

Do Not Use Memcache As a Data Store - toumhi
http://sparklewise.com/?p=506

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petercooper
Your car is a vehicle for transport. Do not consider it as a good way for
cooking food. I have tried to do just that, and it burned me in the end. Let’s
imagine an enthusiast chef, Jimmy, going through the process.

 _Jimmy: Hey, I want to cook and have no tools or even a kitchen. I already
have a car and its engine gets real fast, wow! Maybe I could use it as my
kitchen and save myself the costs of setting one up._

Down that path lies madness.

Problem 1: A car engine is quite volatile and dirty

The car is actually incredibly useful when used as a vehicle, because it can
move along quickly and the engine's heat is manageable. But it's a problem
when using it as a frying pan because I both want heat and my food not to fall
out.

*Jimmy: OK, so I could use my car engine as a frying pan and to prevent food flying out, I could only cook food when I'm at traffic lights or otherwise stationary. (note: if you’re cooking for someone important, hopefully you will have already stopped considering to go the car engine cookery route at this point).

Well, that should get us covered, right? Wrong. That brings us to the second,
tougher and not well-understood problem.

Problem 2: The engine is unpredictable and the wrong size for cooking anyway.
(Or Why You Might Get Hosed Even If Your Engine Well Is Huge)

The problem is that a car engine offers no guarantee that the cooking process
will pan out. You wrap your eggs and bacon in foil and leave them sitting
there for 5 minutes, but the engine might be so hot they're burned the next
minute. Even though your car's engine management system will stop the engine
revving too high or running too hot, the way these systems work do not
guarantee a good, consistent cooking temperature. So your engine may very well
not be out of fuel but running well outside of typical cooking specs! Which
makes cooking rather hard to do if you don't know about this since stuff is
getting a different temperature at different times.

This problem is not theoretical and happens in practice, which made us switch
from cooking our breakfast on an old Model T engine to using a frying pan and
stove, which don't have this problem. This is a real killer if you ever
intended to use your engine as a stove while on the road, say, you could end
up with grease in your carburetor!

A car engine is extremely good at what it should be used for, that is,
propelling the car along. When you want to drive somewhere, get in the car,
start the engine, and drive. You'll get wherever you want to go blazingly fast
without a hiccup from the engine.

So, really, don't ever use your car engine for cooking, it doesn't work. Use a
stove or, if you are concerned with performance and time, use a microwave.
Even a George Foreman will fit the bill better.

~~~
logicpath
So you basically agree with the statement of not using memcache as a data
store? And do you refer to noSQL as microwave and SQL as stove?

~~~
petercooper
No. I think memcache is a great non-persistent data store as long as one
understands its limitations (but Redis is better ;-)). "Data store" doesn't
imply any sort of long-term persistence or stability, merely something that
stores data.

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al_james
In other news: "Don't use a spoon as a knife", "Don't use a hat as a rowing
boat", "Don't use a bicycle as a flying machine". Etc...

