Add wrapper over sled tree to count items (used for big queues)

src/table/data.rs

@@ -7,6 +7,7 @@ use tokio::sync::Notify;
 
 use garage_util::data::*;
 use garage_util::error::*;
+use garage_util::sled_counter::SledCountedTree;
 
 use garage_rpc::system::System;
 
@@ -27,7 +28,7 @@ pub struct TableData<F: TableSchema, R: TableReplication> {
 	pub(crate) merkle_tree: sled::Tree,
 	pub(crate) merkle_todo: sled::Tree,
 	pub(crate) merkle_todo_notify: Notify,
-	pub(crate) gc_todo: sled::Tree,
+	pub(crate) gc_todo: SledCountedTree,
 
 	pub(crate) metrics: TableMetrics,
 }
@@ -52,6 +53,7 @@ where
 		let gc_todo = db
 			.open_tree(&format!("{}:gc_todo_v2", F::TABLE_NAME))
 			.expect("Unable to open DB tree");
+		let gc_todo = SledCountedTree::new(gc_todo);
 
 		let metrics = TableMetrics::new(F::TABLE_NAME, merkle_todo.clone(), gc_todo.clone());
 

src/table/gc.rs

@@ -14,6 +14,7 @@ use tokio::sync::watch;
 
 use garage_util::data::*;
 use garage_util::error::*;
+use garage_util::sled_counter::SledCountedTree;
 use garage_util::time::*;
 
 use garage_rpc::system::System;
@@ -362,7 +363,7 @@ impl GcTodoEntry {
 	}
 
 	/// Saves the GcTodoEntry in the gc_todo tree
-	pub(crate) fn save(&self, gc_todo_tree: &sled::Tree) -> Result<(), Error> {
+	pub(crate) fn save(&self, gc_todo_tree: &SledCountedTree) -> Result<(), Error> {
 		gc_todo_tree.insert(self.todo_table_key(), self.value_hash.as_slice())?;
 		Ok(())
 	}
@@ -372,7 +373,7 @@ impl GcTodoEntry {
 	/// This is usefull to remove a todo entry only under the condition
 	/// that it has not changed since the time it was read, i.e.
 	/// what we have to do is still the same
-	pub(crate) fn remove_if_equal(&self, gc_todo_tree: &sled::Tree) -> Result<(), Error> {
+	pub(crate) fn remove_if_equal(&self, gc_todo_tree: &SledCountedTree) -> Result<(), Error> {
 		let _ = gc_todo_tree.compare_and_swap::<_, _, Vec<u8>>(
 			&self.todo_table_key()[..],
 			Some(self.value_hash),

src/table/metrics.rs

@@ -1,5 +1,7 @@
 use opentelemetry::{global, metrics::*, KeyValue};
 
+use garage_util::sled_counter::SledCountedTree;
+
 /// TableMetrics reference all counter used for metrics
 pub struct TableMetrics {
 	pub(crate) _merkle_todo_len: ValueObserver<u64>,
@@ -17,7 +19,11 @@ pub struct TableMetrics {
 	pub(crate) sync_items_received: Counter<u64>,
 }
 impl TableMetrics {
-	pub fn new(table_name: &'static str, merkle_todo: sled::Tree, gc_todo: sled::Tree) -> Self {
+	pub fn new(
+		table_name: &'static str,
+		merkle_todo: sled::Tree,
+		gc_todo: SledCountedTree,
+	) -> Self {
 		let meter = global::meter(table_name);
 		TableMetrics {
 			_merkle_todo_len: meter