From 87d75f6070f0163151bf7e88990a57b7dd7a8bb0 Mon Sep 17 00:00:00 2001
From: Bojan Serafimov <bojan.serafimov7@gmail.com>
Date: Fri, 2 Dec 2022 15:28:18 -0500
Subject: [PATCH] Test on real data

---
 pageserver/benches/bench_layer_map.rs  | 58 ++++++++++++++++++++++++--
 pageserver/src/tenant/bst_layer_map.rs | 13 ++++--
 2 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/pageserver/benches/bench_layer_map.rs b/pageserver/benches/bench_layer_map.rs
index b0d2dbfc28..acc6266276 100644
--- a/pageserver/benches/bench_layer_map.rs
+++ b/pageserver/benches/bench_layer_map.rs
@@ -246,17 +246,65 @@ fn bench_from_captest_env(c: &mut Criterion) {
 // too long processing layer map queries.
 fn bench_from_real_project(c: &mut Criterion) {
     // TODO consider compressing this file
+
+    // Init layer map
+    let now = Instant::now();
     let layer_map = build_layer_map(PathBuf::from("benches/odd-brook-layernames.txt"));
+    println!("Finished layer map init in {:?}", now.elapsed());
+
+    // Init bst layer map with the same layers
+    let now = Instant::now();
+    let mut bstlm = BSTLM::new();
+    let mut sorted_layers: Vec<_> = layer_map.iter_historic_layers().collect();
+    sorted_layers.sort_by(|a, b| {
+        a.get_lsn_range().start.cmp(&b.get_lsn_range().start)
+    });
+    for layer in sorted_layers {
+        if layer.is_incremental() {
+            // TODO check if they're sorted
+            let kr = layer.get_key_range();
+            let lr = layer.get_lsn_range();
+
+            bstlm.insert(
+                kr.start.to_i128(),
+                kr.end.to_i128(),
+                lr.start.0,
+                format!("Layer {}", lr.start.0),
+            );
+        } else {
+            let kr = layer.get_key_range();
+            let lr = layer.get_lsn_range();
+
+            bstlm.insert(
+                kr.start.to_i128(),
+                kr.end.to_i128(),
+                lr.start.0,
+                format!("Layer {}", lr.start.0),
+            );
+        }
+    }
+    println!("Finished bst init in {:?}", now.elapsed());
+
+    // Choose uniformly distributed queries
     let queries: Vec<(Key, Lsn)> = uniform_query_pattern(&layer_map);
 
-    // Test with uniform query pattern
-    c.bench_function("real_map_uniform_queries", |b| {
+    // Define and name the benchmark function
+    let mut group = c.benchmark_group("real_map_uniform_queries");
+    group.bench_function("current_code", |b| {
         b.iter(|| {
             for q in queries.clone().into_iter() {
                 layer_map.search(q.0, q.1).unwrap();
             }
         });
     });
+    group.bench_function("persistent_bst", |b| {
+        b.iter(|| {
+            for q in queries.clone().into_iter() {
+                bstlm.query(q.0.to_i128(), q.1.0);
+            }
+        });
+    });
+    group.finish();
 }
 
 // Benchmark using synthetic data. Arrange image layers on stacked diagonal lines.
@@ -327,5 +375,7 @@ fn bench_sequential(c: &mut Criterion) {
     group.finish();
 }
 
-criterion_group!(group_3, bench_sequential);
-criterion_main!(group_3);
+// HACK TODO bring back all the bench functions. I remove
+// them here to avoid initializing.
+criterion_group!(group, bench_from_real_project);
+criterion_main!(group);
diff --git a/pageserver/src/tenant/bst_layer_map.rs b/pageserver/src/tenant/bst_layer_map.rs
index 9687a69ae5..735b47b453 100644
--- a/pageserver/src/tenant/bst_layer_map.rs
+++ b/pageserver/src/tenant/bst_layer_map.rs
@@ -34,9 +34,16 @@ impl BSTLM {
     pub fn insert(self: &mut Self, key_begin: i128, key_end: i128, lsn: u64, value: String) {
         // TODO check for off-by-one errors
 
-        // TODO check if LSN is lower than current max LSN. It should be rare for
-        //      that to happen with image layers, and there are solutions, but it's
-        //      tricky.
+        // It's a persistent map, not a retroactive one
+        if let Some(last_entry) = self.historic.iter().rev().next() {
+            let last_lsn = last_entry.0;
+            if lsn == *last_lsn {
+                // TODO there are edge cases to take care of
+            }
+            if lsn < *last_lsn {
+                todo!("smaller lsn not implemented yet")
+            }
+        }
 
         // NOTE The order of the following lines is important!!