1 files changed, 496 insertions, 0 deletions
diff --git a/src/model/index_counter.rs b/src/model/index_counter.rs
new file mode 100644
index 00000000..e6394f0c
--- /dev/null
+++ b/src/model/index_counter.rs
@@ -0,0 +1,496 @@
+use core::ops::Bound;
+use std::collections::{hash_map, BTreeMap, HashMap};
+use std::marker::PhantomData;
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use serde::{Deserialize, Serialize};
+use tokio::sync::{mpsc, watch};
+
+use garage_db as db;
+
+use garage_rpc::ring::Ring;
+use garage_rpc::system::System;
+use garage_util::background::*;
+use garage_util::data::*;
+use garage_util::error::*;
+use garage_util::time::*;
+
+use garage_table::crdt::*;
+use garage_table::replication::*;
+use garage_table::*;
+
+pub trait CountedItem: Clone + PartialEq + Send + Sync + 'static {
+	const COUNTER_TABLE_NAME: &'static str;
+
+	type CP: PartitionKey + Clone + PartialEq + Serialize + for<'de> Deserialize<'de> + Send + Sync;
+	type CS: SortKey + Clone + PartialEq + Serialize + for<'de> Deserialize<'de> + Send + Sync;
+
+	fn counter_partition_key(&self) -> &Self::CP;
+	fn counter_sort_key(&self) -> &Self::CS;
+	fn counts(&self) -> Vec<(&'static str, i64)>;
+}
+
+/// A counter entry in the global table
+#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
+pub struct CounterEntry<T: CountedItem> {
+	pub pk: T::CP,
+	pub sk: T::CS,
+	pub values: BTreeMap<String, CounterValue>,
+}
+
+impl<T: CountedItem> Entry<T::CP, T::CS> for CounterEntry<T> {
+	fn partition_key(&self) -> &T::CP {
+		&self.pk
+	}
+	fn sort_key(&self) -> &T::CS {
+		&self.sk
+	}
+	fn is_tombstone(&self) -> bool {
+		self.values
+			.iter()
+			.all(|(_, v)| v.node_values.iter().all(|(_, (_, v))| *v == 0))
+	}
+}
+
+impl<T: CountedItem> CounterEntry<T> {
+	pub fn filtered_values(&self, ring: &Ring) -> HashMap<String, i64> {
+		let nodes = &ring.layout.node_id_vec[..];
+		self.filtered_values_with_nodes(nodes)
+	}
+
+	pub fn filtered_values_with_nodes(&self, nodes: &[Uuid]) -> HashMap<String, i64> {
+		let mut ret = HashMap::new();
+		for (name, vals) in self.values.iter() {
+			let new_vals = vals
+				.node_values
+				.iter()
+				.filter(|(n, _)| nodes.contains(n))
+				.map(|(_, (_, v))| *v)
+				.collect::<Vec<_>>();
+			if !new_vals.is_empty() {
+				ret.insert(
+					name.clone(),
+					new_vals.iter().fold(i64::MIN, |a, b| std::cmp::max(a, *b)),
+				);
+			}
+		}
+
+		ret
+	}
+}
+
+/// A counter entry in the global table
+#[derive(PartialEq, Eq, Clone, Debug, Serialize, Deserialize)]
+pub struct CounterValue {
+	pub node_values: BTreeMap<Uuid, (u64, i64)>,
+}
+
+impl<T: CountedItem> Crdt for CounterEntry<T> {
+	fn merge(&mut self, other: &Self) {
+		for (name, e2) in other.values.iter() {
+			if let Some(e) = self.values.get_mut(name) {
+				e.merge(e2);
+			} else {
+				self.values.insert(name.clone(), e2.clone());
+			}
+		}
+	}
+}
+
+impl Crdt for CounterValue {
+	fn merge(&mut self, other: &Self) {
+		for (node, (t2, e2)) in other.node_values.iter() {
+			if let Some((t, e)) = self.node_values.get_mut(node) {
+				if t2 > t {
+					*e = *e2;
+				}
+			} else {
+				self.node_values.insert(*node, (*t2, *e2));
+			}
+		}
+	}
+}
+
+pub struct CounterTable<T: CountedItem> {
+	_phantom_t: PhantomData<T>,
+}
+
+impl<T: CountedItem> TableSchema for CounterTable<T> {
+	const TABLE_NAME: &'static str = T::COUNTER_TABLE_NAME;
+
+	type P = T::CP;
+	type S = T::CS;
+	type E = CounterEntry<T>;
+	type Filter = (DeletedFilter, Vec<Uuid>);
+
+	fn matches_filter(entry: &Self::E, filter: &Self::Filter) -> bool {
+		if filter.0 == DeletedFilter::Any {
+			return true;
+		}
+
+		let is_tombstone = entry
+			.filtered_values_with_nodes(&filter.1[..])
+			.iter()
+			.all(|(_, v)| *v == 0);
+		filter.0.apply(is_tombstone)
+	}
+}
+
+// ----
+
+pub struct IndexCounter<T: CountedItem> {
+	this_node: Uuid,
+	local_counter: db::Tree,
+	propagate_tx: mpsc::UnboundedSender<(T::CP, T::CS, LocalCounterEntry<T>)>,
+	pub table: Arc<Table<CounterTable<T>, TableShardedReplication>>,
+}
+
+impl<T: CountedItem> IndexCounter<T> {
+	pub fn new(
+		system: Arc<System>,
+		replication: TableShardedReplication,
+		db: &db::Db,
+	) -> Arc<Self> {
+		let background = system.background.clone();
+
+		let (propagate_tx, propagate_rx) = mpsc::unbounded_channel();
+
+		let this = Arc::new(Self {
+			this_node: system.id,
+			local_counter: db
+				.open_tree(format!("local_counter_v2:{}", T::COUNTER_TABLE_NAME))
+				.expect("Unable to open local counter tree"),
+			propagate_tx,
+			table: Table::new(
+				CounterTable {
+					_phantom_t: Default::default(),
+				},
+				replication,
+				system,
+				db,
+			),
+		});
+
+		background.spawn_worker(IndexPropagatorWorker {
+			index_counter: this.clone(),
+			propagate_rx,
+			buf: HashMap::new(),
+			errors: 0,
+		});
+
+		this
+	}
+
+	pub fn count(
+		&self,
+		tx: &mut db::Transaction,
+		old: Option<&T>,
+		new: Option<&T>,
+	) -> db::TxResult<(), Error> {
+		let pk = old
+			.map(|e| e.counter_partition_key())
+			.unwrap_or_else(|| new.unwrap().counter_partition_key());
+		let sk = old
+			.map(|e| e.counter_sort_key())
+			.unwrap_or_else(|| new.unwrap().counter_sort_key());
+
+		// calculate counter differences
+		let mut counts = HashMap::new();
+		for (k, v) in old.map(|x| x.counts()).unwrap_or_default() {
+			*counts.entry(k).or_insert(0) -= v;
+		}
+		for (k, v) in new.map(|x| x.counts()).unwrap_or_default() {
+			*counts.entry(k).or_insert(0) += v;
+		}
+
+		// update local counter table
+		let tree_key = self.table.data.tree_key(pk, sk);
+
+		let mut entry = match tx.get(&self.local_counter, &tree_key[..])? {
+			Some(old_bytes) => {
+				rmp_serde::decode::from_read_ref::<_, LocalCounterEntry<T>>(&old_bytes)
+					.map_err(Error::RmpDecode)
+					.map_err(db::TxError::Abort)?
+			}
+			None => LocalCounterEntry {
+				pk: pk.clone(),
+				sk: sk.clone(),
+				values: BTreeMap::new(),
+			},
+		};
+
+		let now = now_msec();
+		for (s, inc) in counts.iter() {
+			let mut ent = entry.values.entry(s.to_string()).or_insert((0, 0));
+			ent.0 = std::cmp::max(ent.0 + 1, now);
+			ent.1 += *inc;
+		}
+
+		let new_entry_bytes = rmp_to_vec_all_named(&entry)
+			.map_err(Error::RmpEncode)
+			.map_err(db::TxError::Abort)?;
+		tx.insert(&self.local_counter, &tree_key[..], new_entry_bytes)?;
+
+		if let Err(e) = self.propagate_tx.send((pk.clone(), sk.clone(), entry)) {
+			error!(
+				"Could not propagate updated counter values, failed to send to channel: {}",
+				e
+			);
+		}
+
+		Ok(())
+	}
+
+	pub fn offline_recount_all<TS, TR>(
+		&self,
+		counted_table: &Arc<Table<TS, TR>>,
+	) -> Result<(), Error>
+	where
+		TS: TableSchema<E = T>,
+		TR: TableReplication,
+	{
+		let save_counter_entry = |entry: CounterEntry<T>| -> Result<(), Error> {
+			let entry_k = self
+				.table
+				.data
+				.tree_key(entry.partition_key(), entry.sort_key());
+			self.table
+				.data
+				.update_entry_with(&entry_k, |ent| match ent {
+					Some(mut ent) => {
+						ent.merge(&entry);
+						ent
+					}
+					None => entry.clone(),
+				})?;
+			Ok(())
+		};
+
+		// 1. Set all old local counters to zero
+		let now = now_msec();
+		let mut next_start: Option<Vec<u8>> = None;
+		loop {
+			let low_bound = match next_start.take() {
+				Some(v) => Bound::Excluded(v),
+				None => Bound::Unbounded,
+			};
+			let mut batch = vec![];
+			for item in self.local_counter.range((low_bound, Bound::Unbounded))? {
+				batch.push(item?);
+				if batch.len() > 1000 {
+					break;
+				}
+			}
+
+			if batch.is_empty() {
+				break;
+			}
+
+			info!("zeroing old counters... ({})", hex::encode(&batch[0].0));
+			for (local_counter_k, local_counter) in batch {
+				let mut local_counter =
+					rmp_serde::decode::from_read_ref::<_, LocalCounterEntry<T>>(&local_counter)?;
+
+				for (_, tv) in local_counter.values.iter_mut() {
+					tv.0 = std::cmp::max(tv.0 + 1, now);
+					tv.1 = 0;
+				}
+
+				let local_counter_bytes = rmp_to_vec_all_named(&local_counter)?;
+				self.local_counter
+					.insert(&local_counter_k, &local_counter_bytes)?;
+
+				let counter_entry = local_counter.into_counter_entry(self.this_node);
+				save_counter_entry(counter_entry)?;
+
+				next_start = Some(local_counter_k);
+			}
+		}
+
+		// 2. Recount all table entries
+		let now = now_msec();
+		let mut next_start: Option<Vec<u8>> = None;
+		loop {
+			let low_bound = match next_start.take() {
+				Some(v) => Bound::Excluded(v),
+				None => Bound::Unbounded,
+			};
+			let mut batch = vec![];
+			for item in counted_table
+				.data
+				.store
+				.range((low_bound, Bound::Unbounded))?
+			{
+				batch.push(item?);
+				if batch.len() > 1000 {
+					break;
+				}
+			}
+
+			if batch.is_empty() {
+				break;
+			}
+
+			info!("counting entries... ({})", hex::encode(&batch[0].0));
+			for (counted_entry_k, counted_entry) in batch {
+				let counted_entry = counted_table.data.decode_entry(&counted_entry)?;
+
+				let pk = counted_entry.counter_partition_key();
+				let sk = counted_entry.counter_sort_key();
+				let counts = counted_entry.counts();
+
+				let local_counter_key = self.table.data.tree_key(pk, sk);
+				let mut local_counter = match self.local_counter.get(&local_counter_key)? {
+					Some(old_bytes) => {
+						let ent = rmp_serde::decode::from_read_ref::<_, LocalCounterEntry<T>>(
+							&old_bytes,
+						)?;
+						assert!(ent.pk == *pk);
+						assert!(ent.sk == *sk);
+						ent
+					}
+					None => LocalCounterEntry {
+						pk: pk.clone(),
+						sk: sk.clone(),
+						values: BTreeMap::new(),
+					},
+				};
+				for (s, v) in counts.iter() {
+					let mut tv = local_counter.values.entry(s.to_string()).or_insert((0, 0));
+					tv.0 = std::cmp::max(tv.0 + 1, now);
+					tv.1 += v;
+				}
+
+				let local_counter_bytes = rmp_to_vec_all_named(&local_counter)?;
+				self.local_counter
+					.insert(&local_counter_key, local_counter_bytes)?;
+
+				let counter_entry = local_counter.into_counter_entry(self.this_node);
+				save_counter_entry(counter_entry)?;
+
+				next_start = Some(counted_entry_k);
+			}
+		}
+
+		// Done
+		Ok(())
+	}
+}
+
+struct IndexPropagatorWorker<T: CountedItem> {
+	index_counter: Arc<IndexCounter<T>>,
+	propagate_rx: mpsc::UnboundedReceiver<(T::CP, T::CS, LocalCounterEntry<T>)>,
+
+	buf: HashMap<Vec<u8>, CounterEntry<T>>,
+	errors: usize,
+}
+
+impl<T: CountedItem> IndexPropagatorWorker<T> {
+	fn add_ent(&mut self, pk: T::CP, sk: T::CS, counters: LocalCounterEntry<T>) {
+		let tree_key = self.index_counter.table.data.tree_key(&pk, &sk);
+		let dist_entry = counters.into_counter_entry(self.index_counter.this_node);
+		match self.buf.entry(tree_key) {
+			hash_map::Entry::Vacant(e) => {
+				e.insert(dist_entry);
+			}
+			hash_map::Entry::Occupied(mut e) => {
+				e.get_mut().merge(&dist_entry);
+			}
+		}
+	}
+}
+
+#[async_trait]
+impl<T: CountedItem> Worker for IndexPropagatorWorker<T> {
+	fn name(&self) -> String {
+		format!("{} index counter propagator", T::COUNTER_TABLE_NAME)
+	}
+
+	fn info(&self) -> Option<String> {
+		if !self.buf.is_empty() {
+			Some(format!("{} items in queue", self.buf.len()))
+		} else {
+			None
+		}
+	}
+
+	async fn work(&mut self, must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
+		// This loop batches updates to counters to be sent all at once.
+		// They are sent once the propagate_rx channel has been emptied (or is closed).
+		let closed = loop {
+			match self.propagate_rx.try_recv() {
+				Ok((pk, sk, counters)) => {
+					self.add_ent(pk, sk, counters);
+				}
+				Err(mpsc::error::TryRecvError::Empty) => break false,
+				Err(mpsc::error::TryRecvError::Disconnected) => break true,
+			}
+		};
+
+		if !self.buf.is_empty() {
+			let entries_k = self.buf.keys().take(100).cloned().collect::<Vec<_>>();
+			let entries = entries_k.iter().map(|k| self.buf.get(k).unwrap());
+			if let Err(e) = self.index_counter.table.insert_many(entries).await {
+				self.errors += 1;
+				if self.errors >= 2 && *must_exit.borrow() {
+					error!("({}) Could not propagate {} counter values: {}, these counters will not be updated correctly.", T::COUNTER_TABLE_NAME, self.buf.len(), e);
+					return Ok(WorkerState::Done);
+				}
+				// Propagate error up to worker manager, it will log it, increment a counter,
+				// and sleep for a certain delay (with exponential backoff), waiting for
+				// things to go back to normal
+				return Err(e);
+			} else {
+				for k in entries_k {
+					self.buf.remove(&k);
+				}
+				self.errors = 0;
+			}
+
+			return Ok(WorkerState::Busy);
+		} else if closed {
+			return Ok(WorkerState::Done);
+		} else {
+			return Ok(WorkerState::Idle);
+		}
+	}
+
+	async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
+		match self.propagate_rx.recv().await {
+			Some((pk, sk, counters)) => {
+				self.add_ent(pk, sk, counters);
+				WorkerState::Busy
+			}
+			None => match self.buf.is_empty() {
+				false => WorkerState::Busy,
+				true => WorkerState::Done,
+			},
+		}
+	}
+}
+
+#[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
+struct LocalCounterEntry<T: CountedItem> {
+	pk: T::CP,
+	sk: T::CS,
+	values: BTreeMap<String, (u64, i64)>,
+}
+
+impl<T: CountedItem> LocalCounterEntry<T> {
+	fn into_counter_entry(self, this_node: Uuid) -> CounterEntry<T> {
+		CounterEntry {
+			pk: self.pk,
+			sk: self.sk,
+			values: self
+				.values
+				.into_iter()
+				.map(|(name, (ts, v))| {
+					let mut node_values = BTreeMap::new();
+					node_values.insert(this_node, (ts, v));
+					(name, CounterValue { node_values })
+				})
+				.collect(),
+		}
+	}
+}