I don't care", which would be totally normal (to me) in the US. But to her British colleagues, that word choice made it a very rude thing to say (the appropriate reply being "I don't mind" to indicate that she didn't have a preference and was willing to go anywhere).

Language is complicated. Even to your "I don't care" example in the US, it indeed often means "I don't have a real personal preference, so if others do please go ahead and make a reasonable decision and I'll be fine with it." However, in other circumstances, it can mean something more dismissive in the vein of "I don't give an f what you do. Just go away."

I'm from California.

Did the joke just went over my head or "that's nice" is a bad thing for real?

No it's not, it depends mostly on the tone of the voice. It's often enough sarcastic, but really doesn't have to be.

Tone of voice does not exist in text.

Just like data consistency doesn’t exist in MongoDB

Then you have to follow the principle of charity and assume they're being nice.

I think it sits on the same level as ' it's interesting',when 9/10 times you could see that the person who said so is not even remotely interested.

I'm not sure I agree with that. A lot of the time "interesting" serves as a filler word for "I'm not totally sure what to think about it" or "I'm not ready to articulate in 1000 words why X may or may not be a good approach right now."

"That's nice" is a way of explicitly stating that you don't care to any degree about whatever the other person just said.

It's very context sensitive. "That's nice" (with at least an implied exclamation point) can be a literal reaction to something you like. "Yeah, that's nice" as a reaction to a statement/argument can also be the equivalent of "Whatever." i.e. it's stupid but I'm not even going to dignify it with an explanation of why it's stupid.

What if it really is actually nice?

"How nice!" is a positive exclamation with minimal wording change from "that's nice".

You can also be explicit about who's being nice. "That's nice of you."

This really depends on what you want to mean by "nice".

Then you have to struggle to find another word to say that it's nice, remembering that saying "it's interesting" is forbidden, too.

I use Great so consistently sarcastic that my kids have unfortunately learned that Great means something not great.

Indirectly stating that they aren't good enough to use MongoDB properly could be offensive for thin-skinned developers, but it's only bad attitude.

I'm much more concretely worried by a software design for which the authors (not hostile critics) consider "if you know what you are doing" an acceptable safety and quality standard for data integrity.

I've never used MongoDB and hopefully never will, but I have to defend that phrase in the larger context. A great number of programming problems I've seen have been to do with people not knowing what they're doing with complex tools, it really is that simple.

Actual example: a long time ago someone in my company introduced a race condition into their product because they didn't know about transaction isolation levels (or the locking facilities exposed by MSSQL). I can give many more, as I'm sure anybody here can.

All complex tools need large investment in time to understand. I suspect MongoDB's team are using that as an excuse but in general you must jnow what you're doing with any tool.

Let's make an analogy. To drive a car one needs to "know what they are doing" to the point that driving licenses are mandatory. Let's consider a common accident type: a collision because you turn but your directional lights remain off.

If it happens because the driver just forgot to signal, it's a mistake and it's hard to blame the car. It's like knowing what transaction isolation levels can be used, but asking for the wrong one or trusting a random default.

On the other hand, if the directional lights remain off despite pulling the lever because the car is in a probably illegal power-saving mode, activated by turning the headlights off, and the driver should have reactivated directional lights with an ambiguously named item in the depths of some options menu, blaming the accident on user error would be very partisan: it's the car that doesn't know what it's doing. It's like figuring out the correct transaction isolation level according to DBMS documentation, asking for it, and expecting it is actually used.

It’s not that he’s lying. He just has a tenuous arrangement with the truth.