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One such bad situation would be if you have numeric keys that you shard based on a mod 2. You do this because you want to distribute data between 2 servers, so
by qhoxie 17y ago
One such bad situation would be if you have numeric keys that you shard based on a mod 2. You do this because you want to distribute data between 2 servers, so one will get all even keys and the other will get the odd keys.
A few months down the line your load gets so high that you need to add a third server, but your sharding mechanism is based on mod 2 - so you need to hack around this in one of many ways to utilize the third server effectively.
Make sense?
- davidw 17y agoSo don't people just publish client libs that handle the details for you? It doesn't seem like an unsurmountable problem, but once again, I've never dealt with it in practice.
- qhoxie 17y agoSo don't people just publish client libs that handle the details for you? Sometimes, but oftentimes sharding issues are unique enough that they require custom solutions when the backend technology does not support it natively.