From 49b5d18554c67b84777d97f24423207c2375ae5e Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Thu, 5 Jan 2023 13:11:48 +0100
Subject: K2V history and preparation for range watch

---
 src/model/k2v/rpc.rs | 62 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 55 insertions(+), 7 deletions(-)

(limited to 'src/model/k2v/rpc.rs')

diff --git a/src/model/k2v/rpc.rs b/src/model/k2v/rpc.rs
index f64a7984..1dc396c0 100644
--- a/src/model/k2v/rpc.rs
+++ b/src/model/k2v/rpc.rs
@@ -6,6 +6,7 @@
 //! mean the vector clock gets much larger than needed).
 
 use std::collections::HashMap;
+use std::convert::TryInto;
 use std::sync::Arc;
 use std::time::Duration;
 
@@ -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::*;
 
 use garage_rpc::system::System;
 use garage_rpc::*;
@@ -26,6 +30,7 @@ use garage_table::replication::{TableReplication, TableShardedReplication};
 use garage_table::{PartitionKey, Table};
 
 use crate::k2v::causality::*;
+use crate::k2v::history_table::*;
 use crate::k2v::item_table::*;
 use crate::k2v::poll::*;
 
@@ -59,6 +64,8 @@ impl Rpc for K2VRpc {
 pub struct K2VRpcHandler {
 	system: Arc<System>,
 	item_table: Arc<Table<K2VItemTable, TableShardedReplication>>,
+	history_table: Arc<Table<K2VHistoryTable, TableShardedReplication>>,
+	local_counter_tree: db::Tree,
 	endpoint: Arc<Endpoint<K2VRpc, Self>>,
 	subscriptions: Arc<SubscriptionManager>,
 }
@@ -66,14 +73,21 @@ pub struct K2VRpcHandler {
 impl K2VRpcHandler {
 	pub fn new(
 		system: Arc<System>,
+		db: &db::Db,
 		item_table: Arc<Table<K2VItemTable, TableShardedReplication>>,
+		history_table: Arc<Table<K2VHistoryTable, TableShardedReplication>>,
 		subscriptions: Arc<SubscriptionManager>,
 	) -> Arc<Self> {
+		let local_counter_tree = db
+			.open_tree("k2v_local_counter")
+			.expect("Unable to open DB tree for k2v local counter");
 		let endpoint = system.netapp.endpoint("garage_model/k2v/Rpc".to_string());
 
 		let rpc_handler = Arc::new(Self {
 			system,
 			item_table,
+			history_table,
+			local_counter_tree,
 			endpoint,
 			subscriptions,
 		});
@@ -181,7 +195,7 @@ impl K2VRpcHandler {
 		Ok(())
 	}
 
-	pub async fn poll(
+	pub async fn poll_item(
 		&self,
 		bucket_id: Uuid,
 		partition_key: String,
@@ -273,9 +287,17 @@ impl K2VRpcHandler {
 	}
 
 	fn local_insert(&self, item: &InsertedItem) -> Result<Option<K2VItem>, Error> {
+		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_counter = tx
+					.get(&self.local_counter_tree, b"counter")?
+					.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,
@@ -283,13 +305,39 @@ impl K2VRpcHandler {
 						item.sort_key.clone(),
 					)
 				});
-				ent.update(self.system.id, &item.causal_context, item.value.clone());
-				ent
+				let new_local_counter = ent.update(
+					self.system.id,
+					&item.causal_context,
+					item.value.clone(),
+					old_local_counter,
+				);
+
+				tx.insert(
+					&self.local_counter_tree,
+					b"counter",
+					u64::to_be_bytes(new_local_counter),
+				)?;
+
+				let hist_entry = K2VHistoryEntry {
+					partition: ent.partition.clone(),
+					node_counter: K2VHistorySortKey {
+						node: make_node_id(self.system.id),
+						counter: new_local_counter,
+					},
+					prev_counter: old_local_counter,
+					timestamp: now,
+					ins_sort_key: item.sort_key.clone(),
+					ins_value: item.value.clone(),
+					deleted: false.into(),
+				};
+				self.history_table.queue_insert(tx, &hist_entry)?;
+
+				Ok(ent)
 			})
 	}
 
-	async fn handle_poll(&self, key: &PollKey, ct: &CausalContext) -> Result<K2VItem, Error> {
-		let mut chan = self.subscriptions.subscribe(key);
+	async fn handle_poll_item(&self, key: &PollKey, ct: &CausalContext) -> Result<K2VItem, Error> {
+		let mut chan = self.subscriptions.subscribe_item(key);
 
 		let mut value = self
 			.item_table
@@ -326,7 +374,7 @@ impl EndpointHandler<K2VRpc> for K2VRpcHandler {
 			} => {
 				let delay = tokio::time::sleep(Duration::from_millis(*timeout_msec));
 				select! {
-					ret = self.handle_poll(key, causal_context) => ret.map(Some).map(K2VRpc::PollItemResponse),
+					ret = self.handle_poll_item(key, causal_context) => ret.map(Some).map(K2VRpc::PollItemResponse),
 					_ = delay => Ok(K2VRpc::PollItemResponse(None)),
 				}
 			}
-- 
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