pageserver: only apply ClearVmBits on relevant shards

Log relation existence
Log when vm_size=0
2026-05-01 21:30:37 +00:00 · 2024-11-26 17:30:21 +01:00 · 2024-11-26 13:43:04 +01:00 · 2024-11-26 12:11:04 +01:00 · 2024-11-26 10:51:48 +01:00 · 2024-11-22 12:45:14 +01:00
14 changed files with 393 additions and 29 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -46,6 +46,15 @@ dependencies = [
 "memchr",
 ]

+[[package]]
+name = "aligned-vec"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7e0966165eaf052580bd70eb1b32cb3d6245774c0104d1b2793e9650bf83b52a"
+dependencies = [
+ "equator",
+]
+
 [[package]]
 name = "allocator-api2"
 version = "0.2.16"
@@ -146,6 +155,12 @@ dependencies = [
 "static_assertions",
 ]

+[[package]]
+name = "arrayvec"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
+
 [[package]]
 name = "asn1-rs"
 version = "0.6.2"
@@ -742,7 +757,7 @@ dependencies = [
 "once_cell",
 "paste",
 "pin-project",
- "quick-xml",
+ "quick-xml 0.31.0",
 "rand 0.8.5",
 "reqwest 0.11.19",
 "rustc_version",
@@ -1381,6 +1396,15 @@ version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e496a50fda8aacccc86d7529e2c1e0892dbd0f898a6b5645b5561b89c3210efa"

+[[package]]
+name = "cpp_demangle"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96e58d342ad113c2b878f16d5d034c03be492ae460cdbc02b7f0f2284d310c7d"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "cpufeatures"
 version = "0.2.9"
@@ -1904,6 +1928,26 @@ dependencies = [
 "termcolor",
 ]

+[[package]]
+name = "equator"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c35da53b5a021d2484a7cc49b2ac7f2d840f8236a286f84202369bd338d761ea"
+dependencies = [
+ "equator-macro",
+]
+
+[[package]]
+name = "equator-macro"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3bf679796c0322556351f287a51b49e48f7c4986e727b5dd78c972d30e2e16cc"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.52",
+]
+
 [[package]]
 name = "equivalent"
 version = "1.0.1"
@@ -2011,6 +2055,18 @@ dependencies = [
 "windows-sys 0.48.0",
 ]

+[[package]]
+name = "findshlibs"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40b9e59cd0f7e0806cca4be089683ecb6434e602038df21fe6bf6711b2f07f64"
+dependencies = [
+ "cc",
+ "lazy_static",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "fixedbitset"
 version = "0.4.2"
@@ -2714,6 +2770,24 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "64e9829a50b42bb782c1df523f78d332fe371b10c661e78b7a3c34b0198e9fac"

+[[package]]
+name = "inferno"
+version = "0.11.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "232929e1d75fe899576a3d5c7416ad0d88dbfbb3c3d6aa00873a7408a50ddb88"
+dependencies = [
+ "ahash",
+ "indexmap 2.0.1",
+ "is-terminal",
+ "itoa",
+ "log",
+ "num-format",
+ "once_cell",
+ "quick-xml 0.26.0",
+ "rgb",
+ "str_stack",
+]
+
 [[package]]
 name = "inotify"
 version = "0.9.6"
@@ -3053,6 +3127,15 @@ version = "2.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f665ee40bc4a3c5590afb1e9677db74a508659dfd71e126420da8274909a0167"

+[[package]]
+name = "memmap2"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "45fd3a57831bf88bc63f8cebc0cf956116276e97fef3966103e96416209f7c92"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "memoffset"
 version = "0.7.1"
@@ -3278,6 +3361,16 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "51d515d32fb182ee37cda2ccdcb92950d6a3c2893aa280e540671c2cd0f3b1d9"

+[[package]]
+name = "num-format"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a652d9771a63711fd3c3deb670acfbe5c30a4072e664d7a3bf5a9e1056ac72c3"
+dependencies = [
+ "arrayvec",
+ "itoa",
+]
+
 [[package]]
 name = "num-integer"
 version = "0.1.45"
@@ -4108,6 +4201,31 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"

+[[package]]
+name = "pprof"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ebbe2f8898beba44815fdc9e5a4ae9c929e21c5dc29b0c774a15555f7f58d6d0"
+dependencies = [
+ "aligned-vec",
+ "backtrace",
+ "cfg-if",
+ "criterion",
+ "findshlibs",
+ "inferno",
+ "libc",
+ "log",
+ "nix 0.26.4",
+ "once_cell",
+ "parking_lot 0.12.1",
+ "protobuf",
+ "protobuf-codegen-pure",
+ "smallvec",
+ "symbolic-demangle",
+ "tempfile",
+ "thiserror",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.17"
@@ -4260,6 +4378,31 @@ dependencies = [
 "prost",
 ]

+[[package]]
+name = "protobuf"
+version = "2.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "106dd99e98437432fed6519dedecfade6a06a73bb7b2a1e019fdd2bee5778d94"
+
+[[package]]
+name = "protobuf-codegen"
+version = "2.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "033460afb75cf755fcfc16dfaed20b86468082a2ea24e05ac35ab4a099a017d6"
+dependencies = [
+ "protobuf",
+]
+
+[[package]]
+name = "protobuf-codegen-pure"
+version = "2.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95a29399fc94bcd3eeaa951c715f7bea69409b2445356b00519740bcd6ddd865"
+dependencies = [
+ "protobuf",
+ "protobuf-codegen",
+]
+
 [[package]]
 name = "proxy"
 version = "0.1.0"
@@ -4371,6 +4514,15 @@ dependencies = [
 "zerocopy",
 ]

+[[package]]
+name = "quick-xml"
+version = "0.26.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f50b1c63b38611e7d4d7f68b82d3ad0cc71a2ad2e7f61fc10f1328d917c93cd"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "quick-xml"
 version = "0.31.0"
@@ -4853,6 +5005,15 @@ dependencies = [
 "subtle",
 ]

+[[package]]
+name = "rgb"
+version = "0.8.50"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57397d16646700483b67d2dd6511d79318f9d057fdbd21a4066aeac8b41d310a"
+dependencies = [
+ "bytemuck",
+]
+
 [[package]]
 name = "ring"
 version = "0.17.6"
@@ -5166,6 +5327,7 @@ dependencies = [
 "postgres-protocol",
 "postgres_backend",
 "postgres_ffi",
+ "pprof",
 "pq_proto",
 "rand 0.8.5",
 "regex",
@@ -5712,6 +5874,12 @@ dependencies = [
 "der 0.7.8",
 ]

+[[package]]
+name = "stable_deref_trait"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a8f112729512f8e442d81f95a8a7ddf2b7c6b8a1a6f509a95864142b30cab2d3"
+
 [[package]]
 name = "static_assertions"
 version = "1.1.0"
@@ -5858,6 +6026,12 @@ dependencies = [
 "workspace_hack",
 ]

+[[package]]
+name = "str_stack"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9091b6114800a5f2141aee1d1b9d6ca3592ac062dc5decb3764ec5895a47b4eb"
+
 [[package]]
 name = "stringprep"
 version = "0.1.2"
@@ -5905,6 +6079,29 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20e16a0f46cf5fd675563ef54f26e83e20f2366bcf027bcb3cc3ed2b98aaf2ca"

+[[package]]
+name = "symbolic-common"
+version = "12.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "366f1b4c6baf6cfefc234bbd4899535fca0b06c74443039a73f6dfb2fad88d77"
+dependencies = [
+ "debugid",
+ "memmap2",
+ "stable_deref_trait",
+ "uuid",
+]
+
+[[package]]
+name = "symbolic-demangle"
+version = "12.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aba05ba5b9962ea5617baf556293720a8b2d0a282aa14ee4bf10e22efc7da8c8"
+dependencies = [
+ "cpp_demangle",
+ "rustc-demangle",
+ "symbolic-common",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.109"
@@ -6772,6 +6969,7 @@ dependencies = [
 "once_cell",
 "pin-project-lite",
 "postgres_connection",
+ "pprof",
 "pq_proto",
 "rand 0.8.5",
 "regex",
@@ -7340,6 +7538,7 @@ dependencies = [
 "libc",
 "log",
 "memchr",
+ "nix 0.26.4",
 "nom",
 "num-bigint",
 "num-integer",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -130,6 +130,7 @@ parquet = { version = "53", default-features = false, features = ["zstd"] }
 parquet_derive = "53"
 pbkdf2 = { version = "0.12.1", features = ["simple", "std"] }
 pin-project-lite = "0.2"
+pprof = { version = "0.14", features = ["criterion", "flamegraph", "protobuf", "protobuf-codec"] }
 procfs = "0.16"
 prometheus = {version = "0.13", default-features=false, features = ["process"]} # removes protobuf dependency
 prost = "0.13"
--- a/libs/utils/Cargo.toml
+++ b/libs/utils/Cargo.toml
@@ -29,6 +29,7 @@ jsonwebtoken.workspace = true
 nix.workspace = true
 once_cell.workspace = true
 pin-project-lite.workspace = true
+pprof.workspace = true
 regex.workspace = true
 routerify.workspace = true
 serde.workspace = true
--- a/libs/utils/src/http/endpoint.rs
+++ b/libs/utils/src/http/endpoint.rs
@@ -1,7 +1,8 @@
 use crate::auth::{AuthError, Claims, SwappableJwtAuth};
 use crate::http::error::{api_error_handler, route_error_handler, ApiError};
-use anyhow::Context;
-use hyper::header::{HeaderName, AUTHORIZATION};
+use crate::http::request::{get_query_param, parse_query_param};
+use anyhow::{anyhow, Context};
+use hyper::header::{HeaderName, AUTHORIZATION, CONTENT_DISPOSITION};
 use hyper::http::HeaderValue;
 use hyper::Method;
 use hyper::{header::CONTENT_TYPE, Body, Request, Response};
@@ -12,11 +13,13 @@ use routerify::{Middleware, RequestInfo, Router, RouterBuilder};
 use tracing::{debug, info, info_span, warn, Instrument};

 use std::future::Future;
+use std::io::Write as _;
 use std::str::FromStr;
+use std::time::Duration;

 use bytes::{Bytes, BytesMut};
-use std::io::Write as _;
-use tokio::sync::mpsc;
+use pprof::protos::Message as _;
+use tokio::sync::{mpsc, Mutex};
 use tokio_stream::wrappers::ReceiverStream;

 static SERVE_METRICS_COUNT: Lazy<IntCounter> = Lazy::new(|| {
@@ -328,6 +331,82 @@ pub async fn prometheus_metrics_handler(_req: Request<Body>) -> Result<Response<
    Ok(response)
 }

+/// Generates CPU profiles.
+pub async fn profile_cpu_handler(req: Request<Body>) -> Result<Response<Body>, ApiError> {
+    enum Format {
+        Pprof,
+        Svg,
+    }
+
+    // Parameters.
+    let format = match get_query_param(&req, "format")?.as_deref() {
+        None => Format::Pprof,
+        Some("pprof") => Format::Pprof,
+        Some("svg") => Format::Svg,
+        Some(format) => return Err(ApiError::BadRequest(anyhow!("invalid format {format}"))),
+    };
+    let seconds = match parse_query_param(&req, "seconds")? {
+        None => 5,
+        Some(seconds @ 1..=30) => seconds,
+        Some(_) => return Err(ApiError::BadRequest(anyhow!("duration must be 1-30 secs"))),
+    };
+    let frequency_hz = match parse_query_param(&req, "frequency")? {
+        None => 99,
+        Some(1001..) => return Err(ApiError::BadRequest(anyhow!("frequency must be <=1000 Hz"))),
+        Some(frequency) => frequency,
+    };
+
+    // Only allow one profiler at a time.
+    static PROFILE_LOCK: Lazy<Mutex<()>> = Lazy::new(|| Mutex::new(()));
+    let _lock = PROFILE_LOCK
+        .try_lock()
+        .map_err(|_| ApiError::Conflict("profiler already running".into()))?;
+
+    // Take the profile.
+    let report = tokio::task::spawn_blocking(move || {
+        let guard = pprof::ProfilerGuardBuilder::default()
+            .frequency(frequency_hz)
+            .blocklist(&["libc", "libgcc", "pthread", "vdso"])
+            .build()?;
+        std::thread::sleep(Duration::from_secs(seconds));
+        guard.report().build()
+    })
+    .await
+    .map_err(|join_err| ApiError::InternalServerError(join_err.into()))?
+    .map_err(|pprof_err| ApiError::InternalServerError(pprof_err.into()))?;
+
+    // Return the report in the requested format.
+    match format {
+        Format::Pprof => {
+            let mut body = Vec::new();
+            report
+                .pprof()
+                .map_err(|err| ApiError::InternalServerError(err.into()))?
+                .write_to_vec(&mut body)
+                .map_err(|err| ApiError::InternalServerError(err.into()))?;
+
+            Response::builder()
+                .status(200)
+                .header(CONTENT_TYPE, "application/octet-stream")
+                .header(CONTENT_DISPOSITION, "attachment; filename=\"profile.pb\"")
+                .body(Body::from(body))
+                .map_err(|err| ApiError::InternalServerError(err.into()))
+        }
+
+        Format::Svg => {
+            let mut body = Vec::new();
+            report
+                .flamegraph(&mut body)
+                .map_err(|err| ApiError::InternalServerError(err.into()))?;
+            Response::builder()
+                .status(200)
+                .header(CONTENT_TYPE, "image/svg+xml")
+                .body(Body::from(body))
+                .map_err(|err| ApiError::InternalServerError(err.into()))
+        }
+    }
+}
+
 pub fn add_request_id_middleware<B: hyper::body::HttpBody + Send + Sync + 'static>(
 ) -> Middleware<B, ApiError> {
    Middleware::pre(move |req| async move {
--- a/libs/utils/src/http/request.rs
+++ b/libs/utils/src/http/request.rs
@@ -30,7 +30,7 @@ pub fn parse_request_param<T: FromStr>(
    }
 }

-fn get_query_param<'a>(
+pub fn get_query_param<'a>(
    request: &'a Request<Body>,
    param_name: &str,
 ) -> Result<Option<Cow<'a, str>>, ApiError> {
--- a/pageserver/src/http/routes.rs
+++ b/pageserver/src/http/routes.rs
@@ -55,6 +55,7 @@ use tokio_util::sync::CancellationToken;
 use tracing::*;
 use utils::auth::JwtAuth;
 use utils::failpoint_support::failpoints_handler;
+use utils::http::endpoint::profile_cpu_handler;
 use utils::http::endpoint::prometheus_metrics_handler;
 use utils::http::endpoint::request_span;
 use utils::http::request::must_parse_query_param;
@@ -144,10 +145,16 @@ impl State {
        deletion_queue_client: DeletionQueueClient,
        secondary_controller: SecondaryController,
    ) -> anyhow::Result<Self> {
-        let allowlist_routes = ["/v1/status", "/v1/doc", "/swagger.yml", "/metrics"]
-            .iter()
-            .map(|v| v.parse().unwrap())
-            .collect::<Vec<_>>();
+        let allowlist_routes = [
+            "/v1/status",
+            "/v1/doc",
+            "/swagger.yml",
+            "/metrics",
+            "/profile/cpu",
+        ]
+        .iter()
+        .map(|v| v.parse().unwrap())
+        .collect::<Vec<_>>();
        Ok(Self {
            conf,
            tenant_manager,
@@ -3158,6 +3165,7 @@ pub fn make_router(
    Ok(router
        .data(state)
        .get("/metrics", |r| request_span(r, prometheus_metrics_handler))
+        .get("/profile/cpu", |r| request_span(r, profile_cpu_handler))
        .get("/v1/status", |r| api_handler(r, status_handler))
        .put("/v1/failpoints", |r| {
            testing_api_handler("manage failpoints", r, failpoints_handler)
--- a/pageserver/src/metrics.rs
+++ b/pageserver/src/metrics.rs
@@ -653,6 +653,35 @@ pub(crate) static COMPRESSION_IMAGE_OUTPUT_BYTES: Lazy<IntCounter> = Lazy::new(|
    .expect("failed to define a metric")
 });

+pub(crate) static RELSIZE_CACHE_ENTRIES: Lazy<UIntGauge> = Lazy::new(|| {
+    register_uint_gauge!(
+        "pageserver_relsize_cache_entries",
+        "Number of entries in the relation size cache",
+    )
+    .expect("failed to define a metric")
+});
+
+pub(crate) static RELSIZE_CACHE_HITS: Lazy<IntCounter> = Lazy::new(|| {
+    register_int_counter!("pageserver_relsize_cache_hits", "Relation size cache hits",)
+        .expect("failed to define a metric")
+});
+
+pub(crate) static RELSIZE_CACHE_MISSES: Lazy<IntCounter> = Lazy::new(|| {
+    register_int_counter!(
+        "pageserver_relsize_cache_misses",
+        "Relation size cache misses",
+    )
+    .expect("failed to define a metric")
+});
+
+pub(crate) static RELSIZE_CACHE_MISSES_UPDATED: Lazy<IntCounter> = Lazy::new(|| {
+    register_int_counter!(
+        "pageserver_relsize_cache_misses_updated",
+        "Relation size cache misses where relation update LSN is after lookup LSN",
+    )
+    .expect("failed to define a metric")
+});
+
 pub(crate) mod initial_logical_size {
    use metrics::{register_int_counter, register_int_counter_vec, IntCounter, IntCounterVec};
    use once_cell::sync::Lazy;
--- a/pageserver/src/pgdatadir_mapping.rs
+++ b/pageserver/src/pgdatadir_mapping.rs
@@ -10,6 +10,9 @@ use super::tenant::{PageReconstructError, Timeline};
 use crate::aux_file;
 use crate::context::RequestContext;
 use crate::keyspace::{KeySpace, KeySpaceAccum};
+use crate::metrics::{
+    RELSIZE_CACHE_ENTRIES, RELSIZE_CACHE_HITS, RELSIZE_CACHE_MISSES, RELSIZE_CACHE_MISSES_UPDATED,
+};
 use crate::span::debug_assert_current_span_has_tenant_and_timeline_id_no_shard_id;
 use anyhow::{ensure, Context};
 use bytes::{Buf, Bytes, BytesMut};
@@ -955,9 +958,12 @@ impl Timeline {
        let rel_size_cache = self.rel_size_cache.read().unwrap();
        if let Some((cached_lsn, nblocks)) = rel_size_cache.map.get(tag) {
            if lsn >= *cached_lsn {
+                RELSIZE_CACHE_HITS.inc();
                return Some(*nblocks);
            }
+            RELSIZE_CACHE_MISSES_UPDATED.inc();
        }
+        RELSIZE_CACHE_MISSES.inc();
        None
    }

@@ -982,6 +988,7 @@ impl Timeline {
            }
            hash_map::Entry::Vacant(entry) => {
                entry.insert((lsn, nblocks));
+                RELSIZE_CACHE_ENTRIES.inc();
            }
        }
    }
@@ -989,13 +996,17 @@ impl Timeline {
    /// Store cached relation size
    pub fn set_cached_rel_size(&self, tag: RelTag, lsn: Lsn, nblocks: BlockNumber) {
        let mut rel_size_cache = self.rel_size_cache.write().unwrap();
-        rel_size_cache.map.insert(tag, (lsn, nblocks));
+        if rel_size_cache.map.insert(tag, (lsn, nblocks)).is_none() {
+            RELSIZE_CACHE_ENTRIES.inc();
+        }
    }

    /// Remove cached relation size
    pub fn remove_cached_rel_size(&self, tag: &RelTag) {
        let mut rel_size_cache = self.rel_size_cache.write().unwrap();
-        rel_size_cache.map.remove(tag);
+        if rel_size_cache.map.remove(tag).is_some() {
+            RELSIZE_CACHE_ENTRIES.dec();
+        }
    }
 }

@@ -1011,7 +1022,7 @@ pub struct DatadirModification<'a> {
    pub tline: &'a Timeline,

    /// Current LSN of the modification
-    lsn: Lsn,
+    pub lsn: Lsn,

    // The modifications are not applied directly to the underlying key-value store.
    // The put-functions add the modifications here, and they are flushed to the
--- a/pageserver/src/walingest.rs
+++ b/pageserver/src/walingest.rs
@@ -327,6 +327,25 @@ impl WalIngest {
        let mut new_vm_blk = new_heap_blkno.map(pg_constants::HEAPBLK_TO_MAPBLOCK);
        let mut old_vm_blk = old_heap_blkno.map(pg_constants::HEAPBLK_TO_MAPBLOCK);

+        // Only apply the writes if this shard owns either of the VM pages. These WAL records are
+        // broadcast to all shards, but should only be applied on the relevant ones. See:
+        // https://github.com/neondatabase/neon/issues/9855
+        //
+        // TODO: we should differentiate on old_vm_blk and new_vm_blk since we may only own one of
+        // them, but this is no worse than the old behavior where we applied all records, and will
+        // avoid the performance penalty of the relsize cache miss and DbDir deserialization.
+        //
+        // TODO: consider filtering this during decoding, and avoid the broadcast.
+        let old_is_local = old_vm_blk
+            .map(|blk| self.shard.is_key_local(&rel_block_to_key(vm_rel, blk)))
+            .unwrap_or_default();
+        let new_is_local = new_vm_blk
+            .map(|blk| self.shard.is_key_local(&rel_block_to_key(vm_rel, blk)))
+            .unwrap_or_default();
+        if !old_is_local && !new_is_local {
+            return Ok(());
+        }
+
        // Sometimes, Postgres seems to create heap WAL records with the
        // ALL_VISIBLE_CLEARED flag set, even though the bit in the VM page is
        // not set. In fact, it's possible that the VM page does not exist at all.
@@ -334,7 +353,11 @@ impl WalIngest {
        // replaying it would fail to find the previous image of the page, because
        // it doesn't exist. So check if the VM page(s) exist, and skip the WAL
        // record if it doesn't.
-        let vm_size = get_relsize(modification, vm_rel, ctx).await?;
+        let (vm_size, vm_exists) = get_relsize(modification, vm_rel, ctx).await?;
+        if vm_size == 0 {
+            let lsn = modification.lsn;
+            log::info!("ingest_clear_vm_bits: vm_rel {vm_rel} has size={vm_size} exists={vm_exists} at LSN {lsn}, flags={flags} old={old_heap_blkno:?} new={new_heap_blkno:?}");
+        }
        if let Some(blknum) = new_vm_blk {
            if blknum >= vm_size {
                new_vm_blk = None;
@@ -572,7 +595,7 @@ impl WalIngest {
                modification.put_rel_page_image_zero(rel, fsm_physical_page_no)?;
                fsm_physical_page_no += 1;
            }
-            let nblocks = get_relsize(modification, rel, ctx).await?;
+            let (nblocks, _) = get_relsize(modification, rel, ctx).await?;
            if nblocks > fsm_physical_page_no {
                // check if something to do: FSM is larger than truncate position
                self.put_rel_truncation(modification, rel, fsm_physical_page_no, ctx)
@@ -612,7 +635,7 @@ impl WalIngest {
                )?;
                vm_page_no += 1;
            }
-            let nblocks = get_relsize(modification, rel, ctx).await?;
+            let (nblocks, _) = get_relsize(modification, rel, ctx).await?;
            if nblocks > vm_page_no {
                // check if something to do: VM is larger than truncate position
                self.put_rel_truncation(modification, rel, vm_page_no, ctx)
@@ -1434,20 +1457,22 @@ async fn get_relsize(
    modification: &DatadirModification<'_>,
    rel: RelTag,
    ctx: &RequestContext,
-) -> Result<BlockNumber, PageReconstructError> {
-    let nblocks = if !modification
+) -> Result<(BlockNumber, bool), PageReconstructError> {
+    if !modification
        .tline
        .get_rel_exists(rel, Version::Modified(modification), ctx)
        .await?
    {
-        0
+        Ok((0, false))
    } else {
-        modification
-            .tline
-            .get_rel_size(rel, Version::Modified(modification), ctx)
-            .await?
-    };
-    Ok(nblocks)
+        Ok((
+            modification
+                .tline
+                .get_rel_size(rel, Version::Modified(modification), ctx)
+                .await?,
+            true,
+        ))
+    }
 }

 #[allow(clippy::bool_assert_comparison)]
--- a/safekeeper/Cargo.toml
+++ b/safekeeper/Cargo.toml
@@ -30,6 +30,7 @@ once_cell.workspace = true
 parking_lot.workspace = true
 postgres.workspace = true
 postgres-protocol.workspace = true
+pprof.workspace = true
 rand.workspace = true
 regex.workspace = true
 scopeguard.workspace = true
--- a/safekeeper/benches/README.md
+++ b/safekeeper/benches/README.md
@@ -14,6 +14,10 @@ cargo bench --package safekeeper --bench receive_wal process_msg/fsync=false

 # List available benchmarks.
 cargo bench --package safekeeper --benches -- --list
+
+# Generate flamegraph profiles using pprof-rs, profiling for 10 seconds.
+# Output in target/criterion/*/profile/flamegraph.svg.
+cargo bench --package safekeeper --bench receive_wal process_msg/fsync=false --profile-time 10
 ```

 Additional charts and statistics are available in `target/criterion/report/index.html`.
--- a/safekeeper/benches/receive_wal.rs
+++ b/safekeeper/benches/receive_wal.rs
@@ -10,6 +10,7 @@ use camino_tempfile::tempfile;
 use criterion::{criterion_group, criterion_main, BatchSize, Bencher, Criterion};
 use itertools::Itertools as _;
 use postgres_ffi::v17::wal_generator::{LogicalMessageGenerator, WalGenerator};
+use pprof::criterion::{Output, PProfProfiler};
 use safekeeper::receive_wal::{self, WalAcceptor};
 use safekeeper::safekeeper::{
    AcceptorProposerMessage, AppendRequest, AppendRequestHeader, ProposerAcceptorMessage,
@@ -24,8 +25,9 @@ const GB: usize = 1024 * MB;

 // Register benchmarks with Criterion.
 criterion_group!(
-    benches,
-    bench_process_msg,
+    name = benches;
+    config = Criterion::default().with_profiler(PProfProfiler::new(100, Output::Flamegraph(None)));
+    targets = bench_process_msg,
    bench_wal_acceptor,
    bench_wal_acceptor_throughput,
    bench_file_write
--- a/safekeeper/src/http/routes.rs
+++ b/safekeeper/src/http/routes.rs
@@ -14,7 +14,9 @@ use tokio_stream::wrappers::ReceiverStream;
 use tokio_util::sync::CancellationToken;
 use tracing::{info_span, Instrument};
 use utils::failpoint_support::failpoints_handler;
-use utils::http::endpoint::{prometheus_metrics_handler, request_span, ChannelWriter};
+use utils::http::endpoint::{
+    profile_cpu_handler, prometheus_metrics_handler, request_span, ChannelWriter,
+};
 use utils::http::request::parse_query_param;

 use postgres_ffi::WAL_SEGMENT_SIZE;
@@ -574,7 +576,7 @@ pub fn make_router(conf: SafeKeeperConf) -> RouterBuilder<hyper::Body, ApiError>
        router = router.middleware(auth_middleware(|request| {
            #[allow(clippy::mutable_key_type)]
            static ALLOWLIST_ROUTES: Lazy<HashSet<Uri>> = Lazy::new(|| {
-                ["/v1/status", "/metrics"]
+                ["/v1/status", "/metrics", "/pprof/profile"]
                    .iter()
                    .map(|v| v.parse().unwrap())
                    .collect()
@@ -598,6 +600,7 @@ pub fn make_router(conf: SafeKeeperConf) -> RouterBuilder<hyper::Body, ApiError>
        .data(Arc::new(conf))
        .data(auth)
        .get("/metrics", |r| request_span(r, prometheus_metrics_handler))
+        .get("/profile/cpu", |r| request_span(r, profile_cpu_handler))
        .get("/v1/status", |r| request_span(r, status_handler))
        .put("/v1/failpoints", |r| {
            request_span(r, move |r| async {
--- a/workspace_hack/Cargo.toml
+++ b/workspace_hack/Cargo.toml
@@ -52,6 +52,7 @@ lazy_static = { version = "1", default-features = false, features = ["spin_no_st
 libc = { version = "0.2", features = ["extra_traits", "use_std"] }
 log = { version = "0.4", default-features = false, features = ["std"] }
 memchr = { version = "2" }
+nix = { version = "0.26" }
 nom = { version = "7" }
 num-bigint = { version = "0.4" }
 num-integer = { version = "0.1", features = ["i128"] }
Author	SHA1	Message	Date
Erik Grinaker	4fe36706d9	pageserver: only apply `ClearVmBits` on relevant shards	2024-11-26 17:30:21 +01:00
Erik Grinaker	673815a056	Log relation existence	2024-11-26 13:43:04 +01:00
Erik Grinaker	ee4cbe8778	Log when vm_size=0	2024-11-26 12:11:04 +01:00
Erik Grinaker	204eaa194f	pageserver: add relsize cache metrics	2024-11-26 10:51:48 +01:00
Erik Grinaker	f7cb553ea3	safekeeper,pageserver: add CPU profiling (#9764 ) ## Problem We don't have a convenient way to gather CPU profiles from a running binary, e.g. during production incidents or end-to-end benchmarks, nor during microbenchmarks (particularly on macOS). We would also like to have continuous profiling in production, likely using [Grafana Cloud Profiles](https://grafana.com/products/cloud/profiles-for-continuous-profiling/). We may choose to use either eBPF profiles or pprof profiles for this (pending testing and discussion with SREs), but pprof profiles appear useful regardless for the reasons listed above. See https://github.com/neondatabase/cloud/issues/14888. This PR is intended as a proof of concept, to try it out in staging and drive further discussions about profiling more broadly. Touches #9534. Touches https://github.com/neondatabase/cloud/issues/14888. ## Summary of changes Adds a HTTP route `/profile/cpu` that takes a CPU profile and returns it. Defaults to a 5-second pprof Protobuf profile for use with e.g. `pprof` or Grafana Alloy, but can also emit an SVG flamegraph. Query parameters: * `format`: output format (`pprof` or `svg`) * `frequency`: sampling frequency in microseconds (default 100) * `seconds`: number of seconds to profile (default 5) Also integrates pprof profiles into Criterion benchmarks, such that flamegraph reports can be taken with `cargo bench ... --profile-duration <seconds>`. Output under `target/criterion//profile/flamegraph.svg`. Example profiles: pprof profile (use [`pprof`](https://github.com/google/pprof)): [profile.pb.gz](https://github.com/user-attachments/files/17756788/profile.pb.gz) * Web interface: `pprof -http :6060 profile.pb.gz` * Interactive flamegraph: [profile.svg.gz](https://github.com/user-attachments/files/17756782/profile.svg.gz)	2024-11-22 12:45:14 +01:00