sharray

Sharray

A sharded array, on ipld.

Goals:

• datastructure for a list of CIDs with minimal overhead
• efficient merkle proofs
  • As small as is reasonably possible
  • Fast to compute
  • These will be primarily for Filecoin light clients
• fast
• ipld native

Non-goals:

• Easy random insertions
• Supporting removal of items

Structure

Each sharray has a given width. Each of the leaf nodes contains at most that many elements, and only the final node may have fewer. When the number of leaf nodes grows to be more than the given width, an additional layer is added. Each node has a field specifying which layer the node is in the tree.

Single Layer:
[ H:0; 1, 2, 3, 4]


Two Layer:
[ H:1; A, B ] 

A = [ H:0; 1, 2, 3, 4], B = [ H:0; 5, 6, 7, 8]

Three Layer:

[ H:2; X, Y]

X = [ H:1; A, B, C, D], Y = [ H:1, E, F, G, H]

A = [ H:0; 1, 2, 3, 4] .... (and so on)

License

MIT