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authorTrinity Pointard <trinity.pointard@gmail.com>2021-03-26 19:41:46 +0100
committerAlex Auvolat <alex@adnab.me>2021-04-27 16:37:10 +0200
commitb4376108122bb09bd8cff562b718967d4332ffbe (patch)
tree120910caa43e400c0431463f47ed3fc114af77ea /src/table/replication
parentf8716895715b1a552750062aca9bc1882f6f95c0 (diff)
downloadgarage-b4376108122bb09bd8cff562b718967d4332ffbe.tar.gz
garage-b4376108122bb09bd8cff562b718967d4332ffbe.zip
attempt at documenting table crate
Diffstat (limited to 'src/table/replication')
-rw-r--r--src/table/replication/fullcopy.rs12
-rw-r--r--src/table/replication/mod.rs6
-rw-r--r--src/table/replication/parameters.rs10
-rw-r--r--src/table/replication/sharded.rs17
4 files changed, 28 insertions, 17 deletions
diff --git a/src/table/replication/fullcopy.rs b/src/table/replication/fullcopy.rs
index bd658f63..a6b4c98c 100644
--- a/src/table/replication/fullcopy.rs
+++ b/src/table/replication/fullcopy.rs
@@ -6,19 +6,19 @@ use garage_util::data::*;
use crate::replication::*;
+/// Full replication schema: all nodes store everything
+/// Writes are disseminated in an epidemic manner in the network
+/// Advantage: do all reads locally, extremely fast
+/// Inconvenient: only suitable to reasonably small tables
#[derive(Clone)]
pub struct TableFullReplication {
+ /// The membership manager of this node
pub system: Arc<System>,
+ /// Max number of faults allowed while replicating a record
pub max_faults: usize,
}
impl TableReplication for TableFullReplication {
- // Full replication schema: all nodes store everything
- // Writes are disseminated in an epidemic manner in the network
-
- // Advantage: do all reads locally, extremely fast
- // Inconvenient: only suitable to reasonably small tables
-
fn read_nodes(&self, _hash: &Hash) -> Vec<UUID> {
vec![self.system.id]
}
diff --git a/src/table/replication/mod.rs b/src/table/replication/mod.rs
index d43d7f19..dfcb026a 100644
--- a/src/table/replication/mod.rs
+++ b/src/table/replication/mod.rs
@@ -1,6 +1,8 @@
mod parameters;
-pub mod fullcopy;
-pub mod sharded;
+mod fullcopy;
+mod sharded;
+pub use fullcopy::TableFullReplication;
pub use parameters::*;
+pub use sharded::TableShardedReplication;
diff --git a/src/table/replication/parameters.rs b/src/table/replication/parameters.rs
index e46bd172..0ab9ee5a 100644
--- a/src/table/replication/parameters.rs
+++ b/src/table/replication/parameters.rs
@@ -2,20 +2,26 @@ use garage_rpc::ring::*;
use garage_util::data::*;
+/// Trait to describe how a table shall be replicated
pub trait TableReplication: Send + Sync {
// See examples in table_sharded.rs and table_fullcopy.rs
// To understand various replication methods
- // Which nodes to send reads from
+ /// Which nodes to send read requests to
fn read_nodes(&self, hash: &Hash) -> Vec<UUID>;
+ /// Responses needed to consider a read succesfull
fn read_quorum(&self) -> usize;
- // Which nodes to send writes to
+ /// Which nodes to send writes to
fn write_nodes(&self, hash: &Hash) -> Vec<UUID>;
+ /// Responses needed to consider a write succesfull
fn write_quorum(&self) -> usize;
+ // this feels like its write_nodes().len() - write_quorum()
fn max_write_errors(&self) -> usize;
// Accessing partitions, for Merkle tree & sync
+ /// Get partition for data with given hash
fn partition_of(&self, hash: &Hash) -> Partition;
+ /// List of existing partitions
fn partitions(&self) -> Vec<(Partition, Hash)>;
}
diff --git a/src/table/replication/sharded.rs b/src/table/replication/sharded.rs
index dce74b03..f2d89729 100644
--- a/src/table/replication/sharded.rs
+++ b/src/table/replication/sharded.rs
@@ -6,22 +6,25 @@ 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 {
- // 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) -> Vec<UUID> {
let ring = self.system.ring.borrow().clone();
ring.walk_ring(&hash, self.replication_factor)