A system and method can support metadata compression in a distributed data grid. The system can store a plurality of keys in compact data structure (such as a radix tree) in a heap, wherein each said key is associated with an entry in a journal off-heap. Furthermore, the system can look up the tree for a key, wherein the key is associated with a journal ticket that represents a virtual address of an entry in the journal. Then, the system can use the journal ticket to manage the entry in the journal that is associated with said key.