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use std::sync::Arc;
use garage_rpc::membership::System;
use garage_rpc::ring::Ring;
use garage_util::data::*;
use crate::replication::*;
#[derive(Clone)]
pub struct TableShardedReplication {
pub system: Arc<System>,
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 partition_of(&self, hash: &Hash) -> u16 {
self.system.ring.borrow().partition_of(hash)
}
fn read_nodes(&self, hash: &Hash) -> Vec<UUID> {
let ring = self.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) -> Vec<UUID> {
let ring = self.system.ring.borrow();
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 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
}
}
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