101 lines
2.4 KiB
Rust
101 lines
2.4 KiB
Rust
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use arc_swap::ArcSwapOption;
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use std::sync::Arc;
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use crate::data::*;
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use crate::membership::{Ring, System};
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use crate::table::*;
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#[derive(Clone)]
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pub struct TableFullReplication {
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pub write_factor: usize,
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pub write_quorum: usize,
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neighbors: ArcSwapOption<Neighbors>,
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}
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#[derive(Clone)]
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struct Neighbors {
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ring: Arc<Ring>,
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neighbors: Vec<UUID>,
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}
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impl TableFullReplication {
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pub fn new(write_factor: usize, write_quorum: usize) -> Self {
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TableFullReplication {
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write_factor,
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write_quorum,
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neighbors: ArcSwapOption::from(None),
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}
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}
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fn get_neighbors(&self, system: &System) -> Vec<UUID> {
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let neighbors = self.neighbors.load_full();
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if let Some(n) = neighbors {
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if Arc::ptr_eq(&n.ring, &system.ring.borrow()) {
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return n.neighbors.clone();
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}
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}
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// Recalculate neighbors
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let ring = system.ring.borrow().clone();
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let my_id = system.id.clone();
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let mut nodes = vec![];
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for (node, _) in ring.config.members.iter() {
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let node_ranking = hash(&[node.as_slice(), my_id.as_slice()].concat());
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nodes.push((node.clone(), node_ranking));
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}
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nodes.sort_by(|(_, rank1), (_, rank2)| rank1.cmp(rank2));
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let mut neighbors = nodes
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.drain(..)
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.map(|(node, _)| node)
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.filter(|node| *node != my_id)
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.take(self.write_factor)
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.collect::<Vec<_>>();
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neighbors.push(my_id);
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self.neighbors.swap(Some(Arc::new(Neighbors {
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ring,
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neighbors: neighbors.clone(),
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})));
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neighbors
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}
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}
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impl TableReplication for TableFullReplication {
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// Full replication schema: all nodes store everything
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// Writes are disseminated in an epidemic manner in the network
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// Advantage: do all reads locally, extremely fast
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// Inconvenient: only suitable to reasonably small tables
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fn read_nodes(&self, _hash: &Hash, system: &System) -> Vec<UUID> {
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vec![system.id.clone()]
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}
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fn read_quorum(&self) -> usize {
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1
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}
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fn write_nodes(&self, _hash: &Hash, system: &System) -> Vec<UUID> {
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self.get_neighbors(system)
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}
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fn write_quorum(&self) -> usize {
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self.write_quorum
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}
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fn max_write_errors(&self) -> usize {
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self.write_factor - self.write_quorum
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}
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fn epidemic_writes(&self) -> bool {
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true
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}
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fn replication_nodes(&self, _hash: &Hash, ring: &Ring) -> Vec<UUID> {
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ring.config.members.keys().cloned().collect::<Vec<_>>()
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}
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fn split_points(&self, _ring: &Ring) -> Vec<Hash> {
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let mut ret = vec![];
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ret.push([0u8; 32].into());
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ret.push([0xFFu8; 32].into());
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ret
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}
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}
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