In one exemplary embodiment, a method includes allocating an arena block of a shared memory of a database node server. The arena block is divided into one or more slots. The one or more slots include a discreet and constant area of memory within the arena block. Each slot is assigned a constant-memory address relative to an arena-block's shared memory address. The index is implemented as a red-black tree data structure. Each red-black tree node is mapped to a slot. Each red-black-tree node is provided a pointer to one or more neighbor nodes. The index stored in shared memory can be used during a ‘warm’ rebooting process.