wip

Cargo.lock

@@ -2334,6 +2334,7 @@ dependencies = [
  "num-traits",
  "once_cell",
  "pageserver_api",
+ "persistent_range_query",
  "pin-project-lite",
  "postgres",
  "postgres-protocol",

pageserver/Cargo.toml

@@ -59,6 +59,7 @@ tracing = "0.1.36"
 url = "2"
 walkdir = "2.3.2"
 
+persistent_range_query = { path = "../libs/persistent_range_query" }
 etcd_broker = { path = "../libs/etcd_broker" }
 metrics = { path = "../libs/metrics" }
 pageserver_api = { path = "../libs/pageserver_api" }

pageserver/benches/bench_layer_map.rs

@@ -2,6 +2,7 @@ use anyhow::Result;
 use pageserver::repository::{Key, Value};
 use pageserver::tenant::filename::{DeltaFileName, ImageFileName};
 use pageserver::tenant::layer_map::LayerMap;
+use pageserver::tenant::segment_tree_layer_map::STLM;
 use pageserver::tenant::storage_layer::Layer;
 use pageserver::tenant::storage_layer::ValueReconstructResult;
 use pageserver::tenant::storage_layer::ValueReconstructState;
@@ -259,6 +260,7 @@ fn bench_from_real_project(c: &mut Criterion) {
 // Benchmark using synthetic data. Arrange image layers on stacked diagonal lines.
 fn bench_sequential(c: &mut Criterion) {
     let mut layer_map = LayerMap::default();
+    let mut stlm = STLM::new();
 
     // Init layer map. Create 100_000 layers arranged in 1000 diagonal lines.
     //
@@ -275,9 +277,10 @@ fn bench_sequential(c: &mut Criterion) {
         let zero = Key::from_hex("000000000000000000000000000000000000").unwrap();
         let layer = DummyImage {
             key_range: zero.add(10 * i32)..zero.add(10 * i32 + 1),
-            lsn: Lsn(10 * i),
+            lsn: Lsn(i),
         };
         layer_map.insert_historic(Arc::new(layer));
+        stlm.insert(10 * i32, 10 * i32 + 1);
     }
 
     // Manually measure runtime without criterion because criterion

pageserver/src/tenant.rs

@@ -80,6 +80,7 @@ pub mod filename;
 mod image_layer;
 mod inmemory_layer;
 pub mod layer_map;
+pub mod segment_tree_layer_map;
 
 pub mod metadata;
 mod par_fsync;

pageserver/src/tenant/segment_tree_layer_map.rs

@@ -0,0 +1,317 @@
+use persistent_range_query::naive::{IndexableKey, NaiveVecStorage};
+use persistent_range_query::ops::SameElementsInitializer;
+use persistent_range_query::segment_tree::{MidpointableKey, PersistentSegmentTree};
+use persistent_range_query::{
+    LazyRangeInitializer, PersistentVecStorage, RangeModification, RangeQueryResult,
+    VecReadableVersion,
+};
+use std::cmp::Ordering;
+use std::ops::Range;
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd)]
+struct PageIndex(u32);
+type LayerId = String;
+
+impl IndexableKey for PageIndex {
+    fn index(all_keys: &Range<Self>, key: &Self) -> usize {
+        (key.0 as usize) - (all_keys.start.0 as usize)
+    }
+
+    fn element_range(all_keys: &Range<Self>, index: usize) -> Range<Self> {
+        PageIndex(all_keys.start.0 + index as u32)..PageIndex(all_keys.start.0 + index as u32 + 1)
+    }
+}
+
+impl MidpointableKey for PageIndex {
+    fn midpoint(range: &Range<Self>) -> Self {
+        PageIndex(range.start.0 + (range.end.0 - range.start.0) / 2)
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+struct LayerMapInformation {
+    // Only make sense for a range of length 1.
+    last_layer: Option<LayerId>,
+    last_image_layer: Option<LayerId>,
+    // Work for all ranges
+    max_delta_layers: (usize, Range<PageIndex>),
+}
+
+impl LayerMapInformation {
+    fn last_layers(&self) -> (&Option<LayerId>, &Option<LayerId>) {
+        (&self.last_layer, &self.last_image_layer)
+    }
+
+    fn max_delta_layers(&self) -> &(usize, Range<PageIndex>) {
+        &self.max_delta_layers
+    }
+}
+
+fn merge_ranges(left: &Range<PageIndex>, right: &Range<PageIndex>) -> Range<PageIndex> {
+    if left.is_empty() {
+        right.clone()
+    } else if right.is_empty() {
+        left.clone()
+    } else if left.end == right.start {
+        left.start..right.end
+    } else {
+        left.clone()
+    }
+}
+
+impl RangeQueryResult<PageIndex> for LayerMapInformation {
+    fn new_for_empty_range() -> Self {
+        LayerMapInformation {
+            last_layer: None,
+            last_image_layer: None,
+            max_delta_layers: (0, PageIndex(0)..PageIndex(0)),
+        }
+    }
+
+    fn combine(
+        left: &Self,
+        _left_range: &Range<PageIndex>,
+        right: &Self,
+        _right_range: &Range<PageIndex>,
+    ) -> Self {
+        // Note that either range may be empty.
+        LayerMapInformation {
+            last_layer: left
+                .last_layer
+                .as_ref()
+                .or_else(|| right.last_layer.as_ref())
+                .cloned(),
+            last_image_layer: left
+                .last_image_layer
+                .as_ref()
+                .or_else(|| right.last_image_layer.as_ref())
+                .cloned(),
+            max_delta_layers: match left.max_delta_layers.0.cmp(&right.max_delta_layers.0) {
+                Ordering::Less => right.max_delta_layers.clone(),
+                Ordering::Greater => left.max_delta_layers.clone(),
+                Ordering::Equal => (
+                    left.max_delta_layers.0,
+                    merge_ranges(&left.max_delta_layers.1, &right.max_delta_layers.1),
+                ),
+            },
+        }
+    }
+
+    fn add(
+        left: &mut Self,
+        left_range: &Range<PageIndex>,
+        right: &Self,
+        right_range: &Range<PageIndex>,
+    ) {
+        *left = Self::combine(&left, left_range, right, right_range);
+    }
+}
+
+#[derive(Clone, Debug)]
+struct AddDeltaLayers {
+    last_layer: LayerId,
+    count: usize,
+}
+
+#[derive(Clone, Debug)]
+struct LayerMapModification {
+    add_image_layer: Option<LayerId>,
+    add_delta_layers: Option<AddDeltaLayers>,
+}
+
+impl LayerMapModification {
+    fn add_image_layer(layer: impl Into<LayerId>) -> Self {
+        LayerMapModification {
+            add_image_layer: Some(layer.into()),
+            add_delta_layers: None,
+        }
+    }
+
+    fn add_delta_layer(layer: impl Into<LayerId>) -> Self {
+        LayerMapModification {
+            add_image_layer: None,
+            add_delta_layers: Some(AddDeltaLayers {
+                last_layer: layer.into(),
+                count: 1,
+            }),
+        }
+    }
+}
+
+impl RangeModification<PageIndex> for LayerMapModification {
+    type Result = LayerMapInformation;
+
+    fn no_op() -> Self {
+        LayerMapModification {
+            add_image_layer: None,
+            add_delta_layers: None,
+        }
+    }
+
+    fn is_no_op(&self) -> bool {
+        self.add_image_layer.is_none() && self.add_delta_layers.is_none()
+    }
+
+    fn is_reinitialization(&self) -> bool {
+        self.add_image_layer.is_some()
+    }
+
+    fn apply(&self, result: &mut Self::Result, range: &Range<PageIndex>) {
+        if let Some(layer) = &self.add_image_layer {
+            result.last_layer = Some(layer.clone());
+            result.last_image_layer = Some(layer.clone());
+            result.max_delta_layers = (0, range.clone());
+        }
+        if let Some(AddDeltaLayers { last_layer, count }) = &self.add_delta_layers {
+            result.last_layer = Some(last_layer.clone());
+            result.max_delta_layers.0 += count;
+        }
+    }
+
+    fn compose(later: &Self, earlier: &mut Self) {
+        if later.add_image_layer.is_some() {
+            *earlier = later.clone();
+            return;
+        }
+        if let Some(AddDeltaLayers { last_layer, count }) = &later.add_delta_layers {
+            let res = earlier.add_delta_layers.get_or_insert(AddDeltaLayers {
+                last_layer: LayerId::default(),
+                count: 0,
+            });
+            res.last_layer = last_layer.clone();
+            res.count += count;
+        }
+    }
+}
+
+impl LazyRangeInitializer<LayerMapInformation, PageIndex> for SameElementsInitializer<()> {
+    fn get(&self, range: &Range<PageIndex>) -> LayerMapInformation {
+        LayerMapInformation {
+            last_layer: None,
+            last_image_layer: None,
+            max_delta_layers: (0, range.clone()),
+        }
+    }
+}
+
+pub struct STLM {
+    s: PersistentVecStorage<LayerMapModification, SameElementsInitializer<()>, PageIndex>,
+}
+
+impl STLM {
+    pub fn new() -> Self {
+        STLM {
+            s: PersistentVecStorage::new(
+                PageIndex(0)..PageIndex(100),
+                SameElementsInitializer::new(()),
+            ),
+        }
+    }
+
+    pub fn insert(key_begin: i32, key_end: i32) {
+        s.modify(
+            &(PageIndex(key_begin)..PageIndex(key_end)),
+            &LayerMapModification::add_image_layer("Img0..70"),
+        );
+    }
+}
+
+fn test_layer_map<
+    S: PersistentVecStorage<LayerMapModification, SameElementsInitializer<()>, PageIndex>,
+>() {
+    let mut s = S::new(
+        PageIndex(0)..PageIndex(100),
+        SameElementsInitializer::new(()),
+    );
+    s.modify(
+        &(PageIndex(0)..PageIndex(70)),
+        &LayerMapModification::add_image_layer("Img0..70"),
+    );
+    s.modify(
+        &(PageIndex(50)..PageIndex(100)),
+        &LayerMapModification::add_image_layer("Img50..100"),
+    );
+    s.modify(
+        &(PageIndex(10)..PageIndex(60)),
+        &LayerMapModification::add_delta_layer("Delta10..60"),
+    );
+    let s_before_last_delta = s.freeze();
+    s.modify(
+        &(PageIndex(20)..PageIndex(80)),
+        &LayerMapModification::add_delta_layer("Delta20..80"),
+    );
+
+    assert_eq!(
+        s.get(&(PageIndex(5)..PageIndex(6))).last_layers(),
+        (&Some("Img0..70".to_owned()), &Some("Img0..70".to_owned()))
+    );
+    assert_eq!(
+        s.get(&(PageIndex(15)..PageIndex(16))).last_layers(),
+        (
+            &Some("Delta10..60".to_owned()),
+            &Some("Img0..70".to_owned())
+        )
+    );
+    assert_eq!(
+        s.get(&(PageIndex(25)..PageIndex(26))).last_layers(),
+        (
+            &Some("Delta20..80".to_owned()),
+            &Some("Img0..70".to_owned())
+        )
+    );
+    assert_eq!(
+        s.get(&(PageIndex(65)..PageIndex(66))).last_layers(),
+        (
+            &Some("Delta20..80".to_owned()),
+            &Some("Img50..100".to_owned())
+        )
+    );
+    assert_eq!(
+        s.get(&(PageIndex(95)..PageIndex(96))).last_layers(),
+        (
+            &Some("Img50..100".to_owned()),
+            &Some("Img50..100".to_owned())
+        )
+    );
+
+    assert_eq!(
+        s.get(&(PageIndex(0)..PageIndex(100))).max_delta_layers(),
+        &(2, PageIndex(20)..PageIndex(60)),
+    );
+    assert_eq!(
+        *s_before_last_delta
+            .get(&(PageIndex(0)..PageIndex(100)))
+            .max_delta_layers(),
+        (1, PageIndex(10)..PageIndex(60)),
+    );
+
+    assert_eq!(
+        *s.get(&(PageIndex(10)..PageIndex(30))).max_delta_layers(),
+        (2, PageIndex(20)..PageIndex(30))
+    );
+    assert_eq!(
+        *s.get(&(PageIndex(10)..PageIndex(20))).max_delta_layers(),
+        (1, PageIndex(10)..PageIndex(20))
+    );
+
+    assert_eq!(
+        *s.get(&(PageIndex(70)..PageIndex(80))).max_delta_layers(),
+        (1, PageIndex(70)..PageIndex(80))
+    );
+    assert_eq!(
+        *s_before_last_delta
+            .get(&(PageIndex(70)..PageIndex(80)))
+            .max_delta_layers(),
+        (0, PageIndex(70)..PageIndex(80))
+    );
+}
+
+#[test]
+fn test_naive() {
+    test_layer_map::<NaiveVecStorage<_, _, _>>();
+}
+
+#[test]
+fn test_segment_tree() {
+    test_layer_map::<PersistentSegmentTree<_, _, _>>();
+}