From 96c9fd330c3b58cff5bddc1eed02b0f37734fda3 Mon Sep 17 00:00:00 2001
From: Joonas Koivunen <joonas@neon.tech>
Date: Thu, 24 Aug 2023 17:04:04 +0300
Subject: [PATCH] fix: duplicate residency events on flushing l0

---
 pageserver/src/tenant/timeline.rs               | 12 +-----------
 pageserver/src/tenant/timeline/layer_manager.rs | 10 ++++++++--
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/pageserver/src/tenant/timeline.rs b/pageserver/src/tenant/timeline.rs
index 9d4534f0ea..05b8ab18af 100644
--- a/pageserver/src/tenant/timeline.rs
+++ b/pageserver/src/tenant/timeline.rs
@@ -2389,19 +2389,9 @@ impl Timeline {
 
             if let Some(ref l) = delta_layer_to_add {
                 // TODO: move access stats, metrics update, etc. into layer manager.
-                l.access_stats().record_residence_event(
-                    LayerResidenceStatus::Resident,
-                    LayerResidenceEventReason::LayerCreate,
-                );
-
-                // update metrics
-                let sz = l.layer_desc().file_size;
-                self.metrics.resident_physical_size_gauge.add(sz);
-                self.metrics.num_persistent_files_created.inc_by(1);
-                self.metrics.persistent_bytes_written.inc_by(sz);
             }
 
-            guard.finish_flush_l0_layer(delta_layer_to_add.as_ref(), &frozen_layer);
+            guard.finish_flush_l0_layer(delta_layer_to_add.as_ref(), &frozen_layer, &self.metrics);
             // release lock on 'layers'
         }
 
diff --git a/pageserver/src/tenant/timeline/layer_manager.rs b/pageserver/src/tenant/timeline/layer_manager.rs
index 9e7d54c249..0e59817c0d 100644
--- a/pageserver/src/tenant/timeline/layer_manager.rs
+++ b/pageserver/src/tenant/timeline/layer_manager.rs
@@ -171,13 +171,13 @@ impl LayerManager {
         &mut self,
         delta_layer: Option<&ResidentLayer>,
         frozen_layer_for_check: &Arc<InMemoryLayer>,
+        metrics: &crate::metrics::TimelineMetrics,
     ) {
         let inmem = self
             .layer_map
             .frozen_layers
             .pop_front()
             .expect("there must be a inmem layer to flush");
-        let mut updates = self.layer_map.batch_update();
 
         // Only one task may call this function at a time (for this
         // timeline). If two tasks tried to flush the same frozen
@@ -185,13 +185,19 @@ impl LayerManager {
         assert_eq!(Arc::as_ptr(&inmem), Arc::as_ptr(frozen_layer_for_check));
 
         if let Some(l) = delta_layer {
+            let mut updates = self.layer_map.batch_update();
             l.access_stats().record_residence_event(
                 LayerResidenceStatus::Resident,
                 LayerResidenceEventReason::LayerCreate,
             );
+            let sz = l.layer_desc().file_size;
+            metrics.resident_physical_size_gauge.add(sz);
+            metrics.num_persistent_files_created.inc_by(1);
+            metrics.persistent_bytes_written.inc_by(sz);
+
             Self::insert_historic_layer(l.as_ref().clone(), &mut updates, &mut self.layer_fmgr);
+            updates.flush();
         }
-        updates.flush();
     }
 
     /// Called when compaction is completed.