forked from Deuxfleurs/garage
55 lines
1.4 KiB
Rust
55 lines
1.4 KiB
Rust
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 TableShardedReplication {
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pub replication_factor: usize,
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pub read_quorum: usize,
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pub write_quorum: usize,
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}
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impl TableReplication for TableShardedReplication {
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// Sharded replication schema:
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// - based on the ring of nodes, a certain set of neighbors
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// store entries, given as a function of the position of the
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// entry's hash in the ring
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// - reads are done on all of the nodes that replicate the data
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// - writes as well
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fn read_nodes(&self, hash: &Hash, system: &System) -> Vec<UUID> {
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let ring = system.ring.borrow().clone();
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ring.walk_ring(&hash, self.replication_factor)
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}
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fn read_quorum(&self) -> usize {
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self.read_quorum
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}
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fn write_nodes(&self, hash: &Hash, system: &System) -> Vec<UUID> {
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let ring = system.ring.borrow().clone();
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ring.walk_ring(&hash, self.replication_factor)
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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.replication_factor - self.write_quorum
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}
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fn epidemic_writes(&self) -> bool {
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false
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}
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fn replication_nodes(&self, hash: &Hash, ring: &Ring) -> Vec<UUID> {
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ring.walk_ring(&hash, self.replication_factor)
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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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for entry in ring.ring.iter() {
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ret.push(entry.location);
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}
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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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