> They hit an issue no-one really thinks about: resizing hash tables. No-one thinks about it, as it happens transparently under the surface, but for them, the f

> They hit an issue no-one really thinks about: resizing hash tables. No-one thinks about it, as it happens transparently under the surface, but for them, the few milliseconds it took to resize the hash tables would have enormously detrimental effects on just about every other Google service. Hmm.. not sure I'd agree with your assessment that no-one thinks about it. Certainly most DB engines are very aware of this characteristic of hash tables, and it is one of the reasons B-tree style indexes are preferred (not to mention the advantages of sorting). I think in general, people doing systems development tend to be very aware of these kinds of issues, and perhaps Google is comparatively rare in that it is a company where systems and application development are so vertically integrated. I'm not even sure if that is so terribly unique.