What does this mean? I stumbled across it here:

"If the design requires a million trips to the server, expect a dog." (The last sentence in the paragraph titled Efficiency.)

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    General Reference. Defn 6b](thefreedictionary.com/dog) Something of inferior or low quality. A design requiring a million trips to the server will probably lead to a poor quality piece of software (so that's what you should expect to end up with). Nov 3, 2013 at 19:48
  • So 'expect a dog' is not an idiom: 'dog' is an unusual usage. Nov 3, 2013 at 20:47
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    @Edwin: Try it on your network, and it runs like a dog. I'm perfectly familiar with that exact usage. To run like a dog (= execute, [of program code] very slowly) seems to be particularly common in the software context. I've no idea why, since dogs aren't exactly noted for being slow when it comes to running. Nov 3, 2013 at 21:01
  • @FumbleFingers: As it's obviously in a tech manual (maybe a maintainer's manual), the writer obviously expected the readers to know what he's talking about.
    – ZZMike
    Nov 3, 2013 at 21:59
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    There's a discussion here, which looks at both the relevant sense of dog, its etymology, the whole expression 'run/s like a dog', and its relative rarity. The term 'lemon' used to be quite common for a poor car, washing machine, scholar etc, at least in the UK. Nov 4, 2013 at 7:10

1 Answer 1


In this case, 'expect a dog' probably means 'expect slow responses'. In relation to cars, 'dogging' started out meaning a problem with wheel alignment, which would cause a slower vehicle (via http://en.wikipedia.org/wiki/Dogging). I've heard dogging used in context of slowness for both cars and servers (a car with a manual transmission might dog up a hill, a server with badly-written, long-running queries would dog out). In both cases, the object does not fail at what it's trying to do, it just goes very slowly (and in the case of the server, may time out). The use of dog to mean slow may also stem from 'dogged pursuit' i.e. someone following relentlessly, though not necessarily quickly.

  • Usage of "dog" as low quality seems to date from before cars existed. See etymonline's entry for dog: "Many expressions -- a dog's life (c.1600), go to the dogs (1610s), etc. -- reflect earlier hard use of the animals as hunting accessories, not pampered pets."
    – MrHen
    Nov 4, 2013 at 19:39

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