Introduce config option to automatically create partition snapshots

A new configurable snapshot interval is added, expressed as a minimum number of
records after which a snapshot
of the partition store will be automatically taken.

crates/storage-api/src/fsm_table/mod.rs

@@ -25,6 +25,7 @@ mod fsm_variable {
     pub(crate) const OUTBOX_SEQ_NUMBER: u64 = 1;
 
     pub(crate) const APPLIED_LSN: u64 = 2;
+    pub(crate) const ARCHIVED_LSN: u64 = 3;
 }
 
 pub trait ReadOnlyFsmTable {
@@ -49,6 +50,14 @@ pub trait ReadOnlyFsmTable {
                     .map(|seq_number| seq_number.map(|seq_number| Lsn::from(u64::from(seq_number))))
             })
     }
+
+    fn get_archived_lsn(&mut self) -> impl Future<Output = Result<Option<Lsn>>> + Send + '_ {
+        self.get::<SequenceNumber>(fsm_variable::ARCHIVED_LSN)
+            .map(|result| {
+                result
+                    .map(|seq_number| seq_number.map(|seq_number| Lsn::from(u64::from(seq_number))))
+            })
+    }
 }
 
 pub trait FsmTable: ReadOnlyFsmTable {
@@ -67,6 +76,13 @@ pub trait FsmTable: ReadOnlyFsmTable {
         )
     }
 
+    fn put_archived_lsn(&mut self, lsn: Lsn) -> impl Future<Output = ()> + Send {
+        self.put(
+            fsm_variable::ARCHIVED_LSN,
+            SequenceNumber::from(u64::from(lsn)),
+        )
+    }
+
     fn put_inbox_seq_number(
         &mut self,
         seq_number: MessageIndex,

crates/types/protobuf/restate/cluster.proto

@@ -65,6 +65,7 @@ message PartitionProcessorStatus {
   uint64 num_skipped_records = 8;
   ReplayStatus replay_status = 9;
   optional restate.common.Lsn last_persisted_log_lsn = 10;
+  optional restate.common.Lsn last_archived_log_lsn = 12;
   // Set if replay_status is CATCHING_UP
   optional restate.common.Lsn target_tail_lsn = 11;
 }

crates/types/src/cluster/cluster_state.rs

@@ -128,6 +128,7 @@ pub struct PartitionProcessorStatus {
     pub num_skipped_records: u64,
     pub replay_status: ReplayStatus,
     pub last_persisted_log_lsn: Option<Lsn>,
+    pub last_archived_log_lsn: Option<Lsn>,
     // Set if replay_status is CatchingUp
     pub target_tail_lsn: Option<Lsn>,
 }
@@ -145,6 +146,7 @@ impl Default for PartitionProcessorStatus {
             num_skipped_records: 0,
             replay_status: ReplayStatus::Starting,
             last_persisted_log_lsn: None,
+            last_archived_log_lsn: None,
             target_tail_lsn: None,
         }
     }

crates/types/src/config/common.rs

@@ -233,7 +233,7 @@ static HOSTNAME: Lazy<String> = Lazy::new(|| {
 });
 
 impl CommonOptions {
-    pub fn shutdown_grace_period(&self) -> std::time::Duration {
+    pub fn shutdown_grace_period(&self) -> Duration {
         self.shutdown_timeout.into()
     }
     // todo: It's imperative that the node doesn't change its name after start. Move this to a
@@ -353,7 +353,7 @@ impl Default for CommonOptions {
             histogram_inactivity_timeout: None,
             disable_prometheus: false,
             service_client: Default::default(),
-            shutdown_timeout: std::time::Duration::from_secs(60).into(),
+            shutdown_timeout: Duration::from_secs(60).into(),
             tracing: TracingOptions::default(),
             log_filter: "warn,restate=info".to_string(),
             log_format: Default::default(),
@@ -365,11 +365,11 @@ impl Default for CommonOptions {
             rocksdb_total_memory_size: NonZeroUsize::new(6_000_000_000).unwrap(), // 4GB
             rocksdb_bg_threads: None,
             rocksdb_high_priority_bg_threads: NonZeroU32::new(2).unwrap(),
-            rocksdb_write_stall_threshold: std::time::Duration::from_secs(3).into(),
+            rocksdb_write_stall_threshold: Duration::from_secs(3).into(),
             rocksdb_enable_stall_on_memory_limit: false,
             rocksdb_perf_level: PerfStatsLevel::EnableCount,
             rocksdb: Default::default(),
-            metadata_update_interval: std::time::Duration::from_secs(3).into(),
+            metadata_update_interval: Duration::from_secs(3).into(),
             network_error_retry_policy: RetryPolicy::exponential(
                 Duration::from_millis(10),
                 2.0,
@@ -598,6 +598,7 @@ impl Default for TracingOptions {
         }
     }
 }
+
 #[cfg(test)]
 mod tests {
     use crate::nodes_config::Role;

crates/types/src/config/worker.rs

@@ -10,7 +10,7 @@
 
 use serde::{Deserialize, Serialize};
 use serde_with::serde_as;
-use std::num::{NonZeroU16, NonZeroUsize};
+use std::num::{NonZeroU16, NonZeroU64, NonZeroUsize};
 use std::path::PathBuf;
 use std::time::Duration;
 use tracing::warn;
@@ -61,7 +61,10 @@ pub struct WorkerOptions {
     /// value is, the higher the throughput and latency are.
     max_command_batch_size: NonZeroUsize,
 
-    #[serde(flatten)]
+    /// # Snapshots
+    ///
+    /// When using the replicated loglet in a distributed cluster, snapshots provide a mechanism for
+    /// safely trimming the log and for bootstrapping new worker nodes.
     pub snapshots: SnapshotsOptions,
 }
 
@@ -355,7 +358,24 @@ impl Default for StorageOptions {
 #[cfg_attr(feature = "schemars", schemars(rename = "SnapshotsOptions", default))]
 #[serde(rename_all = "kebab-case")]
 #[builder(default)]
-pub struct SnapshotsOptions {}
+pub struct SnapshotsOptions {
+    /// # Automatic snapshot creation frequency
+    ///
+    /// Number of log records that trigger a snapshot to be created.
+    ///
+    /// As snapshots are created asynchronously, the actual number of new records that will trigger
+    /// a snapshot will vary. The counter for the subsequent snapshot begins from the LSN at which
+    /// the previous snapshot export was initiated. Only leader Partition Processors will take
+    /// snapshots for a given partition.
+    ///
+    /// This setting does not influence explicitly requested snapshots triggered using `restatectl`.
+    ///
+    /// Default: `None` - automatic snapshots are disabled by default
+    pub snapshot_interval_num_records: Option<NonZeroU64>,
+}
+
+// [worker.snapshots]
+// snapshot-interval-num-records = 100_000
 
 impl SnapshotsOptions {
     pub fn snapshots_base_dir(&self) -> PathBuf {

crates/worker/src/partition/mod.rs

@@ -212,6 +212,7 @@ where
             status_watch_tx,
             status,
             inflight_create_snapshot_task: None,
+            last_snapshot_lsn_watch: watch::channel(None),
         })
     }
 
@@ -255,6 +256,7 @@ pub struct PartitionProcessor<Codec, InvokerSender> {
     max_command_batch_size: usize,
     partition_store: PartitionStore,
     inflight_create_snapshot_task: Option<TaskHandle<anyhow::Result<()>>>,
+    last_snapshot_lsn_watch: (watch::Sender<Option<Lsn>>, watch::Receiver<Option<Lsn>>),
 }
 
 impl<Codec, InvokerSender> PartitionProcessor<Codec, InvokerSender>
@@ -291,6 +293,9 @@ where
         let last_applied_lsn = last_applied_lsn.unwrap_or(Lsn::INVALID);
 
         self.status.last_applied_log_lsn = Some(last_applied_lsn);
+        self.last_snapshot_lsn_watch
+            .0
+            .send(partition_store.get_archived_lsn().await?)?;
 
         // propagate errors and let the PPM handle error retries
         let current_tail = self
@@ -399,6 +404,7 @@ where
                     self.on_rpc(rpc, &mut partition_store).await;
                 }
                 _ = status_update_timer.tick() => {
+                    self.status.last_archived_log_lsn = *self.last_snapshot_lsn_watch.1.borrow();
                     self.status_watch_tx.send_modify(|old| {
                         old.clone_from(&self.status);
                         old.updated_at = MillisSinceEpoch::now();
@@ -524,6 +530,8 @@ where
                 let snapshot_base_path = config.worker.snapshots.snapshots_dir(self.partition_id);
                 let partition_store = self.partition_store.clone();
                 let snapshot_span = tracing::info_span!("create-snapshot");
+                let snapshot_lsn_tx = self.last_snapshot_lsn_watch.0.clone();
+
                 let inflight_create_snapshot_task = restate_core::task_center().spawn_unmanaged(
                     TaskKind::PartitionSnapshotProducer,
                     "create-snapshot",
@@ -536,6 +544,11 @@ where
                         )
                         .await;
 
+                        if let Ok(metadata) = result.as_ref() {
+                            // update the Partition Processor's internal state
+                            let _ = snapshot_lsn_tx.send(Some(metadata.min_applied_lsn));
+                        }
+
                         if let Some(tx) = maybe_sender {
                             tx.send(result.map(|metadata| metadata.snapshot_id)).ok();
                         }

crates/worker/src/partition/snapshot_producer.rs

@@ -12,10 +12,12 @@ use std::path::PathBuf;
 use std::time::SystemTime;
 
 use anyhow::bail;
-use tracing::{info, warn};
+use tracing::{debug, info, warn};
 
 use restate_partition_store::snapshots::{PartitionSnapshotMetadata, SnapshotFormatVersion};
 use restate_partition_store::PartitionStore;
+use restate_storage_api::fsm_table::{FsmTable, ReadOnlyFsmTable};
+use restate_storage_api::Transaction;
 use restate_types::identifiers::SnapshotId;
 
 /// Encapsulates producing a Restate partition snapshot out of a partition store.
@@ -69,6 +71,16 @@ impl SnapshotProducer {
             "Partition snapshot written"
         );
 
+        let previous_archived_snapshot_lsn = partition_store.get_archived_lsn().await?;
+        let mut tx = partition_store.transaction();
+        tx.put_archived_lsn(snapshot.min_applied_lsn).await;
+        tx.commit().await?;
+        debug!(
+            previous_archived_lsn = ?previous_archived_snapshot_lsn,
+            updated_archived_lsn = ?snapshot.min_applied_lsn,
+            "Updated persisted archived snapshot LSN"
+        );
+
         Ok(snapshot_meta)
     }
 }

crates/worker/src/partition_processor_manager/mod.rs

@@ -13,14 +13,16 @@ mod persisted_lsn_watchdog;
 mod processor_state;
 mod spawn_processor_task;
 
-use std::collections::BTreeMap;
-use std::ops::RangeInclusive;
-use std::sync::Arc;
-
 use futures::stream::StreamExt;
 use metrics::gauge;
+use std::collections::BTreeMap;
+use std::ops::{Add, RangeInclusive};
+use std::sync::Arc;
+use std::time::Duration;
+use tokio::sync::oneshot;
 use tokio::sync::{mpsc, watch};
 use tokio::task::JoinSet;
+use tokio::time::MissedTickBehavior;
 use tracing::{debug, error, info, instrument, warn};
 
 use crate::metric_definitions::NUM_ACTIVE_PARTITIONS;
@@ -53,7 +55,7 @@ use restate_types::epoch::EpochMetadata;
 use restate_types::health::HealthStatus;
 use restate_types::identifiers::{LeaderEpoch, PartitionId, PartitionKey};
 use restate_types::live::Live;
-use restate_types::logs::Lsn;
+use restate_types::logs::{Lsn, SequenceNumber};
 use restate_types::metadata_store::keys::partition_processor_epoch_key;
 use restate_types::net::metadata::MetadataKind;
 use restate_types::net::partition_processor::{
@@ -215,12 +217,18 @@ impl PartitionProcessorManager {
         let mut logs_version_watcher = self.metadata.watch(MetadataKind::Logs);
         let mut partition_table_version_watcher = self.metadata.watch(MetadataKind::PartitionTable);
 
+        let mut latest_snapshot_check_interval = tokio::time::interval(Duration::from_secs(5));
+        latest_snapshot_check_interval.set_missed_tick_behavior(MissedTickBehavior::Skip);
+
         self.health_status.update(WorkerStatus::Ready);
         loop {
             tokio::select! {
                 Some(command) = self.rx.recv() => {
                     self.on_command(command);
                 }
+                _ = latest_snapshot_check_interval.tick() => {
+                    self.request_partition_snapshots();
+                }
                 Some(control_processors) = self.incoming_update_processors.next() => {
                     self.pending_control_processors = Some(control_processors.into_body());
                     self.on_control_processors();
@@ -285,7 +293,8 @@ impl PartitionProcessorManager {
         }
     }
 
-    #[instrument(level = "debug", skip_all, fields(partition_id = %event.partition_id, event = %<&'static str as From<&EventKind>>::from(&event.inner)))]
+    #[instrument(level = "debug", skip_all, fields(partition_id = %event.partition_id, event = %<&'static str as From<&EventKind>>::from(&event.inner)
+    ))]
     fn on_asynchronous_event(&mut self, event: AsynchronousEvent) {
         let AsynchronousEvent {
             partition_id,
@@ -647,6 +656,52 @@ impl PartitionProcessorManager {
         }
     }
 
+    fn request_partition_snapshots(&mut self) {
+        let Some(records_per_snapshot) = self
+            .updateable_config
+            .live_load()
+            .worker
+            .snapshots
+            .snapshot_interval_num_records
+        else {
+            return;
+        };
+
+        for (partition_id, state) in self.processor_states.iter() {
+            let status = state.partition_processor_status();
+            match status {
+                Some(status)
+                    if status.replay_status == ReplayStatus::Active
+                        && status.last_applied_log_lsn.unwrap_or(Lsn::INVALID)
+                            >= status
+                                .last_archived_log_lsn
+                                .unwrap_or(Lsn::OLDEST)
+                                .add(Lsn::from(records_per_snapshot.get())) =>
+                {
+                    debug!(
+                        %partition_id,
+                        last_archived_lsn = %status.last_archived_log_lsn.unwrap_or(SequenceNumber::OLDEST),
+                        last_applied_lsn = %status.last_applied_log_lsn.unwrap_or(SequenceNumber::INVALID),
+                        "Creating partition snapshot",
+                    );
+                    let (tx, _) = oneshot::channel();
+
+                    // ignore errors and don't request further snapshots if internal queue is full; we will try again later
+                    if self
+                        .tx
+                        .try_send(ProcessorsManagerCommand::CreateSnapshot(*partition_id, tx))
+                        .is_err()
+                    {
+                        break;
+                    }
+                }
+                _ => {
+                    continue;
+                }
+            }
+        }
+    }
+
     /// Creates a task that when started will spawn a new partition processor.
     ///
     /// This allows multiple partition processors to be started concurrently without holding

tools/restatectl/src/commands/partition/list.rs

@@ -41,9 +41,9 @@ use crate::util::grpc_connect;
 #[command(
     after_long_help = "In addition to partition processors, the command displays the current \
     sequencer for the partition's log when the reported applied LSN falls within the tail a \
-    replicated segment, under the heading SEQNCR. If ANSI color is enabled, the leadership epoch \
-    and the active sequencer will be highlighted in green they are the most recent and co-located \
-    with the leader processor, respectively."
+    replicated segment. If ANSI color is enabled, the leadership epoch and the active sequencer \
+    will be highlighted in green they are the most recent and co-located with the leader \
+    processor, respectively."
 )]
 pub struct ListPartitionsOpts {
     /// Sort order
@@ -139,10 +139,11 @@ pub async fn list_partitions(
         "STATUS",
         "LEADER",
         "EPOCH",
-        "SEQNCR",
-        "APPLIED",
-        "PERSISTED",
-        "SKIPPED",
+        "SEQUENCER",
+        "APPLIED-LSN",
+        "PERSISTED-LSN",
+        "SKIPPED-RECORDS",
+        "ARCHIVED-LSN",
         "LAST-UPDATE",
     ]);
 
@@ -271,6 +272,13 @@ pub async fn list_partitions(
                         .unwrap_or("-".to_owned()),
                 ),
                 Cell::new(processor.status.num_skipped_records),
+                Cell::new(
+                    processor
+                        .status
+                        .last_archived_log_lsn
+                        .map(|x| x.to_string())
+                        .unwrap_or("-".to_owned()),
+                ),
                 render_as_duration(processor.status.updated_at, Tense::Past),
             ]);
         });