Hazelcast ConcurrentMap / MultiMap密钥

Question

I am declaring a MultiMap and want to know if it is a good idea to have the key as Integer. Will will speed up retrieving values with Key as Integer vs key as String?

MultiMap<String, Order> mmCustomerOrders = hz.getMultiMap("customerOrders");

vs

MultiMap<Integer, Order> mmCustomerOrders = hz.getMultiMap("customerOrders");

Thx.

Answer 1

It might speed it up a bit especially depending on the length and complexity of the string. Simple ASCII strings are kinda easy to encode/decode but if you have non ASCII chars it will be a bit more complicated. But even on Integers there's a high chance you have to create the Integer object all the time since values are to high, you might can work around this (if you know a range) with overriding the default Integer cache size "java.lang.Integer.IntegerCache.high". Setting this higher than 127 grows the size of the preallocated numbers of Integers.

In reality the question if it makes a real speed difference to you is depending on much more than serialization. I would just try if there is a difference for you otherwise I would see it as premature optimization. It would be different if your objects are heavily complex but for String and Integer it shouldn't give you a real benefit.