1. A method comprising: creating, in a memory of a computer system, a first data structure having a plurality of contiguous buckets of the memory, the buckets configured to store key-value pairs in the order in which the key-value pairs are inserted into an array; and creating, in the memory of the computer system, a second data structure having a plurality of slots of the memory, each of the slots corresponding to a particular key of the key-value pairs, each of the slots configured to store a pointer that points to a bucket of the first data structure containing a value of a key to which the slot corresponds.