From 2dcbdd9e4720d2dfbe906d0470490a229ad76913 Mon Sep 17 00:00:00 2001
From: Bojan Serafimov <bojan.serafimov7@gmail.com>
Date: Fri, 2 Dec 2022 14:52:55 -0500
Subject: [PATCH] Use i128

---
 pageserver/benches/bench_layer_map.rs  | 39 ++++----------------------
 pageserver/src/tenant/bst_layer_map.rs |  8 +++---
 2 files changed, 9 insertions(+), 38 deletions(-)

diff --git a/pageserver/benches/bench_layer_map.rs b/pageserver/benches/bench_layer_map.rs
index 21273f8dd9..6853a41f87 100644
--- a/pageserver/benches/bench_layer_map.rs
+++ b/pageserver/benches/bench_layer_map.rs
@@ -1,4 +1,5 @@
 use anyhow::Result;
+use num_traits::ToPrimitive;
 use pageserver::repository::{Key, Value};
 use pageserver::tenant::bst_layer_map::BSTLM;
 use pageserver::tenant::filename::{DeltaFileName, ImageFileName};
@@ -261,7 +262,6 @@ 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();
     let mut bstlm = BSTLM::new();
 
     // Init layer map. Create 100_000 layers arranged in 1000 diagonal lines.
@@ -272,9 +272,6 @@ fn bench_sequential(c: &mut Criterion) {
     //      because then it runs multiple times during warmup.
     let now = Instant::now();
     for i in 0..100_000 {
-        // TODO try inserting a super-wide layer in between every 10 to reflect
-        //      what often happens with L1 layers that include non-rel changes.
-        //      Maybe do that as a separate test.
         let i32 = (i as u32) % 100;
         let zero = Key::from_hex("000000000000000000000000000000000000").unwrap();
         let layer = DummyImage {
@@ -287,31 +284,12 @@ fn bench_sequential(c: &mut Criterion) {
 
     let now = Instant::now();
     for i in 0..100_000 {
-        // TODO try inserting a super-wide layer in between every 10 to reflect
-        //      what often happens with L1 layers that include non-rel changes.
-        //      Maybe do that as a separate test.
         let i32 = (i as u32) % 100;
         let zero = Key::from_hex("000000000000000000000000000000000000").unwrap();
-        let layer = DummyImage {
-            key_range: zero.add(10 * i32)..zero.add(10 * i32 + 1),
-            lsn: Lsn(i),
-        };
-        stlm.insert(10 * i32, 10 * i32 + 1, i as u32, format!("Layer {}", i));
-    }
-    println!("Finished persistent segment tree init in {:?}", now.elapsed());
+        let begin = zero.add(10 * i32).to_i128();
+        let end = zero.add(10 * i32 + 1).to_i128();
 
-    let now = Instant::now();
-    for i in 0..100_000 {
-        // TODO try inserting a super-wide layer in between every 10 to reflect
-        //      what often happens with L1 layers that include non-rel changes.
-        //      Maybe do that as a separate test.
-        let i32 = (i as u32) % 100;
-        let zero = Key::from_hex("000000000000000000000000000000000000").unwrap();
-        let layer = DummyImage {
-            key_range: zero.add(10 * i32)..zero.add(10 * i32 + 1),
-            lsn: Lsn(i),
-        };
-        bstlm.insert(10 * i32, 10 * i32 + 1, i as u32, format!("Layer {}", i));
+        bstlm.insert(begin, end, i as u64, format!("Layer {}", i));
     }
     println!("Finished bst init in {:?}", now.elapsed());
 
@@ -331,17 +309,10 @@ fn bench_sequential(c: &mut Criterion) {
             }
         });
     });
-    group.bench_function("persistent_segment_tree", |b| {
-        b.iter(|| {
-            for q in queries.clone().into_iter() {
-                stlm.query(q.0.field6, q.1.0 as u32);
-            }
-        });
-    });
     group.bench_function("persistent_bst", |b| {
         b.iter(|| {
             for q in queries.clone().into_iter() {
-                bstlm.query(q.0.field6, q.1.0 as u32);
+                bstlm.query(q.0.to_i128(), q.1.0);
             }
         });
     });
diff --git a/pageserver/src/tenant/bst_layer_map.rs b/pageserver/src/tenant/bst_layer_map.rs
index edef665b19..9687a69ae5 100644
--- a/pageserver/src/tenant/bst_layer_map.rs
+++ b/pageserver/src/tenant/bst_layer_map.rs
@@ -10,10 +10,10 @@ use rpds::RedBlackTreeMap;
 /// so it's missing unnecessary details. Values are String for now.
 pub struct BSTLM {
     /// Mapping key to the latest layer (if any) until the next key
-    head: RedBlackTreeMap<u32, Option<String>>,
+    head: RedBlackTreeMap<i128, Option<String>>,
 
     /// All previous states of `self.head`
-    historic: BTreeMap<u32, RedBlackTreeMap<u32, Option<String>>>,
+    historic: BTreeMap<u64, RedBlackTreeMap<i128, Option<String>>>,
 }
 
 impl std::fmt::Debug for BSTLM {
@@ -31,7 +31,7 @@ impl BSTLM {
         }
     }
 
-    pub fn insert(self: &mut Self, key_begin: u32, key_end: u32, lsn: u32, value: String) {
+    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
@@ -63,7 +63,7 @@ impl BSTLM {
         self.historic.insert(lsn, self.head.clone());
     }
 
-    pub fn query(self: &Self, key: u32, lsn: u32) -> Option<&String> {
+    pub fn query(self: &Self, key: i128, lsn: u64) -> Option<&String> {
         // TODO check for off-by-one errors
 
         let version = self.historic.range(0..=lsn).rev().next()?.1;