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Make K2V item timestamps globally increasing on each node

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This commit is contained in:
Alex Auvolat 2023-01-10 11:01:49 +01:00
parent a48e2e0cb2
commit 9f5419f465
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GPG Key ID: 0E496D15096376BE
4 changed files with 65 additions and 17 deletions
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6
src/model/garage.rs
View File

@ -305,8 +305,10 @@ impl GarageK2V {
fn new(system: Arc<System>, db: &db::Db, meta_rep_param: TableShardedReplication) -> Self {
info!("Initialize K2V counter table...");
let counter_table = IndexCounter::new(system.clone(), meta_rep_param.clone(), db);
info!("Initialize K2V subscription manager...");
let subscriptions = Arc::new(SubscriptionManager::new());
info!("Initialize K2V item table...");
let item_table = Table::new(
K2VItemTable {
@ -317,7 +319,9 @@ impl GarageK2V {
system.clone(),
db,
);
let rpc = K2VRpcHandler::new(system, item_table.clone(), subscriptions);
info!("Initialize K2V RPC handler...");
let rpc = K2VRpcHandler::new(system, db, item_table.clone(), subscriptions);
Self {
item_table,

7
src/model/k2v/item_table.rs
View File

@ -73,7 +73,8 @@ impl K2VItem {
this_node: Uuid,
context: &Option<CausalContext>,
new_value: DvvsValue,
) {
node_ts: u64,
) -> u64 {
if let Some(context) = context {
for (node, t_discard) in context.vector_clock.iter() {
if let Some(e) = self.items.get_mut(node) {
@ -98,7 +99,9 @@ impl K2VItem {
values: vec![],
});
let t_prev = e.max_time();
e.values.push((t_prev + 1, new_value));
let t_new = std::cmp::max(t_prev + 1, node_ts + 1);
e.values.push((t_new, new_value));
t_new
}
/// Extract the causality context of a K2V Item

45
src/model/k2v/rpc.rs
View File

@ -6,7 +6,8 @@
//! mean the vector clock gets much larger than needed).
use std::collections::HashMap;
use std::sync::Arc;
use std::convert::TryInto;
use std::sync::{Arc, Mutex};
use std::time::Duration;
use async_trait::async_trait;
@ -15,9 +16,12 @@ use futures::StreamExt;
use serde::{Deserialize, Serialize};
use tokio::select;
use garage_db as db;
use garage_util::crdt::*;
use garage_util::data::*;
use garage_util::error::*;
use garage_util::time::now_msec;
use garage_rpc::system::System;
use garage_rpc::*;
@ -29,6 +33,8 @@ use crate::k2v::causality::*;
use crate::k2v::item_table::*;
use crate::k2v::sub::*;
const TIMESTAMP_KEY: &'static [u8] = b"timestamp";
/// RPC messages for K2V
#[derive(Debug, Serialize, Deserialize)]
enum K2VRpc {
@ -59,6 +65,7 @@ impl Rpc for K2VRpc {
pub struct K2VRpcHandler {
system: Arc<System>,
item_table: Arc<Table<K2VItemTable, TableShardedReplication>>,
local_timestamp_tree: Mutex<db::Tree>,
endpoint: Arc<Endpoint<K2VRpc, Self>>,
subscriptions: Arc<SubscriptionManager>,
}
@ -66,14 +73,19 @@ pub struct K2VRpcHandler {
impl K2VRpcHandler {
pub fn new(
system: Arc<System>,
db: &db::Db,
item_table: Arc<Table<K2VItemTable, TableShardedReplication>>,
subscriptions: Arc<SubscriptionManager>,
) -> Arc<Self> {
let local_timestamp_tree = db
.open_tree("k2v_local_timestamp")
.expect("Unable to open DB tree for k2v local timestamp");
let endpoint = system.netapp.endpoint("garage_model/k2v/Rpc".to_string());
let rpc_handler = Arc::new(Self {
system,
item_table,
local_timestamp_tree: Mutex::new(local_timestamp_tree),
endpoint,
subscriptions,
});
@ -273,9 +285,22 @@ impl K2VRpcHandler {
}
fn local_insert(&self, item: &InsertedItem) -> Result<Option<K2VItem>, Error> {
// Using a mutex on the local_timestamp_tree is not strictly necessary,
// but it helps to not try to do several inserts at the same time,
// which would create transaction conflicts and force many useless retries.
let local_timestamp_tree = self.local_timestamp_tree.lock().unwrap();
let now = now_msec();
self.item_table
.data
.update_entry_with(&item.partition, &item.sort_key, |ent| {
.update_entry_with(&item.partition, &item.sort_key, |tx, ent| {
let old_local_timestamp = tx
.get(&local_timestamp_tree, TIMESTAMP_KEY)?
.and_then(|x| x.try_into().ok())
.map(u64::from_be_bytes)
.unwrap_or_default();
let mut ent = ent.unwrap_or_else(|| {
K2VItem::new(
item.partition.bucket_id,
@ -283,8 +308,20 @@ impl K2VRpcHandler {
item.sort_key.clone(),
)
});
ent.update(self.system.id, &item.causal_context, item.value.clone());
ent
let new_local_timestamp = ent.update(
self.system.id,
&item.causal_context,
item.value.clone(),
std::cmp::max(old_local_timestamp, now),
);
tx.insert(
&local_timestamp_tree,
TIMESTAMP_KEY,
u64::to_be_bytes(new_local_timestamp),
)?;
Ok(ent)
})
}

24
src/table/data.rs
View File

@ -181,13 +181,17 @@ impl<F: TableSchema, R: TableReplication> TableData<F, R> {
pub(crate) fn update_entry(&self, update_bytes: &[u8]) -> Result<(), Error> {
let update = self.decode_entry(update_bytes)?;
self.update_entry_with(update.partition_key(), update.sort_key(), |ent| match ent {
Some(mut ent) => {
ent.merge(&update);
ent
}
None => update.clone(),
})?;
self.update_entry_with(
update.partition_key(),
update.sort_key(),
|_tx, ent| match ent {
Some(mut ent) => {
ent.merge(&update);
Ok(ent)
}
None => Ok(update.clone()),
},
)?;
Ok(())
}
@ -195,7 +199,7 @@ impl<F: TableSchema, R: TableReplication> TableData<F, R> {
&self,
partition_key: &F::P,
sort_key: &F::S,
f: impl Fn(Option<F::E>) -> F::E,
update_fn: impl Fn(&mut db::Transaction, Option<F::E>) -> db::TxOpResult<F::E>,
) -> Result<Option<F::E>, Error> {
let tree_key = self.tree_key(partition_key, sort_key);
@ -203,10 +207,10 @@ impl<F: TableSchema, R: TableReplication> TableData<F, R> {
let (old_entry, old_bytes, new_entry) = match tx.get(&self.store, &tree_key)? {
Some(old_bytes) => {
let old_entry = self.decode_entry(&old_bytes).map_err(db::TxError::Abort)?;
let new_entry = f(Some(old_entry.clone()));
let new_entry = update_fn(&mut tx, Some(old_entry.clone()))?;
(Some(old_entry), Some(old_bytes), new_entry)
}
None => (None, None, f(None)),
None => (None, None, update_fn(&mut tx, None)?),
};
// Changed can be true in two scenarios