use garage_rpc::membership::System; use garage_rpc::ring::Ring; use garage_util::data::*; use crate::replication::*; #[derive(Clone)] pub struct TableShardedReplication { pub replication_factor: usize, pub read_quorum: usize, pub write_quorum: usize, } impl TableReplication for TableShardedReplication { // Sharded replication schema: // - based on the ring of nodes, a certain set of neighbors // store entries, given as a function of the position of the // entry's hash in the ring // - reads are done on all of the nodes that replicate the data // - writes as well fn read_nodes(&self, hash: &Hash, system: &System) -> Vec<UUID> { let ring = system.ring.borrow().clone(); ring.walk_ring(&hash, self.replication_factor) } fn read_quorum(&self) -> usize { self.read_quorum } fn write_nodes(&self, hash: &Hash, system: &System) -> Vec<UUID> { let ring = system.ring.borrow().clone(); ring.walk_ring(&hash, self.replication_factor) } fn write_quorum(&self, _system: &System) -> usize { self.write_quorum } fn max_write_errors(&self) -> usize { self.replication_factor - self.write_quorum } fn replication_nodes(&self, hash: &Hash, ring: &Ring) -> Vec<UUID> { ring.walk_ring(&hash, self.replication_factor) } fn split_points(&self, ring: &Ring) -> Vec<Hash> { let mut ret = vec![]; for entry in ring.ring.iter() { ret.push(entry.location); } if ret.len() > 0 { assert_eq!(ret[0], [0u8; 32].into()); } ret } }