Re^2: write hash to disk after memory limit

[LanX]

> Today, for a 17 GB data structure I'd seriously consider just buying more RAM so I could get back to work.

And when his laboratory gets expanded to output 170GB he's supposed to run and buy 10 times more RAM?

Clever algorithms pay off buy scaling silently without causing such troubles.

Only counting the day you spend designing is a miscalculation...

Look at the code he showed us and how just re-sorting the dimensions of his data structure will reduce any swapping dramatically.

[FloydATC]

And when his laboratory gets expanded to output 170GB he's supposed to run and buy 10 times more RAM?

Like I said, if the data set was 10 times bigger...

I don't disagree with any of what you say, it's just that having a working data set of 17 GB that simply isn't suitable for anything else than keeping it all in RAM is not unheard of in this day and age.

Assuming for a moment that this isn't a problem that needs to scale for an entire datacenter, and we're not talking about reprogramming a deep space probe launched 20 years ago can also help with reducing the need for throwing man hours on the problem.

If it turns out that in this particular case the data set wasn't really 17 GB after all but only expanded to this size as it was read into memory, that's great :-)

I was merely trying to illustrate why replacing OS swapping with home baked swapping would probably not be worth the effort.

[LanX]

Well yes you are right - somehow...

... let me try to explain:

For me it's obvious that this is a XY Problem.

So it's like the advice to take a taxi if there's no more fuel in the tank - which is of course reasonable!

But I have the feeling the driver keeps the motor running over night, so taking a taxi wouldn't solve his real problem.

Anyway we most likely will never fully know the real problem ... :)