From db72f432e5eb2ff125567c94bb95cd5b48b32af4 Mon Sep 17 00:00:00 2001
From: Bojan Serafimov <bojan.serafimov7@gmail.com>
Date: Tue, 13 Dec 2022 13:42:53 -0500
Subject: [PATCH] Remove 2/3 clones on search path

---
 pageserver/src/tenant/bst_layer_map.rs |  5 +----
 pageserver/src/tenant/layer_map.rs     | 14 ++++++++++----
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/pageserver/src/tenant/bst_layer_map.rs b/pageserver/src/tenant/bst_layer_map.rs
index fbc79148f7..10fd589520 100644
--- a/pageserver/src/tenant/bst_layer_map.rs
+++ b/pageserver/src/tenant/bst_layer_map.rs
@@ -369,10 +369,7 @@ impl<Value: Clone> RetroactiveLayerMap<Value> {
             panic!("rebuild pls")
         }
 
-        match self.map.query(key, lsn) {
-            Some(layer) => Some(layer.clone()),
-            None => None,
-        }
+        self.map.query(key, lsn)
     }
 }
 
diff --git a/pageserver/src/tenant/layer_map.rs b/pageserver/src/tenant/layer_map.rs
index 14b6bdb263..d273f8cc80 100644
--- a/pageserver/src/tenant/layer_map.rs
+++ b/pageserver/src/tenant/layer_map.rs
@@ -274,15 +274,21 @@ impl LayerMap {
         let latest_image = self.images.query(key.to_i128(), end_lsn.0 - 1);
 
         // Check for exact match
-        if let Some(image) = &latest_image {
+        let latest_image = if let Some(image) = latest_image {
             let img_lsn = image.get_lsn_range().start;
             if Lsn(img_lsn.0 + 1) == end_lsn {
                 return Ok(Some(SearchResult {
-                    layer: Arc::clone(&image),
+                    layer: image,
                     lsn_floor: img_lsn,
                 }));
             }
-        }
+
+            // HACK just to give back ownership of latest_image to parent scope.
+            //      There's definitely a cleaner way to do it.
+            Some(image)
+        } else {
+            None
+        };
 
         return Ok(latest_layer.map(|layer| {
             // Compute lsn_floor
@@ -293,7 +299,7 @@ impl LayerMap {
                 }
             }
             SearchResult {
-                layer: Arc::clone(&layer),
+                layer,
                 lsn_floor,
             }
         }));