from Hacker News

Fault in Hong Kong Air Traffic system caused by exceeding 5500 user settings

by dklsf on 4/16/17, 3:08 AM with 5 comments

  • by atonse on 4/16/17, 12:07 PM

    This just doesn't add up to me.

    5500 is an odd number (not power of two) which rules out some kind of overflow issue.

    Was this some kind of fixed size database? Why would it have crashed when storing 5500 rows?

    Maybe storing that many hit a timeout, and maybe they were stored outside a transaction, hence leaving the system in an inconsistent state? But that wouldn't explain the database shutting down.

    Maybe they were trying to store 5500 but hit a limit at 4096 before getting there?

    I feel something is lost in translation (between nerds and non nerds) in the explanation for this outage.

  • by cnvogel on 4/16/17, 2:53 PM

  • by lm2s on 4/16/17, 9:51 AM

    This reminds me of junior (and sometimes not so junior) developers not protecting against the full range of possibilities in conditions, and how hard it's for some to understand that there's glitches that make the counter go +2 instead of +1 before arriving at the condition check.

  • by cpncrunch on 4/16/17, 1:39 PM

    Atrocious site. Popups before seeing site. Then difficult to scroll. Randomly navigates to a new story when scrolling.