From dbb5d0800d1d065b2f919d63bc84c6b376f21b74 Mon Sep 17 00:00:00 2001
From: Bojan Serafimov <bojan.serafimov7@gmail.com>
Date: Wed, 11 Jan 2023 13:59:26 -0500
Subject: [PATCH] Fix lsn bound

---
 pageserver/src/tenant/layer_map.rs                         | 4 +++-
 pageserver/src/tenant/layer_map/historic_layer_coverage.rs | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/pageserver/src/tenant/layer_map.rs b/pageserver/src/tenant/layer_map.rs
index ec3189a18d..539cba91b0 100644
--- a/pageserver/src/tenant/layer_map.rs
+++ b/pageserver/src/tenant/layer_map.rs
@@ -263,7 +263,9 @@ where
         key_range: &Range<Key>,
         lsn: Lsn,
     ) -> Result<Vec<(Range<Key>, Option<Arc<L>>)>> {
-        let version = match self.historic.get().unwrap().get_version(lsn.0 - 1) {
+        // TODO I'm 80% sure the lsn bound is inclusive. Double-check that
+        //      and document it. Do the same for image_layer_exists and count_deltas
+        let version = match self.historic.get().unwrap().get_version(lsn.0) {
             Some(v) => v,
             None => return Ok(vec![]),
         };
diff --git a/pageserver/src/tenant/layer_map/historic_layer_coverage.rs b/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
index f104e615d9..bc12b77a99 100644
--- a/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
+++ b/pageserver/src/tenant/layer_map/historic_layer_coverage.rs
@@ -65,7 +65,7 @@ impl<Value: Clone> HistoricLayerCoverage<Value> {
         self.historic.insert(lsn.start, self.head.clone());
     }
 
-    /// Query at a particular LSN
+    /// Query at a particular LSN, inclusive
     pub fn get_version(self: &Self, lsn: u64) -> Option<&LayerCoverageTuple<Value>> {
         match self.historic.range(..=lsn).rev().next() {
             Some((_, v)) => Some(v),