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use std::sync::Arc;
use garage_rpc::layout::*;
use garage_rpc::system::System;
use garage_util::data::*;
use crate::replication::*;
/// 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
#[derive(Clone)]
pub struct TableShardedReplication {
/// The membership manager of this node
pub system: Arc<System>,
/// How many time each data should be replicated
pub replication_factor: usize,
/// How many nodes to contact for a read, should be at most `replication_factor`
pub read_quorum: usize,
/// How many nodes to contact for a write, should be at most `replication_factor`
pub write_quorum: usize,
}
impl TableReplication for TableShardedReplication {
fn read_nodes(&self, hash: &Hash) -> Vec<Uuid> {
let layout = self.system.layout_watch.borrow();
layout.nodes_of(hash, self.replication_factor)
}
fn read_quorum(&self) -> usize {
self.read_quorum
}
fn write_nodes(&self, hash: &Hash) -> Vec<Uuid> {
let layout = self.system.layout_watch.borrow();
layout.nodes_of(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 partition_of(&self, hash: &Hash) -> Partition {
self.system.layout_watch.borrow().partition_of(hash)
}
fn partitions(&self) -> Vec<(Partition, Hash)> {
self.system.layout_watch.borrow().partitions()
}
}
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