neon_local: pin pageservers and endpoints

hitting latest=true

Cargo.lock

@@ -2106,6 +2106,20 @@ dependencies = [
  "hashbrown 0.13.2",
 ]
 
+[[package]]
+name = "hdrhistogram"
+version = "7.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "765c9198f173dd59ce26ff9f95ef0aafd0a0fe01fb9d72841bc5066a4c06511d"
+dependencies = [
+ "base64 0.21.1",
+ "byteorder",
+ "crossbeam-channel",
+ "flate2",
+ "nom",
+ "num-traits",
+]
+
 [[package]]
 name = "heapless"
 version = "0.8.0"
@@ -3056,6 +3070,28 @@ dependencies = [
  "sha2",
 ]
 
+[[package]]
+name = "pagebench"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "clap",
+ "futures",
+ "hdrhistogram",
+ "humantime",
+ "humantime-serde",
+ "pageserver",
+ "pageserver_api",
+ "pageserver_client",
+ "rand 0.8.5",
+ "serde",
+ "serde_json",
+ "tokio",
+ "tracing",
+ "utils",
+ "workspace_hack",
+]
+
 [[package]]
 name = "pagectl"
 version = "0.1.0"

Cargo.toml

@@ -6,6 +6,7 @@ members = [
     "pageserver",
     "pageserver/ctl",
     "pageserver/client",
+    "pageserver/pagebench",
     "proxy",
     "safekeeper",
     "storage_broker",
@@ -79,6 +80,7 @@ futures-util = "0.3"
 git-version = "0.3"
 hashbrown = "0.13"
 hashlink = "0.8.1"
+hdrhistogram = "7.5.2"
 hex = "0.4"
 hex-literal = "0.4"
 hmac = "0.12.1"

control_plane/src/endpoint.rs

@@ -549,8 +549,10 @@ impl Endpoint {
 
         // Launch compute_ctl
         println!("Starting postgres node at '{}'", self.connstr());
-        let mut cmd = Command::new(self.env.neon_distrib_dir.join("compute_ctl"));
+        let mut cmd = Command::new("/usr/bin/taskset");
-        cmd.args(["--http-port", &self.http_address.port().to_string()])
+        cmd.args(["-c".to_string(), "8-11".to_string()])
+            .args([self.env.neon_distrib_dir.join("compute_ctl")])
+            .args(["--http-port", &self.http_address.port().to_string()])
             .args(["--pgdata", self.pgdata().to_str().unwrap()])
             .args(["--connstr", &self.connstr()])
             .args([

control_plane/src/pageserver.rs

@@ -12,6 +12,7 @@ use std::io::Write;
 use std::num::NonZeroU64;
 use std::path::PathBuf;
 use std::process::{Child, Command};
+use std::str::FromStr;
 use std::time::Duration;
 
 use anyhow::{bail, Context};
@@ -216,11 +217,19 @@ impl PageServerNode {
         if update_config {
             args.push(Cow::Borrowed("--update-config"));
         }
+
+        let mut taskset_args = vec![
+            "-c".to_string(),
+            format!("{}", self.conf.id.0 - 1),
+            self.env.pageserver_bin().to_string_lossy().into(),
+        ];
+        taskset_args.extend(args.into_iter().map(|a| a.to_string()));
+
         background_process::start_process(
             "pageserver",
             &datadir,
-            &self.env.pageserver_bin(),
+            &PathBuf::from_str("/usr/bin/taskset").unwrap(),
-            args.iter().map(Cow::as_ref),
+            taskset_args,
             self.pageserver_env_variables()?,
             background_process::InitialPidFile::Expect(self.pid_file()),
             || async {

libs/pageserver_api/src/models.rs

@@ -370,6 +370,14 @@ pub struct TenantInfo {
     pub attachment_status: TenantAttachmentStatus,
 }
 
+#[derive(Serialize, Deserialize, Clone)]
+pub struct TenantDetails {
+    #[serde(flatten)]
+    pub tenant_info: TenantInfo,
+
+    pub timelines: Vec<TimelineId>,
+}
+
 /// This represents the output of the "timeline_detail" and "timeline_list" API calls.
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct TimelineInfo {

libs/pageserver_api/src/shard.rs

@@ -81,6 +81,10 @@ impl TenantShardId {
     pub fn is_zero(&self) -> bool {
         self.shard_number == ShardNumber(0)
     }
+
+    pub fn is_unsharded(&self) -> bool {
+        self.shard_number == ShardNumber(0) && self.shard_count == ShardCount(0)
+    }
 }
 
 /// Formatting helper

libs/utils/src/lsn.rs

@@ -366,6 +366,47 @@ impl MonotonicCounter<Lsn> for RecordLsn {
     }
 }
 
+/// Implements  [`rand::distributions::uniform::UniformSampler`] so we can sample [`Lsn`]s.
+pub struct LsnSampler(<u64 as rand::distributions::uniform::SampleUniform>::Sampler);
+
+impl rand::distributions::uniform::SampleUniform for Lsn {
+    type Sampler = LsnSampler;
+}
+
+impl rand::distributions::uniform::UniformSampler for LsnSampler {
+    type X = Lsn;
+
+    fn new<B1, B2>(low: B1, high: B2) -> Self
+    where
+        B1: rand::distributions::uniform::SampleBorrow<Self::X> + Sized,
+        B2: rand::distributions::uniform::SampleBorrow<Self::X> + Sized,
+    {
+        Self(
+            <u64 as rand::distributions::uniform::SampleUniform>::Sampler::new(
+                low.borrow().0,
+                high.borrow().0,
+            ),
+        )
+    }
+
+    fn new_inclusive<B1, B2>(low: B1, high: B2) -> Self
+    where
+        B1: rand::distributions::uniform::SampleBorrow<Self::X> + Sized,
+        B2: rand::distributions::uniform::SampleBorrow<Self::X> + Sized,
+    {
+        Self(
+            <u64 as rand::distributions::uniform::SampleUniform>::Sampler::new_inclusive(
+                low.borrow().0,
+                high.borrow().0,
+            ),
+        )
+    }
+
+    fn sample<R: rand::prelude::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
+        Lsn(self.0.sample(rng))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::bin_ser::BeSer;

pageserver/client/src/mgmt_api.rs

@@ -64,6 +64,18 @@ impl Client {
         resp.json().await.map_err(Error::ReceiveBody)
     }
 
+    pub async fn tenant_details(
+        &self,
+        tenant_id: TenantId,
+    ) -> Result<pageserver_api::models::TenantDetails> {
+        let uri = format!("{}/v1/tenant/{tenant_id}", self.mgmt_api_endpoint);
+        self.get(uri)
+            .await?
+            .json()
+            .await
+            .map_err(Error::ReceiveBody)
+    }
+
     pub async fn list_timelines(
         &self,
         tenant_id: TenantId,

pageserver/pagebench/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "pagebench"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow.workspace = true
+clap.workspace = true
+futures.workspace = true
+hdrhistogram.workspace = true
+humantime.workspace = true
+humantime-serde.workspace = true
+rand.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+tracing.workspace = true
+tokio.workspace = true
+
+pageserver = { path = ".." }
+pageserver_client.workspace = true
+pageserver_api.workspace = true
+utils = { path = "../../libs/utils/" }
+workspace_hack = { version = "0.1", path = "../../workspace_hack" }

pageserver/pagebench/src/basebackup.rs

@@ -0,0 +1,273 @@
+use anyhow::Context;
+use pageserver_client::page_service::BasebackupRequest;
+
+use utils::lsn::Lsn;
+
+use rand::prelude::*;
+use tokio::sync::Barrier;
+use tokio::task::JoinSet;
+use tracing::{debug, info, instrument};
+
+use std::collections::HashMap;
+use std::num::NonZeroUsize;
+use std::ops::Range;
+use std::sync::atomic::{AtomicU64, AtomicUsize, Ordering};
+use std::sync::{Arc, Mutex};
+use std::time::Instant;
+
+use crate::cli;
+use crate::util::tenant_timeline_id::TenantTimelineId;
+use crate::util::tokio_thread_local_stats::AllThreadLocalStats;
+use crate::util::{request_stats, tokio_thread_local_stats};
+
+/// basebackup@LatestLSN
+#[derive(clap::Parser)]
+pub(crate) struct Args {
+    #[clap(long, default_value = "http://localhost:9898")]
+    mgmt_api_endpoint: String,
+    #[clap(long, default_value = "localhost:64000")]
+    page_service_host_port: String,
+    #[clap(long)]
+    pageserver_jwt: Option<String>,
+    #[clap(long, default_value = "1")]
+    num_clients: NonZeroUsize,
+    #[clap(long, default_value = "1.0")]
+    gzip_probability: f64,
+    #[clap(long)]
+    runtime: Option<humantime::Duration>,
+    #[clap(long)]
+    limit_to_first_n_targets: Option<usize>,
+    targets: Option<Vec<TenantTimelineId>>,
+}
+
+#[derive(Debug, Default)]
+struct LiveStats {
+    completed_requests: AtomicU64,
+}
+
+impl LiveStats {
+    fn inc(&self) {
+        self.completed_requests.fetch_add(1, Ordering::Relaxed);
+    }
+}
+
+struct Target {
+    timeline: TenantTimelineId,
+    lsn_range: Option<Range<Lsn>>,
+}
+
+#[derive(serde::Serialize)]
+struct Output {
+    total: request_stats::Output,
+}
+
+tokio_thread_local_stats::declare!(STATS: request_stats::Stats);
+
+pub(crate) fn main(args: Args) -> anyhow::Result<()> {
+    tokio_thread_local_stats::main!(STATS, move |thread_local_stats| {
+        main_impl(args, thread_local_stats)
+    })
+}
+
+async fn main_impl(
+    args: Args,
+    all_thread_local_stats: AllThreadLocalStats<request_stats::Stats>,
+) -> anyhow::Result<()> {
+    let args: &'static Args = Box::leak(Box::new(args));
+
+    let mgmt_api_client = Arc::new(pageserver_client::mgmt_api::Client::new(
+        args.mgmt_api_endpoint.clone(),
+        args.pageserver_jwt.as_deref(),
+    ));
+
+    // discover targets
+    let timelines: Vec<TenantTimelineId> = cli::targets::discover(
+        &mgmt_api_client,
+        cli::targets::Spec {
+            limit_to_first_n_targets: args.limit_to_first_n_targets,
+            targets: args.targets.clone(),
+        },
+    )
+    .await?;
+    let mut js = JoinSet::new();
+    for timeline in &timelines {
+        js.spawn({
+            let timeline = *timeline;
+            // FIXME: this triggers initial logical size calculation
+            // https://github.com/neondatabase/neon/issues/6168
+            let info = mgmt_api_client
+                .timeline_info(timeline.tenant_id, timeline.timeline_id)
+                .await
+                .unwrap();
+            async move {
+                anyhow::Ok(Target {
+                    timeline,
+                    // TODO: support lsn_range != latest LSN
+                    lsn_range: Some(info.last_record_lsn..(info.last_record_lsn + 1)),
+                })
+            }
+        });
+    }
+    let mut all_targets: Vec<Target> = Vec::new();
+    while let Some(res) = js.join_next().await {
+        all_targets.push(res.unwrap().unwrap());
+    }
+
+    let live_stats = Arc::new(LiveStats::default());
+
+    let num_client_tasks = timelines.len();
+    let num_live_stats_dump = 1;
+    let num_work_sender_tasks = 1;
+
+    let start_work_barrier = Arc::new(tokio::sync::Barrier::new(
+        num_client_tasks + num_live_stats_dump + num_work_sender_tasks,
+    ));
+    let all_work_done_barrier = Arc::new(tokio::sync::Barrier::new(num_client_tasks));
+
+    tokio::spawn({
+        let stats = Arc::clone(&live_stats);
+        let start_work_barrier = Arc::clone(&start_work_barrier);
+        async move {
+            start_work_barrier.wait().await;
+            loop {
+                let start = std::time::Instant::now();
+                tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+                let completed_requests = stats.completed_requests.swap(0, Ordering::Relaxed);
+                let elapsed = start.elapsed();
+                info!(
+                    "RPS: {:.0}",
+                    completed_requests as f64 / elapsed.as_secs_f64()
+                );
+            }
+        }
+    });
+
+    let mut work_senders = HashMap::new();
+    let mut tasks = Vec::new();
+    for tl in &timelines {
+        let (sender, receiver) = tokio::sync::mpsc::channel(1); // TODO: not sure what the implications of this are
+        work_senders.insert(tl, sender);
+        tasks.push(tokio::spawn(client(
+            args,
+            *tl,
+            Arc::clone(&start_work_barrier),
+            receiver,
+            Arc::clone(&all_work_done_barrier),
+            Arc::clone(&live_stats),
+        )));
+    }
+
+    let work_sender = async move {
+        start_work_barrier.wait().await;
+        loop {
+            let (timeline, work) = {
+                let mut rng = rand::thread_rng();
+                let target = all_targets.choose(&mut rng).unwrap();
+                let lsn = target.lsn_range.clone().map(|r| rng.gen_range(r));
+                (
+                    target.timeline,
+                    Work {
+                        lsn,
+                        gzip: rng.gen_bool(args.gzip_probability),
+                    },
+                )
+            };
+            let sender = work_senders.get(&timeline).unwrap();
+            // TODO: what if this blocks?
+            sender.send(work).await.ok().unwrap();
+        }
+    };
+
+    if let Some(runtime) = args.runtime {
+        match tokio::time::timeout(runtime.into(), work_sender).await {
+            Ok(()) => unreachable!("work sender never terminates"),
+            Err(_timeout) => {
+                // this implicitly drops the work_senders, making all the clients exit
+            }
+        }
+    } else {
+        work_sender.await;
+        unreachable!("work sender never terminates");
+    }
+
+    for t in tasks {
+        t.await.unwrap();
+    }
+
+    let output = Output {
+        total: {
+            let mut agg_stats = request_stats::Stats::new();
+            for stats in all_thread_local_stats.lock().unwrap().iter() {
+                let stats = stats.lock().unwrap();
+                agg_stats.add(&stats);
+            }
+            agg_stats.output()
+        },
+    };
+
+    let output = serde_json::to_string_pretty(&output).unwrap();
+    println!("{output}");
+
+    anyhow::Ok(())
+}
+
+#[derive(Copy, Clone)]
+struct Work {
+    lsn: Option<Lsn>,
+    gzip: bool,
+}
+
+#[instrument(skip_all)]
+async fn client(
+    args: &'static Args,
+    timeline: TenantTimelineId,
+    start_work_barrier: Arc<Barrier>,
+    mut work: tokio::sync::mpsc::Receiver<Work>,
+    all_work_done_barrier: Arc<Barrier>,
+    live_stats: Arc<LiveStats>,
+) {
+    start_work_barrier.wait().await;
+
+    let client = pageserver_client::page_service::Client::new(crate::util::connstring::connstring(
+        &args.page_service_host_port,
+        args.pageserver_jwt.as_deref(),
+    ))
+    .await
+    .unwrap();
+
+    while let Some(Work { lsn, gzip }) = work.recv().await {
+        let start = Instant::now();
+        let copy_out_stream = client
+            .basebackup(&BasebackupRequest {
+                tenant_id: timeline.tenant_id,
+                timeline_id: timeline.timeline_id,
+                lsn,
+                gzip,
+            })
+            .await
+            .with_context(|| format!("start basebackup for {timeline}"))
+            .unwrap();
+
+        use futures::StreamExt;
+        let size = Arc::new(AtomicUsize::new(0));
+        copy_out_stream
+            .for_each({
+                |r| {
+                    let size = Arc::clone(&size);
+                    async move {
+                        let size = Arc::clone(&size);
+                        size.fetch_add(r.unwrap().len(), Ordering::Relaxed);
+                    }
+                }
+            })
+            .await;
+        debug!("basebackup size is {} bytes", size.load(Ordering::Relaxed));
+        let elapsed = start.elapsed();
+        live_stats.inc();
+        STATS.with(|stats| {
+            stats.borrow().lock().unwrap().observe(elapsed).unwrap();
+        });
+    }
+
+    all_work_done_barrier.wait().await;
+}

pageserver/pagebench/src/cli.rs

@@ -0,0 +1 @@
+pub(crate) mod targets;

pageserver/pagebench/src/cli/targets.rs

@@ -0,0 +1,37 @@
+use std::sync::Arc;
+
+use pageserver_client::mgmt_api;
+use tracing::info;
+
+use crate::util::{
+    discover_timelines::get_pageserver_tenant_timelines, tenant_timeline_id::TenantTimelineId,
+};
+
+pub(crate) struct Spec {
+    pub(crate) limit_to_first_n_targets: Option<usize>,
+    pub(crate) targets: Option<Vec<TenantTimelineId>>,
+}
+
+pub(crate) async fn discover(
+    api_client: &Arc<mgmt_api::Client>,
+    spec: Spec,
+) -> anyhow::Result<Vec<TenantTimelineId>> {
+    let mut timelines = if let Some(targets) = spec.targets {
+        targets
+    } else {
+        get_pageserver_tenant_timelines(api_client).await?
+    };
+
+    if let Some(limit) = spec.limit_to_first_n_targets {
+        timelines.sort(); // for determinism
+        timelines.truncate(limit);
+        if timelines.len() < limit {
+            anyhow::bail!("pageserver has less than limit_to_first_n_targets={limit} tenants");
+        }
+    }
+
+    info!("timelines:\n{:?}", timelines);
+    info!("number of timelines:\n{:?}", timelines.len());
+
+    Ok(timelines)
+}

pageserver/pagebench/src/getpage_latest_lsn.rs

@@ -0,0 +1,341 @@
+use anyhow::Context;
+use futures::future::join_all;
+use pageserver::pgdatadir_mapping::key_to_rel_block;
+use pageserver::repository;
+use pageserver_api::key::is_rel_block_key;
+use pageserver_client::page_service::RelTagBlockNo;
+
+use utils::lsn::Lsn;
+
+use rand::prelude::*;
+use tokio::sync::Barrier;
+use tokio::task::JoinSet;
+use tracing::{info, instrument};
+
+use std::collections::HashMap;
+use std::future::Future;
+use std::num::NonZeroUsize;
+use std::pin::Pin;
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::{Arc, Mutex};
+use std::time::{Duration, Instant};
+
+use crate::cli;
+
+use crate::util::tenant_timeline_id::TenantTimelineId;
+use crate::util::tokio_thread_local_stats::AllThreadLocalStats;
+use crate::util::{request_stats, tokio_thread_local_stats};
+
+/// GetPage@LatestLSN, uniformly distributed across the compute-accessible keyspace.
+#[derive(clap::Parser)]
+pub(crate) struct Args {
+    #[clap(long, default_value = "http://localhost:9898")]
+    mgmt_api_endpoint: String,
+    #[clap(long, default_value = "postgres://postgres@localhost:64000")]
+    page_service_connstring: String,
+    #[clap(long)]
+    pageserver_jwt: Option<String>,
+    #[clap(long, default_value = "1")]
+    num_clients: NonZeroUsize,
+    #[clap(long)]
+    runtime: Option<humantime::Duration>,
+    #[clap(long)]
+    per_target_rate_limit: Option<usize>,
+    #[clap(long)]
+    limit_to_first_n_targets: Option<usize>,
+    targets: Option<Vec<TenantTimelineId>>,
+}
+
+#[derive(Debug, Default)]
+struct LiveStats {
+    completed_requests: AtomicU64,
+}
+
+impl LiveStats {
+    fn inc(&self) {
+        self.completed_requests.fetch_add(1, Ordering::Relaxed);
+    }
+}
+
+#[derive(Clone)]
+struct KeyRange {
+    timeline: TenantTimelineId,
+    timeline_lsn: Lsn,
+    start: i128,
+    end: i128,
+}
+
+impl KeyRange {
+    fn len(&self) -> i128 {
+        self.end - self.start
+    }
+}
+
+#[derive(serde::Serialize)]
+struct Output {
+    total: request_stats::Output,
+}
+
+tokio_thread_local_stats::declare!(STATS: request_stats::Stats);
+
+pub(crate) fn main(args: Args) -> anyhow::Result<()> {
+    tokio_thread_local_stats::main!(STATS, move |thread_local_stats| {
+        main_impl(args, thread_local_stats)
+    })
+}
+
+async fn main_impl(
+    args: Args,
+    all_thread_local_stats: AllThreadLocalStats<request_stats::Stats>,
+) -> anyhow::Result<()> {
+    let args: &'static Args = Box::leak(Box::new(args));
+
+    let mgmt_api_client = Arc::new(pageserver_client::mgmt_api::Client::new(
+        args.mgmt_api_endpoint.clone(),
+        args.pageserver_jwt.as_deref(),
+    ));
+
+    // discover targets
+    let timelines: Vec<TenantTimelineId> = cli::targets::discover(
+        &mgmt_api_client,
+        cli::targets::Spec {
+            limit_to_first_n_targets: args.limit_to_first_n_targets,
+            targets: args.targets.clone(),
+        },
+    )
+    .await?;
+
+    let mut js = JoinSet::new();
+    for timeline in &timelines {
+        js.spawn({
+            let mgmt_api_client = Arc::clone(&mgmt_api_client);
+            let timeline = *timeline;
+            async move {
+                let partitioning = mgmt_api_client
+                    .keyspace(timeline.tenant_id, timeline.timeline_id)
+                    .await?;
+                let lsn = partitioning.at_lsn;
+
+                let ranges = partitioning
+                    .keys
+                    .ranges
+                    .iter()
+                    .filter_map(|r| {
+                        let start = r.start;
+                        let end = r.end;
+                        // filter out non-relblock keys
+                        match (is_rel_block_key(&start), is_rel_block_key(&end)) {
+                            (true, true) => Some(KeyRange {
+                                timeline,
+                                timeline_lsn: lsn,
+                                start: start.to_i128(),
+                                end: end.to_i128(),
+                            }),
+                            (true, false) | (false, true) => {
+                                unimplemented!("split up range")
+                            }
+                            (false, false) => None,
+                        }
+                    })
+                    .collect::<Vec<_>>();
+
+                anyhow::Ok(ranges)
+            }
+        });
+    }
+    let mut all_ranges: Vec<KeyRange> = Vec::new();
+    while let Some(res) = js.join_next().await {
+        all_ranges.extend(res.unwrap().unwrap());
+    }
+
+    let live_stats = Arc::new(LiveStats::default());
+
+    let num_client_tasks = timelines.len();
+    let num_live_stats_dump = 1;
+    let num_work_sender_tasks = 1;
+
+    let start_work_barrier = Arc::new(tokio::sync::Barrier::new(
+        num_client_tasks + num_live_stats_dump + num_work_sender_tasks,
+    ));
+    let all_work_done_barrier = Arc::new(tokio::sync::Barrier::new(num_client_tasks));
+
+    tokio::spawn({
+        let stats = Arc::clone(&live_stats);
+        let start_work_barrier = Arc::clone(&start_work_barrier);
+        async move {
+            start_work_barrier.wait().await;
+            loop {
+                let start = std::time::Instant::now();
+                tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+                let completed_requests = stats.completed_requests.swap(0, Ordering::Relaxed);
+                let elapsed = start.elapsed();
+                info!(
+                    "RPS: {:.0}",
+                    completed_requests as f64 / elapsed.as_secs_f64()
+                );
+            }
+        }
+    });
+
+    let mut work_senders = HashMap::new();
+    let mut tasks = Vec::new();
+    for tl in &timelines {
+        let (sender, receiver) = tokio::sync::mpsc::channel(10); // TODO: not sure what the implications of this are
+        work_senders.insert(tl, sender);
+        tasks.push(tokio::spawn(client(
+            args,
+            *tl,
+            Arc::clone(&start_work_barrier),
+            receiver,
+            Arc::clone(&all_work_done_barrier),
+            Arc::clone(&live_stats),
+        )));
+    }
+
+    let work_sender: Pin<Box<dyn Send + Future<Output = ()>>> = match args.per_target_rate_limit {
+        None => Box::pin(async move {
+            let weights = rand::distributions::weighted::WeightedIndex::new(
+                all_ranges.iter().map(|v| v.len()),
+            )
+            .unwrap();
+
+            start_work_barrier.wait().await;
+
+            loop {
+                let (range, key) = {
+                    let mut rng = rand::thread_rng();
+                    let r = &all_ranges[weights.sample(&mut rng)];
+                    let key: i128 = rng.gen_range(r.start..r.end);
+                    let key = repository::Key::from_i128(key);
+                    if key.field6 == 0xffffffff {
+                        // Hack around bug
+                        continue;
+                    }
+                    let (rel_tag, block_no) =
+                        key_to_rel_block(key).expect("we filter non-rel-block keys out above");
+                    (r, RelTagBlockNo { rel_tag, block_no })
+                };
+                let sender = work_senders.get(&range.timeline).unwrap();
+                // TODO: what if this blocks?
+                sender.send((key, range.timeline_lsn)).await.ok().unwrap();
+            }
+        }),
+        Some(rps_limit) => Box::pin(async move {
+            let period = Duration::from_secs_f64(1.0 / (rps_limit as f64));
+
+            let make_timeline_task: &dyn Fn(
+                TenantTimelineId,
+            )
+                -> Pin<Box<dyn Send + Future<Output = ()>>> = &|timeline| {
+                let sender = work_senders.get(&timeline).unwrap();
+                let ranges: Vec<KeyRange> = all_ranges
+                    .iter()
+                    .filter(|r| r.timeline == timeline)
+                    .cloned()
+                    .collect();
+                let weights = rand::distributions::weighted::WeightedIndex::new(
+                    ranges.iter().map(|v| v.len()),
+                )
+                .unwrap();
+
+                Box::pin(async move {
+                    let mut ticker = tokio::time::interval(period);
+                    ticker.set_missed_tick_behavior(
+                        /* TODO review this choice */
+                        tokio::time::MissedTickBehavior::Burst,
+                    );
+                    loop {
+                        ticker.tick().await;
+                        let (range, key) = {
+                            let mut rng = rand::thread_rng();
+                            let r = &ranges[weights.sample(&mut rng)];
+                            let key: i128 = rng.gen_range(r.start..r.end);
+                            let key = repository::Key::from_i128(key);
+                            let (rel_tag, block_no) = key_to_rel_block(key)
+                                .expect("we filter non-rel-block keys out above");
+                            (r, RelTagBlockNo { rel_tag, block_no })
+                        };
+                        sender.send((key, range.timeline_lsn)).await.ok().unwrap();
+                    }
+                })
+            };
+
+            let tasks: Vec<_> = work_senders
+                .keys()
+                .map(|tl| make_timeline_task(**tl))
+                .collect();
+
+            start_work_barrier.wait().await;
+
+            join_all(tasks).await;
+        }),
+    };
+
+    if let Some(runtime) = args.runtime {
+        match tokio::time::timeout(runtime.into(), work_sender).await {
+            Ok(()) => unreachable!("work sender never terminates"),
+            Err(_timeout) => {
+                // this implicitly drops the work_senders, making all the clients exit
+            }
+        }
+    } else {
+        work_sender.await;
+        unreachable!("work sender never terminates");
+    }
+
+    for t in tasks {
+        t.await.unwrap();
+    }
+
+    let output = Output {
+        total: {
+            let mut agg_stats = request_stats::Stats::new();
+            for stats in all_thread_local_stats.lock().unwrap().iter() {
+                let stats = stats.lock().unwrap();
+                agg_stats.add(&stats);
+            }
+            agg_stats.output()
+        },
+    };
+
+    let output = serde_json::to_string_pretty(&output).unwrap();
+    println!("{output}");
+
+    anyhow::Ok(())
+}
+
+#[instrument(skip_all)]
+async fn client(
+    args: &'static Args,
+    timeline: TenantTimelineId,
+    start_work_barrier: Arc<Barrier>,
+    mut work: tokio::sync::mpsc::Receiver<(RelTagBlockNo, Lsn)>,
+    all_work_done_barrier: Arc<Barrier>,
+    live_stats: Arc<LiveStats>,
+) {
+    start_work_barrier.wait().await;
+
+    let client = pageserver_client::page_service::Client::new(args.page_service_connstring.clone())
+        .await
+        .unwrap();
+    let mut client = client
+        .pagestream(timeline.tenant_id, timeline.timeline_id)
+        .await
+        .unwrap();
+
+    while let Some((key, lsn)) = work.recv().await {
+        let start = Instant::now();
+        client
+            .getpage(key, lsn)
+            .await
+            .with_context(|| format!("getpage for {timeline}"))
+            .unwrap();
+        let elapsed = start.elapsed();
+        live_stats.inc();
+        STATS.with(|stats| {
+            stats.borrow().lock().unwrap().observe(elapsed).unwrap();
+        });
+    }
+
+    all_work_done_barrier.wait().await;
+}

pageserver/pagebench/src/main.rs

@@ -0,0 +1,34 @@
+use clap::Parser;
+use utils::logging;
+
+pub(crate) mod cli;
+pub(crate) mod util;
+
+mod basebackup;
+mod getpage_latest_lsn;
+mod trigger_initial_size_calculation;
+
+/// Component-level performance test for pageserver.
+#[derive(clap::Parser)]
+enum Args {
+    Basebackup(basebackup::Args),
+    GetPageLatestLsn(getpage_latest_lsn::Args),
+    TriggerInitialSizeCalculation(trigger_initial_size_calculation::Args),
+}
+
+fn main() {
+    logging::init(
+        logging::LogFormat::Plain,
+        logging::TracingErrorLayerEnablement::Disabled,
+        logging::Output::Stderr,
+    )
+    .unwrap();
+
+    let args = Args::parse();
+    match args {
+        Args::Basebackup(args) => basebackup::main(args),
+        Args::GetPageLatestLsn(args) => getpage_latest_lsn::main(args),
+        Args::TriggerInitialSizeCalculation(args) => trigger_initial_size_calculation::main(args),
+    }
+    .unwrap()
+}

pageserver/pagebench/src/trigger_initial_size_calculation.rs

@@ -0,0 +1,86 @@
+use std::sync::Arc;
+
+use humantime::Duration;
+use tokio::task::JoinSet;
+
+use crate::{cli, util::tenant_timeline_id::TenantTimelineId};
+
+#[derive(clap::Parser)]
+pub(crate) struct Args {
+    #[clap(long, default_value = "http://localhost:9898")]
+    mgmt_api_endpoint: String,
+    #[clap(long, default_value = "localhost:64000")]
+    page_service_host_port: String,
+    #[clap(long)]
+    pageserver_jwt: Option<String>,
+    #[clap(
+        long,
+        help = "if specified, poll mgmt api to check whether init logical size calculation has completed"
+    )]
+    poll_for_completion: Option<Duration>,
+    #[clap(long)]
+    limit_to_first_n_targets: Option<usize>,
+    targets: Option<Vec<TenantTimelineId>>,
+}
+
+pub(crate) fn main(args: Args) -> anyhow::Result<()> {
+    let rt = tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()
+        .unwrap();
+
+    let main_task = rt.spawn(main_impl(args));
+    rt.block_on(main_task).unwrap()
+}
+
+async fn main_impl(args: Args) -> anyhow::Result<()> {
+    let args: &'static Args = Box::leak(Box::new(args));
+
+    let mgmt_api_client = Arc::new(pageserver_client::mgmt_api::Client::new(
+        args.mgmt_api_endpoint.clone(),
+        args.pageserver_jwt.as_deref(),
+    ));
+
+    // discover targets
+    let timelines: Vec<TenantTimelineId> = cli::targets::discover(
+        &mgmt_api_client,
+        cli::targets::Spec {
+            limit_to_first_n_targets: args.limit_to_first_n_targets,
+            targets: args.targets.clone(),
+        },
+    )
+    .await?;
+
+    // kick it off
+
+    let mut js = JoinSet::new();
+    for tl in timelines {
+        let mgmt_api_client = Arc::clone(&mgmt_api_client);
+        js.spawn(async move {
+            // TODO: API to explicitly trigger initial logical size computation.
+            // Should probably also avoid making it a side effect of timeline details to trigger initial logical size calculation.
+            // => https://github.com/neondatabase/neon/issues/6168
+            let info = mgmt_api_client
+                .timeline_info(tl.tenant_id, tl.timeline_id)
+                .await
+                .unwrap();
+
+            if let Some(period) = args.poll_for_completion {
+                let mut ticker = tokio::time::interval(period.into());
+                ticker.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Delay);
+                let mut info = info;
+                while !info.current_logical_size_is_accurate {
+                    ticker.tick().await;
+                    info = mgmt_api_client
+                        .timeline_info(tl.tenant_id, tl.timeline_id)
+                        .await
+                        .unwrap();
+                }
+            }
+        });
+    }
+    while let Some(res) = js.join_next().await {
+        let _: () = res.unwrap();
+    }
+    Ok(())
+}

pageserver/pagebench/src/util.rs

@@ -0,0 +1,6 @@
+pub(crate) mod connstring;
+pub(crate) mod discover_timelines;
+pub(crate) mod request_stats;
+pub(crate) mod tenant_timeline_id;
+#[macro_use]
+pub(crate) mod tokio_thread_local_stats;

pageserver/pagebench/src/util/connstring.rs

@@ -0,0 +1,8 @@
+pub(crate) fn connstring(host_port: &str, jwt: Option<&str>) -> String {
+    let colon_and_jwt = if let Some(jwt) = jwt {
+        format!(":{jwt}") // TODO: urlescape
+    } else {
+        String::new()
+    };
+    format!("postgres://postgres{colon_and_jwt}@{host_port}")
+}

pageserver/pagebench/src/util/discover_timelines.rs

@@ -0,0 +1,45 @@
+use std::sync::Arc;
+
+use pageserver_client::mgmt_api;
+use tokio::task::JoinSet;
+use utils::id::TenantId;
+
+use super::tenant_timeline_id::TenantTimelineId;
+
+pub(crate) async fn get_pageserver_tenant_timelines(
+    api_client: &Arc<mgmt_api::Client>,
+) -> anyhow::Result<Vec<TenantTimelineId>> {
+    let mut timelines: Vec<TenantTimelineId> = Vec::new();
+    let mut tenants: Vec<TenantId> = Vec::new();
+    for ti in api_client.list_tenants().await? {
+        if !ti.id.is_unsharded() {
+            anyhow::bail!(
+                "only unsharded tenants are supported at this time: {}",
+                ti.id
+            );
+        }
+        tenants.push(ti.id.tenant_id)
+    }
+    let mut js = JoinSet::new();
+    for tenant_id in tenants {
+        js.spawn({
+            let mgmt_api_client = Arc::clone(api_client);
+            async move {
+                (
+                    tenant_id,
+                    mgmt_api_client.tenant_details(tenant_id).await.unwrap(),
+                )
+            }
+        });
+    }
+    while let Some(res) = js.join_next().await {
+        let (tenant_id, details) = res.unwrap();
+        for timeline_id in details.timelines {
+            timelines.push(TenantTimelineId {
+                tenant_id,
+                timeline_id,
+            });
+        }
+    }
+    Ok(timelines)
+}

pageserver/pagebench/src/util/request_stats.rs

@@ -0,0 +1,88 @@
+use std::time::Duration;
+
+use anyhow::Context;
+
+pub(crate) struct Stats {
+    latency_histo: hdrhistogram::Histogram<u64>,
+}
+
+impl Stats {
+    pub(crate) fn new() -> Self {
+        Self {
+            // Initialize with fixed bounds so that we panic at runtime instead of resizing the histogram,
+            // which would skew the benchmark results.
+            latency_histo: hdrhistogram::Histogram::new_with_bounds(1, 1_000_000_000, 3).unwrap(),
+        }
+    }
+    pub(crate) fn observe(&mut self, latency: Duration) -> anyhow::Result<()> {
+        let micros: u64 = latency
+            .as_micros()
+            .try_into()
+            .context("latency greater than u64")?;
+        self.latency_histo
+            .record(micros)
+            .context("add to histogram")?;
+        Ok(())
+    }
+    pub(crate) fn output(&self) -> Output {
+        let latency_percentiles = std::array::from_fn(|idx| {
+            let micros = self
+                .latency_histo
+                .value_at_percentile(LATENCY_PERCENTILES[idx]);
+            Duration::from_micros(micros)
+        });
+        Output {
+            request_count: self.latency_histo.len(),
+            latency_mean: Duration::from_micros(self.latency_histo.mean() as u64),
+            latency_percentiles: LatencyPercentiles {
+                latency_percentiles,
+            },
+        }
+    }
+    pub(crate) fn add(&mut self, other: &Self) {
+        let Self {
+            ref mut latency_histo,
+        } = self;
+        latency_histo.add(&other.latency_histo).unwrap();
+    }
+}
+
+impl Default for Stats {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+const LATENCY_PERCENTILES: [f64; 4] = [95.0, 99.00, 99.90, 99.99];
+
+struct LatencyPercentiles {
+    latency_percentiles: [Duration; 4],
+}
+
+impl serde::Serialize for LatencyPercentiles {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        use serde::ser::SerializeMap;
+        let mut ser = serializer.serialize_map(Some(LATENCY_PERCENTILES.len()))?;
+        for p in LATENCY_PERCENTILES {
+            ser.serialize_entry(
+                &format!("p{p}"),
+                &format!(
+                    "{}",
+                    &humantime::format_duration(self.latency_percentiles[0])
+                ),
+            )?;
+        }
+        ser.end()
+    }
+}
+
+#[derive(serde::Serialize)]
+pub(crate) struct Output {
+    request_count: u64,
+    #[serde(with = "humantime_serde")]
+    latency_mean: Duration,
+    latency_percentiles: LatencyPercentiles,
+}

pageserver/pagebench/src/util/tenant_timeline_id.rs

@@ -0,0 +1,34 @@
+use std::str::FromStr;
+
+use anyhow::Context;
+use utils::id::{TenantId, TimelineId};
+
+#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy, PartialOrd, Ord)]
+pub(crate) struct TenantTimelineId {
+    pub(crate) tenant_id: TenantId,
+    pub(crate) timeline_id: TimelineId,
+}
+
+impl FromStr for TenantTimelineId {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let (tenant_id, timeline_id) = s
+            .split_once('/')
+            .context("tenant and timeline id must be separated by `/`")?;
+        let tenant_id = TenantId::from_str(tenant_id)
+            .with_context(|| format!("invalid tenant id: {tenant_id:?}"))?;
+        let timeline_id = TimelineId::from_str(timeline_id)
+            .with_context(|| format!("invalid timeline id: {timeline_id:?}"))?;
+        Ok(Self {
+            tenant_id,
+            timeline_id,
+        })
+    }
+}
+
+impl std::fmt::Display for TenantTimelineId {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}/{}", self.tenant_id, self.timeline_id)
+    }
+}

pageserver/pagebench/src/util/tokio_thread_local_stats.rs

@@ -0,0 +1,45 @@
+pub(crate) type ThreadLocalStats<T> = Arc<Mutex<T>>;
+pub(crate) type AllThreadLocalStats<T> = Arc<Mutex<Vec<ThreadLocalStats<T>>>>;
+
+macro_rules! declare {
+    ($THREAD_LOCAL_NAME:ident: $T:ty) => {
+        thread_local! {
+            pub static $THREAD_LOCAL_NAME: std::cell::RefCell<crate::util::tokio_thread_local_stats::ThreadLocalStats<$T>> = std::cell::RefCell::new(
+                std::sync::Arc::new(std::sync::Mutex::new(Default::default()))
+            );
+        }
+    };
+}
+
+use std::sync::{Arc, Mutex};
+
+pub(crate) use declare;
+
+macro_rules! main {
+    ($THREAD_LOCAL_NAME:ident, $main_impl:expr) => {{
+        let main_impl = $main_impl;
+        let all = Arc::new(Mutex::new(Vec::new()));
+
+        let rt = tokio::runtime::Builder::new_multi_thread()
+            .on_thread_start({
+                let all = Arc::clone(&all);
+                move || {
+                    // pre-initialize the thread local stats by accessesing them
+                    // (some stats like requests_stats::Stats are quite costly to initialize,
+                    //  we don't want to pay that cost during the measurement period)
+                    $THREAD_LOCAL_NAME.with(|stats| {
+                        let stats: Arc<_> = Arc::clone(&*stats.borrow());
+                        all.lock().unwrap().push(stats);
+                    });
+                }
+            })
+            .enable_all()
+            .build()
+            .unwrap();
+
+        let main_task = rt.spawn(main_impl(all));
+        rt.block_on(main_task).unwrap()
+    }};
+}
+
+pub(crate) use main;

pageserver/src/http/routes.rs

@@ -14,6 +14,7 @@ use hyper::header;
 use hyper::StatusCode;
 use hyper::{Body, Request, Response, Uri};
 use metrics::launch_timestamp::LaunchTimestamp;
+use pageserver_api::models::TenantDetails;
 use pageserver_api::models::{
     DownloadRemoteLayersTaskSpawnRequest, LocationConfigMode, TenantAttachRequest,
     TenantLoadRequest, TenantLocationConfigRequest,
@@ -872,11 +873,14 @@ async fn tenant_status(
         }
 
         let state = tenant.current_state();
-        Result::<_, ApiError>::Ok(TenantInfo {
+        Result::<_, ApiError>::Ok(TenantDetails {
+            tenant_info: TenantInfo {
                 id: tenant_shard_id,
                 state: state.clone(),
                 current_physical_size: Some(current_physical_size),
                 attachment_status: state.attachment_status(),
+            },
+            timelines: tenant.list_timeline_ids(),
         })
     }
     .instrument(info_span!("tenant_status_handler",

pageserver/src/metrics.rs

@@ -343,15 +343,6 @@ pub(crate) mod page_cache_eviction_metrics {
     }
 }
 
-pub(crate) static PAGE_CACHE_ACQUIRE_PINNED_SLOT_TIME: Lazy<Histogram> = Lazy::new(|| {
-    register_histogram!(
-        "pageserver_page_cache_acquire_pinned_slot_seconds",
-        "Time spent acquiring a pinned slot in the page cache",
-        CRITICAL_OP_BUCKETS.into(),
-    )
-    .expect("failed to define a metric")
-});
-
 static PAGE_CACHE_ERRORS: Lazy<IntCounterVec> = Lazy::new(|| {
     register_int_counter_vec!(
         "page_cache_errors_total",

pageserver/src/page_cache.rs

@@ -550,7 +550,6 @@ impl PageCache {
     // not require changes.
 
     async fn try_get_pinned_slot_permit(&self) -> anyhow::Result<PinnedSlotsPermit> {
-        let timer = crate::metrics::PAGE_CACHE_ACQUIRE_PINNED_SLOT_TIME.start_timer();
         match tokio::time::timeout(
             // Choose small timeout, neon_smgr does its own retries.
             // https://neondb.slack.com/archives/C04DGM6SMTM/p1694786876476869
@@ -563,7 +562,6 @@ impl PageCache {
                 res.expect("this semaphore is never closed"),
             )),
             Err(_timeout) => {
-                timer.stop_and_discard();
                 crate::metrics::page_cache_errors_inc(
                     crate::metrics::PageCacheErrorKind::AcquirePinnedSlotTimeout,
                 );

pageserver/src/pgdatadir_mapping.rs

@@ -173,14 +173,25 @@ impl Timeline {
             ));
         }
 
-        let nblocks = self.get_rel_size(tag, lsn, latest, ctx).await?;
+        // let nblocks = self.get_rel_size(tag, lsn, latest, ctx).await?;
-        if blknum >= nblocks {
+        // if blknum >= nblocks {
-            debug!(
+        //     tracing::info!(
-                "read beyond EOF at {} blk {} at {}, size is {}: returning all-zeros page",
+        //         "read beyond EOF at {} blk {} at {}, size is {}: returning all-zeros page",
-                tag, blknum, lsn, nblocks
+        //         tag,
-            );
+        //         blknum,
-            return Ok(ZERO_PAGE.clone());
+        //         lsn,
-        }
+        //         nblocks
+        //     );
+        //     return Ok(ZERO_PAGE.clone());
+        // } else {
+        //     tracing::info!(
+        //         "read within bounds at {} blk {} at {}, size is {}",
+        //         tag,
+        //         blknum,
+        //         lsn,
+        //         nblocks
+        //     );
+        // }
 
         let key = rel_block_to_key(tag, blknum);
         self.get(key, lsn, ctx).await
@@ -235,6 +246,7 @@ impl Timeline {
         }
 
         let key = rel_size_to_key(tag);
+        tracing::info!("rel size cache miss {tag} {lsn} {latest}");
         let mut buf = self.get(key, lsn, ctx).await?;
         let nblocks = buf.get_u32_le();
 
@@ -1776,6 +1788,7 @@ pub fn is_inherited_key(key: Key) -> bool {
     key != AUX_FILES_KEY
 }
 
+/// Guaranteed to return `Ok()` if [[is_rel_block_key]] returns `true` for `key`.
 pub fn key_to_rel_block(key: Key) -> anyhow::Result<(RelTag, BlockNumber)> {
     Ok(match key.field1 {
         0x00 => (
@@ -1790,7 +1803,6 @@ pub fn key_to_rel_block(key: Key) -> anyhow::Result<(RelTag, BlockNumber)> {
         _ => anyhow::bail!("unexpected value kind 0x{:02x}", key.field1),
     })
 }
-
 pub fn is_rel_fsm_block_key(key: Key) -> bool {
     key.field1 == 0x00 && key.field4 != 0 && key.field5 == FSM_FORKNUM && key.field6 != 0xffffffff
 }

pageserver/src/tenant.rs

@@ -1552,6 +1552,10 @@ impl Tenant {
             .collect()
     }
 
+    pub fn list_timeline_ids(&self) -> Vec<TimelineId> {
+        self.timelines.lock().unwrap().keys().cloned().collect()
+    }
+
     /// This is used to create the initial 'main' timeline during bootstrapping,
     /// or when importing a new base backup. The caller is expected to load an
     /// initial image of the datadir to the new timeline after this.

pageserver/src/tenant/block_io.rs

@@ -22,6 +22,8 @@ pub trait BlockReader {
     /// A cursor caches the last accessed page, allowing for faster
     /// access if the same block is accessed repeatedly.
     fn block_cursor(&self) -> BlockCursor<'_>;
+
+    fn block_cursor_direct(&self) -> BlockCursor<'_>;
 }
 
 impl<B> BlockReader for &B
@@ -31,12 +33,17 @@ where
     fn block_cursor(&self) -> BlockCursor<'_> {
         (*self).block_cursor()
     }
+
+    fn block_cursor_direct(&self) -> BlockCursor<'_> {
+        (*self).block_cursor()
+    }
 }
 
 /// Reference to an in-memory copy of an immutable on-disk block.
 pub enum BlockLease<'a> {
     PageReadGuard(PageReadGuard<'static>),
     EphemeralFileMutableTail(&'a [u8; PAGE_SZ]),
+    Direct(bytes::Bytes),
     #[cfg(test)]
     Arc(std::sync::Arc<[u8; PAGE_SZ]>),
 }
@@ -61,6 +68,7 @@ impl<'a> Deref for BlockLease<'a> {
         match self {
             BlockLease::PageReadGuard(v) => v.deref(),
             BlockLease::EphemeralFileMutableTail(v) => v,
+            BlockLease::Direct(b) => <&[u8; PAGE_SZ]>::try_from(b as &[u8]).unwrap(),
             #[cfg(test)]
             BlockLease::Arc(v) => v.deref(),
         }
@@ -99,6 +107,24 @@ impl<'a> BlockReaderRef<'a> {
             VirtualFile(r) => r.read_blk(blknum).await,
         }
     }
+
+    #[inline(always)]
+    async fn read_blk_direct(
+        &self,
+        blknum: u32,
+        ctx: &RequestContext,
+    ) -> Result<BlockLease, std::io::Error> {
+        use BlockReaderRef::*;
+        match self {
+            FileBlockReader(r) => r.read_blk_direct(blknum, ctx).await,
+            EphemeralFile(r) => r.read_blk(blknum, ctx).await,
+            Adapter(r) => r.read_blk(blknum, ctx).await,
+            #[cfg(test)]
+            TestDisk(r) => r.read_blk(blknum),
+            #[cfg(test)]
+            VirtualFile(r) => r.read_blk(blknum).await,
+        }
+    }
 }
 
 ///
@@ -121,17 +147,28 @@ impl<'a> BlockReaderRef<'a> {
 /// ```
 ///
 pub struct BlockCursor<'a> {
+    direct: bool,
     reader: BlockReaderRef<'a>,
 }
 
 impl<'a> BlockCursor<'a> {
     pub(crate) fn new(reader: BlockReaderRef<'a>) -> Self {
-        BlockCursor { reader }
+        BlockCursor {
+            reader,
+            direct: false,
+        }
+    }
+    pub(crate) fn new_direct(reader: BlockReaderRef<'a>) -> Self {
+        BlockCursor {
+            reader,
+            direct: true,
+        }
     }
     // Needed by cli
     pub fn new_fileblockreader(reader: &'a FileBlockReader) -> Self {
         BlockCursor {
             reader: BlockReaderRef::FileBlockReader(reader),
+            direct: false,
         }
     }
 
@@ -146,8 +183,12 @@ impl<'a> BlockCursor<'a> {
         blknum: u32,
         ctx: &RequestContext,
     ) -> Result<BlockLease, std::io::Error> {
+        if self.direct {
+            self.reader.read_blk_direct(blknum, ctx).await
+        } else {
             self.reader.read_blk(blknum, ctx).await
         }
+    }
 }
 
 /// An adapter for reading a (virtual) file using the page cache.
@@ -203,12 +244,27 @@ impl FileBlockReader {
             }
         }
     }
+
+    pub async fn read_blk_direct(
+        &self,
+        blknum: u32,
+        _ctx: &RequestContext,
+    ) -> Result<BlockLease, std::io::Error> {
+        let mut buf = bytes::BytesMut::zeroed(PAGE_SZ);
+        let buffer = <&mut [u8; PAGE_SZ]>::try_from(&mut buf as &mut [u8]).unwrap();
+        self.fill_buffer(buffer, blknum).await?;
+        Ok(BlockLease::Direct(buf.into()))
+    }
 }
 
 impl BlockReader for FileBlockReader {
     fn block_cursor(&self) -> BlockCursor<'_> {
         BlockCursor::new(BlockReaderRef::FileBlockReader(self))
     }
+
+    fn block_cursor_direct(&self) -> BlockCursor<'_> {
+        BlockCursor::new_direct(BlockReaderRef::FileBlockReader(self))
+    }
 }
 
 ///

pageserver/src/tenant/ephemeral_file.rs

@@ -266,6 +266,10 @@ impl BlockReader for EphemeralFile {
     fn block_cursor(&self) -> super::block_io::BlockCursor<'_> {
         BlockCursor::new(super::block_io::BlockReaderRef::EphemeralFile(self))
     }
+
+    fn block_cursor_direct(&self) -> super::block_io::BlockCursor<'_> {
+        BlockCursor::new(super::block_io::BlockReaderRef::EphemeralFile(self))
+    }
 }
 
 #[cfg(test)]

pageserver/src/tenant/storage_layer/delta_layer.rs

@@ -770,7 +770,7 @@ impl DeltaLayerInner {
             .build();
 
         // Ok, 'offsets' now contains the offsets of all the entries we need to read
-        let cursor = file.block_cursor();
+        let cursor = file.block_cursor_direct();
         let mut buf = Vec::new();
         for (entry_lsn, pos) in offsets {
             cursor

pageserver/src/tenant/storage_layer/image_layer.rs

@@ -427,7 +427,7 @@ impl ImageLayerInner {
             .await?
         {
             let blob = file
-                .block_cursor()
+                .block_cursor_direct()
                 .read_blob(
                     offset,
                     &RequestContextBuilder::extend(ctx)

pageserver/src/tenant/timeline.rs

@@ -14,6 +14,7 @@ use enumset::EnumSet;
 use fail::fail_point;
 use itertools::Itertools;
 use pageserver_api::{
+    key::is_rel_block_key,
     models::{
         DownloadRemoteLayersTaskInfo, DownloadRemoteLayersTaskSpawnRequest, LayerMapInfo,
         TimelineState,
@@ -508,7 +509,10 @@ impl Timeline {
         // The cached image can be returned directly if there is no WAL between the cached image
         // and requested LSN. The cached image can also be used to reduce the amount of WAL needed
         // for redo.
-        let cached_page_img = match self.lookup_cached_page(&key, lsn, ctx).await {
+        let cached_page_img = if is_rel_block_key(&key) && key.field6 != 0xffffffff {
+            None
+        } else {
+            match self.lookup_cached_page(&key, lsn, ctx).await {
                 Some((cached_lsn, cached_img)) => {
                     match cached_lsn.cmp(&lsn) {
                         Ordering::Less => {} // there might be WAL between cached_lsn and lsn, we need to check
@@ -523,6 +527,7 @@ impl Timeline {
                     Some((cached_lsn, cached_img))
                 }
                 None => None,
+            }
         };
 
         let mut reconstruct_state = ValueReconstructState {
@@ -4189,7 +4194,9 @@ impl Timeline {
                     Err(e) => return Err(PageReconstructError::from(e)),
                 };
 
-                if img.len() == page_cache::PAGE_SZ {
+                if img.len() == page_cache::PAGE_SZ
+                    && !(is_rel_block_key(&key) && key.field6 != 0xffffffff)
+                {
                     let cache = page_cache::get();
                     if let Err(e) = cache
                         .memorize_materialized_page(