sketch interface

pageserver/src/tenant/timeline.rs

@@ -68,7 +68,9 @@ use crate::{
     tenant::{
         layer_map::{LayerMap, SearchResult},
         metadata::TimelineMetadata,
-        storage_layer::{inmemory_layer::IndexEntry, PersistentLayerDesc},
+        storage_layer::{
+            inmemory_layer::IndexEntry, LayerId, PersistentLayerDesc, ValueReconstructSituation,
+        },
     },
     walredo,
 };
@@ -1126,6 +1128,14 @@ impl Timeline {
             .await?;
         get_data_timer.stop_and_record();
 
+        // transform reconstruct state which is per key into a map
+        // layer => all reads from that layer
+        struct KeyWaiter {
+            img: Option<oneshot::Receiver<Bytes>>,
+            values: Vec<oneshot::Receiver<Bytes>>,
+        }
+        let mut key_waiters: BTreeMap<Key, Result<KeyWaiter, PageReconstructError>> = todo!();
+
         let reconstruct_timer = crate::metrics::RECONSTRUCT_TIME
             .for_get_kind(get_kind)
             .start_timer();

pageserver/src/tenant/vectored_blob_io.rs

@@ -18,6 +18,7 @@
 use std::collections::BTreeMap;
 
 use bytes::BytesMut;
+use futures::channel::oneshot;
 use pageserver_api::key::Key;
 use tokio::io::AsyncWriteExt;
 use tokio_epoll_uring::BoundedBuf;
@@ -665,6 +666,7 @@ impl StreamingVectoredReadPlanner {
         start_offset: u64,
         end_offset: u64,
         is_last_blob_in_read: bool,
+        // destination: oneshot::Sender<Result<Bytes, std::io::Error>>,
     ) -> Option<VectoredRead> {
         match &mut self.read_builder {
             Some(read_builder) => {