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Why HN was down

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Re: Why HN was down

#211

Post by confluence »

davesims wrote: post #59
DanielBMarkham wrote: post #7

Amazing that such a large percentage of debugging involves determining exactly what you are debugging. The definition of the problem, many times, is the solution. Might be a good time to mention Rubber Duck Debuggging. http://en.wikipedia.org/wiki/Rubber_duck_debugging

A few times a month, I'll look up at one of my colleagues and say, "hey, got a sec? I need to talk to the duck," and they know this means I'm going to talk to their head but they can basically keep doing what they're doing and nod occasionally. This serves several purposes: (1) It's less insane-sounding than actually talking to an inanimate object in an open work environment. (2) It actually feels better and forces m…

I call it the House method :)

You bring a detailed problem and break it down, and talk about it to someone else (who often isn't qualified to answer your questions due to knowledge/time constraints) - and in doing so - resolve the problem by challenging one's own assumptions.

This was effectively how every House episode was resolved.

Re: Why HN was down

#212

Post by dguaraglia »

wpietri wrote: post #122
jgrahamc wrote: post #102

Earlier quoted context omitted.

"No deflecting blame" Who were they going to blame?

He could have blamed the new server. Or whatever distracted him. Or the user, for being dumb. I've seen people do all of those. Or he could have just dodged the blame entirely.

Some people are just freaking difficult to work with. I've worked with people that wouldn't accept responsibility even after every other possible cause was ruled out. I've even gotten this reply: "well, you must have been unlucky to get the faulty e-mail, because it seems to work most of the time". Yeah, because that's how programming works: cowboy coding and hoping for the best.

This guy actually called bugfixes "optimizations": "hey, X the feedback widget on the front page isn't working", "oh, yeah, I haven't worked on that because that's code that needs to be 'optimized', so it's low on my issues list". Ugh.

I've learned my lesson now. In fact, that's an incredible lesson for a startup founder: never, ever, hire someone who dodges a question on an interview. And the first time they avoid taking responsibility for something that was clearly their fault, fire them. The last thing you want is someone who'll blame everyone and anything else for their issues. It's a great way to kill morale and create rifts in a small team.

Re: Why HN was down

#213

Post by confluence »

z-e-r-o wrote: post #64
DanielBMarkham wrote: post #7

Amazing that such a large percentage of debugging involves determining exactly what you are debugging. The definition of the problem, many times, is the solution. Might be a good time to mention Rubber Duck Debuggging. http://en.wikipedia.org/wiki/Rubber_duck_debugging

For me, this should be called stackoverflow debugging. I genuinely solved a lot of my problems by trying to write a _good_ question on SO about my problem. The problem seems really difficult when I try to ask it in one sentence, just out of my head. However once I try to describe the background, what I'm trying to achieve, what I'm using, when does the problem happen, simplified down to sub-cases, usually by the time…

I'm a serial SO self-answerer. I write really in depth, complicated questions for complicated problems, with code, data and testable cases - and by the time I've finished the question and posted it - I've figured out the solution - or I'll have it a few hours later.

I usually just leave the question/answer online so that others can benefit for it.

Re: Why HN was down

#214

Post by kisielk »

luser001 wrote: post #89
lifeisstillgood wrote: post #67

There are a number of comments that add up to "what steps will you take to ensure this does not happen again" - akin to a incident review. As speculation that's fine, as advice, I don't think it should be listened to. I am reminded of an long-in-the-tooth sysadmin of my acquaintance who logged in everywhere as root. His theory - "they are my boxes. I screw it up, I fix it." I eventually realised that typing sudo ever…

> I eventually realised that typing sudo every time he touched a box was no defence against doing the wrong thing. IIRC, sudo logs all commands to syslog. Which might come in handy. Yes, root commands will be logged by bash to .bash_history, but there are limits of # of commands lots, what happens if you are logged in multiple times into same account etc. Anyway, that's why I like sudo.

I find most of the time I'm using sudo I don't want to type it before every command and so I use sudo -i which pretty much negates the benefit of logging anything other than to tell that I was sudo at some point.

Re: Why HN was down

#215

Post by zzzeek »

erichocean wrote: post #207
zzzeek wrote: post #202

Earlier quoted context omitted.

use CHECK constraints to prevent invalid data patterns when possible.

Sadly, even that isn't enough. In our production database, I used CHECK constraints religiously. Worked great. Then one day, I was no longer able to commit ANY transactions to a particular table, even completely innocuous ones. The problem? The database itself had violated its own CHECK constraint on a previous commit, but was enforcing it on all subsequent commits, causing them to fail. Brilliant. Moral: not even CH…

> The problem? The database itself had violated its own CHECK constraint on a previous commit, but was enforcing it on all subsequent commits, causing them to fail. Brilliant.

I've never heard of that, and unless you're using a really buggy, broken database, it should not be possible.

> P.s. This was a proprietary database, and when I reported the problem to the vendor

well there you go. I think in practice, a simple CHECK constraint like the one we'd do here (literally, comment_id > parent_comment_id) is pretty easy to put one's faith into.

Re: Why HN was down

#218

Post by vl »

tolmasky wrote: post #106

Why do "self posts" like this show up in the same light gray as posts with negative vote counts? My eyes aren't great and I find it hard to read

I'm using "Hacker News Enhancement Suite" Chrome extension - it fixes multiple problems, including this one.

Re: Why HN was down

#219

Post by swah »

irahul wrote: post #193
swah wrote: post #66

Earlier quoted context omitted.

I was thinking something like (supposing the comments were stored as "closure tables" like Karwin suggests): CREATE TABLE comment_tree ( ascestor_id REFERENCES comments(id) NOT NULL, descendant_id REFERENCES comments(id) NOT NULL, CHECK ( ascestor_id descendant_id ) ) but I'm probably overlooking something. (I'm aware that HN uses flat files, I was just making a counter-point to the "simple assert" solution...)

That will prevent a child being its own parent. It won't work for more than one level i.e a post being its own grandchild. Assume (post_id, parent_id) sequence: (1, 3) -> (2, 1) -> (3, 2).

Please note that the "Closure Table solution involves storing all paths through the tree, not just those with a direct parent-child relationship."

Re: Why HN was down

#220

Post by irahul »

swah wrote: post #219
irahul wrote: post #193

Earlier quoted context omitted.

That will prevent a child being its own parent. It won't work for more than one level i.e a post being its own grandchild. Assume (post_id, parent_id) sequence: (1, 3) -> (2, 1) -> (3, 2).

Please note that the "Closure Table solution involves storing all paths through the tree, not just those with a direct parent-child relationship."

My bad. I was speed reading, and didn't read the "Closure Table" part.
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