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The whole post hinges on the statement: "When MongoDB is all you have, it’s a cache with no backing store behind it. It will become inconsistent. Not eventuall
by No1 13y ago
The whole post hinges on the statement:
"When MongoDB is all you have, it’s a cache with no backing store behind it. It will become inconsistent. Not eventually consistent — just plain, flat-out inconsistent, for all time."
OK, here is a chance to share a little insight. At what point did Mongo become hopelessly inconsistent? Were you ever able to determine why? Why bother with cute pictures and verbose explanations of simple schemas when the conclusion is just that Mongo breaks no matter what without further explanation?
- gcv 13y agoProbably because the project was forced to keep copies of data all over the place, and was distributed to boot. There was probably a reasonable bug or edge case which caused some copies to conflict with each other, and since writes are destructive, it became impossible to reconcile the conflicts.
- MoosePlissken 13y agoI thought this statement was confusing as well. I can see how the given schema could cause problems with inconsistency, but there seem to be a few logical steps missing in the jump from that to "Mongo will never be consistent and we need to migrate to mysql".
- regularfry 13y agoThat's not a property of Mongo, it's a property of any non-trivial caching layer that you can't regenerate. Something will go wrong, and then you're stuffed.