LCOV - code coverage report
Current view: top level - pageserver/src - deletion_queue.rs (source / functions) Coverage Total Hit
Test: 691a4c28fe7169edd60b367c52d448a0a6605f1f.info Lines: 85.2 % 843 718
Test Date: 2024-05-10 13:18:37 Functions: 56.1 % 132 74

            Line data    Source code
       1              : mod deleter;
       2              : mod list_writer;
       3              : mod validator;
       4              : 
       5              : use std::collections::HashMap;
       6              : use std::sync::Arc;
       7              : use std::time::Duration;
       8              : 
       9              : use crate::control_plane_client::ControlPlaneGenerationsApi;
      10              : use crate::metrics;
      11              : use crate::tenant::remote_timeline_client::remote_layer_path;
      12              : use crate::tenant::remote_timeline_client::remote_timeline_path;
      13              : use crate::tenant::remote_timeline_client::LayerFileMetadata;
      14              : use crate::virtual_file::MaybeFatalIo;
      15              : use crate::virtual_file::VirtualFile;
      16              : use anyhow::Context;
      17              : use camino::Utf8PathBuf;
      18              : use pageserver_api::shard::TenantShardId;
      19              : use remote_storage::{GenericRemoteStorage, RemotePath};
      20              : use serde::Deserialize;
      21              : use serde::Serialize;
      22              : use thiserror::Error;
      23              : use tokio_util::sync::CancellationToken;
      24              : use tracing::Instrument;
      25              : use tracing::{debug, error};
      26              : use utils::crashsafe::path_with_suffix_extension;
      27              : use utils::generation::Generation;
      28              : use utils::id::TimelineId;
      29              : use utils::lsn::AtomicLsn;
      30              : use utils::lsn::Lsn;
      31              : 
      32              : use self::deleter::Deleter;
      33              : use self::list_writer::DeletionOp;
      34              : use self::list_writer::ListWriter;
      35              : use self::list_writer::RecoverOp;
      36              : use self::validator::Validator;
      37              : use deleter::DeleterMessage;
      38              : use list_writer::ListWriterQueueMessage;
      39              : use validator::ValidatorQueueMessage;
      40              : 
      41              : use crate::{config::PageServerConf, tenant::storage_layer::LayerName};
      42              : 
      43              : // TODO: configurable for how long to wait before executing deletions
      44              : 
      45              : /// We aggregate object deletions from many tenants in one place, for several reasons:
      46              : /// - Coalesce deletions into fewer DeleteObjects calls
      47              : /// - Enable Tenant/Timeline lifetimes to be shorter than the time it takes
      48              : ///   to flush any outstanding deletions.
      49              : /// - Globally control throughput of deletions, as these are a low priority task: do
      50              : ///   not compete with the same S3 clients/connections used for higher priority uploads.
      51              : /// - Enable gating deletions on validation of a tenant's generation number, to make
      52              : ///   it safe to multi-attach tenants (see docs/rfcs/025-generation-numbers.md)
      53              : ///
      54              : /// There are two kinds of deletion: deferred and immediate.  A deferred deletion
      55              : /// may be intentionally delayed to protect passive readers of S3 data, and is
      56              : /// subject to a generation number validation step.  An immediate deletion is
      57              : /// ready to execute immediately, and is only queued up so that it can be coalesced
      58              : /// with other deletions in flight.
      59              : ///
      60              : /// Deferred deletions pass through three steps:
      61              : /// - ListWriter: accumulate deletion requests from Timelines, and batch them up into
      62              : ///   DeletionLists, which are persisted to disk.
      63              : /// - Validator: accumulate deletion lists, and validate them en-masse prior to passing
      64              : ///   the keys in the list onward for actual deletion.  Also validate remote_consistent_lsn
      65              : ///   updates for running timelines.
      66              : /// - Deleter: accumulate object keys that the validator has validated, and execute them in
      67              : ///   batches of 1000 keys via DeleteObjects.
      68              : ///
      69              : /// Non-deferred deletions, such as during timeline deletion, bypass the first
      70              : /// two stages and are passed straight into the Deleter.
      71              : ///
      72              : /// Internally, each stage is joined by a channel to the next.  On disk, there is only
      73              : /// one queue (of DeletionLists), which is written by the frontend and consumed
      74              : /// by the backend.
      75              : #[derive(Clone)]
      76              : pub struct DeletionQueue {
      77              :     client: DeletionQueueClient,
      78              : 
      79              :     // Parent cancellation token for the tokens passed into background workers
      80              :     cancel: CancellationToken,
      81              : }
      82              : 
      83              : /// Opaque wrapper around individual worker tasks, to avoid making the
      84              : /// worker objects themselves public
      85              : pub struct DeletionQueueWorkers<C>
      86              : where
      87              :     C: ControlPlaneGenerationsApi + Send + Sync,
      88              : {
      89              :     frontend: ListWriter,
      90              :     backend: Validator<C>,
      91              :     executor: Deleter,
      92              : }
      93              : 
      94              : impl<C> DeletionQueueWorkers<C>
      95              : where
      96              :     C: ControlPlaneGenerationsApi + Send + Sync + 'static,
      97              : {
      98            8 :     pub fn spawn_with(mut self, runtime: &tokio::runtime::Handle) -> tokio::task::JoinHandle<()> {
      99            8 :         let jh_frontend = runtime.spawn(async move {
     100            8 :             self.frontend
     101            8 :                 .background()
     102            8 :                 .instrument(tracing::info_span!(parent:None, "deletion frontend"))
     103           52 :                 .await
     104            8 :         });
     105            8 :         let jh_backend = runtime.spawn(async move {
     106            8 :             self.backend
     107            8 :                 .background()
     108            8 :                 .instrument(tracing::info_span!(parent:None, "deletion backend"))
     109           58 :                 .await
     110            8 :         });
     111            8 :         let jh_executor = runtime.spawn(async move {
     112            8 :             self.executor
     113            8 :                 .background()
     114            8 :                 .instrument(tracing::info_span!(parent:None, "deletion executor"))
     115           28 :                 .await
     116            8 :         });
     117            8 : 
     118            8 :         runtime.spawn({
     119            8 :             async move {
     120            8 :                 jh_frontend.await.expect("error joining frontend worker");
     121            2 :                 jh_backend.await.expect("error joining backend worker");
     122            2 :                 drop(jh_executor.await.expect("error joining executor worker"));
     123            8 :             }
     124            8 :         })
     125            8 :     }
     126              : }
     127              : 
     128              : /// A FlushOp is just a oneshot channel, where we send the transmit side down
     129              : /// another channel, and the receive side will receive a message when the channel
     130              : /// we're flushing has reached the FlushOp we sent into it.
     131              : ///
     132              : /// The only extra behavior beyond the channel is that the notify() method does not
     133              : /// return an error when the receive side has been dropped, because in this use case
     134              : /// it is harmless (the code that initiated the flush no longer cares about the result).
     135              : #[derive(Debug)]
     136              : struct FlushOp {
     137              :     tx: tokio::sync::oneshot::Sender<()>,
     138              : }
     139              : 
     140              : impl FlushOp {
     141           42 :     fn new() -> (Self, tokio::sync::oneshot::Receiver<()>) {
     142           42 :         let (tx, rx) = tokio::sync::oneshot::channel::<()>();
     143           42 :         (Self { tx }, rx)
     144           42 :     }
     145              : 
     146           42 :     fn notify(self) {
     147           42 :         if self.tx.send(()).is_err() {
     148              :             // oneshot channel closed. This is legal: a client could be destroyed while waiting for a flush.
     149            0 :             debug!("deletion queue flush from dropped client");
     150           42 :         };
     151           42 :     }
     152              : }
     153              : 
     154              : #[derive(Clone, Debug)]
     155              : pub struct DeletionQueueClient {
     156              :     tx: tokio::sync::mpsc::UnboundedSender<ListWriterQueueMessage>,
     157              :     executor_tx: tokio::sync::mpsc::Sender<DeleterMessage>,
     158              : 
     159              :     lsn_table: Arc<std::sync::RwLock<VisibleLsnUpdates>>,
     160              : }
     161              : 
     162           18 : #[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
     163              : struct TenantDeletionList {
     164              :     /// For each Timeline, a list of key fragments to append to the timeline remote path
     165              :     /// when reconstructing a full key
     166              :     timelines: HashMap<TimelineId, Vec<String>>,
     167              : 
     168              :     /// The generation in which this deletion was emitted: note that this may not be the
     169              :     /// same as the generation of any layers being deleted.  The generation of the layer
     170              :     /// has already been absorbed into the keys in `objects`
     171              :     generation: Generation,
     172              : }
     173              : 
     174              : impl TenantDeletionList {
     175           10 :     pub(crate) fn len(&self) -> usize {
     176           10 :         self.timelines.values().map(|v| v.len()).sum()
     177           10 :     }
     178              : }
     179              : 
     180              : /// Files ending with this suffix will be ignored and erased
     181              : /// during recovery as startup.
     182              : const TEMP_SUFFIX: &str = "tmp";
     183              : 
     184           30 : #[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
     185              : struct DeletionList {
     186              :     /// Serialization version, for future use
     187              :     version: u8,
     188              : 
     189              :     /// Used for constructing a unique key for each deletion list we write out.
     190              :     sequence: u64,
     191              : 
     192              :     /// To avoid repeating tenant/timeline IDs in every key, we store keys in
     193              :     /// nested HashMaps by TenantTimelineID.  Each Tenant only appears once
     194              :     /// with one unique generation ID: if someone tries to push a second generation
     195              :     /// ID for the same tenant, we will start a new DeletionList.
     196              :     tenants: HashMap<TenantShardId, TenantDeletionList>,
     197              : 
     198              :     /// Avoid having to walk `tenants` to calculate the number of keys in
     199              :     /// the nested deletion lists
     200              :     size: usize,
     201              : 
     202              :     /// Set to true when the list has undergone validation with the control
     203              :     /// plane and the remaining contents of `tenants` are valid.  A list may
     204              :     /// also be implicitly marked valid by DeletionHeader.validated_sequence
     205              :     /// advancing to >= DeletionList.sequence
     206              :     #[serde(default)]
     207              :     #[serde(skip_serializing_if = "std::ops::Not::not")]
     208              :     validated: bool,
     209              : }
     210              : 
     211            0 : #[derive(Debug, Serialize, Deserialize)]
     212              : struct DeletionHeader {
     213              :     /// Serialization version, for future use
     214              :     version: u8,
     215              : 
     216              :     /// The highest sequence number (inclusive) that has been validated.  All deletion
     217              :     /// lists on disk with a sequence <= this value are safe to execute.
     218              :     validated_sequence: u64,
     219              : }
     220              : 
     221              : impl DeletionHeader {
     222              :     const VERSION_LATEST: u8 = 1;
     223              : 
     224            8 :     fn new(validated_sequence: u64) -> Self {
     225            8 :         Self {
     226            8 :             version: Self::VERSION_LATEST,
     227            8 :             validated_sequence,
     228            8 :         }
     229            8 :     }
     230              : 
     231            8 :     async fn save(&self, conf: &'static PageServerConf) -> anyhow::Result<()> {
     232            8 :         debug!("Saving deletion list header {:?}", self);
     233            8 :         let header_bytes = serde_json::to_vec(self).context("serialize deletion header")?;
     234            8 :         let header_path = conf.deletion_header_path();
     235            8 :         let temp_path = path_with_suffix_extension(&header_path, TEMP_SUFFIX);
     236            8 :         VirtualFile::crashsafe_overwrite(header_path, temp_path, header_bytes)
     237            8 :             .await
     238            8 :             .maybe_fatal_err("save deletion header")?;
     239              : 
     240            8 :         Ok(())
     241            8 :     }
     242              : }
     243              : 
     244              : impl DeletionList {
     245              :     const VERSION_LATEST: u8 = 1;
     246           20 :     fn new(sequence: u64) -> Self {
     247           20 :         Self {
     248           20 :             version: Self::VERSION_LATEST,
     249           20 :             sequence,
     250           20 :             tenants: HashMap::new(),
     251           20 :             size: 0,
     252           20 :             validated: false,
     253           20 :         }
     254           20 :     }
     255              : 
     256           28 :     fn is_empty(&self) -> bool {
     257           28 :         self.tenants.is_empty()
     258           28 :     }
     259              : 
     260           60 :     fn len(&self) -> usize {
     261           60 :         self.size
     262           60 :     }
     263              : 
     264              :     /// Returns true if the push was accepted, false if the caller must start a new
     265              :     /// deletion list.
     266           14 :     fn push(
     267           14 :         &mut self,
     268           14 :         tenant: &TenantShardId,
     269           14 :         timeline: &TimelineId,
     270           14 :         generation: Generation,
     271           14 :         objects: &mut Vec<RemotePath>,
     272           14 :     ) -> bool {
     273           14 :         if objects.is_empty() {
     274              :             // Avoid inserting an empty TimelineDeletionList: this preserves the property
     275              :             // that if we have no keys, then self.objects is empty (used in Self::is_empty)
     276            0 :             return true;
     277           14 :         }
     278           14 : 
     279           14 :         let tenant_entry = self
     280           14 :             .tenants
     281           14 :             .entry(*tenant)
     282           14 :             .or_insert_with(|| TenantDeletionList {
     283           12 :                 timelines: HashMap::new(),
     284           12 :                 generation,
     285           14 :             });
     286           14 : 
     287           14 :         if tenant_entry.generation != generation {
     288              :             // Only one generation per tenant per list: signal to
     289              :             // caller to start a new list.
     290            2 :             return false;
     291           12 :         }
     292           12 : 
     293           12 :         let timeline_entry = tenant_entry.timelines.entry(*timeline).or_default();
     294           12 : 
     295           12 :         let timeline_remote_path = remote_timeline_path(tenant, timeline);
     296           12 : 
     297           12 :         self.size += objects.len();
     298           12 :         timeline_entry.extend(objects.drain(..).map(|p| {
     299           12 :             p.strip_prefix(&timeline_remote_path)
     300           12 :                 .expect("Timeline paths always start with the timeline prefix")
     301           12 :                 .to_string()
     302           12 :         }));
     303           12 :         true
     304           14 :     }
     305              : 
     306           10 :     fn into_remote_paths(self) -> Vec<RemotePath> {
     307           10 :         let mut result = Vec::new();
     308           10 :         for (tenant, tenant_deletions) in self.tenants.into_iter() {
     309            6 :             for (timeline, timeline_layers) in tenant_deletions.timelines.into_iter() {
     310            6 :                 let timeline_remote_path = remote_timeline_path(&tenant, &timeline);
     311            6 :                 result.extend(
     312            6 :                     timeline_layers
     313            6 :                         .into_iter()
     314            6 :                         .map(|l| timeline_remote_path.join(&Utf8PathBuf::from(l))),
     315            6 :                 );
     316            6 :             }
     317              :         }
     318              : 
     319           10 :         result
     320           10 :     }
     321              : 
     322           14 :     async fn save(&self, conf: &'static PageServerConf) -> anyhow::Result<()> {
     323           14 :         let path = conf.deletion_list_path(self.sequence);
     324           14 :         let temp_path = path_with_suffix_extension(&path, TEMP_SUFFIX);
     325           14 : 
     326           14 :         let bytes = serde_json::to_vec(self).expect("Failed to serialize deletion list");
     327           14 : 
     328           14 :         VirtualFile::crashsafe_overwrite(path, temp_path, bytes)
     329           14 :             .await
     330           14 :             .maybe_fatal_err("save deletion list")
     331           14 :             .map_err(Into::into)
     332           14 :     }
     333              : }
     334              : 
     335              : impl std::fmt::Display for DeletionList {
     336            0 :     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     337            0 :         write!(
     338            0 :             f,
     339            0 :             "DeletionList<seq={}, tenants={}, keys={}>",
     340            0 :             self.sequence,
     341            0 :             self.tenants.len(),
     342            0 :             self.size
     343            0 :         )
     344            0 :     }
     345              : }
     346              : 
     347              : struct PendingLsn {
     348              :     projected: Lsn,
     349              :     result_slot: Arc<AtomicLsn>,
     350              : }
     351              : 
     352              : struct TenantLsnState {
     353              :     timelines: HashMap<TimelineId, PendingLsn>,
     354              : 
     355              :     // In what generation was the most recent update proposed?
     356              :     generation: Generation,
     357              : }
     358              : 
     359              : #[derive(Default)]
     360              : struct VisibleLsnUpdates {
     361              :     tenants: HashMap<TenantShardId, TenantLsnState>,
     362              : }
     363              : 
     364              : impl VisibleLsnUpdates {
     365          126 :     fn new() -> Self {
     366          126 :         Self {
     367          126 :             tenants: HashMap::new(),
     368          126 :         }
     369          126 :     }
     370              : }
     371              : 
     372              : impl std::fmt::Debug for VisibleLsnUpdates {
     373            0 :     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     374            0 :         write!(f, "VisibleLsnUpdates({} tenants)", self.tenants.len())
     375            0 :     }
     376              : }
     377              : 
     378            0 : #[derive(Error, Debug)]
     379              : pub enum DeletionQueueError {
     380              :     #[error("Deletion queue unavailable during shutdown")]
     381              :     ShuttingDown,
     382              : }
     383              : 
     384              : impl DeletionQueueClient {
     385            0 :     pub(crate) fn broken() -> Self {
     386            0 :         // Channels whose receivers are immediately dropped.
     387            0 :         let (tx, _rx) = tokio::sync::mpsc::unbounded_channel();
     388            0 :         let (executor_tx, _executor_rx) = tokio::sync::mpsc::channel(1);
     389            0 :         Self {
     390            0 :             tx,
     391            0 :             executor_tx,
     392            0 :             lsn_table: Arc::default(),
     393            0 :         }
     394            0 :     }
     395              : 
     396              :     /// This is cancel-safe.  If you drop the future before it completes, the message
     397              :     /// is not pushed, although in the context of the deletion queue it doesn't matter: once
     398              :     /// we decide to do a deletion the decision is always final.
     399          212 :     fn do_push<T>(
     400          212 :         &self,
     401          212 :         queue: &tokio::sync::mpsc::UnboundedSender<T>,
     402          212 :         msg: T,
     403          212 :     ) -> Result<(), DeletionQueueError> {
     404          212 :         match queue.send(msg) {
     405          212 :             Ok(_) => Ok(()),
     406            0 :             Err(e) => {
     407            0 :                 // This shouldn't happen, we should shut down all tenants before
     408            0 :                 // we shut down the global delete queue.  If we encounter a bug like this,
     409            0 :                 // we may leak objects as deletions won't be processed.
     410            0 :                 error!("Deletion queue closed while pushing, shutting down? ({e})");
     411            0 :                 Err(DeletionQueueError::ShuttingDown)
     412              :             }
     413              :         }
     414          212 :     }
     415              : 
     416            8 :     pub(crate) fn recover(
     417            8 :         &self,
     418            8 :         attached_tenants: HashMap<TenantShardId, Generation>,
     419            8 :     ) -> Result<(), DeletionQueueError> {
     420            8 :         self.do_push(
     421            8 :             &self.tx,
     422            8 :             ListWriterQueueMessage::Recover(RecoverOp { attached_tenants }),
     423            8 :         )
     424            8 :     }
     425              : 
     426              :     /// When a Timeline wishes to update the remote_consistent_lsn that it exposes to the outside
     427              :     /// world, it must validate its generation number before doing so.  Rather than do this synchronously,
     428              :     /// we allow the timeline to publish updates at will via this API, and then read back what LSN was most
     429              :     /// recently validated separately.
     430              :     ///
     431              :     /// In this function we publish the LSN to the `projected` field of the timeline's entry in the VisibleLsnUpdates.  The
     432              :     /// backend will later wake up and notice that the tenant's generation requires validation.
     433         1144 :     pub(crate) async fn update_remote_consistent_lsn(
     434         1144 :         &self,
     435         1144 :         tenant_shard_id: TenantShardId,
     436         1144 :         timeline_id: TimelineId,
     437         1144 :         current_generation: Generation,
     438         1144 :         lsn: Lsn,
     439         1144 :         result_slot: Arc<AtomicLsn>,
     440         1144 :     ) {
     441         1144 :         let mut locked = self
     442         1144 :             .lsn_table
     443         1144 :             .write()
     444         1144 :             .expect("Lock should never be poisoned");
     445         1144 : 
     446         1144 :         let tenant_entry = locked
     447         1144 :             .tenants
     448         1144 :             .entry(tenant_shard_id)
     449         1144 :             .or_insert(TenantLsnState {
     450         1144 :                 timelines: HashMap::new(),
     451         1144 :                 generation: current_generation,
     452         1144 :             });
     453         1144 : 
     454         1144 :         if tenant_entry.generation != current_generation {
     455            0 :             // Generation might have changed if we were detached and then re-attached: in this case,
     456            0 :             // state from the previous generation cannot be trusted.
     457            0 :             tenant_entry.timelines.clear();
     458            0 :             tenant_entry.generation = current_generation;
     459         1144 :         }
     460              : 
     461         1144 :         tenant_entry.timelines.insert(
     462         1144 :             timeline_id,
     463         1144 :             PendingLsn {
     464         1144 :                 projected: lsn,
     465         1144 :                 result_slot,
     466         1144 :             },
     467         1144 :         );
     468         1144 :     }
     469              : 
     470              :     /// Submit a list of layers for deletion: this function will return before the deletion is
     471              :     /// persistent, but it may be executed at any time after this function enters: do not push
     472              :     /// layers until you're sure they can be deleted safely (i.e. remote metadata no longer
     473              :     /// references them).
     474              :     ///
     475              :     /// The `current_generation` is the generation of this pageserver's current attachment.  The
     476              :     /// generations in `layers` are the generations in which those layers were written.
     477          180 :     pub(crate) async fn push_layers(
     478          180 :         &self,
     479          180 :         tenant_shard_id: TenantShardId,
     480          180 :         timeline_id: TimelineId,
     481          180 :         current_generation: Generation,
     482          180 :         layers: Vec<(LayerName, LayerFileMetadata)>,
     483          180 :     ) -> Result<(), DeletionQueueError> {
     484          180 :         if current_generation.is_none() {
     485            0 :             debug!("Enqueuing deletions in legacy mode, skipping queue");
     486              : 
     487            0 :             let mut layer_paths = Vec::new();
     488            0 :             for (layer, meta) in layers {
     489            0 :                 layer_paths.push(remote_layer_path(
     490            0 :                     &tenant_shard_id.tenant_id,
     491            0 :                     &timeline_id,
     492            0 :                     meta.shard,
     493            0 :                     &layer,
     494            0 :                     meta.generation,
     495            0 :                 ));
     496            0 :             }
     497            0 :             self.push_immediate(layer_paths).await?;
     498            0 :             return self.flush_immediate().await;
     499          180 :         }
     500          180 : 
     501          180 :         self.push_layers_sync(tenant_shard_id, timeline_id, current_generation, layers)
     502          180 :     }
     503              : 
     504              :     /// When a Tenant has a generation, push_layers is always synchronous because
     505              :     /// the ListValidator channel is an unbounded channel.
     506              :     ///
     507              :     /// This can be merged into push_layers when we remove the Generation-less mode
     508              :     /// support (`<https://github.com/neondatabase/neon/issues/5395>`)
     509          180 :     pub(crate) fn push_layers_sync(
     510          180 :         &self,
     511          180 :         tenant_shard_id: TenantShardId,
     512          180 :         timeline_id: TimelineId,
     513          180 :         current_generation: Generation,
     514          180 :         layers: Vec<(LayerName, LayerFileMetadata)>,
     515          180 :     ) -> Result<(), DeletionQueueError> {
     516          180 :         metrics::DELETION_QUEUE
     517          180 :             .keys_submitted
     518          180 :             .inc_by(layers.len() as u64);
     519          180 :         self.do_push(
     520          180 :             &self.tx,
     521          180 :             ListWriterQueueMessage::Delete(DeletionOp {
     522          180 :                 tenant_shard_id,
     523          180 :                 timeline_id,
     524          180 :                 layers,
     525          180 :                 generation: current_generation,
     526          180 :                 objects: Vec::new(),
     527          180 :             }),
     528          180 :         )
     529          180 :     }
     530              : 
     531              :     /// This is cancel-safe.  If you drop the future the flush may still happen in the background.
     532           24 :     async fn do_flush<T>(
     533           24 :         &self,
     534           24 :         queue: &tokio::sync::mpsc::UnboundedSender<T>,
     535           24 :         msg: T,
     536           24 :         rx: tokio::sync::oneshot::Receiver<()>,
     537           24 :     ) -> Result<(), DeletionQueueError> {
     538           24 :         self.do_push(queue, msg)?;
     539           24 :         if rx.await.is_err() {
     540              :             // This shouldn't happen if tenants are shut down before deletion queue.  If we
     541              :             // encounter a bug like this, then a flusher will incorrectly believe it has flushed
     542              :             // when it hasn't, possibly leading to leaking objects.
     543            0 :             error!("Deletion queue dropped flush op while client was still waiting");
     544            0 :             Err(DeletionQueueError::ShuttingDown)
     545              :         } else {
     546           24 :             Ok(())
     547              :         }
     548           24 :     }
     549              : 
     550              :     /// Wait until all previous deletions are persistent (either executed, or written to a DeletionList)
     551              :     ///
     552              :     /// This is cancel-safe.  If you drop the future the flush may still happen in the background.
     553           14 :     pub async fn flush(&self) -> Result<(), DeletionQueueError> {
     554           14 :         let (flush_op, rx) = FlushOp::new();
     555           14 :         self.do_flush(&self.tx, ListWriterQueueMessage::Flush(flush_op), rx)
     556           14 :             .await
     557           14 :     }
     558              : 
     559              :     /// Issue a flush without waiting for it to complete.  This is useful on advisory flushes where
     560              :     /// the caller wants to avoid the risk of waiting for lots of enqueued work, such as on tenant
     561              :     /// detach where flushing is nice but not necessary.
     562              :     ///
     563              :     /// This function provides no guarantees of work being done.
     564            0 :     pub fn flush_advisory(&self) {
     565            0 :         let (flush_op, _) = FlushOp::new();
     566            0 : 
     567            0 :         // Transmit the flush message, ignoring any result (such as a closed channel during shutdown).
     568            0 :         drop(self.tx.send(ListWriterQueueMessage::FlushExecute(flush_op)));
     569            0 :     }
     570              : 
     571              :     // Wait until all previous deletions are executed
     572           10 :     pub(crate) async fn flush_execute(&self) -> Result<(), DeletionQueueError> {
     573           10 :         debug!("flush_execute: flushing to deletion lists...");
     574              :         // Flush any buffered work to deletion lists
     575           10 :         self.flush().await?;
     576              : 
     577              :         // Flush the backend into the executor of deletion lists
     578           10 :         let (flush_op, rx) = FlushOp::new();
     579           10 :         debug!("flush_execute: flushing backend...");
     580           10 :         self.do_flush(&self.tx, ListWriterQueueMessage::FlushExecute(flush_op), rx)
     581           10 :             .await?;
     582           10 :         debug!("flush_execute: finished flushing backend...");
     583              : 
     584              :         // Flush any immediate-mode deletions (the above backend flush will only flush
     585              :         // the executor if deletions had flowed through the backend)
     586           10 :         debug!("flush_execute: flushing execution...");
     587           10 :         self.flush_immediate().await?;
     588           10 :         debug!("flush_execute: finished flushing execution...");
     589           10 :         Ok(())
     590           10 :     }
     591              : 
     592              :     /// This interface bypasses the persistent deletion queue, and any validation
     593              :     /// that this pageserver is still elegible to execute the deletions.  It is for
     594              :     /// use in timeline deletions, where the control plane is telling us we may
     595              :     /// delete everything in the timeline.
     596              :     ///
     597              :     /// DO NOT USE THIS FROM GC OR COMPACTION CODE.  Use the regular `push_layers`.
     598            0 :     pub(crate) async fn push_immediate(
     599            0 :         &self,
     600            0 :         objects: Vec<RemotePath>,
     601            0 :     ) -> Result<(), DeletionQueueError> {
     602            0 :         metrics::DELETION_QUEUE
     603            0 :             .keys_submitted
     604            0 :             .inc_by(objects.len() as u64);
     605            0 :         self.executor_tx
     606            0 :             .send(DeleterMessage::Delete(objects))
     607            0 :             .await
     608            0 :             .map_err(|_| DeletionQueueError::ShuttingDown)
     609            0 :     }
     610              : 
     611              :     /// Companion to push_immediate.  When this returns Ok, all prior objects sent
     612              :     /// into push_immediate have been deleted from remote storage.
     613           10 :     pub(crate) async fn flush_immediate(&self) -> Result<(), DeletionQueueError> {
     614           10 :         let (flush_op, rx) = FlushOp::new();
     615           10 :         self.executor_tx
     616           10 :             .send(DeleterMessage::Flush(flush_op))
     617            0 :             .await
     618           10 :             .map_err(|_| DeletionQueueError::ShuttingDown)?;
     619              : 
     620           10 :         rx.await.map_err(|_| DeletionQueueError::ShuttingDown)
     621           10 :     }
     622              : }
     623              : 
     624              : impl DeletionQueue {
     625            8 :     pub fn new_client(&self) -> DeletionQueueClient {
     626            8 :         self.client.clone()
     627            8 :     }
     628              : 
     629              :     /// Caller may use the returned object to construct clients with new_client.
     630              :     /// Caller should tokio::spawn the background() members of the two worker objects returned:
     631              :     /// we don't spawn those inside new() so that the caller can use their runtime/spans of choice.
     632              :     ///
     633              :     /// If remote_storage is None, then the returned workers will also be None.
     634            8 :     pub fn new<C>(
     635            8 :         remote_storage: Option<GenericRemoteStorage>,
     636            8 :         control_plane_client: Option<C>,
     637            8 :         conf: &'static PageServerConf,
     638            8 :     ) -> (Self, Option<DeletionQueueWorkers<C>>)
     639            8 :     where
     640            8 :         C: ControlPlaneGenerationsApi + Send + Sync,
     641            8 :     {
     642            8 :         // Unbounded channel: enables non-async functions to submit deletions.  The actual length is
     643            8 :         // constrained by how promptly the ListWriter wakes up and drains it, which should be frequent
     644            8 :         // enough to avoid this taking pathologically large amount of memory.
     645            8 :         let (tx, rx) = tokio::sync::mpsc::unbounded_channel();
     646            8 : 
     647            8 :         // Shallow channel: it carries DeletionLists which each contain up to thousands of deletions
     648            8 :         let (backend_tx, backend_rx) = tokio::sync::mpsc::channel(16);
     649            8 : 
     650            8 :         // Shallow channel: it carries lists of paths, and we expect the main queueing to
     651            8 :         // happen in the backend (persistent), not in this queue.
     652            8 :         let (executor_tx, executor_rx) = tokio::sync::mpsc::channel(16);
     653            8 : 
     654            8 :         let lsn_table = Arc::new(std::sync::RwLock::new(VisibleLsnUpdates::new()));
     655            8 : 
     656            8 :         // The deletion queue has an independent cancellation token to
     657            8 :         // the general pageserver shutdown token, because it stays alive a bit
     658            8 :         // longer to flush after Tenants have all been torn down.
     659            8 :         let cancel = CancellationToken::new();
     660              : 
     661            8 :         let remote_storage = match remote_storage {
     662              :             None => {
     663            0 :                 return (
     664            0 :                     Self {
     665            0 :                         client: DeletionQueueClient {
     666            0 :                             tx,
     667            0 :                             executor_tx,
     668            0 :                             lsn_table: lsn_table.clone(),
     669            0 :                         },
     670            0 :                         cancel,
     671            0 :                     },
     672            0 :                     None,
     673            0 :                 )
     674              :             }
     675            8 :             Some(r) => r,
     676            8 :         };
     677            8 : 
     678            8 :         (
     679            8 :             Self {
     680            8 :                 client: DeletionQueueClient {
     681            8 :                     tx,
     682            8 :                     executor_tx: executor_tx.clone(),
     683            8 :                     lsn_table: lsn_table.clone(),
     684            8 :                 },
     685            8 :                 cancel: cancel.clone(),
     686            8 :             },
     687            8 :             Some(DeletionQueueWorkers {
     688            8 :                 frontend: ListWriter::new(conf, rx, backend_tx, cancel.clone()),
     689            8 :                 backend: Validator::new(
     690            8 :                     conf,
     691            8 :                     backend_rx,
     692            8 :                     executor_tx,
     693            8 :                     control_plane_client,
     694            8 :                     lsn_table.clone(),
     695            8 :                     cancel.clone(),
     696            8 :                 ),
     697            8 :                 executor: Deleter::new(remote_storage, executor_rx, cancel.clone()),
     698            8 :             }),
     699            8 :         )
     700            8 :     }
     701              : 
     702            0 :     pub async fn shutdown(&mut self, timeout: Duration) {
     703            0 :         match tokio::time::timeout(timeout, self.client.flush()).await {
     704              :             Ok(Ok(())) => {
     705            0 :                 tracing::info!("Deletion queue flushed successfully on shutdown")
     706              :             }
     707              :             Ok(Err(DeletionQueueError::ShuttingDown)) => {
     708              :                 // This is not harmful for correctness, but is unexpected: the deletion
     709              :                 // queue's workers should stay alive as long as there are any client handles instantiated.
     710            0 :                 tracing::warn!("Deletion queue stopped prematurely");
     711              :             }
     712            0 :             Err(_timeout) => {
     713            0 :                 tracing::warn!("Timed out flushing deletion queue on shutdown")
     714              :             }
     715              :         }
     716              : 
     717              :         // We only cancel _after_ flushing: otherwise we would be shutting down the
     718              :         // components that do the flush.
     719            0 :         self.cancel.cancel();
     720            0 :     }
     721              : }
     722              : 
     723              : #[cfg(test)]
     724              : mod test {
     725              :     use camino::Utf8Path;
     726              :     use hex_literal::hex;
     727              :     use pageserver_api::{shard::ShardIndex, upcall_api::ReAttachResponseTenant};
     728              :     use std::{io::ErrorKind, time::Duration};
     729              :     use tracing::info;
     730              : 
     731              :     use remote_storage::{RemoteStorageConfig, RemoteStorageKind};
     732              :     use tokio::task::JoinHandle;
     733              : 
     734              :     use crate::{
     735              :         control_plane_client::RetryForeverError,
     736              :         repository::Key,
     737              :         tenant::{harness::TenantHarness, storage_layer::DeltaLayerName},
     738              :     };
     739              : 
     740              :     use super::*;
     741              :     pub const TIMELINE_ID: TimelineId =
     742              :         TimelineId::from_array(hex!("11223344556677881122334455667788"));
     743              : 
     744              :     pub const EXAMPLE_LAYER_NAME: LayerName = LayerName::Delta(DeltaLayerName {
     745              :         key_range: Key::from_i128(0x0)..Key::from_i128(0xFFFFFFFFFFFFFFFF),
     746              :         lsn_range: Lsn(0x00000000016B59D8)..Lsn(0x00000000016B5A51),
     747              :     });
     748              : 
     749              :     // When you need a second layer in a test.
     750              :     pub const EXAMPLE_LAYER_NAME_ALT: LayerName = LayerName::Delta(DeltaLayerName {
     751              :         key_range: Key::from_i128(0x0)..Key::from_i128(0xFFFFFFFFFFFFFFFF),
     752              :         lsn_range: Lsn(0x00000000016B5A51)..Lsn(0x00000000016B5A61),
     753              :     });
     754              : 
     755              :     struct TestSetup {
     756              :         harness: TenantHarness,
     757              :         remote_fs_dir: Utf8PathBuf,
     758              :         storage: GenericRemoteStorage,
     759              :         mock_control_plane: MockControlPlane,
     760              :         deletion_queue: DeletionQueue,
     761              :         worker_join: JoinHandle<()>,
     762              :     }
     763              : 
     764              :     impl TestSetup {
     765              :         /// Simulate a pageserver restart by destroying and recreating the deletion queue
     766            2 :         async fn restart(&mut self) {
     767            2 :             let (deletion_queue, workers) = DeletionQueue::new(
     768            2 :                 Some(self.storage.clone()),
     769            2 :                 Some(self.mock_control_plane.clone()),
     770            2 :                 self.harness.conf,
     771            2 :             );
     772            2 : 
     773            2 :             tracing::debug!("Spawning worker for new queue queue");
     774            2 :             let worker_join = workers
     775            2 :                 .unwrap()
     776            2 :                 .spawn_with(&tokio::runtime::Handle::current());
     777            2 : 
     778            2 :             let old_worker_join = std::mem::replace(&mut self.worker_join, worker_join);
     779            2 :             let old_deletion_queue = std::mem::replace(&mut self.deletion_queue, deletion_queue);
     780            2 : 
     781            2 :             tracing::debug!("Joining worker from previous queue");
     782            2 :             old_deletion_queue.cancel.cancel();
     783            2 :             old_worker_join
     784            2 :                 .await
     785            2 :                 .expect("Failed to join workers for previous deletion queue");
     786            2 :         }
     787              : 
     788            6 :         fn set_latest_generation(&self, gen: Generation) {
     789            6 :             let tenant_shard_id = self.harness.tenant_shard_id;
     790            6 :             self.mock_control_plane
     791            6 :                 .latest_generation
     792            6 :                 .lock()
     793            6 :                 .unwrap()
     794            6 :                 .insert(tenant_shard_id, gen);
     795            6 :         }
     796              : 
     797              :         /// Returns remote layer file name, suitable for use in assert_remote_files
     798            6 :         fn write_remote_layer(
     799            6 :             &self,
     800            6 :             file_name: LayerName,
     801            6 :             gen: Generation,
     802            6 :         ) -> anyhow::Result<String> {
     803            6 :             let tenant_shard_id = self.harness.tenant_shard_id;
     804            6 :             let relative_remote_path = remote_timeline_path(&tenant_shard_id, &TIMELINE_ID);
     805            6 :             let remote_timeline_path = self.remote_fs_dir.join(relative_remote_path.get_path());
     806            6 :             std::fs::create_dir_all(&remote_timeline_path)?;
     807            6 :             let remote_layer_file_name = format!("{}{}", file_name, gen.get_suffix());
     808            6 : 
     809            6 :             let content: Vec<u8> = format!("placeholder contents of {file_name}").into();
     810            6 : 
     811            6 :             std::fs::write(
     812            6 :                 remote_timeline_path.join(remote_layer_file_name.clone()),
     813            6 :                 content,
     814            6 :             )?;
     815              : 
     816            6 :             Ok(remote_layer_file_name)
     817            6 :         }
     818              :     }
     819              : 
     820              :     #[derive(Debug, Clone)]
     821              :     struct MockControlPlane {
     822              :         pub latest_generation: std::sync::Arc<std::sync::Mutex<HashMap<TenantShardId, Generation>>>,
     823              :     }
     824              : 
     825              :     impl MockControlPlane {
     826            6 :         fn new() -> Self {
     827            6 :             Self {
     828            6 :                 latest_generation: Arc::default(),
     829            6 :             }
     830            6 :         }
     831              :     }
     832              : 
     833              :     impl ControlPlaneGenerationsApi for MockControlPlane {
     834            0 :         async fn re_attach(
     835            0 :             &self,
     836            0 :             _conf: &PageServerConf,
     837            0 :         ) -> Result<HashMap<TenantShardId, ReAttachResponseTenant>, RetryForeverError> {
     838            0 :             unimplemented!()
     839              :         }
     840              : 
     841            8 :         async fn validate(
     842            8 :             &self,
     843            8 :             tenants: Vec<(TenantShardId, Generation)>,
     844            8 :         ) -> Result<HashMap<TenantShardId, bool>, RetryForeverError> {
     845            8 :             let mut result = HashMap::new();
     846            8 : 
     847            8 :             let latest_generation = self.latest_generation.lock().unwrap();
     848              : 
     849           16 :             for (tenant_shard_id, generation) in tenants {
     850            8 :                 if let Some(latest) = latest_generation.get(&tenant_shard_id) {
     851            8 :                     result.insert(tenant_shard_id, *latest == generation);
     852            8 :                 }
     853              :             }
     854              : 
     855            8 :             Ok(result)
     856            8 :         }
     857              :     }
     858              : 
     859            6 :     fn setup(test_name: &str) -> anyhow::Result<TestSetup> {
     860            6 :         let test_name = Box::leak(Box::new(format!("deletion_queue__{test_name}")));
     861            6 :         let harness = TenantHarness::create(test_name)?;
     862              : 
     863              :         // We do not load() the harness: we only need its config and remote_storage
     864              : 
     865              :         // Set up a GenericRemoteStorage targetting a directory
     866            6 :         let remote_fs_dir = harness.conf.workdir.join("remote_fs");
     867            6 :         std::fs::create_dir_all(remote_fs_dir)?;
     868            6 :         let remote_fs_dir = harness.conf.workdir.join("remote_fs").canonicalize_utf8()?;
     869            6 :         let storage_config = RemoteStorageConfig {
     870            6 :             storage: RemoteStorageKind::LocalFs(remote_fs_dir.clone()),
     871            6 :             timeout: RemoteStorageConfig::DEFAULT_TIMEOUT,
     872            6 :         };
     873            6 :         let storage = GenericRemoteStorage::from_config(&storage_config).unwrap();
     874            6 : 
     875            6 :         let mock_control_plane = MockControlPlane::new();
     876            6 : 
     877            6 :         let (deletion_queue, worker) = DeletionQueue::new(
     878            6 :             Some(storage.clone()),
     879            6 :             Some(mock_control_plane.clone()),
     880            6 :             harness.conf,
     881            6 :         );
     882            6 : 
     883            6 :         let worker = worker.unwrap();
     884            6 :         let worker_join = worker.spawn_with(&tokio::runtime::Handle::current());
     885            6 : 
     886            6 :         Ok(TestSetup {
     887            6 :             harness,
     888            6 :             remote_fs_dir,
     889            6 :             storage,
     890            6 :             mock_control_plane,
     891            6 :             deletion_queue,
     892            6 :             worker_join,
     893            6 :         })
     894            6 :     }
     895              : 
     896              :     // TODO: put this in a common location so that we can share with remote_timeline_client's tests
     897           18 :     fn assert_remote_files(expected: &[&str], remote_path: &Utf8Path) {
     898           18 :         let mut expected: Vec<String> = expected.iter().map(|x| String::from(*x)).collect();
     899           18 :         expected.sort();
     900           18 : 
     901           18 :         let mut found: Vec<String> = Vec::new();
     902           18 :         let dir = match std::fs::read_dir(remote_path) {
     903           18 :             Ok(d) => d,
     904            0 :             Err(e) => {
     905            0 :                 if e.kind() == ErrorKind::NotFound {
     906            0 :                     if expected.is_empty() {
     907              :                         // We are asserting prefix is empty: it is expected that the dir is missing
     908            0 :                         return;
     909              :                     } else {
     910            0 :                         assert_eq!(expected, Vec::<String>::new());
     911            0 :                         unreachable!();
     912              :                     }
     913              :                 } else {
     914            0 :                     panic!("Unexpected error listing {remote_path}: {e}");
     915              :                 }
     916              :             }
     917              :         };
     918              : 
     919           18 :         for entry in dir.flatten() {
     920           16 :             let entry_name = entry.file_name();
     921           16 :             let fname = entry_name.to_str().unwrap();
     922           16 :             found.push(String::from(fname));
     923           16 :         }
     924           18 :         found.sort();
     925           18 : 
     926           18 :         assert_eq!(expected, found);
     927           18 :     }
     928              : 
     929           10 :     fn assert_local_files(expected: &[&str], directory: &Utf8Path) {
     930           10 :         let dir = match std::fs::read_dir(directory) {
     931            8 :             Ok(d) => d,
     932              :             Err(_) => {
     933            2 :                 assert_eq!(expected, &Vec::<String>::new());
     934            2 :                 return;
     935              :             }
     936              :         };
     937            8 :         let mut found = Vec::new();
     938           18 :         for dentry in dir {
     939           10 :             let dentry = dentry.unwrap();
     940           10 :             let file_name = dentry.file_name();
     941           10 :             let file_name_str = file_name.to_string_lossy();
     942           10 :             found.push(file_name_str.to_string());
     943           10 :         }
     944            8 :         found.sort();
     945            8 :         assert_eq!(expected, found);
     946           10 :     }
     947              : 
     948              :     #[tokio::test]
     949            2 :     async fn deletion_queue_smoke() -> anyhow::Result<()> {
     950            2 :         // Basic test that the deletion queue processes the deletions we pass into it
     951            2 :         let ctx = setup("deletion_queue_smoke").expect("Failed test setup");
     952            2 :         let client = ctx.deletion_queue.new_client();
     953            2 :         client.recover(HashMap::new())?;
     954            2 : 
     955            2 :         let layer_file_name_1: LayerName = "000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__00000000016B59D8-00000000016B5A51".parse().unwrap();
     956            2 :         let tenant_shard_id = ctx.harness.tenant_shard_id;
     957            2 : 
     958            2 :         let content: Vec<u8> = "victim1 contents".into();
     959            2 :         let relative_remote_path = remote_timeline_path(&tenant_shard_id, &TIMELINE_ID);
     960            2 :         let remote_timeline_path = ctx.remote_fs_dir.join(relative_remote_path.get_path());
     961            2 :         let deletion_prefix = ctx.harness.conf.deletion_prefix();
     962            2 : 
     963            2 :         // Exercise the distinction between the generation of the layers
     964            2 :         // we delete, and the generation of the running Tenant.
     965            2 :         let layer_generation = Generation::new(0xdeadbeef);
     966            2 :         let now_generation = Generation::new(0xfeedbeef);
     967            2 :         let layer_metadata =
     968            2 :             LayerFileMetadata::new(0xf00, layer_generation, ShardIndex::unsharded());
     969            2 : 
     970            2 :         let remote_layer_file_name_1 =
     971            2 :             format!("{}{}", layer_file_name_1, layer_generation.get_suffix());
     972            2 : 
     973            2 :         // Set mock control plane state to valid for our generation
     974            2 :         ctx.set_latest_generation(now_generation);
     975            2 : 
     976            2 :         // Inject a victim file to remote storage
     977            2 :         info!("Writing");
     978            2 :         std::fs::create_dir_all(&remote_timeline_path)?;
     979            2 :         std::fs::write(
     980            2 :             remote_timeline_path.join(remote_layer_file_name_1.clone()),
     981            2 :             content,
     982            2 :         )?;
     983            2 :         assert_remote_files(&[&remote_layer_file_name_1], &remote_timeline_path);
     984            2 : 
     985            2 :         // File should still be there after we push it to the queue (we haven't pushed enough to flush anything)
     986            2 :         info!("Pushing");
     987            2 :         client
     988            2 :             .push_layers(
     989            2 :                 tenant_shard_id,
     990            2 :                 TIMELINE_ID,
     991            2 :                 now_generation,
     992            2 :                 [(layer_file_name_1.clone(), layer_metadata)].to_vec(),
     993            2 :             )
     994            2 :             .await?;
     995            2 :         assert_remote_files(&[&remote_layer_file_name_1], &remote_timeline_path);
     996            2 : 
     997            2 :         assert_local_files(&[], &deletion_prefix);
     998            2 : 
     999            2 :         // File should still be there after we write a deletion list (we haven't pushed enough to execute anything)
    1000            2 :         info!("Flushing");
    1001            2 :         client.flush().await?;
    1002            2 :         assert_remote_files(&[&remote_layer_file_name_1], &remote_timeline_path);
    1003            2 :         assert_local_files(&["0000000000000001-01.list"], &deletion_prefix);
    1004            2 : 
    1005            2 :         // File should go away when we execute
    1006            2 :         info!("Flush-executing");
    1007            6 :         client.flush_execute().await?;
    1008            2 :         assert_remote_files(&[], &remote_timeline_path);
    1009            2 :         assert_local_files(&["header-01"], &deletion_prefix);
    1010            2 : 
    1011            2 :         // Flushing on an empty queue should succeed immediately, and not write any lists
    1012            2 :         info!("Flush-executing on empty");
    1013            6 :         client.flush_execute().await?;
    1014            2 :         assert_local_files(&["header-01"], &deletion_prefix);
    1015            2 : 
    1016            2 :         Ok(())
    1017            2 :     }
    1018              : 
    1019              :     #[tokio::test]
    1020            2 :     async fn deletion_queue_validation() -> anyhow::Result<()> {
    1021            2 :         let ctx = setup("deletion_queue_validation").expect("Failed test setup");
    1022            2 :         let client = ctx.deletion_queue.new_client();
    1023            2 :         client.recover(HashMap::new())?;
    1024            2 : 
    1025            2 :         // Generation that the control plane thinks is current
    1026            2 :         let latest_generation = Generation::new(0xdeadbeef);
    1027            2 :         // Generation that our DeletionQueue thinks the tenant is running with
    1028            2 :         let stale_generation = latest_generation.previous();
    1029            2 :         // Generation that our example layer file was written with
    1030            2 :         let layer_generation = stale_generation.previous();
    1031            2 :         let layer_metadata =
    1032            2 :             LayerFileMetadata::new(0xf00, layer_generation, ShardIndex::unsharded());
    1033            2 : 
    1034            2 :         ctx.set_latest_generation(latest_generation);
    1035            2 : 
    1036            2 :         let tenant_shard_id = ctx.harness.tenant_shard_id;
    1037            2 :         let relative_remote_path = remote_timeline_path(&tenant_shard_id, &TIMELINE_ID);
    1038            2 :         let remote_timeline_path = ctx.remote_fs_dir.join(relative_remote_path.get_path());
    1039            2 : 
    1040            2 :         // Initial state: a remote layer exists
    1041            2 :         let remote_layer_name = ctx.write_remote_layer(EXAMPLE_LAYER_NAME, layer_generation)?;
    1042            2 :         assert_remote_files(&[&remote_layer_name], &remote_timeline_path);
    1043            2 : 
    1044            2 :         tracing::debug!("Pushing...");
    1045            2 :         client
    1046            2 :             .push_layers(
    1047            2 :                 tenant_shard_id,
    1048            2 :                 TIMELINE_ID,
    1049            2 :                 stale_generation,
    1050            2 :                 [(EXAMPLE_LAYER_NAME.clone(), layer_metadata.clone())].to_vec(),
    1051            2 :             )
    1052            2 :             .await?;
    1053            2 : 
    1054            2 :         // We enqueued the operation in a stale generation: it should have failed validation
    1055            2 :         tracing::debug!("Flushing...");
    1056            6 :         tokio::time::timeout(Duration::from_secs(5), client.flush_execute()).await??;
    1057            2 :         assert_remote_files(&[&remote_layer_name], &remote_timeline_path);
    1058            2 : 
    1059            2 :         tracing::debug!("Pushing...");
    1060            2 :         client
    1061            2 :             .push_layers(
    1062            2 :                 tenant_shard_id,
    1063            2 :                 TIMELINE_ID,
    1064            2 :                 latest_generation,
    1065            2 :                 [(EXAMPLE_LAYER_NAME.clone(), layer_metadata.clone())].to_vec(),
    1066            2 :             )
    1067            2 :             .await?;
    1068            2 : 
    1069            2 :         // We enqueued the operation in a fresh generation: it should have passed validation
    1070            2 :         tracing::debug!("Flushing...");
    1071            6 :         tokio::time::timeout(Duration::from_secs(5), client.flush_execute()).await??;
    1072            2 :         assert_remote_files(&[], &remote_timeline_path);
    1073            2 : 
    1074            2 :         Ok(())
    1075            2 :     }
    1076              : 
    1077              :     #[tokio::test]
    1078            2 :     async fn deletion_queue_recovery() -> anyhow::Result<()> {
    1079            2 :         // Basic test that the deletion queue processes the deletions we pass into it
    1080            2 :         let mut ctx = setup("deletion_queue_recovery").expect("Failed test setup");
    1081            2 :         let client = ctx.deletion_queue.new_client();
    1082            2 :         client.recover(HashMap::new())?;
    1083            2 : 
    1084            2 :         let tenant_shard_id = ctx.harness.tenant_shard_id;
    1085            2 : 
    1086            2 :         let relative_remote_path = remote_timeline_path(&tenant_shard_id, &TIMELINE_ID);
    1087            2 :         let remote_timeline_path = ctx.remote_fs_dir.join(relative_remote_path.get_path());
    1088            2 :         let deletion_prefix = ctx.harness.conf.deletion_prefix();
    1089            2 : 
    1090            2 :         let layer_generation = Generation::new(0xdeadbeef);
    1091            2 :         let now_generation = Generation::new(0xfeedbeef);
    1092            2 :         let layer_metadata =
    1093            2 :             LayerFileMetadata::new(0xf00, layer_generation, ShardIndex::unsharded());
    1094            2 : 
    1095            2 :         // Inject a deletion in the generation before generation_now: after restart,
    1096            2 :         // this deletion should _not_ get executed (only the immediately previous
    1097            2 :         // generation gets that treatment)
    1098            2 :         let remote_layer_file_name_historical =
    1099            2 :             ctx.write_remote_layer(EXAMPLE_LAYER_NAME, layer_generation)?;
    1100            2 :         client
    1101            2 :             .push_layers(
    1102            2 :                 tenant_shard_id,
    1103            2 :                 TIMELINE_ID,
    1104            2 :                 now_generation.previous(),
    1105            2 :                 [(EXAMPLE_LAYER_NAME.clone(), layer_metadata.clone())].to_vec(),
    1106            2 :             )
    1107            2 :             .await?;
    1108            2 : 
    1109            2 :         // Inject a deletion in the generation before generation_now: after restart,
    1110            2 :         // this deletion should get executed, because we execute deletions in the
    1111            2 :         // immediately previous generation on the same node.
    1112            2 :         let remote_layer_file_name_previous =
    1113            2 :             ctx.write_remote_layer(EXAMPLE_LAYER_NAME_ALT, layer_generation)?;
    1114            2 :         client
    1115            2 :             .push_layers(
    1116            2 :                 tenant_shard_id,
    1117            2 :                 TIMELINE_ID,
    1118            2 :                 now_generation,
    1119            2 :                 [(EXAMPLE_LAYER_NAME_ALT.clone(), layer_metadata.clone())].to_vec(),
    1120            2 :             )
    1121            2 :             .await?;
    1122            2 : 
    1123            2 :         client.flush().await?;
    1124            2 :         assert_remote_files(
    1125            2 :             &[
    1126            2 :                 &remote_layer_file_name_historical,
    1127            2 :                 &remote_layer_file_name_previous,
    1128            2 :             ],
    1129            2 :             &remote_timeline_path,
    1130            2 :         );
    1131            2 : 
    1132            2 :         // Different generatinos for the same tenant will cause two separate
    1133            2 :         // deletion lists to be emitted.
    1134            2 :         assert_local_files(
    1135            2 :             &["0000000000000001-01.list", "0000000000000002-01.list"],
    1136            2 :             &deletion_prefix,
    1137            2 :         );
    1138            2 : 
    1139            2 :         // Simulate a node restart: the latest generation advances
    1140            2 :         let now_generation = now_generation.next();
    1141            2 :         ctx.set_latest_generation(now_generation);
    1142            2 : 
    1143            2 :         // Restart the deletion queue
    1144            2 :         drop(client);
    1145            2 :         ctx.restart().await;
    1146            2 :         let client = ctx.deletion_queue.new_client();
    1147            2 :         client.recover(HashMap::from([(tenant_shard_id, now_generation)]))?;
    1148            2 : 
    1149            2 :         info!("Flush-executing");
    1150            6 :         client.flush_execute().await?;
    1151            2 :         // The deletion from immediately prior generation was executed, the one from
    1152            2 :         // an older generation was not.
    1153            2 :         assert_remote_files(&[&remote_layer_file_name_historical], &remote_timeline_path);
    1154            2 :         Ok(())
    1155            2 :     }
    1156              : }
    1157              : 
    1158              : /// A lightweight queue which can issue ordinary DeletionQueueClient objects, but doesn't do any persistence
    1159              : /// or coalescing, and doesn't actually execute any deletions unless you call pump() to kick it.
    1160              : #[cfg(test)]
    1161              : pub(crate) mod mock {
    1162              :     use tracing::info;
    1163              : 
    1164              :     use super::*;
    1165              :     use std::sync::atomic::{AtomicUsize, Ordering};
    1166              : 
    1167              :     pub struct ConsumerState {
    1168              :         rx: tokio::sync::mpsc::UnboundedReceiver<ListWriterQueueMessage>,
    1169              :         executor_rx: tokio::sync::mpsc::Receiver<DeleterMessage>,
    1170              :         cancel: CancellationToken,
    1171              :     }
    1172              : 
    1173              :     impl ConsumerState {
    1174            2 :         async fn consume(&mut self, remote_storage: &GenericRemoteStorage) -> usize {
    1175            2 :             let mut executed = 0;
    1176            2 : 
    1177            2 :             info!("Executing all pending deletions");
    1178              : 
    1179              :             // Transform all executor messages to generic frontend messages
    1180            2 :             while let Ok(msg) = self.executor_rx.try_recv() {
    1181            0 :                 match msg {
    1182            0 :                     DeleterMessage::Delete(objects) => {
    1183            0 :                         for path in objects {
    1184            0 :                             match remote_storage.delete(&path, &self.cancel).await {
    1185              :                                 Ok(_) => {
    1186            0 :                                     debug!("Deleted {path}");
    1187              :                                 }
    1188            0 :                                 Err(e) => {
    1189            0 :                                     error!("Failed to delete {path}, leaking object! ({e})");
    1190              :                                 }
    1191              :                             }
    1192            0 :                             executed += 1;
    1193              :                         }
    1194              :                     }
    1195            0 :                     DeleterMessage::Flush(flush_op) => {
    1196            0 :                         flush_op.notify();
    1197            0 :                     }
    1198              :                 }
    1199              :             }
    1200              : 
    1201            4 :             while let Ok(msg) = self.rx.try_recv() {
    1202            2 :                 match msg {
    1203            2 :                     ListWriterQueueMessage::Delete(op) => {
    1204            2 :                         let mut objects = op.objects;
    1205            4 :                         for (layer, meta) in op.layers {
    1206            2 :                             objects.push(remote_layer_path(
    1207            2 :                                 &op.tenant_shard_id.tenant_id,
    1208            2 :                                 &op.timeline_id,
    1209            2 :                                 meta.shard,
    1210            2 :                                 &layer,
    1211            2 :                                 meta.generation,
    1212            2 :                             ));
    1213            2 :                         }
    1214              : 
    1215            4 :                         for path in objects {
    1216            2 :                             info!("Executing deletion {path}");
    1217            2 :                             match remote_storage.delete(&path, &self.cancel).await {
    1218              :                                 Ok(_) => {
    1219            2 :                                     debug!("Deleted {path}");
    1220              :                                 }
    1221            0 :                                 Err(e) => {
    1222            0 :                                     error!("Failed to delete {path}, leaking object! ({e})");
    1223              :                                 }
    1224              :                             }
    1225            2 :                             executed += 1;
    1226              :                         }
    1227              :                     }
    1228            0 :                     ListWriterQueueMessage::Flush(op) => {
    1229            0 :                         op.notify();
    1230            0 :                     }
    1231            0 :                     ListWriterQueueMessage::FlushExecute(op) => {
    1232            0 :                         // We have already executed all prior deletions because mock does them inline
    1233            0 :                         op.notify();
    1234            0 :                     }
    1235            0 :                     ListWriterQueueMessage::Recover(_) => {
    1236            0 :                         // no-op in mock
    1237            0 :                     }
    1238              :                 }
    1239            2 :                 info!("All pending deletions have been executed");
    1240              :             }
    1241              : 
    1242            2 :             executed
    1243            2 :         }
    1244              :     }
    1245              : 
    1246              :     pub struct MockDeletionQueue {
    1247              :         tx: tokio::sync::mpsc::UnboundedSender<ListWriterQueueMessage>,
    1248              :         executor_tx: tokio::sync::mpsc::Sender<DeleterMessage>,
    1249              :         executed: Arc<AtomicUsize>,
    1250              :         remote_storage: Option<GenericRemoteStorage>,
    1251              :         consumer: std::sync::Mutex<ConsumerState>,
    1252              :         lsn_table: Arc<std::sync::RwLock<VisibleLsnUpdates>>,
    1253              :     }
    1254              : 
    1255              :     impl MockDeletionQueue {
    1256          118 :         pub fn new(remote_storage: Option<GenericRemoteStorage>) -> Self {
    1257          118 :             let (tx, rx) = tokio::sync::mpsc::unbounded_channel();
    1258          118 :             let (executor_tx, executor_rx) = tokio::sync::mpsc::channel(16384);
    1259          118 : 
    1260          118 :             let executed = Arc::new(AtomicUsize::new(0));
    1261          118 : 
    1262          118 :             Self {
    1263          118 :                 tx,
    1264          118 :                 executor_tx,
    1265          118 :                 executed,
    1266          118 :                 remote_storage,
    1267          118 :                 consumer: std::sync::Mutex::new(ConsumerState {
    1268          118 :                     rx,
    1269          118 :                     executor_rx,
    1270          118 :                     cancel: CancellationToken::new(),
    1271          118 :                 }),
    1272          118 :                 lsn_table: Arc::new(std::sync::RwLock::new(VisibleLsnUpdates::new())),
    1273          118 :             }
    1274          118 :         }
    1275              : 
    1276              :         #[allow(clippy::await_holding_lock)]
    1277            2 :         pub async fn pump(&self) {
    1278            2 :             if let Some(remote_storage) = &self.remote_storage {
    1279              :                 // Permit holding mutex across await, because this is only ever
    1280              :                 // called once at a time in tests.
    1281            2 :                 let mut locked = self.consumer.lock().unwrap();
    1282            2 :                 let count = locked.consume(remote_storage).await;
    1283            2 :                 self.executed.fetch_add(count, Ordering::Relaxed);
    1284            0 :             }
    1285            2 :         }
    1286              : 
    1287          128 :         pub(crate) fn new_client(&self) -> DeletionQueueClient {
    1288          128 :             DeletionQueueClient {
    1289          128 :                 tx: self.tx.clone(),
    1290          128 :                 executor_tx: self.executor_tx.clone(),
    1291          128 :                 lsn_table: self.lsn_table.clone(),
    1292          128 :             }
    1293          128 :         }
    1294              :     }
    1295              : 
    1296              :     /// Test round-trip serialization/deserialization, and test stability of the format
    1297              :     /// vs. a static expected string for the serialized version.
    1298              :     #[test]
    1299            2 :     fn deletion_list_serialization() -> anyhow::Result<()> {
    1300            2 :         let tenant_id = "ad6c1a56f5680419d3a16ff55d97ec3c"
    1301            2 :             .to_string()
    1302            2 :             .parse::<TenantShardId>()?;
    1303            2 :         let timeline_id = "be322c834ed9e709e63b5c9698691910"
    1304            2 :             .to_string()
    1305            2 :             .parse::<TimelineId>()?;
    1306            2 :         let generation = Generation::new(123);
    1307              : 
    1308            2 :         let object =
    1309            2 :             RemotePath::from_string(&format!("tenants/{tenant_id}/timelines/{timeline_id}/foo"))?;
    1310            2 :         let mut objects = [object].to_vec();
    1311            2 : 
    1312            2 :         let mut example = DeletionList::new(1);
    1313            2 :         example.push(&tenant_id, &timeline_id, generation, &mut objects);
    1314              : 
    1315            2 :         let encoded = serde_json::to_string(&example)?;
    1316              : 
    1317            2 :         let expected = "{\"version\":1,\"sequence\":1,\"tenants\":{\"ad6c1a56f5680419d3a16ff55d97ec3c\":{\"timelines\":{\"be322c834ed9e709e63b5c9698691910\":[\"foo\"]},\"generation\":123}},\"size\":1}".to_string();
    1318            2 :         assert_eq!(encoded, expected);
    1319              : 
    1320            2 :         let decoded = serde_json::from_str::<DeletionList>(&encoded)?;
    1321            2 :         assert_eq!(example, decoded);
    1322              : 
    1323            2 :         Ok(())
    1324            2 :     }
    1325              : }
        

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