node.js - mongo - better solution when i have to update each mongo document usually? -

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let say, if have document this, , collection have huge documents.

{   _id: objectid('e1312313dddqqe….'),   ra: {     energy: 80,     times: 1377496519   } }

i have update ra.energy (per 15 mins), use formula

var pow = (now - ra.times) / 86400; ra.energy = ra.energy * ( math.pow(0.5, pow) );

currently, use cronjob, query each documents, calculate , update each ra.energy field, slow down our mongodb.

is there have better design update. suggestion?

thanks.


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