feat: cache processed tombstones (#4030)

* test: allow to mock time in `iox_test`

* feat: cache processed tombstones

For #3974.

* refactor: introduce `TTL_NOT_PROCESSED`

iox_tests/src/util.rs

@@ -24,7 +24,7 @@ pub struct TestCatalog {
     pub catalog: Arc<dyn Catalog>,
     pub metric_registry: Arc<metric::Registry>,
     pub object_store: Arc<ObjectStore>,
-    pub time_provider: Arc<dyn TimeProvider>,
+    pub time_provider: Arc<MockProvider>,
     pub exec: Arc<Executor>,
 }
 
@@ -61,9 +61,18 @@ impl TestCatalog {
         Arc::clone(&self.object_store)
     }
 
+    /// Return the mockable version of the catalog's time provider.
+    ///
+    /// If you need a generic time provider, use [`time_provider`](Self::time_provider) instead.
+    pub fn mock_time_provider(&self) -> &MockProvider {
+        self.time_provider.as_ref()
+    }
+
     /// Return the catalog's time provider
+    ///
+    /// If you need to mock the time, use [`mock_time_provider`](Self::mock_time_provider) instead.
     pub fn time_provider(&self) -> Arc<dyn TimeProvider> {
-        Arc::clone(&self.time_provider)
+        Arc::clone(&self.time_provider) as _
     }
 
     /// Return the catalog's executor

querier/src/cache/mod.rs

@@ -1,11 +1,16 @@
 use backoff::BackoffConfig;
 use iox_catalog::interface::Catalog;
 use std::sync::Arc;
+use time::TimeProvider;
 
-use self::{namespace::NamespaceCache, partition::PartitionCache, table::TableCache};
+use self::{
+    namespace::NamespaceCache, partition::PartitionCache,
+    processed_tombstones::ProcessedTombstonesCache, table::TableCache,
+};
 
 pub mod namespace;
 pub mod partition;
+pub mod processed_tombstones;
 pub mod table;
 
 #[cfg(test)]
@@ -25,22 +30,28 @@ pub struct CatalogCache {
 
     /// Namespace cache.
     namespace_cache: NamespaceCache,
+
+    /// Processed tombstone cache.
+    processed_tombstones: ProcessedTombstonesCache,
 }
 
 impl CatalogCache {
     /// Create empty cache.
-    pub fn new(catalog: Arc<dyn Catalog>) -> Self {
+    pub fn new(catalog: Arc<dyn Catalog>, time_provider: Arc<dyn TimeProvider>) -> Self {
         let backoff_config = BackoffConfig::default();
 
         let namespace_cache = NamespaceCache::new(Arc::clone(&catalog), backoff_config.clone());
         let table_cache = TableCache::new(Arc::clone(&catalog), backoff_config.clone());
-        let partition_cache = PartitionCache::new(Arc::clone(&catalog), backoff_config);
+        let partition_cache = PartitionCache::new(Arc::clone(&catalog), backoff_config.clone());
+        let processed_tombstones =
+            ProcessedTombstonesCache::new(Arc::clone(&catalog), backoff_config, time_provider);
 
         Self {
             catalog,
             partition_cache,
             table_cache,
             namespace_cache,
+            processed_tombstones,
         }
     }
 
@@ -63,4 +74,9 @@ impl CatalogCache {
     pub fn partition(&self) -> &PartitionCache {
         &self.partition_cache
     }
+
+    /// Processed tombstone cache.
+    pub fn processed_tombstones(&self) -> &ProcessedTombstonesCache {
+        &self.processed_tombstones
+    }
 }

querier/src/cache/processed_tombstones.rs

@@ -0,0 +1,162 @@
+use std::{collections::HashMap, sync::Arc, time::Duration};
+
+use backoff::{Backoff, BackoffConfig};
+use data_types2::{ParquetFileId, TombstoneId};
+use iox_catalog::interface::Catalog;
+use time::TimeProvider;
+
+use crate::cache_system::{
+    backend::ttl::{TtlBackend, TtlProvider},
+    driver::Cache,
+    loader::FunctionLoader,
+};
+
+/// Duration to keep "tombstone is NOT processed yet".
+///
+/// Marking tombstones as processed is a mere optimization, so we can keep this cache entry for a while.
+pub const TTL_NOT_PROCESSED: Duration = Duration::from_secs(100);
+
+/// Cache for processed tombstones.
+#[derive(Debug)]
+pub struct ProcessedTombstonesCache {
+    cache: Cache<(ParquetFileId, TombstoneId), bool>,
+}
+
+impl ProcessedTombstonesCache {
+    /// Create new empty cache.
+    pub fn new(
+        catalog: Arc<dyn Catalog>,
+        backoff_config: BackoffConfig,
+        time_provider: Arc<dyn TimeProvider>,
+    ) -> Self {
+        let loader = Arc::new(FunctionLoader::new(
+            move |(parquet_file_id, tombstone_id)| {
+                let catalog = Arc::clone(&catalog);
+                let backoff_config = backoff_config.clone();
+
+                async move {
+                    Backoff::new(&backoff_config)
+                        .retry_all_errors("processed tombstone exists", || async {
+                            catalog
+                                .repositories()
+                                .await
+                                .processed_tombstones()
+                                .exist(parquet_file_id, tombstone_id)
+                                .await
+                        })
+                        .await
+                        .expect("retry forever")
+                }
+            },
+        ));
+
+        let backend = Box::new(HashMap::new());
+        let backend = Box::new(TtlBackend::new(
+            backend,
+            Arc::new(KeepExistsForever {}),
+            time_provider,
+        ));
+
+        Self {
+            cache: Cache::new(loader, backend),
+        }
+    }
+
+    /// Check if the specified tombstone is mark as "processed" for the given parquet file.
+    pub async fn exists(&self, parquet_file_id: ParquetFileId, tombstone_id: TombstoneId) -> bool {
+        self.cache.get((parquet_file_id, tombstone_id)).await
+    }
+}
+
+#[derive(Debug)]
+struct KeepExistsForever;
+
+impl TtlProvider for KeepExistsForever {
+    type K = (ParquetFileId, TombstoneId);
+    type V = bool;
+
+    fn expires_in(&self, _k: &Self::K, v: &Self::V) -> Option<Duration> {
+        if *v {
+            // keep forever
+            None
+        } else {
+            // marking tombstones as processed is a mere optimization, so we can keep this cache entry for a while
+            Some(TTL_NOT_PROCESSED)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use iox_tests::util::TestCatalog;
+    use time::{MockProvider, Time};
+
+    use crate::cache::test_util::assert_histogram_metric_count;
+
+    use super::*;
+
+    #[tokio::test]
+    async fn test() {
+        let catalog = TestCatalog::new();
+
+        let ns = catalog.create_namespace("ns").await;
+        let table = ns.create_table("table").await;
+        let sequencer = ns.create_sequencer(1).await;
+        let partition = table.with_sequencer(&sequencer).create_partition("k").await;
+
+        let file1 = partition.create_parquet_file("table foo=1 11").await;
+        let file2 = partition.create_parquet_file("table foo=1 11").await;
+        let ts1 = table
+            .with_sequencer(&sequencer)
+            .create_tombstone(1, 1, 10, "foo=1")
+            .await;
+        let ts2 = table
+            .with_sequencer(&sequencer)
+            .create_tombstone(2, 1, 10, "foo=1")
+            .await;
+
+        ts1.mark_processed(&file1).await;
+
+        let time_provider = Arc::new(MockProvider::new(Time::from_timestamp_nanos(0)));
+        let cache = ProcessedTombstonesCache::new(
+            catalog.catalog(),
+            BackoffConfig::default(),
+            Arc::clone(&time_provider) as _,
+        );
+
+        assert!(cache.exists(file1.parquet_file.id, ts1.tombstone.id).await);
+        assert!(!cache.exists(file1.parquet_file.id, ts2.tombstone.id).await);
+        assert!(!cache.exists(file2.parquet_file.id, ts1.tombstone.id).await);
+        assert!(!cache.exists(file2.parquet_file.id, ts2.tombstone.id).await);
+
+        assert_histogram_metric_count(&catalog.metric_registry, "processed_tombstone_exist", 4);
+
+        ts2.mark_processed(&file2).await;
+
+        // values are cached for a while
+        assert!(TTL_NOT_PROCESSED > Duration::from_millis(1));
+        time_provider.inc(TTL_NOT_PROCESSED - Duration::from_millis(1));
+        assert!(!cache.exists(file2.parquet_file.id, ts2.tombstone.id).await);
+        assert_histogram_metric_count(&catalog.metric_registry, "processed_tombstone_exist", 4);
+
+        time_provider.inc(Duration::from_millis(1));
+        assert!(cache.exists(file2.parquet_file.id, ts2.tombstone.id).await);
+        assert_histogram_metric_count(&catalog.metric_registry, "processed_tombstone_exist", 5);
+
+        // "true" results are cached forever
+        assert!(cache.exists(file1.parquet_file.id, ts1.tombstone.id).await);
+        assert_histogram_metric_count(&catalog.metric_registry, "processed_tombstone_exist", 5);
+
+        // cache key has two dimensions
+        assert!(cache.exists(file1.parquet_file.id, ts1.tombstone.id).await);
+        assert!(!cache.exists(file1.parquet_file.id, ts2.tombstone.id).await);
+        assert!(!cache.exists(file2.parquet_file.id, ts1.tombstone.id).await);
+        assert!(cache.exists(file2.parquet_file.id, ts2.tombstone.id).await);
+        ts1.mark_processed(&file2).await;
+        time_provider.inc(TTL_NOT_PROCESSED);
+        assert!(cache.exists(file1.parquet_file.id, ts1.tombstone.id).await);
+        assert!(!cache.exists(file1.parquet_file.id, ts2.tombstone.id).await);
+        assert!(cache.exists(file2.parquet_file.id, ts1.tombstone.id).await);
+        assert!(cache.exists(file2.parquet_file.id, ts2.tombstone.id).await);
+    }
+}

querier/src/chunk.rs

@@ -165,7 +165,10 @@ mod tests {
         let catalog = TestCatalog::new();
 
         let adapter = ParquetChunkAdapter::new(
-            Arc::new(CatalogCache::new(catalog.catalog())),
+            Arc::new(CatalogCache::new(
+                catalog.catalog(),
+                catalog.time_provider(),
+            )),
             catalog.object_store(),
             catalog.metric_registry(),
             catalog.time_provider(),

querier/src/database.rs

@@ -63,7 +63,10 @@ impl QuerierDatabase {
         time_provider: Arc<dyn TimeProvider>,
         exec: Arc<Executor>,
     ) -> Self {
-        let catalog_cache = Arc::new(CatalogCache::new(Arc::clone(&catalog)));
+        let catalog_cache = Arc::new(CatalogCache::new(
+            Arc::clone(&catalog),
+            Arc::clone(&time_provider),
+        ));
 
         Self {
             backoff_config: BackoffConfig::default(),

querier/src/namespace/mod.rs

@@ -575,17 +575,11 @@ impl QuerierNamespace {
 
                     let mut predicates_filtered = vec![];
                     for (tombstone_id, predicate) in predicates {
-                        let is_processed = Backoff::new(&self.backoff_config)
-                            .retry_all_errors("processed tombstone exists", || async {
-                                self.catalog
-                                    .repositories()
-                                    .await
-                                    .processed_tombstones()
-                                    .exist(parquet_file_id, *tombstone_id)
-                                    .await
-                            })
-                            .await
-                            .expect("retry forever");
+                        let is_processed = self
+                            .catalog_cache
+                            .processed_tombstones()
+                            .exists(parquet_file_id, *tombstone_id)
+                            .await;
 
                         if !is_processed {
                             predicates_filtered.push(Arc::clone(predicate));
@@ -606,7 +600,9 @@ impl QuerierNamespace {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::namespace::test_util::querier_namespace;
+    use crate::{
+        cache::processed_tombstones::TTL_NOT_PROCESSED, namespace::test_util::querier_namespace,
+    };
     use data_types2::{ChunkAddr, ChunkId, ColumnType, PartitionAddr};
     use iox_tests::util::{TestCatalog, TestParquetFile};
     use schema::{builder::SchemaBuilder, InfluxColumnType, InfluxFieldType};
@@ -617,7 +613,10 @@ mod tests {
         let catalog = TestCatalog::new();
 
         let querier_namespace = QuerierNamespace::new(
-            Arc::new(CatalogCache::new(catalog.catalog())),
+            Arc::new(CatalogCache::new(
+                catalog.catalog(),
+                catalog.time_provider(),
+            )),
             "ns".into(),
             NamespaceId::new(1),
             catalog.metric_registry(),
@@ -935,6 +934,7 @@ mod tests {
             .with_sequencer(&sequencer1)
             .create_tombstone(4, 1, 10, "foo=4")
             .await;
+        catalog.mock_time_provider().inc(TTL_NOT_PROCESSED); // cache timeout for processed tombstones
         querier_namespace.sync().await;
         assert_eq!(
             delete_predicates(&querier_namespace),

querier/src/namespace/test_util.rs

@@ -7,7 +7,10 @@ use super::QuerierNamespace;
 
 pub fn querier_namespace(catalog: &Arc<TestCatalog>, ns: &Arc<TestNamespace>) -> QuerierNamespace {
     QuerierNamespace::new(
-        Arc::new(CatalogCache::new(catalog.catalog())),
+        Arc::new(CatalogCache::new(
+            catalog.catalog(),
+            catalog.time_provider(),
+        )),
         ns.namespace.name.clone().into(),
         ns.namespace.id,
         catalog.metric_registry(),