From 709a6ad29ba528a84f7fb461a345df4cb6f5fc00 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <christian@neon.tech>
Date: Sat, 14 Sep 2024 12:05:42 +0000
Subject: [PATCH] WIP

---
 pageserver/src/tenant/storage_layer.rs | 38 ++++++++------------------
 1 file changed, 12 insertions(+), 26 deletions(-)

diff --git a/pageserver/src/tenant/storage_layer.rs b/pageserver/src/tenant/storage_layer.rs
index f30e068883..a344948d5c 100644
--- a/pageserver/src/tenant/storage_layer.rs
+++ b/pageserver/src/tenant/storage_layer.rs
@@ -87,17 +87,13 @@ pub(crate) struct VectoredValueReconstructState {
         Lsn,
         tokio::sync::oneshot::Receiver<Result<Bytes, std::io::Error>>,
     )>,
-    pub(crate) img: Option<(
-        Lsn,
-        tokio::sync::oneshot::Receiver<Result<Bytes, std::io::Error>>,
-    )>,
 
     pub(crate) situation: ValueReconstructSituation,
 }
 
 impl VectoredValueReconstructState {
     fn get_cached_lsn(&self) -> Option<Lsn> {
-        self.img.as_ref().map(|img| img.0)
+        None
     }
 }
 
@@ -107,6 +103,7 @@ pub(crate) async fn convert(
 ) -> Result<ValueReconstructState, PageReconstructError> {
     let mut to = ValueReconstructState::default();
 
+    let mut inited = false;
     for (lsn, fut) in from.records {
         match fut.await {
             Ok(res) => match res {
@@ -114,13 +111,18 @@ pub(crate) async fn convert(
                     let value = Value::des(&bytes)
                         .map_err(|err| PageReconstructError::Other(err.into()))?;
 
-                    match value {
-                        Value::WalRecord(rec) => {
+                    match (inited, value) {
+                        (true, _) => {
+                            panic!("multiple will_init records, plan was wrong");
+                        }
+                        (false, Value::WalRecord(rec)) => {
+                            inited = rec.will_init();
                             to.records.push((lsn, rec));
-                        },
-                        Value::Image(img) => {
+                        }
+                        (false, Value::Image(img)) => {
                             assert!(to.img.is_none());
                             to.img = Some((lsn, img));
+                            inited = true;
                         }
                     }
                 }
@@ -133,23 +135,7 @@ pub(crate) async fn convert(
             }
         }
     }
-
-    if to.img.is_none() && from.img.is_some() {
-        let (lsn, fut) = from.img.expect("Has an image");
-        match fut.await {
-            Ok(res) => match res {
-                Ok(bytes) => {
-                    to.img = Some((lsn, bytes));
-                }
-                Err(err) => {
-                    return Err(PageReconstructError::Other(err.into()));
-                }
-            },
-            Err(err) => {
-                return Err(PageReconstructError::Other(err.into()));
-            }
-        }
-    }
+    // do not assert inited=true here because it's kinda legitimate to ask for key that doesn't exist
 
     Ok(to)
 }