Refactor sharding logic; coming next: full replication with epidemic dissemination

1 files changed, 55 insertions, 0 deletions

diff --git a/src/table_sharded.rs b/src/table_sharded.rs
new file mode 100644
index 00000000..485a9212
--- /dev/null
+++ b/src/table_sharded.rs
@@ -0,0 +1,55 @@
+use crate::data::*;
+use crate::membership::{System, Ring};
+use crate::table::*;
+
+#[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) -> usize {
+		self.write_quorum
+	}
+	fn max_write_errors(&self) -> usize {
+		self.replication_factor - self.write_quorum
+	}
+	fn epidemic_writes(&self) -> bool {
+		false
+	}
+
+	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![];
+
+		ret.push([0u8; 32].into());
+		for entry in ring.ring.iter() {
+			ret.push(entry.location.clone());
+		}
+		ret.push([0xFFu8; 32].into());
+		ret
+	}
+}