proxy: refactor redis batching

The first line in /etc/ld.so.conf is:

	/etc/ld.so.conf.d/*

We want to control library load order so that our compiled binaries are
picked up before others from system packages. The previous solution
allowed the system libraries to load before ours.

Part-of: https://github.com/neondatabase/neon/issues/11857

Signed-off-by: Tristan Partin <tristan@neon.tech>

Cargo.lock

@@ -1303,6 +1303,7 @@ dependencies = [
  "futures",
  "http 1.1.0",
  "indexmap 2.0.1",
+ "itertools 0.10.5",
  "jsonwebtoken",
  "metrics",
  "nix 0.27.1",

compute/compute-node.Dockerfile

@@ -1971,7 +1971,8 @@ COPY --from=sql_exporter_preprocessor --chmod=0644 /home/nonroot/compute/etc/sql
 COPY --from=sql_exporter_preprocessor --chmod=0644 /home/nonroot/compute/etc/neon_collector_autoscaling.yml /etc/neon_collector_autoscaling.yml
 
 # Make the libraries we built available
-RUN echo '/usr/local/lib' >> /etc/ld.so.conf && /sbin/ldconfig
+COPY --chmod=0666 compute/etc/ld.so.conf.d/00-neon.conf /etc/ld.so.conf.d/00-neon.conf
+RUN /sbin/ldconfig
 
 # rsyslog config permissions
 # directory for rsyslogd pid file

compute/etc/ld.so.conf.d/00-neon.conf

@@ -0,0 +1 @@
+/usr/local/lib

compute_tools/Cargo.toml

@@ -28,6 +28,7 @@ flate2.workspace = true
 futures.workspace = true
 http.workspace = true
 indexmap.workspace = true
+itertools.workspace = true
 jsonwebtoken.workspace = true
 metrics.workspace = true
 nix.workspace = true

compute_tools/src/compute.rs

@@ -11,6 +11,7 @@ use compute_api::spec::{
 use futures::StreamExt;
 use futures::future::join_all;
 use futures::stream::FuturesUnordered;
+use itertools::Itertools;
 use nix::sys::signal::{Signal, kill};
 use nix::unistd::Pid;
 use once_cell::sync::Lazy;
@@ -18,7 +19,7 @@ use postgres;
 use postgres::NoTls;
 use postgres::error::SqlState;
 use remote_storage::{DownloadError, RemotePath};
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::net::SocketAddr;
 use std::os::unix::fs::{PermissionsExt, symlink};
 use std::path::Path;
@@ -1995,23 +1996,40 @@ LIMIT 100",
         tokio::spawn(conn);
 
         // TODO: support other types of grants apart from schemas?
-        let query = format!(
-            "GRANT {} ON SCHEMA {} TO {}",
-            privileges
-                .iter()
-                // should not be quoted as it's part of the command.
-                // is already sanitized so it's ok
-                .map(|p| p.as_str())
-                .collect::<Vec<&'static str>>()
-                .join(", "),
-            // quote the schema and role name as identifiers to sanitize them.
-            schema_name.pg_quote(),
-            role_name.pg_quote(),
-        );
-        db_client
-            .simple_query(&query)
+
+        // check the role grants first - to gracefully handle read-replicas.
+        let select = "SELECT privilege_type
+            FROM pg_namespace
+                JOIN LATERAL (SELECT * FROM aclexplode(nspacl) AS x) acl ON true
+                JOIN pg_user users ON acl.grantee = users.usesysid
+            WHERE users.usename = $1
+                AND nspname = $2";
+        let rows = db_client
+            .query(select, &[role_name, schema_name])
             .await
-            .with_context(|| format!("Failed to execute query: {}", query))?;
+            .with_context(|| format!("Failed to execute query: {select}"))?;
+
+        let already_granted: HashSet<String> = rows.into_iter().map(|row| row.get(0)).collect();
+
+        let grants = privileges
+            .iter()
+            .filter(|p| !already_granted.contains(p.as_str()))
+            // should not be quoted as it's part of the command.
+            // is already sanitized so it's ok
+            .map(|p| p.as_str())
+            .join(", ");
+
+        if !grants.is_empty() {
+            // quote the schema and role name as identifiers to sanitize them.
+            let schema_name = schema_name.pg_quote();
+            let role_name = role_name.pg_quote();
+
+            let query = format!("GRANT {grants} ON SCHEMA {schema_name} TO {role_name}",);
+            db_client
+                .simple_query(&query)
+                .await
+                .with_context(|| format!("Failed to execute query: {}", query))?;
+        }
 
         Ok(())
     }

compute_tools/src/config.rs

@@ -224,7 +224,10 @@ pub fn write_postgres_conf(
             writeln!(file, "pgaudit.log_rotation_age=5")?;
 
             // Enable audit logs for pg_session_jwt extension
-            writeln!(file, "pg_session_jwt.audit_log=on")?;
+            // TODO: Consider a good approach for shipping pg_session_jwt logs to the same sink as
+            // pgAudit - additional context in https://github.com/neondatabase/cloud/issues/28863
+            //
+            // writeln!(file, "pg_session_jwt.audit_log=on")?;
 
             // Add audit shared_preload_libraries, if they are not present.
             //

docker-compose/compute_wrapper/shell/compute.sh

@@ -14,6 +14,14 @@ PG_VERSION=${PG_VERSION:-14}
 CONFIG_FILE_ORG=/var/db/postgres/configs/config.json
 CONFIG_FILE=/tmp/config.json
 
+# Test that the first library path that the dynamic loader looks in is the path
+# that we use for custom compiled software
+first_path="$(ldconfig --verbose 2>/dev/null \
+    | grep --invert-match ^$'\t' \
+    | cut --delimiter=: --fields=1 \
+    | head --lines=1)"
+test "$first_path" == '/usr/local/lib' || true # Remove the || true in a follow-up PR. Needed for backwards compat.
+
 echo "Waiting pageserver become ready."
 while ! nc -z pageserver 6400; do
      sleep 1;

docker-compose/pageserver_config/pageserver.toml

@@ -5,3 +5,4 @@ listen_http_addr='0.0.0.0:9898'
 remote_storage={ endpoint='http://minio:9000', bucket_name='neon', bucket_region='eu-north-1', prefix_in_bucket='/pageserver' }
 control_plane_api='http://0.0.0.0:6666' # No storage controller in docker compose, specify a junk address
 control_plane_emergency_mode=true
+virtual_file_io_mode="buffered" # the CI runners where we run the docker compose tests have slow disks

docs/rfcs/030-vectored-timeline-get.md

@@ -7,6 +7,8 @@ Author: Christian Schwarz
 
 A brief RFC / GitHub Epic describing a vectored version of the `Timeline::get` method that is at the heart of Pageserver.
 
+**EDIT**: the implementation of this feature is described in [Vlad's (internal) tech talk](https://drive.google.com/file/d/1vfY24S869UP8lEUUDHRWKF1AJn8fpWoJ/view?usp=drive_link).
+
 # Motivation
 
 During basebackup, we issue many `Timeline::get` calls for SLRU pages that are *adjacent* in key space.

docs/rfcs/2025-04-30-direct-io-for-pageserver.md

@@ -0,0 +1,362 @@
+# Direct IO For Pageserver
+
+Date: Apr 30, 2025
+
+## Summary
+
+This document is a retroactive RFC. It
+- provides some background on what direct IO is,
+- motivates why Pageserver should be using it for its IO, and
+- describes how we changed Pageserver to use it.
+
+The [initial proposal](https://github.com/neondatabase/neon/pull/8240) that kicked off the work can be found in this closed GitHub PR.
+
+People primarily involved in this project were:
+- Yuchen Liang <yuchen@neon.tech>
+- Vlad Lazar <vlad@neon.tech>
+- Christian Schwarz <christian@neon.tech>
+
+## Timeline
+
+For posterity, here is the rough timeline of the development work that got us to where we are today.
+
+- Jan 2024: [integrate `tokio-epoll-uring`](https://github.com/neondatabase/neon/pull/5824) along with owned buffers API
+- March 2024: `tokio-epoll-uring` enabled in all regions in buffered IO mode
+- Feb 2024 to June 2024: PS PageCache Bypass For Data Blocks
+  - Feb 2024: [Vectored Get Implementation](https://github.com/neondatabase/neon/pull/6576) bypasses delta & image layer blocks for page requests
+  - Apr to June 2024: [Epic: bypass PageCache for use data blocks](https://github.com/neondatabase/neon/issues/7386) addresses remaining users
+- Aug to Nov 2024: direct IO: first code; preliminaries; read path coding; BufferedWriter; benchmarks show perf regressions too high, no-go.
+- Nov 2024 to Jan 2025: address perf regressions by developing page_service pipelining (aka batching) and concurrent IO ([Epic](https://github.com/neondatabase/neon/issues/9376))
+- Feb to March 2024: rollout batching, then concurrent+direct IO => read path and InMemoryLayer is now direct IO
+- Apr 2025: develop & roll out direct IO for the write path
+
+## Background: Terminology & Glossary
+
+**kernel page cache**: the Linux kernel's page cache is a write-back cache for filesystem contents.
+The cached unit is memory-page-sized & aligned chunks of the files that are being cached (typically 4k).
+The cache lives in kernel memory and is not directly accessible through userspace.
+
+**Buffered IO**: an application's read/write system calls go through the kernel page cache.
+For example, a 10 byte sized read or write to offset 5000 in a file will load the file contents
+at offset `[4096,8192)` into a free page in the kernel page cache. If necessary, it will evict
+a page to make room (cf eviction). Then, the kernel performs a memory-to-memory copy of 10 bytes
+from/to the offset `4` (`5000 = 4096 + 4`) within the cached page. If it's a write, the kernel keeps
+track of the fact that the page is now "dirty" in some ancillary structure.
+
+**Writeback**: a buffered read/write syscall returns after the memory-to-memory copy. The modifications
+made by e.g. write system calls are not even *issued* to disk, let alone durable. Instead, the kernel
+asynchronously writes back dirtied pages based on a variety of conditions. For us, the most relevant
+ones are a) explicit request by userspace (`fsync`) and b) memory pressure.
+
+**Memory pressure**: the kernel page cache is a best effort service and a user of spare memory capacity.
+If there is no free memory, the kernel page allocator will take pages used by page cache to satisfy allocations.
+Before reusing a page like that, the page has to be written back (writeback, see above).
+The far-reaching consequence of this is that **any allocation of anonymous memory can do IO** if the only
+way to get that memory is by eviction & re-using a dirty page cache page.
+Notably, this includes a simple `malloc` in userspace, because eventually that boils down to `mmap(..., MAP_ANON, ...)`.
+I refer to this effect as the "malloc latency backscatter" caused by buffered IO.
+
+**Direct IO** allows application's read/write system calls to bypass the kernel page cache. The filesystem
+is still involved because it is ultimately in charge of mapping the concept of files & offsets within them
+to sectors on block devices. Typically, the filesystem poses size and alignment requirements for memory buffers
+and file offsets (statx `Dio_mem_align` / `Dio_offset_align`), see [this gist](https://gist.github.com/problame/1c35cac41b7cd617779f8aae50f97155).
+The IO operations will fail at runtime with EINVAL if the alignment requirements are not met.
+
+**"buffered" vs "direct"**: the central distinction between buffered and direct IO is about who allocates and
+fills the IO buffers, and who controls when exactly the IOs are issued. In buffered IO, it's the syscall handlers,
+kernel page cache, and memory management subsystems (cf "writeback"). In direct IO, all of it is done by
+the application.
+It takes more effort by the application to program with direct instead of buffered IO.
+The return is precise control over and a clear distinction between consumption/modification of memory vs disk.
+
+**Pageserver PageCache**: Pageserver has an additional `PageCache` (referred to as PS PageCache from here on, as opposed to "kernel page cache").
+Its caching unit is 8KiB blocks of the layer files written by Pageserver.
+A miss in PageCache is filled by reading from the filesystem, through the `VirtualFile` abstraction layer.
+The default size is tiny (64MiB), very much like Postgres's `shared_buffers`.
+We ran production at 128MiB for a long time but gradually moved it up to 2GiB over the past ~year.
+
+**VirtualFile** is Pageserver's abstraction for file IO, very similar to the facility in Postgres that bears the same name.
+Its historical purpose appears to be working around open file descriptor limitations, which is practically irrelevant on Linux.
+However, the facility in Pageserver is useful as an intermediary layer for metrics and abstracts over the different kinds of
+IO engines that Pageserver supports (`std-fs` vs `tokio-epoll-uring`).
+
+## Background: History Of Caching In Pageserver
+
+For multiple years, Pageserver's `PageCache` was on the path of all read _and write_ IO.
+It performed write-back to the kernel using buffered IO.
+
+We converted it into a read-only cache of immutable data in [PR 4994](https://github.com/neondatabase/neon/pull/4994).
+
+The introduction of `tokio-epoll-uring` required converting the code base to used owned IO buffers.
+The `PageCache` pages are usable as owned IO buffers.
+
+We then started bypassing PageCache for user data blocks.
+Data blocks are the 8k blocks of data in layer files that hold the multiple `Value`s, as opposed to the disk btree index blocks that tell us which values exist in a file at what offsets.
+The disk btree embedded in delta & image layers remains `PageCache`'d.
+Epics for that work were:
+- Vectored `Timeline::get` (cf RFC 30) skipped delta and image layer data block `PageCache`ing outright.
+- Epic https://github.com/neondatabase/neon/issues/7386 took care of the remaining users for data blocks:
+  - Materialized page cache (cached materialized pages; shown to be ~0% hit rate in practice)
+  - InMemoryLayer
+  - Compaction
+
+The outcome of the above:
+1. All data blocks are always read through the `VirtualFile` APIs, hitting the kernel buffered read path (=> kernel page cache).
+2. Indirect blocks (=disk btree blocks) would be cached in the PS `PageCache`.
+
+In production we size the PS `PageCache` to be 2GiB.
+Thus drives hit rate up to ~99.95% and the eviction rate / replacement rates down to less than 200/second on a 1-minute average, on the busiest machines.
+High baseline replacement rates are treated as a signal of resource exhaustion (page cache insufficient to host working set of the PS).
+The response to this is to migrate tenants away, or increase PS `PageCache` size.
+It is currently manual but could be automated, e.g., in Storage Controller.
+
+In the future, we may eliminate the `PageCache` even for indirect blocks.
+For example with an LRU cache that has as unit the entire disk btree content
+instead of individual blocks.
+
+## High-Level Design
+
+So, before work on this project started, all data block reads and the entire write path of Pageserver were using kernel-buffered IO, i.e., the kernel page cache.
+We now want to get the kernel page cache out of the picture by using direct IO for all interaction with the filesystem.
+This achieves the following system properties:
+
+**Predictable VirtualFile latencies**
+* With buffered IO, reads are sometimes fast, sometimes slow, depending on kernel page cache hit/miss.
+* With buffered IO, appends when writing out new layer files during ingest or compaction are sometimes fast, sometimes slow because of write-back backpressure.
+* With buffered IO, the "malloc backscatter" phenomenon pointed out in the Glossary section is not something we actively observe.
+  But we do have occasional spikes in Dirty memory amount and Memory PSI graphs, so it may already be affecting to some degree.
+* By switching to direct IO, above operations will have the (predictable) device latency -- always.
+  Reads and appends always go to disk.
+  And malloc will not have to write back dirty data.
+
+**Explicitness & Tangibility of resource usage**
+* In a multi-tenant system, it is generally desirable and valuable to be *explicit* about the main resources we use for each tenant.
+* By using direct IO, we become explicit about the resources *disk IOPs*  and *memory capacity* in a way that was previously being conflated through the kernel page cache, outside our immediate control.
+* We will be able to build per-tenant observability of resource usage ("what tenant is causing the actual IOs that are sent to the disk?").
+* We will be able to build accounting & QoS by implementing an IO scheduler that is tenant aware. The kernel is not tenant-aware and can't do that.
+
+**CPU Efficiency**
+* The involvement of the kernel page cache means one additional memory-to-memory copy on read and write path.
+* Direct IO will eliminate that memory-to-memory copy, if we can make the userspace buffers used for the IO calls satisfy direct IO alignment requirements.
+
+The **trade-off** is that we no longer get the theoretical benefits of the kernel page cache. These are:
+- read latency improvements for repeat reads of the same data ("locality of reference")
+  - asterisk: only if that state is still cache-resident by time of next access
+- write throughput by having kernel page cache batch small VFS writes into bigger disk writes
+  - asterisk: only if memory pressure is low enough that the kernel can afford to delay writeback
+
+We are **happy to make this trade-off**:
+- Because of the advantages listed above.
+- Because we empirically have enough DRAM on Pageservers to serve metadata (=index blocks) from PS PageCache.
+  (At just 2GiB PS PageCache size, we average a 99.95% hit rate).
+  So, the latency of going to disk is only for data block reads, not the index traversal.
+- Because **the kernel page cache is ineffective** at high tenant density anyway (#tenants/pageserver instance).
+  And because dense packing of tenants will always be desirable to drive COGS down, we should design the system for it.
+  (See the appendix for a more detailed explanation why this is).
+- So, we accept that some reads that used to be fast by circumstance will have higher but **predictable** latency than before.
+
+### Desired End State
+
+The desired end state of the project is as follows, and with some asterisks, we have achieved it.
+
+All IOs of the Pageserver data path use direct IO, thereby bypassing the kernel page cache.
+
+In particular, the "data path" includes
+- the wal ingest path
+- compaction
+- anything on the `Timeline::get` / `Timeline::get_vectored` path.
+
+The production Pageserver config is tuned such that virtually all non-data blocks are cached in the PS PageCache.
+Hit rate target is 99.95%.
+
+There are no regressions to ingest latency.
+
+The total "wait-for-disk time" contribution to random getpage request latency is `O(1 read IOP latency)`.
+We accomplish that by having a near 100% PS PageCache hit rate so that layer index traversal effectively never needs not wait for IO.
+Thereby, it can issue all the data blocks as it traverses the index, and only wait at the end of it (concurrent IO).
+
+The amortized "wait-for-disk time" contribution of this direct IO proposal to a series of sequential getpage requests is `1/32 * read IOP latency` for each getpage request.
+We accomplish this by server-side batching of up to 32 reads into a single `Timeline::get_vectored` call.
+(This is an ideal world where our batches are full - that's not the case in prod today because of lack of queue depth).
+
+## Design & Implementation
+
+### Prerequisites
+
+A lot of prerequisite work had to happen to enable use of direct IO.
+
+To meet the "wait-for-disk time" requirements from the DoD, we implement for the read path:
+- page_service level server-side batching (config field `page_service_pipelining`)
+- concurrent IO (config field `get_vectored_concurrent_io`)
+The work for both of these these was tracked [in the epic](https://github.com/neondatabase/neon/issues/9376).
+Server-side batching will likely be obsoleted by the [#proj-compute-communicator](https://github.com/neondatabase/neon/pull/10799).
+The Concurrent IO work is described in retroactive RFC `2025-04-30-pageserver-concurrent-io-on-read-path.md`.
+The implementation is relatively brittle and needs further investment, see the `Future Work` section in that RFC.
+
+For the write path, and especially WAL ingest, we need to hide write latency.
+We accomplish this by implementing a (`BufferedWriter`) type that does double-buffering: flushes of the filled
+buffer happen in a sidecar tokio task while new writes fill a new buffer.
+We refactor InMemoryLayer as well as BlobWriter (=> delta and image layer writers) to use this new `BufferedWriter`.
+The most comprehensive write-up of this work is in [the PR description](https://github.com/neondatabase/neon/pull/11558).
+
+### Ensuring Adherence to Alignment Requirements
+
+Direct IO puts requirements on
+- memory buffer alignment
+- io size (=memory buffer size)
+- file offset alignment
+
+The requirements are specific to a combination of filesystem/block-device/architecture(hardware page size!).
+
+In Neon production environments we currently use ext4 with Linux 6.1.X on AWS and Azure storage-optimized instances (locally attached NVMe).
+Instead of dynamic discovery using `statx`, we statically hard-code 512 bytes as the buffer/offset alignment and size-multiple.
+We made this decision because:
+- a) it is compatible with all the environments we need to run in
+- b) our primary workload can be small-random-read-heavy (we do merge adjacent reads if possible, but the worst case is that all `Value`s that needs to be read are far apart)
+- c) 512-byte tail latency on the production instance types is much better than 4k (p99.9: 3x lower, p99.99 5x lower).
+- d) hard-coding at compile-time allows us to use the Rust type system to enforce the use of only aligned IO buffers, eliminating a source of runtime errors typically associated with direct IO.
+
+This was [discussed here](https://neondb.slack.com/archives/C07BZ38E6SD/p1725036790965549?thread_ts=1725026845.455259&cid=C07BZ38E6SD).
+
+The new `IoBufAligned` / `IoBufAlignedMut` marker traits indicate that a given buffer meets memory alignment requirements.
+All `VirtualFile` APIs and several software layers built on top of them only accept buffers that implement those traits.
+Implementors of the marker traits are:
+- `IoBuffer` / `IoBufferMut`: used for most reads and writes
+- `PageWriteGuardBuf`: for filling PS PageCache pages (index blocks!)
+
+The alignment requirement is infectious; it permeates bottom-up throughout the code base.
+We stop the infection at roughly the same layers in the code base where we stopped permeating the
+use of owned-buffers-style API for tokio-epoll-uring. The way the stopping works is by introducing
+a memory-to-memory copy from/to some unaligned memory location on the stack/current/heap.
+The places where we currently stop permeating are sort of arbitrary. For example, it would probably
+make sense to replace more usage of `Bytes` that we know holds 8k pages with 8k-sized `IoBuffer`s.
+
+The `IoBufAligned` / `IoBufAlignedMut` types do not protect us from the following types of runtime errors:
+- non-adherence to file offset alignment requirements
+- non-adherence to io size requirements
+
+The following higher-level constructs ensure we meet the requirements:
+- read path: the `ChunkedVectoredReadBuilder` and `mod vectored_dio_read` ensure reads happen at aligned offsets and in appropriate size multiples.
+- write path: `BufferedWriter` only writes in multiples of the capacity, at offsets that are `start_offset+N*capacity`; see its doc comment.
+
+Note that these types are used always, regardless of whether direct IO is enabled or not.
+There are some cases where this adds unnecessary overhead to buffered IO (e.g. all memcpy's inflated to multiples of 512).
+But we could not identify meaningful impact in practice when we shipped these changes while we were still using buffered IO.
+
+### Configuration / Feature Flagging
+
+In the previous section we described how all users of VirtualFile were changed to always adhere to direct IO alignment and size-multiple requirements.
+To actually enable direct IO, all we need to do is set the `O_DIRECT` flag in `open` syscalls / io_uring operations.
+
+We set `O_DIRECT` based on:
+- the VirtualFile API used to create/open the VirtualFile instance
+- the `virtual_file_io_mode` configuration flag
+- the OpenOptions `read` and/or `write` flags.
+
+The VirtualFile APIs suffixed with `_v2` are the only ones that _may_ open with `O_DIRECT` depending on the other two factors in above list.
+Other APIs never use `O_DIRECT`.
+(The name is bad and should really be `_maybe_direct_io`.)
+
+The reason for having new APIs is because all code used VirtualFile but implementation and rollout happened in consecutive phases (read path, InMemoryLayer, write path).
+At the VirtualFile level, context on whether an instance of VirtualFile is on read path, InMemoryLayer, or write path is not available.
+
+The `_v2` APIs then check make the decision to set `O_DIRECT` based on the `virtual_file_io_mode` flag and the OpenOptions `read`/`write` flags.
+The result is the following runtime behavior:
+
+|what|OpenOptions|`v_f_io_mode`<br/>=`buffered`|`v_f_io_mode`<br/>=`direct`|`v_f_io_mode`<br/>=`direct-rw`|
+|-|-|-|-|-|
+|`DeltaLayerInner`|read|()|O_DIRECT|O_DIRECT|
+|`ImageLayerInner`|read|()|O_DIRECT|O_DIRECT|
+|`InMemoryLayer`|read + write|()|()*|O_DIRECT|
+|`DeltaLayerWriter`| write | () | () |  O_DIRECT |
+|`ImageLayerWriter`| write | () | () |  O_DIRECT |
+|`download_layer_file`|write |()|()|O_DIRECT|
+
+The `InMemoryLayer` is marked with `*` because there was a period when it *did* use O_DIRECT under `=direct`.
+That period was when we implemented and shipped the first version of `BufferedWriter`.
+We used it in `InMemoryLayer` and `download_layer_file` but it was only sensitive to `v_f_io_mode` in `InMemoryLayer`.
+The introduction of `=direct-rw`, and the switch of the remaining write path to `BufferedWriter`, happened later,
+in https://github.com/neondatabase/neon/pull/11558.
+
+Note that this way of feature flagging inside VirtualFile makes it less and less a general purpose POSIX file access abstraction.
+For example, with `=direct-rw` enabled, it is no longer possible to open a `VirtualFile` without `O_DIRECT`. It'll always be set.
+
+## Correctness Validation
+
+The correctness risks with this project were:
+- Memory safety issues in the `IoBuffer` / `IoBufferMut` implementation.
+  These types expose an API that is largely identical to that of the `bytes` crate and/or Vec.
+- Runtime errors (=> downtime / unavailability) because of non-adherence to alignment/size-multiple requirements, resulting in EINVAL on the read path.
+
+We sadly do not have infrastructure to run pageserver under `cargo miri`.
+So for memory safety issues, we relied on careful peer review.
+
+We do assert the production-like alignment requirements in testing builds.
+However, these asserts were added retroactively.
+The actual validation before rollout happened in staging and pre-prod.
+We eventually enabled  `=direct`/`=direct-rw` for Rust unit tests and the regression test suite.
+I cannot recall a single instance of staging/pre-prod/production errors caused by non-adherence to alignment/size-multiple requirements.
+Evidently developer testing was good enough.
+
+## Performance Validation
+
+The read path went through a lot of iterations of benchmarking in staging and pre-prod.
+The benchmarks in those environments demonstrated performance regressions early in the implementation.
+It was actually this performance testing that made us implement batching and concurrent IO to avoid unacceptable regressions.
+
+The write path was much quicker to validate because `bench_ingest` covered all of the (less numerous) access patterns.
+
+## Future Work
+
+There is minor and major follow-up work that can be considered in the future.
+Check the (soon-to-be-closed) Epic https://github.com/neondatabase/neon/issues/8130's "Follow-Ups" section for a current list.
+
+Read Path:
+- PS PageCache hit rate is crucial to unlock concurrent IO and reasonable latency for random reads generally.
+  Instead of reactively sizing PS PageCache, we should estimate the required PS PageCache size
+  and potentially also use that to drive placement decisions of shards from StorageController
+  https://github.com/neondatabase/neon/issues/9288
+- ... unless we get rid of PS PageCache entirely and cache the index block in a more specialized cache.
+  But even then, an estimation of the working set would be helpful to figure out caching strategy.
+
+Write Path:
+- BlobWriter and its users could switch back to a borrowed API  https://github.com/neondatabase/neon/issues/10129
+- ... unless we want to implement bypass mode for large writes https://github.com/neondatabase/neon/issues/10101
+- The `TempVirtualFile` introduced as part of this project could internalize more of the common usage pattern: https://github.com/neondatabase/neon/issues/11692
+- Reduce conditional compilation around `virtual_file_io_mode`: https://github.com/neondatabase/neon/issues/11676
+
+Both:
+- A performance simulation mode that pads VirtualFile op latencies to typical NVMe latencies, even if the underlying storage is faster.
+  This would avoid misleadingly good performance on developer systems and in benchmarks on systems that are less busy than production hosts.
+  However, padding latencies at microsecond scale is non-trivial.
+
+Misc:
+- We should finish trimming VirtualFile's scope to be truly limited to core data path read & write.
+  Abstractions for reading & writing pageserver config, location config, heatmaps, etc, should use
+  APIs in a different package (`VirtualFile::crashsafe_overwrite` and `VirtualFile::read_to_string`
+  are good entrypoints for cleanup.) https://github.com/neondatabase/neon/issues/11809
+
+# Appendix
+
+## Why Kernel Page Cache Is Ineffective At Tenant High Density
+
+In the Motivation section, we stated:
+
+> - **The kernel page cache ineffective** at high tenant density anyways (#tenants/pageserver instance).
+
+The reason is that the  Pageserver workload sent from Computes is whatever is a Compute cache(s) miss.
+That's either sequential scans or random reads.
+A random read workload simply causes cache thrashing because a packed Pageserver NVMe drive (`im4gn.2xlarge`) has ~100x more capacity than DRAM available.
+It is complete waste to have the kernel page cache cache data blocks in this case.
+Sequential read workloads *can* benefit iff those pages have been updated recently (=no image layer yet) and together in time/LSN space.
+In such cases, the WAL records of those updates likely sit on the same delta layer block.
+When Compute does a sequential scan, it sends a series of single-page requests for these individual pages.
+When Pageserver processes the second request in such a series, it goes to the same delta layer block and have a kernel page cache hit.
+This dependence on kernel page cache for sequential scan performance is significant, but the solution is at a higher level than generic data block caching.
+We can either add a small per-connection LRU cache for such delta layer blocks.
+Or we can merge those sequential requests into a larger vectored get request, which is designed to never read a block twice.
+This amortizes the read latency for our delta layer block across the vectored get batch size (which currently is up to 32).
+
+There are Pageserver-internal workloads that do sequential access (compaction, image layer generation), but these
+1. are not latency-critical and can do batched access outside of the `page_service` protocol constraints (image layer generation)
+2. don't actually need to reconstruct images and therefore can use totally different access methods (=> compaction can use k-way merge iterators with their own internal buffering / prefetching).

docs/rfcs/2025-04-30-pageserver-concurrent-io-on-read-path.md

@@ -0,0 +1,251 @@
+# Concurrent IO for Pageserver Read Path
+
+Date: May 6, 2025
+
+## Summary
+
+This document is a retroactive RFC on the Pageserver Concurrent IO work that happened in late 2024 / early 2025.
+
+The gist of it is that Pageserver's `Timeline::get_vectored` now _issues_ the data block read operations against layer files
+_as it traverses the layer map_ and only _wait_ once, for all of them, after traversal is complete.
+
+Assuming a good PS PageCache hits on the index blocks during traversal, this drives down the "wait-for-disk" time
+contribution down from `random_read_io_latency * O(number_of_values)` to `random_read_io_latency * O(1 + traversal)`.
+
+The motivation for why this work had to happen when it happened was the switch of Pageserver to
+- not cache user data blocks in PS PageCache and
+- switch to use direct IO.
+More context on this are given in complimentary RFC `./rfcs/2025-04-30-direct-io-for-pageserver.md`.
+
+### Refs
+
+- Epic: https://github.com/neondatabase/neon/issues/9378
+- Prototyping happened during the Lisbon 2024 Offsite hackathon: https://github.com/neondatabase/neon/pull/9002
+- Main implementation PR with good description: https://github.com/neondatabase/neon/issues/9378
+
+Design and implementation by:
+- Vlad Lazar <vlad@neon.tech>
+- Christian Schwarz <christian@neon.tech>
+
+## Background & Motivation
+
+The Pageserver read path (`Timeline::get_vectored`) consists of two high-level steps:
+- Retrieve the delta and image `Value`s required to reconstruct the requested Page@LSN (`Timeline::get_values_reconstruct_data`).
+- Pass these values to walredo to reconstruct the page images.
+
+The read path used to be single-key but has been made multi-key some time ago.
+([Internal tech talk by Vlad](https://drive.google.com/file/d/1vfY24S869UP8lEUUDHRWKF1AJn8fpWoJ/view?usp=drive_link))
+However, for simplicity, most of this doc will explain things in terms of a single key being requested.
+
+The `Value` retrieval step above can be broken down into the following functions:
+- **Traversal** of the layer map to figure out which `Value`s from which layer files are required for the page reconstruction.
+- **Read IO Planning**: planning of the read IOs that need to be issued to the layer files / filesystem / disk.
+  The main job here is to coalesce the small value reads into larger filesystem-level read operations.
+  This layer also takes care of direct IO alignment and size-multiple requirements (cf the RFC for details.)
+  Check `struct VectoredReadPlanner` and `mod vectored_dio_read` for how it's done.
+- **Perform the read IO** using `tokio-epoll-uring`.
+
+Before this project, above functions were sequentially interleaved, meaning:
+1. we would advance traversal, ...
+2. discover, that we need to read a value, ...
+3. read it from disk using `tokio-epoll-uring`, ...
+4. goto 1 unless we're done.
+
+This meant that if N `Value`s need to be read to reconstruct a page,
+the time we spend waiting for disk will be we `random_read_io_latency * O(number_of_values)`.
+
+## Design
+
+The **traversal** and **read IO Planning** jobs still happen sequentially, layer by layer, as before.
+But instead of performing the read IOs inline, we submit the IOs to a concurrent tokio task for execution.
+After the last read from the last layer is submitted, we wait for the IOs to complete.
+
+Assuming the filesystem / disk is able to actually process the submitted IOs without queuing,
+we arrive at _time spent waiting for disk_ ~ `random_read_io_latency * O(1 + traversal)`.
+
+Note this whole RFC is concerned with the steady state where all layer files required for reconstruction are resident on local NVMe.
+Traversal will stall on on-demand layer download if a layer is not yet resident.
+It cannot proceed without the layer being resident beccause its next step depends on the contents of the layer index.
+
+### Avoiding Waiting For IO During Traversal
+
+The `traversal` component in above time-spent-waiting-for-disk estimation is dominant and needs to be minimized.
+
+Before this project, traversal needed to perform IOs for the following:
+1. The time we are waiting on PS PageCache to page in the visited layers' disk btree index blocks.
+2. When visiting a delta layer, reading the data block that contains a `Value` for a requested key,
+   to determine whether the `Value::will_init` the page and therefore traversal can stop for this key.
+
+The solution for (1) is to raise the PS PageCache size such that the hit rate is practically 100%.
+(Check out the `Background: History Of Caching In Pageserver` section in the RFC on Direct IO for more details.)
+
+The solution for (2) is source `will_init` from the disk btree index keys, which fortunately
+already encode this bit of information since the introduction of the current storage/layer format.
+
+### Concurrent IOs, Submission & Completion
+
+To separate IO submission from waiting for its completion,
+we introduce the notion of an `IoConcurrency` struct through which IOs are issued.
+
+An IO is an opaque future that
+- captures the `tx` side of a `oneshot` channel
+- performs the read IO by calling `VirtualFile::read_exact_at().await`
+- sending the result into the `tx`
+
+Issuing an IO means `Box`ing the future above and handing that `Box` over to the `IoConcurrency` struct.
+
+The traversal code that submits the IO stores the the corresponding `oneshot::Receiver`
+in the `VectoredValueReconstructState`, in the the place where we previously stored
+the sequentially read `img` and `records` fields.
+
+When we're done with traversal, we wait for all submitted IOs:
+for each key, there is a future that awaits all the `oneshot::Receiver`s
+for that key, and then calls into walredo to reconstruct the page image.
+Walredo is now invoked concurrently for each value instead of sequentially.
+Walredo itself remains unchanged.
+
+The spawned IO futures are driven to completion by a sidecar tokio task that
+is separate from the task that performs all the layer visiting and spawning of IOs.
+That tasks receives the IO futures via an unbounded mpsc channel and
+drives them to completion inside a `FuturedUnordered`.
+
+### Error handling, Panics, Cancellation-Safety
+
+There are two error classes during reconstruct data retrieval:
+* traversal errors: index lookup, move to next layer, and the like
+* value read IO errors
+
+A traversal error fails the entire `get_vectored` request, as before this PR.
+A value read error only fails reconstruction of that value.
+
+Panics and dropping of the `get_vectored` future before it completes
+leaves the sidecar task running and does not cancel submitted IOs
+(see next section for details on sidecar task lifecycle).
+All of this is safe, but, today's preference in the team is to close out
+all resource usage explicitly if possible, rather than cancelling + forgetting
+about it on drop. So, there is warning if we drop a
+`VectoredValueReconstructState`/`ValuesReconstructState` that still has uncompleted IOs.
+
+### Sidecar Task Lifecycle
+
+The sidecar tokio task is spawned as part of the `IoConcurrency::spawn_from_conf` struct.
+The `IoConcurrency` object acts as a handle through which IO futures are submitted.
+
+The spawned tokio task holds the `Timeline::gate` open.
+It is _not_ sensitive to `Timeline::cancel`, but instead to the `IoConcurrency` object being dropped.
+
+Once the `IoConcurrency` struct is dropped, no new IO futures can come in
+but already submitted IO futures will be driven to completion regardless.
+We _could_ safely stop polling these futures because `tokio-epoll-uring` op futures are cancel-safe.
+But the underlying kernel and hardware resources are not magically freed up by that.
+So, again, in the interest of closing out all outstanding resource usage, we make timeline shutdown wait for sidecar tasks and their IOs to complete.
+Under normal conditions, this should be in the low hundreds of microseconds.
+
+It is advisable to make the `IoConcurrency` as long-lived as possible to minimize the amount of
+tokio task churn (=> lower pressure on tokio). Generally this means creating it "high up" in the call stack.
+The pain with this is that the `IoConcurrency` reference needs to be propagated "down" to
+the (short-lived) functions/scope where we issue the IOs.
+We would like to use `RequestContext` for this propagation in the future (issue [here](https://github.com/neondatabase/neon/issues/10460)).
+For now, we just add another argument to the relevant code paths.
+
+### Feature Gating
+
+The `IoConcurrency` is an `enum` with two variants: `Sequential` and `SidecarTask`.
+
+The behavior from before this project is available through `IoConcurrency::Sequential`,
+which awaits the IO futures in place, without "spawning" or "submitting" them anywhere.
+
+The `get_vectored_concurrent_io` pageserver config variable determines the runtime value,
+**except** for the places that use `IoConcurrency::sequential` to get an `IoConcurrency` object.
+
+### Alternatives Explored & Caveats Encountered
+
+A few words on the rationale behind having a sidecar *task* and what
+alternatives were considered but abandoned.
+
+#### Why We Need A Sidecar *Task* / Why Just `FuturesUnordered` Doesn't Work
+
+We explored to not have a sidecar task, and instead have a `FuturesUnordered` per
+`Timeline::get_vectored`. We would queue all IO futures in it and poll it for the
+first time after traversal is complete (i.e., at `collect_pending_ios`).
+
+The obvious disadvantage, but not showstopper, is that we wouldn't be submitting
+IOs until traversal is complete.
+
+The showstopper however, is that deadlocks happen if we don't drive the
+IO futures to completion independently of the traversal task.
+The reason is that both the IO futures and the traversal task may hold _some_,
+_and_ try to acquire _more_, shared limited resources.
+For example, both the travseral task and IO future may try to acquire
+* a `VirtualFile` file descriptor cache slot async mutex (observed during impl)
+* a `tokio-epoll-uring` submission slot (observed during impl)
+* a `PageCache` slot (currently this is not the case but we may move more code into the IO futures in the future)
+
+#### Why We Don't Do `tokio::task`-per-IO-future
+
+Another option is to spawn a short-lived `tokio::task` for each IO future.
+We implemented and benchmarked it during development, but found little
+throughput improvement and moderate mean & tail latency degradation.
+Concerns about pressure on the tokio scheduler led us to abandon this variant.
+
+## Future Work
+
+In addition to what is listed here, also check the "Punted" list in the epic:
+https://github.com/neondatabase/neon/issues/9378
+
+### Enable `Timeline::get`
+
+The only major code path that still uses `IoConcurrency::sequential` is `Timeline::get`.
+The impact is that roughly the following parts of pageserver do not benefit yet:
+- parts of basebackup
+- reads performed by the ingest path
+- most internal operations that read metadata keys (e.g. `collect_keyspace`!)
+
+The solution is to propagate `IoConcurrency` via `RequestContext`:https://github.com/neondatabase/neon/issues/10460
+
+The tricky part is to figure out at which level of the code the `IoConcurrency` is spawned (and added to the RequestContext).
+
+Also, propagation via `RequestContext` makes makes it harder to tell during development whether a given
+piece of code uses concurrent vs sequential mode: one has to recurisvely walk up the call tree to find the
+place that puts the `IoConcurrency` into the `RequestContext`.
+We'd have to use `::Sequential` as the conservative default value in a fresh `RequestContext`, and add some
+observability to weed out places that fail to enrich with a properly spanwed `IoConcurrency::spawn_from_conf`.
+
+### Concurrent On-Demand Downloads enabled by Detached Indices
+
+As stated earlier, traversal stalls on on-demand download because its next step depends on the contents of the layer index.
+Once we have separated indices from data blocks (=> https://github.com/neondatabase/neon/issues/11695)
+we will only need to stall if the index is not resident. The download of the data blocks can happen concurrently or in the background. For example:
+- Move the `Layer::get_or_maybe_download().await` inside the IO futures.
+  This goes in the opposite direction of the next "future work" item below, but it's easy to do.
+- Serve the IO future directly from object storage and dispatch the layer download
+  to some other actor, e.g., an actor that is responsible for both downloads & eviction.
+
+### New `tokio-epoll-uring` API That Separates Submission & Wait-For-Completion
+
+Instead of `$op().await` style API, it would be useful to have a different `tokio-epoll-uring` API
+that separates enqueuing (without necessarily `io_uring_enter`ing the kernel each time), submission,
+and then wait for completion.
+
+The `$op().await` API is too opaque, so we _have_ to stuff it into a `FuturesUnordered`.
+
+A split API as sketched above would allow traversal to ensure an IO operation is enqueued to the kernel/disk (and get back-pressure iff the io_uring squeue is full).
+While avoiding spending of CPU cycles on processing of completions while we're still traversing.
+
+The idea gets muddied by the fact that we may self-deadlock if we submit too much without completing.
+So, the submission part of the split API needs to process completions if squeue is full.
+
+In any way, this split API is precondition for the bigger issue with the design presented here,
+which we dicsuss in the next section.
+
+### Opaque Futures Are Brittle
+
+The use of opaque futures to represent submitted IOs is a clever hack to minimize changes & allow for near-perfect feature-gating.
+However, we take on **brittleness** because callers must guarantee that the submitted futures are independent.
+By our experience, it is non-trivial to identify or rule out the interdependencies.
+See the lengthy doc comment on the `IoConcurrency::spawn_io` method for more details.
+
+The better interface and proper subsystem boundary is a _descriptive_ struct of what needs to be done ("read this range from this VirtualFile into this buffer")
+and get back a means to wait for completion.
+The subsystem can thereby reason by its own how operations may be related;
+unlike today, where the submitted opaque future can do just about anything.

libs/pageserver_api/src/models.rs

@@ -1832,6 +1832,7 @@ pub mod virtual_file {
         Eq,
         Hash,
         strum_macros::EnumString,
+        strum_macros::EnumIter,
         strum_macros::Display,
         serde_with::DeserializeFromStr,
         serde_with::SerializeDisplay,
@@ -1843,10 +1844,8 @@ pub mod virtual_file {
         /// Uses buffered IO.
         Buffered,
         /// Uses direct IO for reads only.
-        #[cfg(target_os = "linux")]
         Direct,
         /// Use direct IO for reads and writes.
-        #[cfg(target_os = "linux")]
         DirectRw,
     }
 
@@ -1854,26 +1853,13 @@ pub mod virtual_file {
         pub fn preferred() -> Self {
             // The default behavior when running Rust unit tests without any further
             // flags is to use the newest behavior (DirectRw).
-            // The CI uses the following environment variable to unit tests for all
-            // different modes.
+            // The CI uses the environment variable to unit tests for all different modes.
             // NB: the Python regression & perf tests have their own defaults management
             // that writes pageserver.toml; they do not use this variable.
-            if cfg!(test) {
-                static CACHED: LazyLock<IoMode> = LazyLock::new(|| {
-                    utils::env::var_serde_json_string(
-                        "NEON_PAGESERVER_UNIT_TEST_VIRTUAL_FILE_IO_MODE",
-                    )
-                    .unwrap_or(
-                        #[cfg(target_os = "linux")]
-                        IoMode::DirectRw,
-                        #[cfg(not(target_os = "linux"))]
-                        IoMode::Buffered,
-                    )
-                });
-                *CACHED
-            } else {
-                IoMode::Buffered
-            }
+            static ENV_OVERRIDE: LazyLock<Option<IoMode>> = LazyLock::new(|| {
+                utils::env::var_serde_json_string("NEON_PAGESERVER_UNIT_TEST_VIRTUAL_FILE_IO_MODE")
+            });
+            ENV_OVERRIDE.unwrap_or(IoMode::DirectRw)
         }
     }
 
@@ -1883,9 +1869,7 @@ pub mod virtual_file {
         fn try_from(value: u8) -> Result<Self, Self::Error> {
             Ok(match value {
                 v if v == (IoMode::Buffered as u8) => IoMode::Buffered,
-                #[cfg(target_os = "linux")]
                 v if v == (IoMode::Direct as u8) => IoMode::Direct,
-                #[cfg(target_os = "linux")]
                 v if v == (IoMode::DirectRw as u8) => IoMode::DirectRw,
                 x => return Err(x),
             })

libs/safekeeper_api/src/models.rs

@@ -299,6 +299,7 @@ pub struct PullTimelineRequest {
     pub tenant_id: TenantId,
     pub timeline_id: TimelineId,
     pub http_hosts: Vec<String>,
+    pub ignore_tombstone: Option<bool>,
 }
 
 #[derive(Debug, Serialize, Deserialize)]

pageserver/benches/bench_ingest.rs

@@ -14,6 +14,7 @@ use pageserver_api::key::Key;
 use pageserver_api::models::virtual_file::IoMode;
 use pageserver_api::shard::TenantShardId;
 use pageserver_api::value::Value;
+use strum::IntoEnumIterator;
 use tokio_util::sync::CancellationToken;
 use utils::bin_ser::BeSer;
 use utils::id::{TenantId, TimelineId};
@@ -244,13 +245,7 @@ fn criterion_benchmark(c: &mut Criterion) {
     ];
     let exploded_parameters = {
         let mut out = Vec::new();
-        for io_mode in [
-            IoMode::Buffered,
-            #[cfg(target_os = "linux")]
-            IoMode::Direct,
-            #[cfg(target_os = "linux")]
-            IoMode::DirectRw,
-        ] {
+        for io_mode in IoMode::iter() {
             for param in expect.clone() {
                 let HandPickedParameters {
                     volume_mib,

pageserver/src/tenant/timeline/compaction.rs

@@ -1277,6 +1277,8 @@ impl Timeline {
             return Ok(CompactionOutcome::YieldForL0);
         }
 
+        let gc_cutoff = *self.applied_gc_cutoff_lsn.read();
+
         // 2. Repartition and create image layers if necessary
         match self
             .repartition(
@@ -1287,7 +1289,7 @@ impl Timeline {
             )
             .await
         {
-            Ok(((dense_partitioning, sparse_partitioning), lsn)) => {
+            Ok(((dense_partitioning, sparse_partitioning), lsn)) if lsn >= gc_cutoff => {
                 // Disables access_stats updates, so that the files we read remain candidates for eviction after we're done with them
                 let image_ctx = RequestContextBuilder::from(ctx)
                     .access_stats_behavior(AccessStatsBehavior::Skip)
@@ -1341,6 +1343,10 @@ impl Timeline {
                 }
             }
 
+            Ok(_) => {
+                info!("skipping repartitioning due to image compaction LSN being below GC cutoff");
+            }
+
             // Suppress errors when cancelled.
             Err(_) if self.cancel.is_cancelled() => {}
             Err(err) if err.is_cancel() => {}
@@ -3606,6 +3612,13 @@ impl Timeline {
                     last_key = Some(key);
                 }
                 accumulated_values.push((key, lsn, val));
+
+                if accumulated_values.len() >= 65536 {
+                    // Assume all of them are images, that would be 512MB of data in memory for a single key.
+                    return Err(CompactionError::Other(anyhow!(
+                        "too many values for a single key, giving up gc-compaction"
+                    )));
+                }
             } else {
                 let last_key: &mut Key = last_key.as_mut().unwrap();
                 stat.on_unique_key_visited(); // TODO: adjust statistics for partial compaction

pageserver/src/virtual_file.rs

@@ -74,6 +74,8 @@ pub struct VirtualFile {
 
 impl VirtualFile {
     /// Open a file in read-only mode. Like File::open.
+    ///
+    /// Insensitive to `virtual_file_io_mode` setting.
     pub async fn open<P: AsRef<Utf8Path>>(
         path: P,
         ctx: &RequestContext,
@@ -95,31 +97,20 @@ impl VirtualFile {
         Self::open_with_options_v2(path.as_ref(), OpenOptions::new().read(true), ctx).await
     }
 
+    /// `O_DIRECT` will be enabled base on `virtual_file_io_mode`.
     pub async fn open_with_options_v2<P: AsRef<Utf8Path>>(
         path: P,
-        #[cfg_attr(not(target_os = "linux"), allow(unused_mut))] mut open_options: OpenOptions,
+        mut open_options: OpenOptions,
         ctx: &RequestContext,
     ) -> Result<Self, std::io::Error> {
         let mode = get_io_mode();
-        let set_o_direct = match (mode, open_options.is_write()) {
+        let direct = match (mode, open_options.is_write()) {
             (IoMode::Buffered, _) => false,
-            #[cfg(target_os = "linux")]
             (IoMode::Direct, false) => true,
-            #[cfg(target_os = "linux")]
             (IoMode::Direct, true) => false,
-            #[cfg(target_os = "linux")]
             (IoMode::DirectRw, _) => true,
         };
-        if set_o_direct {
-            #[cfg(target_os = "linux")]
-            {
-                open_options = open_options.custom_flags(nix::libc::O_DIRECT);
-            }
-            #[cfg(not(target_os = "linux"))]
-            unreachable!(
-                "O_DIRECT is not supported on this platform, IoMode's that result in set_o_direct=true shouldn't even be defined"
-            );
-        }
+        open_options = open_options.direct(direct);
         let inner = VirtualFileInner::open_with_options(path, open_options, ctx).await?;
         Ok(VirtualFile { inner, _mode: mode })
     }
@@ -791,6 +782,12 @@ impl VirtualFileInner {
     where
         Buf: tokio_epoll_uring::IoBufMut + Send,
     {
+        self.validate_direct_io(
+            Slice::stable_ptr(&buf).addr(),
+            Slice::bytes_total(&buf),
+            offset,
+        );
+
         let file_guard = match self
             .lock_file()
             .await
@@ -816,6 +813,8 @@ impl VirtualFileInner {
         offset: u64,
         ctx: &RequestContext,
     ) -> (FullSlice<B>, Result<usize, Error>) {
+        self.validate_direct_io(buf.as_ptr().addr(), buf.len(), offset);
+
         let file_guard = match self.lock_file().await {
             Ok(file_guard) => file_guard,
             Err(e) => return (buf, Err(e)),
@@ -830,6 +829,64 @@ impl VirtualFileInner {
             (buf, result)
         })
     }
+
+    /// Validate all reads and writes to adhere to the O_DIRECT requirements of our production systems.
+    ///
+    /// Validating it iin userspace sets a consistent bar, independent of what actual OS/filesystem/block device is in use.
+    fn validate_direct_io(&self, addr: usize, size: usize, offset: u64) {
+        // TODO: eventually enable validation in the builds we use in real environments like staging, preprod, and prod.
+        if !(cfg!(feature = "testing") || cfg!(test)) {
+            return;
+        }
+        if !self.open_options.is_direct() {
+            return;
+        }
+
+        // Validate buffer memory alignment.
+        //
+        // What practically matters as of Linux 6.1 is bdev_dma_alignment()
+        // which is practically between 512 and 4096.
+        // On our production systems, the value is 512.
+        // The IoBuffer/IoBufferMut hard-code that value.
+        //
+        // Because the alloctor might return _more_ aligned addresses than requested,
+        // there is a chance that testing would not catch violations of a runtime requirement stricter than 512.
+        {
+            let requirement = 512;
+            let remainder = addr % requirement;
+            assert!(
+                remainder == 0,
+                "Direct I/O buffer must be aligned: buffer_addr=0x{addr:x} % 0x{requirement:x} = 0x{remainder:x}"
+            );
+        }
+
+        // Validate offset alignment.
+        //
+        // We hard-code 512 throughout the code base.
+        // So enforce just that and not anything more restrictive.
+        // Even the shallowest testing will expose more restrictive requirements if those ever arise.
+        {
+            let requirement = 512;
+            let remainder = offset % requirement;
+            assert!(
+                remainder == 0,
+                "Direct I/O offset must be aligned: offset=0x{offset:x} % 0x{requirement:x} = 0x{remainder:x}"
+            );
+        }
+
+        // Validate buffer size multiple requirement.
+        //
+        // The requirement in Linux 6.1 is bdev_logical_block_size().
+        // On our production systems, that is 512.
+        {
+            let requirement = 512;
+            let remainder = size % requirement;
+            assert!(
+                remainder == 0,
+                "Direct I/O buffer size must be a multiple of {requirement}: size=0x{size:x} % 0x{requirement:x} = 0x{remainder:x}"
+            );
+        }
+    }
 }
 
 // Adapted from https://doc.rust-lang.org/1.72.0/src/std/os/unix/fs.rs.html#117-135
@@ -1218,7 +1275,6 @@ mod tests {
     use std::sync::Arc;
 
     use owned_buffers_io::io_buf_ext::IoBufExt;
-    use owned_buffers_io::slice::SliceMutExt;
     use rand::seq::SliceRandom;
     use rand::{Rng, thread_rng};
 
@@ -1226,162 +1282,38 @@ mod tests {
     use crate::context::DownloadBehavior;
     use crate::task_mgr::TaskKind;
 
-    enum MaybeVirtualFile {
-        VirtualFile(VirtualFile),
-        File(File),
-    }
-
-    impl From<VirtualFile> for MaybeVirtualFile {
-        fn from(vf: VirtualFile) -> Self {
-            MaybeVirtualFile::VirtualFile(vf)
-        }
-    }
-
-    impl MaybeVirtualFile {
-        async fn read_exact_at(
-            &self,
-            mut slice: tokio_epoll_uring::Slice<IoBufferMut>,
-            offset: u64,
-            ctx: &RequestContext,
-        ) -> Result<tokio_epoll_uring::Slice<IoBufferMut>, Error> {
-            match self {
-                MaybeVirtualFile::VirtualFile(file) => file.read_exact_at(slice, offset, ctx).await,
-                MaybeVirtualFile::File(file) => {
-                    let rust_slice: &mut [u8] = slice.as_mut_rust_slice_full_zeroed();
-                    file.read_exact_at(rust_slice, offset).map(|()| slice)
-                }
-            }
-        }
-        async fn write_all_at<Buf: IoBufAligned + Send>(
-            &self,
-            buf: FullSlice<Buf>,
-            offset: u64,
-            ctx: &RequestContext,
-        ) -> Result<(), Error> {
-            match self {
-                MaybeVirtualFile::VirtualFile(file) => {
-                    let (_buf, res) = file.write_all_at(buf, offset, ctx).await;
-                    res
-                }
-                MaybeVirtualFile::File(file) => file.write_all_at(&buf[..], offset),
-            }
-        }
-
-        // Helper function to slurp a portion of a file into a string
-        async fn read_string_at(
-            &mut self,
-            pos: u64,
-            len: usize,
-            ctx: &RequestContext,
-        ) -> Result<String, Error> {
-            let slice = IoBufferMut::with_capacity(len).slice_full();
-            assert_eq!(slice.bytes_total(), len);
-            let slice = self.read_exact_at(slice, pos, ctx).await?;
-            let buf = slice.into_inner();
-            assert_eq!(buf.len(), len);
-
-            Ok(String::from_utf8(buf.to_vec()).unwrap())
-        }
-    }
-
     #[tokio::test]
     async fn test_virtual_files() -> anyhow::Result<()> {
-        // The real work is done in the test_files() helper function. This
-        // allows us to run the same set of tests against a native File, and
-        // VirtualFile. We trust the native Files and wouldn't need to test them,
-        // but this allows us to verify that the operations return the same
-        // results with VirtualFiles as with native Files. (Except that with
-        // native files, you will run out of file descriptors if the ulimit
-        // is low enough.)
-        struct A;
-
-        impl Adapter for A {
-            async fn open(
-                path: Utf8PathBuf,
-                opts: OpenOptions,
-                ctx: &RequestContext,
-            ) -> Result<MaybeVirtualFile, anyhow::Error> {
-                let vf = VirtualFile::open_with_options_v2(&path, opts, ctx).await?;
-                Ok(MaybeVirtualFile::VirtualFile(vf))
-            }
-        }
-        test_files::<A>("virtual_files").await
-    }
-
-    #[tokio::test]
-    async fn test_physical_files() -> anyhow::Result<()> {
-        struct B;
-
-        impl Adapter for B {
-            async fn open(
-                path: Utf8PathBuf,
-                opts: OpenOptions,
-                _ctx: &RequestContext,
-            ) -> Result<MaybeVirtualFile, anyhow::Error> {
-                Ok(MaybeVirtualFile::File({
-                    let owned_fd = opts.open(path.as_std_path()).await?;
-                    File::from(owned_fd)
-                }))
-            }
-        }
-
-        test_files::<B>("physical_files").await
-    }
-
-    /// This is essentially a closure which returns a MaybeVirtualFile, but because rust edition
-    /// 2024 is not yet out with new lifetime capture or outlives rules, this is a async function
-    /// in trait which benefits from the new lifetime capture rules already.
-    trait Adapter {
-        async fn open(
-            path: Utf8PathBuf,
-            opts: OpenOptions,
-            ctx: &RequestContext,
-        ) -> Result<MaybeVirtualFile, anyhow::Error>;
-    }
-
-    async fn test_files<A>(testname: &str) -> anyhow::Result<()>
-    where
-        A: Adapter,
-    {
         let ctx =
             RequestContext::new(TaskKind::UnitTest, DownloadBehavior::Error).with_scope_unit_test();
-        let testdir = crate::config::PageServerConf::test_repo_dir(testname);
+        let testdir = crate::config::PageServerConf::test_repo_dir("test_virtual_files");
         std::fs::create_dir_all(&testdir)?;
 
+        let zeropad512 = |content: &[u8]| {
+            let mut buf = IoBufferMut::with_capacity_zeroed(512);
+            buf[..content.len()].copy_from_slice(content);
+            buf.freeze().slice_len()
+        };
+
         let path_a = testdir.join("file_a");
-        let mut file_a = A::open(
+        let file_a = VirtualFile::open_with_options_v2(
             path_a.clone(),
             OpenOptions::new()
+                .read(true)
                 .write(true)
+                // set create & truncate flags to ensure when we trigger a reopen later in this test,
+                // the reopen_options must have masked out those flags; if they don't, then
+                // the after reopen we will fail to read the `content_a` that we write here.
                 .create(true)
-                .truncate(true)
-                .to_owned(),
+                .truncate(true),
             &ctx,
         )
         .await?;
+        let (_, res) = file_a.write_all_at(zeropad512(b"content_a"), 0, &ctx).await;
+        res?;
 
-        file_a
-            .write_all_at(IoBuffer::from(b"foobar").slice_len(), 0, &ctx)
-            .await?;
-
-        // cannot read from a file opened in write-only mode
-        let _ = file_a.read_string_at(0, 1, &ctx).await.unwrap_err();
-
-        // Close the file and re-open for reading
-        let mut file_a = A::open(path_a, OpenOptions::new().read(true), &ctx).await?;
-
-        // cannot write to a file opened in read-only mode
-        let _ = file_a
-            .write_all_at(IoBuffer::from(b"bar").slice_len(), 0, &ctx)
-            .await
-            .unwrap_err();
-
-        // Try simple read
-        assert_eq!("foobar", file_a.read_string_at(0, 6, &ctx).await?);
-
-        // Create another test file, and try FileExt functions on it.
         let path_b = testdir.join("file_b");
-        let mut file_b = A::open(
+        let file_b = VirtualFile::open_with_options_v2(
             path_b.clone(),
             OpenOptions::new()
                 .read(true)
@@ -1391,37 +1323,44 @@ mod tests {
             &ctx,
         )
         .await?;
-        file_b
-            .write_all_at(IoBuffer::from(b"BAR").slice_len(), 3, &ctx)
-            .await?;
-        file_b
-            .write_all_at(IoBuffer::from(b"FOO").slice_len(), 0, &ctx)
-            .await?;
+        let (_, res) = file_b.write_all_at(zeropad512(b"content_b"), 0, &ctx).await;
+        res?;
 
-        assert_eq!(file_b.read_string_at(2, 3, &ctx).await?, "OBA");
+        let assert_first_512_eq = async |vfile: &VirtualFile, expect: &[u8]| {
+            let buf = vfile
+                .read_exact_at(IoBufferMut::with_capacity_zeroed(512).slice_full(), 0, &ctx)
+                .await
+                .unwrap();
+            assert_eq!(&buf[..], &zeropad512(expect)[..]);
+        };
 
-        // Open a lot of files, enough to cause some evictions. (Or to be precise,
-        // open the same file many times. The effect is the same.)
+        // Open a lot of file descriptors / VirtualFile instances.
+        // Enough to cause some evictions in the fd cache.
 
-        let mut vfiles = Vec::new();
+        let mut file_b_dupes = Vec::new();
         for _ in 0..100 {
-            let mut vfile = A::open(path_b.clone(), OpenOptions::new().read(true), &ctx).await?;
-            assert_eq!("FOOBAR", vfile.read_string_at(0, 6, &ctx).await?);
-            vfiles.push(vfile);
+            let vfile = VirtualFile::open_with_options_v2(
+                path_b.clone(),
+                OpenOptions::new().read(true),
+                &ctx,
+            )
+            .await?;
+            assert_first_512_eq(&vfile, b"content_b").await;
+            file_b_dupes.push(vfile);
         }
 
         // make sure we opened enough files to definitely cause evictions.
-        assert!(vfiles.len() > TEST_MAX_FILE_DESCRIPTORS * 2);
+        assert!(file_b_dupes.len() > TEST_MAX_FILE_DESCRIPTORS * 2);
 
         // The underlying file descriptor for 'file_a' should be closed now. Try to read
-        // from it again.
-        assert_eq!("foobar", file_a.read_string_at(0, 6, &ctx).await?);
+        // from it again. The VirtualFile reopens the file internally.
+        assert_first_512_eq(&file_a, b"content_a").await;
 
         // Check that all the other FDs still work too. Use them in random order for
         // good measure.
-        vfiles.as_mut_slice().shuffle(&mut thread_rng());
-        for vfile in vfiles.iter_mut() {
-            assert_eq!("OOBAR", vfile.read_string_at(1, 5, &ctx).await?);
+        file_b_dupes.as_mut_slice().shuffle(&mut thread_rng());
+        for vfile in file_b_dupes.iter_mut() {
+            assert_first_512_eq(vfile, b"content_b").await;
         }
 
         Ok(())
@@ -1452,7 +1391,7 @@ mod tests {
         // Open the file many times.
         let mut files = Vec::new();
         for _ in 0..VIRTUAL_FILES {
-            let f = VirtualFileInner::open_with_options(
+            let f = VirtualFile::open_with_options_v2(
                 &test_file_path,
                 OpenOptions::new().read(true),
                 &ctx,
@@ -1497,8 +1436,6 @@ mod tests {
 
     #[tokio::test]
     async fn test_atomic_overwrite_basic() {
-        let ctx =
-            RequestContext::new(TaskKind::UnitTest, DownloadBehavior::Error).with_scope_unit_test();
         let testdir = crate::config::PageServerConf::test_repo_dir("test_atomic_overwrite_basic");
         std::fs::create_dir_all(&testdir).unwrap();
 
@@ -1508,26 +1445,22 @@ mod tests {
         VirtualFileInner::crashsafe_overwrite(path.clone(), tmp_path.clone(), b"foo".to_vec())
             .await
             .unwrap();
-        let mut file = MaybeVirtualFile::from(VirtualFile::open(&path, &ctx).await.unwrap());
-        let post = file.read_string_at(0, 3, &ctx).await.unwrap();
+
+        let post = std::fs::read_to_string(&path).unwrap();
         assert_eq!(post, "foo");
         assert!(!tmp_path.exists());
-        drop(file);
 
         VirtualFileInner::crashsafe_overwrite(path.clone(), tmp_path.clone(), b"bar".to_vec())
             .await
             .unwrap();
-        let mut file = MaybeVirtualFile::from(VirtualFile::open(&path, &ctx).await.unwrap());
-        let post = file.read_string_at(0, 3, &ctx).await.unwrap();
+
+        let post = std::fs::read_to_string(&path).unwrap();
         assert_eq!(post, "bar");
         assert!(!tmp_path.exists());
-        drop(file);
     }
 
     #[tokio::test]
     async fn test_atomic_overwrite_preexisting_tmp() {
-        let ctx =
-            RequestContext::new(TaskKind::UnitTest, DownloadBehavior::Error).with_scope_unit_test();
         let testdir =
             crate::config::PageServerConf::test_repo_dir("test_atomic_overwrite_preexisting_tmp");
         std::fs::create_dir_all(&testdir).unwrap();
@@ -1542,10 +1475,8 @@ mod tests {
             .await
             .unwrap();
 
-        let mut file = MaybeVirtualFile::from(VirtualFile::open(&path, &ctx).await.unwrap());
-        let post = file.read_string_at(0, 3, &ctx).await.unwrap();
+        let post = std::fs::read_to_string(&path).unwrap();
         assert_eq!(post, "foo");
         assert!(!tmp_path.exists());
-        drop(file);
     }
 }

pageserver/src/virtual_file/open_options.rs

@@ -8,7 +8,13 @@ use super::io_engine::IoEngine;
 
 #[derive(Debug, Clone)]
 pub struct OpenOptions {
+    /// We keep a copy of the write() flag we pass to the `inner`` `OptionOptions`
+    /// to support [`Self::is_write`].
     write: bool,
+    /// We don't expose + pass through a raw `custom_flags()` style API.
+    /// The only custom flag we support is `O_DIRECT`, which we track here
+    /// and map to `custom_flags()` in the [`Self::open`] method.
+    direct: bool,
     inner: Inner,
 }
 #[derive(Debug, Clone)]
@@ -30,6 +36,7 @@ impl Default for OpenOptions {
         };
         Self {
             write: false,
+            direct: false,
             inner,
         }
     }
@@ -44,6 +51,10 @@ impl OpenOptions {
         self.write
     }
 
+    pub(super) fn is_direct(&self) -> bool {
+        self.direct
+    }
+
     pub fn read(mut self, read: bool) -> Self {
         match &mut self.inner {
             Inner::StdFs(x) => {
@@ -116,13 +127,38 @@ impl OpenOptions {
     }
 
     pub(in crate::virtual_file) async fn open(&self, path: &Path) -> std::io::Result<OwnedFd> {
-        match &self.inner {
-            Inner::StdFs(x) => x.open(path).map(|file| file.into()),
+        #[cfg_attr(not(target_os = "linux"), allow(unused_mut))]
+        let mut custom_flags = 0;
+        if self.direct {
             #[cfg(target_os = "linux")]
-            Inner::TokioEpollUring(x) => {
+            {
+                custom_flags |= nix::libc::O_DIRECT;
+            }
+            #[cfg(not(target_os = "linux"))]
+            {
+                // Other platforms may be used for development but don't necessarily have a 1:1 equivalent to Linux's O_DIRECT (macOS!).
+                // Just don't set the flag; to catch alignment bugs typical for O_DIRECT,
+                // we have a runtime validation layer inside `VirtualFile::write_at` and `VirtualFile::read_at`.
+                static WARNING: std::sync::Once = std::sync::Once::new();
+                WARNING.call_once(|| {
+                    let span = tracing::info_span!(parent: None, "open_options");
+                    let _enter = span.enter();
+                    tracing::warn!("your platform is not a supported production platform, ignoing request for O_DIRECT; this could hide alignment bugs; this warning is logged once per process");
+                });
+            }
+        }
+
+        match self.inner.clone() {
+            Inner::StdFs(mut x) => x
+                .custom_flags(custom_flags)
+                .open(path)
+                .map(|file| file.into()),
+            #[cfg(target_os = "linux")]
+            Inner::TokioEpollUring(mut x) => {
+                x.custom_flags(custom_flags);
                 let system = super::io_engine::tokio_epoll_uring_ext::thread_local_system().await;
                 let (_, res) = super::io_engine::retry_ecanceled_once((), |()| async {
-                    let res = system.open(path, x).await;
+                    let res = system.open(path, &x).await;
                     ((), res)
                 })
                 .await;
@@ -144,19 +180,8 @@ impl OpenOptions {
         self
     }
 
-    pub fn custom_flags(mut self, flags: i32) -> Self {
-        if flags & nix::libc::O_APPEND != 0 {
-            super::io_engine::panic_operation_must_be_idempotent();
-        }
-        match &mut self.inner {
-            Inner::StdFs(x) => {
-                let _ = x.custom_flags(flags);
-            }
-            #[cfg(target_os = "linux")]
-            Inner::TokioEpollUring(x) => {
-                let _ = x.custom_flags(flags);
-            }
-        }
+    pub fn direct(mut self, direct: bool) -> Self {
+        self.direct = direct;
         self
     }
 }

pgxn/neon/communicator.c

@@ -425,15 +425,12 @@ compact_prefetch_buffers(void)
  * point inside and outside PostgreSQL.
  *
  * This still does throw errors when it receives malformed responses from PS.
- *
- * When we're not called from CHECK_FOR_INTERRUPTS (indicated by
- * IsHandlingInterrupts) we also report we've ended prefetch receive work,
- * just in case state tracking was lost due to an error in the sync getPage
- * response code.
  */
 void
-communicator_prefetch_pump_state(bool IsHandlingInterrupts)
+communicator_prefetch_pump_state(void)
 {
+	START_PREFETCH_RECEIVE_WORK();
+
 	while (MyPState->ring_receive != MyPState->ring_flush)
 	{
 		NeonResponse   *response;
@@ -482,9 +479,7 @@ communicator_prefetch_pump_state(bool IsHandlingInterrupts)
 		}
 	}
 
-	/* We never pump the prefetch state while handling other pages */
-	if (!IsHandlingInterrupts)
-		END_PREFETCH_RECEIVE_WORK();
+	END_PREFETCH_RECEIVE_WORK();
 
 	communicator_reconfigure_timeout_if_needed();
 }
@@ -672,9 +667,10 @@ prefetch_wait_for(uint64 ring_index)
 
 	Assert(MyPState->ring_unused > ring_index);
 
+	START_PREFETCH_RECEIVE_WORK();
+
 	while (MyPState->ring_receive <= ring_index)
 	{
-		START_PREFETCH_RECEIVE_WORK();
 		entry = GetPrfSlot(MyPState->ring_receive);
 
 		Assert(entry->status == PRFS_REQUESTED);
@@ -683,17 +679,18 @@ prefetch_wait_for(uint64 ring_index)
 			result = false;
 			break;
 		}
-
-		END_PREFETCH_RECEIVE_WORK();
 		CHECK_FOR_INTERRUPTS();
 	}
+
 	if (result)
 	{
 		/* Check that slot is actually received (srver can be disconnected in prefetch_pump_state called from CHECK_FOR_INTERRUPTS */
 		PrefetchRequest *slot = GetPrfSlot(ring_index);
-		return slot->status == PRFS_RECEIVED;
+		result = slot->status == PRFS_RECEIVED;
 	}
-	return false;
+	END_PREFETCH_RECEIVE_WORK();
+
+	return result;
 ;
 }
 
@@ -720,6 +717,7 @@ prefetch_read(PrefetchRequest *slot)
 	Assert(slot->status == PRFS_REQUESTED);
 	Assert(slot->response == NULL);
 	Assert(slot->my_ring_index == MyPState->ring_receive);
+	Assert(readpage_reentrant_guard);
 
 	if (slot->status != PRFS_REQUESTED ||
 		slot->response != NULL ||
@@ -802,6 +800,7 @@ communicator_prefetch_receive(BufferTag tag)
 	PrfHashEntry *entry;
 	PrefetchRequest hashkey;
 
+	Assert(readpage_reentrant_guard);
 	hashkey.buftag = tag;
 	entry = prfh_lookup(MyPState->prf_hash, &hashkey);
 	if (entry != NULL && prefetch_wait_for(entry->slot->my_ring_index))
@@ -821,8 +820,12 @@ communicator_prefetch_receive(BufferTag tag)
 void
 prefetch_on_ps_disconnect(void)
 {
+	bool save_readpage_reentrant_guard = readpage_reentrant_guard;
 	MyPState->ring_flush = MyPState->ring_unused;
 
+	/* Prohibit callig of prefetch_pump_state */
+	START_PREFETCH_RECEIVE_WORK();
+
 	while (MyPState->ring_receive < MyPState->ring_unused)
 	{
 		PrefetchRequest *slot;
@@ -851,6 +854,9 @@ prefetch_on_ps_disconnect(void)
 		MyNeonCounters->getpage_prefetch_discards_total += 1;
 	}
 
+	/* Restore guard */
+	readpage_reentrant_guard = save_readpage_reentrant_guard;
+
 	/*
 	 * We can have gone into retry due to network error, so update stats with
 	 * the latest available
@@ -2509,7 +2515,7 @@ communicator_processinterrupts(void)
 	if (timeout_signaled)
 	{
 		if (!readpage_reentrant_guard && readahead_getpage_pull_timeout_ms > 0)
-			communicator_prefetch_pump_state(true);
+			communicator_prefetch_pump_state();
 
 		timeout_signaled = false;
 		communicator_reconfigure_timeout_if_needed();

pgxn/neon/communicator.h

@@ -44,7 +44,7 @@ extern int communicator_read_slru_segment(SlruKind kind, int64 segno,
 										  void *buffer);
 
 extern void communicator_reconfigure_timeout_if_needed(void);
-extern void communicator_prefetch_pump_state(bool IsHandlingInterrupts);
+extern void communicator_prefetch_pump_state(void);
 
 
 #endif

pgxn/neon/libpagestore.c

@@ -433,7 +433,6 @@ pageserver_connect(shardno_t shard_no, int elevel)
 
 		now = GetCurrentTimestamp();
 		us_since_last_attempt = (int64) (now - shard->last_reconnect_time);
-		shard->last_reconnect_time = now;
 
 		/*
 		 * Make sure we don't do exponential backoff with a constant multiplier
@@ -447,14 +446,23 @@ pageserver_connect(shardno_t shard_no, int elevel)
 		/*
 		 * If we did other tasks between reconnect attempts, then we won't
 		 * need to wait as long as a full delay.
+		 *
+		 * This is a loop to protect against interrupted sleeps.
 		 */
-		if (us_since_last_attempt < shard->delay_us)
+		while (us_since_last_attempt < shard->delay_us)
 		{
 			pg_usleep(shard->delay_us - us_since_last_attempt);
+
+			/* At least we should handle cancellations here */
+			CHECK_FOR_INTERRUPTS();
+
+			now = GetCurrentTimestamp();
+			us_since_last_attempt = (int64) (now - shard->last_reconnect_time);
 		}
 
 		/* update the delay metric */
 		shard->delay_us = Min(shard->delay_us * 2, MAX_RECONNECT_INTERVAL_USEC);
+		shard->last_reconnect_time = now;
 
 		/*
 		 * Connect using the connection string we got from the

pgxn/neon/pagestore_smgr.c

@@ -1179,7 +1179,7 @@ neon_prefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		blocknum += iterblocks;
 	}
 
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 	return false;
 }
@@ -1218,7 +1218,7 @@ neon_prefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum)
 
 	communicator_prefetch_register_bufferv(tag, NULL, 1, NULL);
 
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 	return false;
 }
@@ -1262,7 +1262,7 @@ neon_writeback(SMgrRelation reln, ForkNumber forknum,
 	 */
 	neon_log(SmgrTrace, "writeback noop");
 
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 #ifdef DEBUG_COMPARE_LOCAL
 	if (IS_LOCAL_REL(reln))
@@ -1315,7 +1315,7 @@ neon_read(SMgrRelation reln, ForkNumber forkNum, BlockNumber blkno, void *buffer
 	}
 
 	/* Try to read PS results if they are available */
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 	neon_get_request_lsns(InfoFromSMgrRel(reln), forkNum, blkno, &request_lsns, 1);
 
@@ -1339,7 +1339,7 @@ neon_read(SMgrRelation reln, ForkNumber forkNum, BlockNumber blkno, void *buffer
 	/*
 	 * Try to receive prefetch results once again just to make sure we don't leave the smgr code while the OS might still have buffered bytes.
 	 */
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 #ifdef DEBUG_COMPARE_LOCAL
 	if (forkNum == MAIN_FORKNUM && IS_LOCAL_REL(reln))
@@ -1449,7 +1449,7 @@ neon_readv(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 				 nblocks, PG_IOV_MAX);
 
 	/* Try to read PS results if they are available */
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 	neon_get_request_lsns(InfoFromSMgrRel(reln), forknum, blocknum,
 						  request_lsns, nblocks);
@@ -1480,7 +1480,7 @@ neon_readv(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	/*
 	 * Try to receive prefetch results once again just to make sure we don't leave the smgr code while the OS might still have buffered bytes.
 	 */
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 #ifdef DEBUG_COMPARE_LOCAL
 	if (forknum == MAIN_FORKNUM && IS_LOCAL_REL(reln))
@@ -1665,7 +1665,7 @@ neon_write(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum, const vo
 
 	lfc_write(InfoFromSMgrRel(reln), forknum, blocknum, buffer);
 
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 #ifdef DEBUG_COMPARE_LOCAL
 	if (IS_LOCAL_REL(reln))
@@ -1727,7 +1727,7 @@ neon_writev(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
 
 	lfc_writev(InfoFromSMgrRel(reln), forknum, blkno, buffers, nblocks);
 
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 #ifdef DEBUG_COMPARE_LOCAL
 	if (IS_LOCAL_REL(reln))
@@ -1902,7 +1902,7 @@ neon_immedsync(SMgrRelation reln, ForkNumber forknum)
 
 	neon_log(SmgrTrace, "[NEON_SMGR] immedsync noop");
 
-	communicator_prefetch_pump_state(false);
+	communicator_prefetch_pump_state();
 
 #ifdef DEBUG_COMPARE_LOCAL
 	if (IS_LOCAL_REL(reln))

proxy/src/binary/local_proxy.rs

@@ -423,8 +423,8 @@ async fn refresh_config_inner(
     if let Some(tls_config) = data.tls {
         let tls_config = tokio::task::spawn_blocking(move || {
             crate::tls::server_config::configure_tls(
-                &tls_config.key_path,
-                &tls_config.cert_path,
+                tls_config.key_path.as_ref(),
+                tls_config.cert_path.as_ref(),
                 None,
                 false,
             )

proxy/src/binary/pg_sni_router.rs

@@ -1,8 +1,10 @@
-/// A stand-alone program that routes connections, e.g. from
-/// `aaa--bbb--1234.external.domain` to `aaa.bbb.internal.domain:1234`.
-///
-/// This allows connecting to pods/services running in the same Kubernetes cluster from
-/// the outside. Similar to an ingress controller for HTTPS.
+//! A stand-alone program that routes connections, e.g. from
+//! `aaa--bbb--1234.external.domain` to `aaa.bbb.internal.domain:1234`.
+//!
+//! This allows connecting to pods/services running in the same Kubernetes cluster from
+//! the outside. Similar to an ingress controller for HTTPS.
+
+use std::path::Path;
 use std::{net::SocketAddr, sync::Arc};
 
 use anyhow::{Context, anyhow, bail, ensure};
@@ -86,46 +88,7 @@ pub async fn run() -> anyhow::Result<()> {
         args.get_one::<String>("tls-key"),
         args.get_one::<String>("tls-cert"),
     ) {
-        (Some(key_path), Some(cert_path)) => {
-            let key = {
-                let key_bytes = std::fs::read(key_path).context("TLS key file")?;
-
-                let mut keys =
-                    rustls_pemfile::pkcs8_private_keys(&mut &key_bytes[..]).collect_vec();
-
-                ensure!(keys.len() == 1, "keys.len() = {} (should be 1)", keys.len());
-                PrivateKeyDer::Pkcs8(
-                    keys.pop()
-                        .expect("keys should not be empty")
-                        .context(format!("Failed to read TLS keys at '{key_path}'"))?,
-                )
-            };
-
-            let cert_chain_bytes = std::fs::read(cert_path)
-                .context(format!("Failed to read TLS cert file at '{cert_path}.'"))?;
-
-            let cert_chain: Vec<_> = {
-                rustls_pemfile::certs(&mut &cert_chain_bytes[..])
-                .try_collect()
-                .with_context(|| {
-                    format!("Failed to read TLS certificate chain from bytes from file at '{cert_path}'.")
-                })?
-            };
-
-            // needed for channel bindings
-            let first_cert = cert_chain.first().context("missing certificate")?;
-            let tls_server_end_point = TlsServerEndPoint::new(first_cert)?;
-
-            let tls_config =
-                rustls::ServerConfig::builder_with_provider(Arc::new(ring::default_provider()))
-                    .with_protocol_versions(&[&rustls::version::TLS13, &rustls::version::TLS12])
-                    .context("ring should support TLS1.2 and TLS1.3")?
-                    .with_no_client_auth()
-                    .with_single_cert(cert_chain, key)?
-                    .into();
-
-            (tls_config, tls_server_end_point)
-        }
+        (Some(key_path), Some(cert_path)) => parse_tls(key_path.as_ref(), cert_path.as_ref())?,
         _ => bail!("tls-key and tls-cert must be specified"),
     };
 
@@ -188,7 +151,58 @@ pub async fn run() -> anyhow::Result<()> {
     match signal {}
 }
 
-async fn task_main(
+pub(super) fn parse_tls(
+    key_path: &Path,
+    cert_path: &Path,
+) -> anyhow::Result<(Arc<rustls::ServerConfig>, TlsServerEndPoint)> {
+    let key = {
+        let key_bytes = std::fs::read(key_path).context("TLS key file")?;
+
+        let mut keys = rustls_pemfile::pkcs8_private_keys(&mut &key_bytes[..]).collect_vec();
+
+        ensure!(keys.len() == 1, "keys.len() = {} (should be 1)", keys.len());
+        PrivateKeyDer::Pkcs8(
+            keys.pop()
+                .expect("keys should not be empty")
+                .context(format!(
+                    "Failed to read TLS keys at '{}'",
+                    key_path.display()
+                ))?,
+        )
+    };
+
+    let cert_chain_bytes = std::fs::read(cert_path).context(format!(
+        "Failed to read TLS cert file at '{}.'",
+        cert_path.display()
+    ))?;
+
+    let cert_chain: Vec<_> = {
+        rustls_pemfile::certs(&mut &cert_chain_bytes[..])
+            .try_collect()
+            .with_context(|| {
+                format!(
+                    "Failed to read TLS certificate chain from bytes from file at '{}'.",
+                    cert_path.display()
+                )
+            })?
+    };
+
+    // needed for channel bindings
+    let first_cert = cert_chain.first().context("missing certificate")?;
+    let tls_server_end_point = TlsServerEndPoint::new(first_cert)?;
+
+    let tls_config =
+        rustls::ServerConfig::builder_with_provider(Arc::new(ring::default_provider()))
+            .with_protocol_versions(&[&rustls::version::TLS13, &rustls::version::TLS12])
+            .context("ring should support TLS1.2 and TLS1.3")?
+            .with_no_client_auth()
+            .with_single_cert(cert_chain, key)?
+            .into();
+
+    Ok((tls_config, tls_server_end_point))
+}
+
+pub(super) async fn task_main(
     dest_suffix: Arc<String>,
     tls_config: Arc<rustls::ServerConfig>,
     compute_tls_config: Option<Arc<rustls::ClientConfig>>,

proxy/src/binary/proxy.rs

@@ -1,9 +1,10 @@
 use std::net::SocketAddr;
+use std::path::PathBuf;
 use std::pin::pin;
 use std::sync::Arc;
 use std::time::Duration;
 
-use anyhow::bail;
+use anyhow::{bail, ensure};
 use arc_swap::ArcSwapOption;
 use futures::future::Either;
 use remote_storage::RemoteStorageConfig;
@@ -62,18 +63,18 @@ struct ProxyCliArgs {
     region: String,
     /// listen for incoming client connections on ip:port
     #[clap(short, long, default_value = "127.0.0.1:4432")]
-    proxy: String,
+    proxy: SocketAddr,
     #[clap(value_enum, long, default_value_t = AuthBackendType::ConsoleRedirect)]
     auth_backend: AuthBackendType,
     /// listen for management callback connection on ip:port
     #[clap(short, long, default_value = "127.0.0.1:7000")]
-    mgmt: String,
+    mgmt: SocketAddr,
     /// listen for incoming http connections (metrics, etc) on ip:port
     #[clap(long, default_value = "127.0.0.1:7001")]
-    http: String,
+    http: SocketAddr,
     /// listen for incoming wss connections on ip:port
     #[clap(long)]
-    wss: Option<String>,
+    wss: Option<SocketAddr>,
     /// redirect unauthenticated users to the given uri in case of console redirect auth
     #[clap(short, long, default_value = "http://localhost:3000/psql_session/")]
     uri: String,
@@ -99,18 +100,18 @@ struct ProxyCliArgs {
     ///
     /// tls-key and tls-cert are for backwards compatibility, we can put all certs in one dir
     #[clap(short = 'k', long, alias = "ssl-key")]
-    tls_key: Option<String>,
+    tls_key: Option<PathBuf>,
     /// path to TLS cert for client postgres connections
     ///
     /// tls-key and tls-cert are for backwards compatibility, we can put all certs in one dir
     #[clap(short = 'c', long, alias = "ssl-cert")]
-    tls_cert: Option<String>,
+    tls_cert: Option<PathBuf>,
     /// Allow writing TLS session keys to the given file pointed to by the environment variable `SSLKEYLOGFILE`.
     #[clap(long, alias = "allow-ssl-keylogfile")]
     allow_tls_keylogfile: bool,
     /// path to directory with TLS certificates for client postgres connections
     #[clap(long)]
-    certs_dir: Option<String>,
+    certs_dir: Option<PathBuf>,
     /// timeout for the TLS handshake
     #[clap(long, default_value = "15s", value_parser = humantime::parse_duration)]
     handshake_timeout: tokio::time::Duration,
@@ -229,6 +230,9 @@ struct ProxyCliArgs {
     // TODO: rename to `console_redirect_confirmation_timeout`.
     #[clap(long, default_value = "2m", value_parser = humantime::parse_duration)]
     webauth_confirmation_timeout: std::time::Duration,
+
+    #[clap(flatten)]
+    pg_sni_router: PgSniRouterArgs,
 }
 
 #[derive(clap::Args, Clone, Copy, Debug)]
@@ -277,6 +281,25 @@ struct SqlOverHttpArgs {
     sql_over_http_max_response_size_bytes: usize,
 }
 
+#[derive(clap::Args, Clone, Debug)]
+struct PgSniRouterArgs {
+    /// listen for incoming client connections on ip:port
+    #[clap(id = "sni-router-listen", long, default_value = "127.0.0.1:4432")]
+    listen: SocketAddr,
+    /// listen for incoming client connections on ip:port, requiring TLS to compute
+    #[clap(id = "sni-router-listen-tls", long, default_value = "127.0.0.1:4433")]
+    listen_tls: SocketAddr,
+    /// path to TLS key for client postgres connections
+    #[clap(id = "sni-router-tls-key", long)]
+    tls_key: Option<PathBuf>,
+    /// path to TLS cert for client postgres connections
+    #[clap(id = "sni-router-tls-cert", long)]
+    tls_cert: Option<PathBuf>,
+    /// append this domain zone to the SNI hostname to get the destination address
+    #[clap(id = "sni-router-destination", long)]
+    dest: Option<String>,
+}
+
 pub async fn run() -> anyhow::Result<()> {
     let _logging_guard = crate::logging::init().await?;
     let _panic_hook_guard = utils::logging::replace_panic_hook_with_tracing_panic_hook();
@@ -307,73 +330,51 @@ pub async fn run() -> anyhow::Result<()> {
         Either::Right(auth_backend) => info!("Authentication backend: {auth_backend:?}"),
     }
     info!("Using region: {}", args.aws_region);
-
-    // TODO: untangle the config args
-    let regional_redis_client = match (args.redis_auth_type.as_str(), &args.redis_notifications) {
-        ("plain", redis_url) => match redis_url {
-            None => {
-                bail!("plain auth requires redis_notifications to be set");
-            }
-            Some(url) => {
-                Some(ConnectionWithCredentialsProvider::new_with_static_credentials(url.clone()))
-            }
-        },
-        ("irsa", _) => match (&args.redis_host, args.redis_port) {
-            (Some(host), Some(port)) => Some(
-                ConnectionWithCredentialsProvider::new_with_credentials_provider(
-                    host.to_string(),
-                    port,
-                    elasticache::CredentialsProvider::new(
-                        args.aws_region,
-                        args.redis_cluster_name,
-                        args.redis_user_id,
-                    )
-                    .await,
-                ),
-            ),
-            (None, None) => {
-                warn!(
-                    "irsa auth requires redis-host and redis-port to be set, continuing without regional_redis_client"
-                );
-                None
-            }
-            _ => {
-                bail!("redis-host and redis-port must be specified together");
-            }
-        },
-        _ => {
-            bail!("unknown auth type given");
-        }
-    };
-
-    let redis_notifications_client = if let Some(url) = args.redis_notifications {
-        Some(ConnectionWithCredentialsProvider::new_with_static_credentials(url))
-    } else {
-        regional_redis_client.clone()
-    };
+    let (regional_redis_client, redis_notifications_client) = configure_redis(&args).await?;
 
     // Check that we can bind to address before further initialization
-    let http_address: SocketAddr = args.http.parse()?;
-    info!("Starting http on {http_address}");
-    let http_listener = TcpListener::bind(http_address).await?.into_std()?;
+    info!("Starting http on {}", args.http);
+    let http_listener = TcpListener::bind(args.http).await?.into_std()?;
 
-    let mgmt_address: SocketAddr = args.mgmt.parse()?;
-    info!("Starting mgmt on {mgmt_address}");
-    let mgmt_listener = TcpListener::bind(mgmt_address).await?;
+    info!("Starting mgmt on {}", args.mgmt);
+    let mgmt_listener = TcpListener::bind(args.mgmt).await?;
 
     let proxy_listener = if args.is_auth_broker {
         None
     } else {
-        let proxy_address: SocketAddr = args.proxy.parse()?;
-        info!("Starting proxy on {proxy_address}");
+        info!("Starting proxy on {}", args.proxy);
+        Some(TcpListener::bind(args.proxy).await?)
+    };
 
-        Some(TcpListener::bind(proxy_address).await?)
+    let sni_router_listeners = {
+        let args = &args.pg_sni_router;
+        if args.dest.is_some() {
+            ensure!(
+                args.tls_key.is_some(),
+                "sni-router-tls-key must be provided"
+            );
+            ensure!(
+                args.tls_cert.is_some(),
+                "sni-router-tls-cert must be provided"
+            );
+
+            info!(
+                "Starting pg-sni-router on {} and {}",
+                args.listen, args.listen_tls
+            );
+
+            Some((
+                TcpListener::bind(args.listen).await?,
+                TcpListener::bind(args.listen_tls).await?,
+            ))
+        } else {
+            None
+        }
     };
 
     // TODO: rename the argument to something like serverless.
     // It now covers more than just websockets, it also covers SQL over HTTP.
     let serverless_listener = if let Some(serverless_address) = args.wss {
-        let serverless_address: SocketAddr = serverless_address.parse()?;
         info!("Starting wss on {serverless_address}");
         Some(TcpListener::bind(serverless_address).await?)
     } else if args.is_auth_broker {
@@ -458,6 +459,37 @@ pub async fn run() -> anyhow::Result<()> {
         }
     }
 
+    // spawn pg-sni-router mode.
+    if let Some((listen, listen_tls)) = sni_router_listeners {
+        let args = args.pg_sni_router;
+        let dest = args.dest.expect("already asserted it is set");
+        let key_path = args.tls_key.expect("already asserted it is set");
+        let cert_path = args.tls_cert.expect("already asserted it is set");
+
+        let (tls_config, tls_server_end_point) =
+            super::pg_sni_router::parse_tls(&key_path, &cert_path)?;
+
+        let dest = Arc::new(dest);
+
+        client_tasks.spawn(super::pg_sni_router::task_main(
+            dest.clone(),
+            tls_config.clone(),
+            None,
+            tls_server_end_point,
+            listen,
+            cancellation_token.clone(),
+        ));
+
+        client_tasks.spawn(super::pg_sni_router::task_main(
+            dest,
+            tls_config,
+            Some(config.connect_to_compute.tls.clone()),
+            tls_server_end_point,
+            listen_tls,
+            cancellation_token.clone(),
+        ));
+    }
+
     client_tasks.spawn(crate::context::parquet::worker(
         cancellation_token.clone(),
         args.parquet_upload,
@@ -565,7 +597,7 @@ fn build_config(args: &ProxyCliArgs) -> anyhow::Result<&'static ProxyConfig> {
         (Some(key_path), Some(cert_path)) => Some(config::configure_tls(
             key_path,
             cert_path,
-            args.certs_dir.as_ref(),
+            args.certs_dir.as_deref(),
             args.allow_tls_keylogfile,
         )?),
         (None, None) => None,
@@ -811,6 +843,60 @@ fn build_auth_backend(
     }
 }
 
+async fn configure_redis(
+    args: &ProxyCliArgs,
+) -> anyhow::Result<(
+    Option<ConnectionWithCredentialsProvider>,
+    Option<ConnectionWithCredentialsProvider>,
+)> {
+    // TODO: untangle the config args
+    let regional_redis_client = match (args.redis_auth_type.as_str(), &args.redis_notifications) {
+        ("plain", redis_url) => match redis_url {
+            None => {
+                bail!("plain auth requires redis_notifications to be set");
+            }
+            Some(url) => {
+                Some(ConnectionWithCredentialsProvider::new_with_static_credentials(url.clone()))
+            }
+        },
+        ("irsa", _) => match (&args.redis_host, args.redis_port) {
+            (Some(host), Some(port)) => Some(
+                ConnectionWithCredentialsProvider::new_with_credentials_provider(
+                    host.to_string(),
+                    port,
+                    elasticache::CredentialsProvider::new(
+                        args.aws_region.clone(),
+                        args.redis_cluster_name.clone(),
+                        args.redis_user_id.clone(),
+                    )
+                    .await,
+                ),
+            ),
+            (None, None) => {
+                // todo: upgrade to error?
+                warn!(
+                    "irsa auth requires redis-host and redis-port to be set, continuing without regional_redis_client"
+                );
+                None
+            }
+            _ => {
+                bail!("redis-host and redis-port must be specified together");
+            }
+        },
+        _ => {
+            bail!("unknown auth type given");
+        }
+    };
+
+    let redis_notifications_client = if let Some(url) = &args.redis_notifications {
+        Some(ConnectionWithCredentialsProvider::new_with_static_credentials(&**url))
+    } else {
+        regional_redis_client.clone()
+    };
+
+    Ok((regional_redis_client, redis_notifications_client))
+}
+
 #[cfg(test)]
 mod tests {
     use std::time::Duration;

proxy/src/cancellation.rs

@@ -6,12 +6,12 @@ use ipnet::{IpNet, Ipv4Net, Ipv6Net};
 use postgres_client::CancelToken;
 use postgres_client::tls::MakeTlsConnect;
 use pq_proto::CancelKeyData;
-use redis::{FromRedisValue, Pipeline, Value, pipe};
+use redis::{Cmd, FromRedisValue, Value};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 use tokio::net::TcpStream;
 use tokio::sync::{mpsc, oneshot};
-use tracing::{debug, info, warn};
+use tracing::{debug, error, info, warn};
 
 use crate::auth::backend::ComputeUserInfo;
 use crate::auth::{AuthError, check_peer_addr_is_in_list};
@@ -56,8 +56,86 @@ pub enum CancelKeyOp {
     },
 }
 
+type Callback = Box<dyn FnOnce(anyhow::Result<&[redis::Value]>) + Send>;
+pub struct Pipeline {
+    inner: redis::Pipeline,
+    // vec![(number of commands, fn(values))]
+    replies: Vec<(usize, Callback)>,
+}
+
+impl Pipeline {
+    fn with_capacity(n: usize) -> Self {
+        Self {
+            inner: redis::Pipeline::with_capacity(n),
+            replies: Vec::with_capacity(n),
+        }
+    }
+
+    async fn execute(&mut self, client: &mut RedisKVClient) {
+        let commands = self.inner.len();
+        let batch_size = self.replies.len();
+
+        match client.query(&self.inner).await {
+            Ok(Value::Array(values)) if values.len() == commands => {
+                debug!(
+                    commands,
+                    batch_size, "successfully completed cancellation jobs",
+                );
+                let mut values = &*values;
+                for (n, resp) in self.replies.drain(..) {
+                    let (v, rest) = values.split_at(n);
+                    values = rest;
+                    resp(Ok(v));
+                }
+            }
+            Ok(value) => {
+                error!(
+                    commands,
+                    batch_size,
+                    ?value,
+                    "unexpected redis return value"
+                );
+                for (_n, resp) in self.replies.drain(..) {
+                    resp(Err(anyhow!("incorrect response type from redis")));
+                }
+            }
+            Err(err) => {
+                for (_n, resp) in self.replies.drain(..) {
+                    resp(Err(anyhow!("could not send cmd to redis: {err}")));
+                }
+            }
+        }
+
+        self.inner.clear();
+        self.replies.clear();
+    }
+
+    /// Add a batch of commands to the pipeline, and run the resp fn when they are all done.
+    ///
+    /// If multiple commands are provided, the response should be able to decode
+    /// all of the values. You can provide a tuple in that case.
+    fn add_commands<F, T, const N: usize>(&mut self, cmds: [Cmd; N], resp: F)
+    where
+        F: FnOnce(anyhow::Result<T>) + Send + 'static,
+        T: FromRedisValue,
+    {
+        for cmd in cmds {
+            self.inner.add_command(cmd);
+        }
+        let reply = Box::new(move |res: anyhow::Result<&[redis::Value]>| {
+            let res = match res {
+                Ok(v) => T::from_redis_value(&redis::Value::Array(v.to_owned()))
+                    .context("could not parse value"),
+                Err(e) => Err(e),
+            };
+            resp(res);
+        });
+        self.replies.push((N, reply as Box<_>));
+    }
+}
+
 impl CancelKeyOp {
-    fn register(self, pipe: &mut Pipeline) -> Option<CancelReplyOp> {
+    fn register(self, pipe: &mut Pipeline) {
         #[allow(clippy::used_underscore_binding)]
         match self {
             CancelKeyOp::StoreCancelKey {
@@ -68,18 +146,30 @@ impl CancelKeyOp {
                 _guard,
                 expire,
             } => {
-                pipe.hset(&key, field, value);
-                pipe.expire(key, expire);
-                let resp_tx = resp_tx?;
-                Some(CancelReplyOp::StoreCancelKey { resp_tx, _guard })
+                pipe.add_commands(
+                    [Cmd::hset(&key, field, value), Cmd::expire(key, expire)],
+                    // ignore all results
+                    move |res: anyhow::Result<()>| {
+                        let _guard = _guard;
+                        if let Some(resp_tx) = resp_tx {
+                            if resp_tx.send(res).is_err() {
+                                tracing::debug!("could not send reply");
+                            }
+                        }
+                    },
+                );
             }
             CancelKeyOp::GetCancelData {
                 key,
                 resp_tx,
                 _guard,
             } => {
-                pipe.hgetall(key);
-                Some(CancelReplyOp::GetCancelData { resp_tx, _guard })
+                pipe.add_commands([Cmd::hgetall(key)], move |res| {
+                    let _guard = _guard;
+                    if resp_tx.send(res).is_err() {
+                        tracing::debug!("could not send reply");
+                    }
+                });
             }
             CancelKeyOp::RemoveCancelKey {
                 key,
@@ -87,79 +177,14 @@ impl CancelKeyOp {
                 resp_tx,
                 _guard,
             } => {
-                pipe.hdel(key, field);
-                let resp_tx = resp_tx?;
-                Some(CancelReplyOp::RemoveCancelKey { resp_tx, _guard })
-            }
-        }
-    }
-}
-
-// Message types for sending through mpsc channel
-pub enum CancelReplyOp {
-    StoreCancelKey {
-        resp_tx: oneshot::Sender<anyhow::Result<()>>,
-        _guard: CancelChannelSizeGuard<'static>,
-    },
-    GetCancelData {
-        resp_tx: oneshot::Sender<anyhow::Result<Vec<(String, String)>>>,
-        _guard: CancelChannelSizeGuard<'static>,
-    },
-    RemoveCancelKey {
-        resp_tx: oneshot::Sender<anyhow::Result<()>>,
-        _guard: CancelChannelSizeGuard<'static>,
-    },
-}
-
-impl CancelReplyOp {
-    fn send_err(self, e: anyhow::Error) {
-        match self {
-            CancelReplyOp::StoreCancelKey { resp_tx, _guard } => {
-                resp_tx
-                    .send(Err(e))
-                    .inspect_err(|_| tracing::debug!("could not send reply"))
-                    .ok();
-            }
-            CancelReplyOp::GetCancelData { resp_tx, _guard } => {
-                resp_tx
-                    .send(Err(e))
-                    .inspect_err(|_| tracing::debug!("could not send reply"))
-                    .ok();
-            }
-            CancelReplyOp::RemoveCancelKey { resp_tx, _guard } => {
-                resp_tx
-                    .send(Err(e))
-                    .inspect_err(|_| tracing::debug!("could not send reply"))
-                    .ok();
-            }
-        }
-    }
-
-    fn send_value(self, v: redis::Value) {
-        match self {
-            CancelReplyOp::StoreCancelKey { resp_tx, _guard } => {
-                let send =
-                    FromRedisValue::from_owned_redis_value(v).context("could not parse value");
-                resp_tx
-                    .send(send)
-                    .inspect_err(|_| tracing::debug!("could not send reply"))
-                    .ok();
-            }
-            CancelReplyOp::GetCancelData { resp_tx, _guard } => {
-                let send =
-                    FromRedisValue::from_owned_redis_value(v).context("could not parse value");
-                resp_tx
-                    .send(send)
-                    .inspect_err(|_| tracing::debug!("could not send reply"))
-                    .ok();
-            }
-            CancelReplyOp::RemoveCancelKey { resp_tx, _guard } => {
-                let send =
-                    FromRedisValue::from_owned_redis_value(v).context("could not parse value");
-                resp_tx
-                    .send(send)
-                    .inspect_err(|_| tracing::debug!("could not send reply"))
-                    .ok();
+                pipe.add_commands([Cmd::hdel(key, field)], move |res| {
+                    let _guard = _guard;
+                    if let Some(resp_tx) = resp_tx {
+                        if resp_tx.send(res).is_err() {
+                            tracing::debug!("could not send reply");
+                        }
+                    }
+                });
             }
         }
     }
@@ -170,8 +195,8 @@ pub async fn handle_cancel_messages(
     client: &mut RedisKVClient,
     mut rx: mpsc::Receiver<CancelKeyOp>,
 ) -> anyhow::Result<()> {
-    let mut batch = Vec::new();
-    let mut replies = vec![];
+    let mut batch = Vec::with_capacity(BATCH_SIZE);
+    let mut pipeline = Pipeline::with_capacity(BATCH_SIZE);
 
     loop {
         if rx.recv_many(&mut batch, BATCH_SIZE).await == 0 {
@@ -182,42 +207,11 @@ pub async fn handle_cancel_messages(
         let batch_size = batch.len();
         debug!(batch_size, "running cancellation jobs");
 
-        let mut pipe = pipe();
         for msg in batch.drain(..) {
-            if let Some(reply) = msg.register(&mut pipe) {
-                replies.push(reply);
-            } else {
-                pipe.ignore();
-            }
+            msg.register(&mut pipeline);
         }
 
-        let responses = replies.len();
-
-        match client.query(pipe).await {
-            // for each reply, we expect that many values.
-            Ok(Value::Array(values)) if values.len() == responses => {
-                debug!(
-                    batch_size,
-                    responses, "successfully completed cancellation jobs",
-                );
-                for (value, reply) in std::iter::zip(values, replies.drain(..)) {
-                    reply.send_value(value);
-                }
-            }
-            Ok(value) => {
-                debug!(?value, "unexpected redis return value");
-                for reply in replies.drain(..) {
-                    reply.send_err(anyhow!("incorrect response type from redis"));
-                }
-            }
-            Err(err) => {
-                for reply in replies.drain(..) {
-                    reply.send_err(anyhow!("could not send cmd to redis: {err}"));
-                }
-            }
-        }
-
-        replies.clear();
+        pipeline.execute(client).await;
     }
 }
 

proxy/src/redis/kv_ops.rs

@@ -47,7 +47,7 @@ impl RedisKVClient {
 
     pub(crate) async fn query<T: FromRedisValue>(
         &mut self,
-        q: impl Queryable,
+        q: &impl Queryable,
     ) -> anyhow::Result<T> {
         if !self.limiter.check() {
             tracing::info!("Rate limit exceeded. Skipping query");

proxy/src/tls/server_config.rs

@@ -1,4 +1,5 @@
 use std::collections::{HashMap, HashSet};
+use std::path::Path;
 use std::sync::Arc;
 
 use anyhow::{Context, bail};
@@ -21,9 +22,9 @@ pub struct TlsConfig {
 
 /// Configure TLS for the main endpoint.
 pub fn configure_tls(
-    key_path: &str,
-    cert_path: &str,
-    certs_dir: Option<&String>,
+    key_path: &Path,
+    cert_path: &Path,
+    certs_dir: Option<&Path>,
     allow_tls_keylogfile: bool,
 ) -> anyhow::Result<TlsConfig> {
     // add default certificate
@@ -39,8 +40,7 @@ pub fn configure_tls(
                 let key_path = path.join("tls.key");
                 let cert_path = path.join("tls.crt");
                 if key_path.exists() && cert_path.exists() {
-                    cert_resolver
-                        .add_cert_path(&key_path.to_string_lossy(), &cert_path.to_string_lossy())?;
+                    cert_resolver.add_cert_path(&key_path, &cert_path)?;
                 }
             }
         }
@@ -86,7 +86,7 @@ pub struct CertResolver {
 }
 
 impl CertResolver {
-    fn parse_new(key_path: &str, cert_path: &str) -> anyhow::Result<Self> {
+    fn parse_new(key_path: &Path, cert_path: &Path) -> anyhow::Result<Self> {
         let (priv_key, cert_chain) = parse_key_cert(key_path, cert_path)?;
         Self::new(priv_key, cert_chain)
     }
@@ -103,7 +103,7 @@ impl CertResolver {
         Ok(Self { certs, default })
     }
 
-    fn add_cert_path(&mut self, key_path: &str, cert_path: &str) -> anyhow::Result<()> {
+    fn add_cert_path(&mut self, key_path: &Path, cert_path: &Path) -> anyhow::Result<()> {
         let (priv_key, cert_chain) = parse_key_cert(key_path, cert_path)?;
         self.add_cert(priv_key, cert_chain)
     }
@@ -124,26 +124,29 @@ impl CertResolver {
 }
 
 fn parse_key_cert(
-    key_path: &str,
-    cert_path: &str,
+    key_path: &Path,
+    cert_path: &Path,
 ) -> anyhow::Result<(PrivateKeyDer<'static>, Vec<CertificateDer<'static>>)> {
     let priv_key = {
         let key_bytes = std::fs::read(key_path)
-            .with_context(|| format!("Failed to read TLS keys at '{key_path}'"))?;
+            .with_context(|| format!("Failed to read TLS keys at '{}'", key_path.display()))?;
         rustls_pemfile::private_key(&mut &key_bytes[..])
-            .with_context(|| format!("Failed to parse TLS keys at '{key_path}'"))?
-            .with_context(|| format!("Failed to parse TLS keys at '{key_path}'"))?
+            .with_context(|| format!("Failed to parse TLS keys at '{}'", key_path.display()))?
+            .with_context(|| format!("Failed to parse TLS keys at '{}'", key_path.display()))?
     };
 
-    let cert_chain_bytes = std::fs::read(cert_path)
-        .context(format!("Failed to read TLS cert file at '{cert_path}.'"))?;
+    let cert_chain_bytes = std::fs::read(cert_path).context(format!(
+        "Failed to read TLS cert file at '{}.'",
+        cert_path.display()
+    ))?;
 
     let cert_chain = {
         rustls_pemfile::certs(&mut &cert_chain_bytes[..])
             .try_collect()
             .with_context(|| {
                 format!(
-                    "Failed to read TLS certificate chain from bytes from file at '{cert_path}'."
+                    "Failed to read TLS certificate chain from bytes from file at '{}'.",
+                    cert_path.display()
                 )
             })?
     };

safekeeper/src/pull_timeline.rs

@@ -468,12 +468,15 @@ pub async fn handle_request(
     assert!(status.tenant_id == request.tenant_id);
     assert!(status.timeline_id == request.timeline_id);
 
+    let check_tombstone = !request.ignore_tombstone.unwrap_or_default();
+
     match pull_timeline(
         status,
         safekeeper_host,
         sk_auth_token,
         http_client,
         global_timelines,
+        check_tombstone,
     )
     .await
     {
@@ -499,6 +502,7 @@ async fn pull_timeline(
     sk_auth_token: Option<SecretString>,
     http_client: reqwest::Client,
     global_timelines: Arc<GlobalTimelines>,
+    check_tombstone: bool,
 ) -> Result<PullTimelineResponse> {
     let ttid = TenantTimelineId::new(status.tenant_id, status.timeline_id);
     info!(
@@ -570,7 +574,7 @@ async fn pull_timeline(
 
     // Finally, load the timeline.
     let _tli = global_timelines
-        .load_temp_timeline(ttid, &tli_dir_path, false)
+        .load_temp_timeline(ttid, &tli_dir_path, check_tombstone)
         .await?;
 
     Ok(PullTimelineResponse {

storage_controller/src/service.rs

@@ -3886,10 +3886,10 @@ impl Service {
 
             None
         } else if safekeepers {
-            // Note that we do not support creating the timeline on the safekeepers
-            // for imported timelines. The `start_lsn` of the timeline is not known
-            // until the import finshes.
-            // https://github.com/neondatabase/neon/issues/11569
+            // Note that for imported timelines, we do not create the timeline on the safekeepers
+            // straight away. Instead, we do it once the import finalized such that we know what
+            // start LSN to provide for the safekeepers. This is done in
+            // [`Self::finalize_timeline_import`].
             let res = self
                 .tenant_timeline_create_safekeepers(tenant_id, &timeline_info)
                 .instrument(tracing::info_span!("timeline_create_safekeepers", %tenant_id, timeline_id=%timeline_info.timeline_id))
@@ -3966,11 +3966,22 @@ impl Service {
                 let active = self.timeline_active_on_all_shards(&import).await?;
 
                 match active {
-                    true => {
+                    Some(timeline_info) => {
                         tracing::info!("Timeline became active on all shards");
+
+                        if self.config.timelines_onto_safekeepers {
+                            // Now that we know the start LSN of this timeline, create it on the
+                            // safekeepers.
+                            self.tenant_timeline_create_safekeepers_until_success(
+                                import.tenant_id,
+                                timeline_info,
+                            )
+                            .await?;
+                        }
+
                         break;
                     }
-                    false => {
+                    None => {
                         tracing::info!("Timeline not active on all shards yet");
 
                         tokio::select! {
@@ -4004,9 +4015,6 @@ impl Service {
             .range_mut(TenantShardId::tenant_range(import.tenant_id))
             .for_each(|(_id, shard)| shard.importing = TimelineImportState::Idle);
 
-        // TODO(vlad): Timeline creations in import mode do not return a correct initdb lsn,
-        // so we can't create the timeline on the safekeepers. Fix by moving creation here.
-        // https://github.com/neondatabase/neon/issues/11569
         tracing::info!(%import_failed, "Timeline import complete");
 
         Ok(())
@@ -4021,10 +4029,16 @@ impl Service {
         .await;
     }
 
+    /// If the timeline is active on all shards, returns the [`TimelineInfo`]
+    /// collected from shard 0.
+    ///
+    /// An error is returned if the shard layout has changed during the import.
+    /// This is guarded against within the storage controller and the pageserver,
+    /// and, therefore, unexpected.
     async fn timeline_active_on_all_shards(
         self: &Arc<Self>,
         import: &TimelineImport,
-    ) -> anyhow::Result<bool> {
+    ) -> anyhow::Result<Option<TimelineInfo>> {
         let targets = {
             let locked = self.inner.read().unwrap();
             let mut targets = Vec::new();
@@ -4048,13 +4062,17 @@ impl Service {
                         .expect("Pageservers may not be deleted while referenced");
                     targets.push((*tenant_shard_id, node.clone()));
                 } else {
-                    return Ok(false);
+                    return Ok(None);
                 }
             }
 
             targets
         };
 
+        if targets.is_empty() {
+            anyhow::bail!("No shards found to finalize import for");
+        }
+
         let results = self
             .tenant_for_shards_api(
                 targets,
@@ -4070,10 +4088,17 @@ impl Service {
             )
             .await;
 
-        Ok(results.into_iter().all(|res| match res {
+        let all_active = results.iter().all(|res| match res {
             Ok(info) => info.state == TimelineState::Active,
             Err(_) => false,
-        }))
+        });
+
+        if all_active {
+            // Both unwraps are validated above
+            Ok(Some(results.into_iter().next().unwrap().unwrap()))
+        } else {
+            Ok(None)
+        }
     }
 
     pub(crate) async fn tenant_timeline_archival_config(

storage_controller/src/service/safekeeper_reconciler.rs

@@ -1,4 +1,9 @@
-use std::{collections::HashMap, str::FromStr, sync::Arc, time::Duration};
+use std::{
+    collections::HashMap,
+    str::FromStr,
+    sync::{Arc, atomic::AtomicU64},
+    time::Duration,
+};
 
 use clashmap::{ClashMap, Entry};
 use safekeeper_api::models::PullTimelineRequest;
@@ -169,10 +174,17 @@ pub(crate) struct ScheduleRequest {
     pub(crate) kind: SafekeeperTimelineOpKind,
 }
 
+/// A way to keep ongoing/queued reconcile requests apart
+#[derive(Copy, Clone, PartialEq, Eq)]
+struct TokenId(u64);
+
+type OngoingTokens = ClashMap<(TenantId, Option<TimelineId>), (CancellationToken, TokenId)>;
+
 /// Handle to per safekeeper reconciler.
 struct ReconcilerHandle {
-    tx: UnboundedSender<(ScheduleRequest, CancellationToken)>,
-    ongoing_tokens: Arc<ClashMap<(TenantId, Option<TimelineId>), CancellationToken>>,
+    tx: UnboundedSender<(ScheduleRequest, CancellationToken, TokenId)>,
+    ongoing_tokens: Arc<OngoingTokens>,
+    token_id_counter: AtomicU64,
     cancel: CancellationToken,
 }
 
@@ -185,24 +197,28 @@ impl ReconcilerHandle {
         &self,
         tenant_id: TenantId,
         timeline_id: Option<TimelineId>,
-    ) -> CancellationToken {
+    ) -> (CancellationToken, TokenId) {
+        let token_id = self
+            .token_id_counter
+            .fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+        let token_id = TokenId(token_id);
         let entry = self.ongoing_tokens.entry((tenant_id, timeline_id));
         if let Entry::Occupied(entry) = &entry {
-            let cancel: &CancellationToken = entry.get();
+            let (cancel, _) = entry.get();
             cancel.cancel();
         }
-        entry.insert(self.cancel.child_token()).clone()
+        entry.insert((self.cancel.child_token(), token_id)).clone()
     }
     /// Cancel an ongoing reconciliation
     fn cancel_reconciliation(&self, tenant_id: TenantId, timeline_id: Option<TimelineId>) {
-        if let Some((_, cancel)) = self.ongoing_tokens.remove(&(tenant_id, timeline_id)) {
+        if let Some((_, (cancel, _id))) = self.ongoing_tokens.remove(&(tenant_id, timeline_id)) {
             cancel.cancel();
         }
     }
     fn schedule_reconcile(&self, req: ScheduleRequest) {
-        let cancel = self.new_token_slot(req.tenant_id, req.timeline_id);
+        let (cancel, token_id) = self.new_token_slot(req.tenant_id, req.timeline_id);
         let hostname = req.safekeeper.skp.host.clone();
-        if let Err(err) = self.tx.send((req, cancel)) {
+        if let Err(err) = self.tx.send((req, cancel, token_id)) {
             tracing::info!("scheduling request onto {hostname} returned error: {err}");
         }
     }
@@ -211,13 +227,14 @@ impl ReconcilerHandle {
 pub(crate) struct SafekeeperReconciler {
     inner: SafekeeperReconcilerInner,
     concurrency_limiter: Arc<Semaphore>,
-    rx: UnboundedReceiver<(ScheduleRequest, CancellationToken)>,
+    rx: UnboundedReceiver<(ScheduleRequest, CancellationToken, TokenId)>,
     cancel: CancellationToken,
 }
 
 /// Thin wrapper over `Service` to not clutter its inherent functions
 #[derive(Clone)]
 struct SafekeeperReconcilerInner {
+    ongoing_tokens: Arc<OngoingTokens>,
     service: Arc<Service>,
 }
 
@@ -226,15 +243,20 @@ impl SafekeeperReconciler {
         // We hold the ServiceInner lock so we don't want to make sending to the reconciler channel to be blocking.
         let (tx, rx) = mpsc::unbounded_channel();
         let concurrency = service.config.safekeeper_reconciler_concurrency;
+        let ongoing_tokens = Arc::new(ClashMap::new());
         let mut reconciler = SafekeeperReconciler {
-            inner: SafekeeperReconcilerInner { service },
+            inner: SafekeeperReconcilerInner {
+                service,
+                ongoing_tokens: ongoing_tokens.clone(),
+            },
             rx,
             concurrency_limiter: Arc::new(Semaphore::new(concurrency)),
             cancel: cancel.clone(),
         };
         let handle = ReconcilerHandle {
             tx,
-            ongoing_tokens: Arc::new(ClashMap::new()),
+            ongoing_tokens,
+            token_id_counter: AtomicU64::new(0),
             cancel,
         };
         tokio::spawn(async move { reconciler.run().await });
@@ -246,7 +268,9 @@ impl SafekeeperReconciler {
                 req = self.rx.recv() => req,
                 _ = self.cancel.cancelled() => break,
             };
-            let Some((req, req_cancel)) = req else { break };
+            let Some((req, req_cancel, req_token_id)) = req else {
+                break;
+            };
 
             let permit_res = tokio::select! {
                 req = self.concurrency_limiter.clone().acquire_owned() => req,
@@ -265,7 +289,7 @@ impl SafekeeperReconciler {
                 let timeline_id = req.timeline_id;
                 let node_id = req.safekeeper.skp.id;
                 inner
-                    .reconcile_one(req, req_cancel)
+                    .reconcile_one(req, req_cancel, req_token_id)
                     .instrument(tracing::info_span!(
                         "reconcile_one",
                         ?kind,
@@ -280,8 +304,14 @@ impl SafekeeperReconciler {
 }
 
 impl SafekeeperReconcilerInner {
-    async fn reconcile_one(&self, req: ScheduleRequest, req_cancel: CancellationToken) {
+    async fn reconcile_one(
+        &self,
+        req: ScheduleRequest,
+        req_cancel: CancellationToken,
+        req_token_id: TokenId,
+    ) {
         let req_host = req.safekeeper.skp.host.clone();
+        let success;
         match req.kind {
             SafekeeperTimelineOpKind::Pull => {
                 let Some(timeline_id) = req.timeline_id else {
@@ -301,20 +331,24 @@ impl SafekeeperReconcilerInner {
                     http_hosts,
                     tenant_id: req.tenant_id,
                     timeline_id,
+                    ignore_tombstone: Some(false),
                 };
-                self.reconcile_inner(
-                    req,
-                    async |client| client.pull_timeline(&pull_req).await,
-                    |resp| {
-                        if let Some(host) = resp.safekeeper_host {
-                            tracing::info!("pulled timeline from {host} onto {req_host}");
-                        } else {
-                            tracing::info!("timeline already present on safekeeper on {req_host}");
-                        }
-                    },
-                    req_cancel,
-                )
-                .await;
+                success = self
+                    .reconcile_inner(
+                        &req,
+                        async |client| client.pull_timeline(&pull_req).await,
+                        |resp| {
+                            if let Some(host) = resp.safekeeper_host {
+                                tracing::info!("pulled timeline from {host} onto {req_host}");
+                            } else {
+                                tracing::info!(
+                                    "timeline already present on safekeeper on {req_host}"
+                                );
+                            }
+                        },
+                        req_cancel,
+                    )
+                    .await;
             }
             SafekeeperTimelineOpKind::Exclude => {
                 // TODO actually exclude instead of delete here
@@ -325,22 +359,23 @@ impl SafekeeperReconcilerInner {
                     );
                     return;
                 };
-                self.reconcile_inner(
-                    req,
-                    async |client| client.delete_timeline(tenant_id, timeline_id).await,
-                    |_resp| {
-                        tracing::info!("deleted timeline from {req_host}");
-                    },
-                    req_cancel,
-                )
-                .await;
+                success = self
+                    .reconcile_inner(
+                        &req,
+                        async |client| client.delete_timeline(tenant_id, timeline_id).await,
+                        |_resp| {
+                            tracing::info!("deleted timeline from {req_host}");
+                        },
+                        req_cancel,
+                    )
+                    .await;
             }
             SafekeeperTimelineOpKind::Delete => {
                 let tenant_id = req.tenant_id;
                 if let Some(timeline_id) = req.timeline_id {
-                    let deleted = self
+                    success = self
                         .reconcile_inner(
-                            req,
+                            &req,
                             async |client| client.delete_timeline(tenant_id, timeline_id).await,
                             |_resp| {
                                 tracing::info!("deleted timeline from {req_host}");
@@ -348,13 +383,13 @@ impl SafekeeperReconcilerInner {
                             req_cancel,
                         )
                         .await;
-                    if deleted {
+                    if success {
                         self.delete_timeline_from_db(tenant_id, timeline_id).await;
                     }
                 } else {
-                    let deleted = self
+                    success = self
                         .reconcile_inner(
-                            req,
+                            &req,
                             async |client| client.delete_tenant(tenant_id).await,
                             |_resp| {
                                 tracing::info!(%tenant_id, "deleted tenant from {req_host}");
@@ -362,12 +397,21 @@ impl SafekeeperReconcilerInner {
                             req_cancel,
                         )
                         .await;
-                    if deleted {
+                    if success {
                         self.delete_tenant_timelines_from_db(tenant_id).await;
                     }
                 }
             }
         }
+        if success {
+            self.ongoing_tokens.remove_if(
+                &(req.tenant_id, req.timeline_id),
+                |_ttid, (_cancel, token_id)| {
+                    // Ensure that this request is indeed the request we just finished and not a new one
+                    req_token_id == *token_id
+                },
+            );
+        }
     }
     async fn delete_timeline_from_db(&self, tenant_id: TenantId, timeline_id: TimelineId) {
         match self
@@ -421,10 +465,10 @@ impl SafekeeperReconcilerInner {
             self.delete_timeline_from_db(tenant_id, timeline_id).await;
         }
     }
-    /// Returns whether the reconciliation happened successfully
+    /// Returns whether the reconciliation happened successfully (or we got cancelled)
     async fn reconcile_inner<T, F, U>(
         &self,
-        req: ScheduleRequest,
+        req: &ScheduleRequest,
         closure: impl Fn(SafekeeperClient) -> F,
         log_success: impl FnOnce(T) -> U,
         req_cancel: CancellationToken,

storage_controller/src/service/safekeeper_service.rs

@@ -323,6 +323,42 @@ impl Service {
         })
     }
 
+    pub(crate) async fn tenant_timeline_create_safekeepers_until_success(
+        self: &Arc<Self>,
+        tenant_id: TenantId,
+        timeline_info: TimelineInfo,
+    ) -> anyhow::Result<()> {
+        const BACKOFF: Duration = Duration::from_secs(5);
+
+        loop {
+            if self.cancel.is_cancelled() {
+                anyhow::bail!("Shut down requested while finalizing import");
+            }
+
+            let res = self
+                .tenant_timeline_create_safekeepers(tenant_id, &timeline_info)
+                .await;
+
+            match res {
+                Ok(_) => {
+                    tracing::info!("Timeline created on safekeepers");
+                    break;
+                }
+                Err(err) => {
+                    tracing::error!("Failed to create timeline on safekeepers: {err}");
+                    tokio::select! {
+                        _ = self.cancel.cancelled() => {
+                            anyhow::bail!("Shut down requested while finalizing import");
+                        },
+                        _ = tokio::time::sleep(BACKOFF) => {}
+                    };
+                }
+            }
+        }
+
+        Ok(())
+    }
+
     /// Directly insert the timeline into the database without reconciling it with safekeepers.
     ///
     /// Useful if the timeline already exists on the specified safekeepers,

storage_scrubber/src/checks.rs

@@ -355,6 +355,7 @@ pub(crate) async fn list_timeline_blobs(
     match res {
         ListTimelineBlobsResult::Ready(data) => Ok(data),
         ListTimelineBlobsResult::MissingIndexPart(_) => {
+            tracing::warn!("listing raced with removal of an index, retrying");
             // Retry if listing raced with removal of an index
             let data = list_timeline_blobs_impl(remote_client, id, root_target)
                 .await?
@@ -441,7 +442,7 @@ async fn list_timeline_blobs_impl(
     }
 
     if index_part_keys.is_empty() && s3_layers.is_empty() {
-        tracing::debug!("Timeline is empty: expected post-deletion state.");
+        tracing::info!("Timeline is empty: expected post-deletion state.");
         if initdb_archive {
             tracing::info!("Timeline is post deletion but initdb archive is still present.");
         }

storage_scrubber/src/pageserver_physical_gc.rs

@@ -593,6 +593,7 @@ async fn gc_timeline(
             index_part_snapshot_time: _,
         } => (index_part, *index_part_generation, data.unused_index_keys),
         BlobDataParseResult::Relic => {
+            tracing::info!("Skipping timeline {ttid}, it is a relic");
             // Post-deletion tenant location: don't try and GC it.
             return Ok(summary);
         }

test_runner/fixtures/neon_fixtures.py

@@ -1274,6 +1274,8 @@ class NeonEnv:
 
             if self.pageserver_virtual_file_io_engine is not None:
                 ps_cfg["virtual_file_io_engine"] = self.pageserver_virtual_file_io_engine
+            if self.pageserver_virtual_file_io_mode is not None:
+                ps_cfg["virtual_file_io_mode"] = self.pageserver_virtual_file_io_mode
             if config.pageserver_default_tenant_config_compaction_algorithm is not None:
                 tenant_config = ps_cfg.setdefault("tenant_config", {})
                 tenant_config["compaction_algorithm"] = (
@@ -3605,6 +3607,8 @@ class NeonProxy(PgProtocol):
         http_port: int,
         mgmt_port: int,
         external_http_port: int,
+        router_port: int,
+        router_tls_port: int,
         auth_backend: NeonProxy.AuthBackend,
         metric_collection_endpoint: str | None = None,
         metric_collection_interval: str | None = None,
@@ -3621,6 +3625,8 @@ class NeonProxy(PgProtocol):
         self.test_output_dir = test_output_dir
         self.proxy_port = proxy_port
         self.mgmt_port = mgmt_port
+        self.router_port = router_port
+        self.router_tls_port = router_tls_port
         self.auth_backend = auth_backend
         self.metric_collection_endpoint = metric_collection_endpoint
         self.metric_collection_interval = metric_collection_interval
@@ -3635,6 +3641,14 @@ class NeonProxy(PgProtocol):
         key_path = self.test_output_dir / "proxy.key"
         generate_proxy_tls_certs("*.local.neon.build", key_path, crt_path)
 
+        # generate key for pg-sni-router.
+        # endpoint.namespace.local.neon.build resolves to 127.0.0.1
+        generate_proxy_tls_certs(
+            "endpoint.namespace.local.neon.build",
+            self.test_output_dir / "router.key",
+            self.test_output_dir / "router.crt",
+        )
+
         args = [
             str(self.neon_binpath / "proxy"),
             *["--http", f"{self.host}:{self.http_port}"],
@@ -3644,6 +3658,11 @@ class NeonProxy(PgProtocol):
             *["--sql-over-http-timeout", f"{self.http_timeout_seconds}s"],
             *["-c", str(crt_path)],
             *["-k", str(key_path)],
+            *["--sni-router-listen", f"{self.host}:{self.router_port}"],
+            *["--sni-router-listen-tls", f"{self.host}:{self.router_tls_port}"],
+            *["--sni-router-tls-cert", str(self.test_output_dir / "router.crt")],
+            *["--sni-router-tls-key", str(self.test_output_dir / "router.key")],
+            *["--sni-router-destination", "local.neon.build"],
             *self.auth_backend.extra_args(),
         ]
 
@@ -3943,6 +3962,8 @@ def link_proxy(
     proxy_port = port_distributor.get_port()
     mgmt_port = port_distributor.get_port()
     external_http_port = port_distributor.get_port()
+    router_port = port_distributor.get_port()
+    router_tls_port = port_distributor.get_port()
 
     with NeonProxy(
         neon_binpath=neon_binpath,
@@ -3950,6 +3971,8 @@ def link_proxy(
         proxy_port=proxy_port,
         http_port=http_port,
         mgmt_port=mgmt_port,
+        router_port=router_port,
+        router_tls_port=router_tls_port,
         external_http_port=external_http_port,
         auth_backend=NeonProxy.Link(),
     ) as proxy:
@@ -3983,6 +4006,8 @@ def static_proxy(
     mgmt_port = port_distributor.get_port()
     http_port = port_distributor.get_port()
     external_http_port = port_distributor.get_port()
+    router_port = port_distributor.get_port()
+    router_tls_port = port_distributor.get_port()
 
     with NeonProxy(
         neon_binpath=neon_binpath,
@@ -3990,6 +4015,8 @@ def static_proxy(
         proxy_port=proxy_port,
         http_port=http_port,
         mgmt_port=mgmt_port,
+        router_port=router_port,
+        router_tls_port=router_tls_port,
         external_http_port=external_http_port,
         auth_backend=NeonProxy.Postgres(auth_endpoint),
     ) as proxy:
@@ -4613,7 +4640,10 @@ class EndpointFactory:
         return self
 
     def new_replica(
-        self, origin: Endpoint, endpoint_id: str, config_lines: list[str] | None = None
+        self,
+        origin: Endpoint,
+        endpoint_id: str | None = None,
+        config_lines: list[str] | None = None,
     ):
         branch_name = origin.branch_name
         assert origin in self.endpoints
@@ -4629,7 +4659,10 @@ class EndpointFactory:
         )
 
     def new_replica_start(
-        self, origin: Endpoint, endpoint_id: str, config_lines: list[str] | None = None
+        self,
+        origin: Endpoint,
+        endpoint_id: str | None = None,
+        config_lines: list[str] | None = None,
     ):
         branch_name = origin.branch_name
         assert origin in self.endpoints

test_runner/fixtures/pageserver/allowed_errors.py

@@ -111,6 +111,13 @@ DEFAULT_PAGESERVER_ALLOWED_ERRORS = (
     ".*stalling layer flushes for compaction backpressure.*",
     ".*layer roll waiting for flush due to compaction backpressure.*",
     ".*BatchSpanProcessor.*",
+    *(
+        [
+            r".*your platform is not a supported production platform, ignoing request for O_DIRECT; this could hide alignment bugs.*"
+        ]
+        if sys.platform != "linux"
+        else []
+    ),
 )
 
 

test_runner/regress/test_import_pgdata.py

@@ -24,6 +24,7 @@ from fixtures.utils import (
     skip_in_debug_build,
     wait_until,
 )
+from fixtures.workload import Workload
 from mypy_boto3_kms import KMSClient
 from mypy_boto3_kms.type_defs import EncryptResponseTypeDef
 from mypy_boto3_s3 import S3Client
@@ -97,6 +98,10 @@ def test_pgdata_import_smoke(
         f"http://{cplane_mgmt_api_server.host}:{cplane_mgmt_api_server.port}/storage/api/v1/"
     )
 
+    if neon_env_builder.storage_controller_config is None:
+        neon_env_builder.storage_controller_config = {}
+    neon_env_builder.storage_controller_config["timelines_onto_safekeepers"] = True
+
     env = neon_env_builder.init_start()
 
     # The test needs LocalFs support, which is only built in testing mode.
@@ -286,34 +291,28 @@ def test_pgdata_import_smoke(
     #
     # validate that we can write
     #
-    rw_endpoint = env.endpoints.create_start(
-        branch_name=import_branch_name,
-        endpoint_id="rw",
-        tenant_id=tenant_id,
-        config_lines=ep_config,
-    )
-    rw_endpoint.safe_psql("create table othertable(values text)")
-    rw_lsn = Lsn(rw_endpoint.safe_psql_scalar("select pg_current_wal_flush_lsn()"))
+    workload = Workload(env, tenant_id, timeline_id, branch_name=import_branch_name)
+    workload.init()
+    workload.write_rows(64)
+    workload.validate()
 
-    # TODO: consider using `class Workload` here
-    # to do compaction and whatnot?
+    rw_lsn = Lsn(workload.endpoint().safe_psql_scalar("select pg_current_wal_flush_lsn()"))
 
     #
     # validate that we can branch (important use case)
     #
 
     # ... at the tip
-    _ = env.create_branch(
+    child_timeline_id = env.create_branch(
         new_branch_name="br-tip",
         ancestor_branch_name=import_branch_name,
         tenant_id=tenant_id,
         ancestor_start_lsn=rw_lsn,
     )
-    br_tip_endpoint = env.endpoints.create_start(
-        branch_name="br-tip", endpoint_id="br-tip-ro", tenant_id=tenant_id, config_lines=ep_config
-    )
-    validate_vanilla_equivalence(br_tip_endpoint)
-    br_tip_endpoint.safe_psql("select * from othertable")
+    child_workload = workload.branch(timeline_id=child_timeline_id, branch_name="br-tip")
+    child_workload.validate()
+
+    validate_vanilla_equivalence(child_workload.endpoint())
 
     # ... at the initdb lsn
     _ = env.create_branch(
@@ -330,7 +329,7 @@ def test_pgdata_import_smoke(
     )
     validate_vanilla_equivalence(br_initdb_endpoint)
     with pytest.raises(psycopg2.errors.UndefinedTable):
-        br_initdb_endpoint.safe_psql("select * from othertable")
+        br_initdb_endpoint.safe_psql(f"select * from {workload.table}")
 
 
 @run_only_on_default_postgres(reason="PG version is irrelevant here")

test_runner/regress/test_proxy_metric_collection.py

@@ -52,6 +52,8 @@ def proxy_with_metric_collector(
     proxy_port = port_distributor.get_port()
     mgmt_port = port_distributor.get_port()
     external_http_port = port_distributor.get_port()
+    router_port = port_distributor.get_port()
+    router_tls_port = port_distributor.get_port()
 
     (host, port) = httpserver_listen_address
     metric_collection_endpoint = f"http://{host}:{port}/billing/api/v1/usage_events"
@@ -63,6 +65,8 @@ def proxy_with_metric_collector(
         proxy_port=proxy_port,
         http_port=http_port,
         mgmt_port=mgmt_port,
+        router_port=router_port,
+        router_tls_port=router_tls_port,
         external_http_port=external_http_port,
         metric_collection_endpoint=metric_collection_endpoint,
         metric_collection_interval=metric_collection_interval,

test_runner/regress/test_role_grants.py

@@ -39,3 +39,10 @@ def test_role_grants(neon_simple_env: NeonEnv):
         res = cur.fetchall()
 
         assert res == [(1,)], "select should not succeed"
+
+    # confirm that replicas can also ensure the grants are correctly set.
+    replica = env.endpoints.new_replica_start(endpoint)
+    replica_client = replica.http_client()
+    replica_client.set_role_grants(
+        "test_role_grants", "test_role", "test_schema", ["CREATE", "USAGE"]
+    )

test_runner/regress/test_sni_router.py

@@ -6,7 +6,7 @@ from typing import TYPE_CHECKING
 
 import backoff
 from fixtures.log_helper import log
-from fixtures.neon_fixtures import PgProtocol, VanillaPostgres
+from fixtures.neon_fixtures import NeonProxy, PgProtocol, VanillaPostgres
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -41,6 +41,7 @@ class PgSniRouter(PgProtocol):
         self,
         neon_binpath: Path,
         port: int,
+        tls_port: int,
         destination: str,
         tls_cert: Path,
         tls_key: Path,
@@ -53,6 +54,7 @@ class PgSniRouter(PgProtocol):
         self.host = host
         self.neon_binpath = neon_binpath
         self.port = port
+        self.tls_port = tls_port
         self.destination = destination
         self.tls_cert = tls_cert
         self.tls_key = tls_key
@@ -64,6 +66,7 @@ class PgSniRouter(PgProtocol):
         args = [
             str(self.neon_binpath / "pg_sni_router"),
             *["--listen", f"127.0.0.1:{self.port}"],
+            *["--listen-tls", f"127.0.0.1:{self.tls_port}"],
             *["--tls-cert", str(self.tls_cert)],
             *["--tls-key", str(self.tls_key)],
             *["--destination", self.destination],
@@ -127,10 +130,12 @@ def test_pg_sni_router(
     pg_port = vanilla_pg.default_options["port"]
 
     router_port = port_distributor.get_port()
+    router_tls_port = port_distributor.get_port()
 
     with PgSniRouter(
         neon_binpath=neon_binpath,
         port=router_port,
+        tls_port=router_tls_port,
         destination="local.neon.build",
         tls_cert=test_output_dir / "router.crt",
         tls_key=test_output_dir / "router.key",
@@ -146,3 +151,22 @@ def test_pg_sni_router(
             hostaddr="127.0.0.1",
         )
         assert out[0][0] == 1
+
+
+def test_pg_sni_router_in_proxy(
+    static_proxy: NeonProxy,
+    vanilla_pg: VanillaPostgres,
+):
+    # static_proxy starts this.
+    assert vanilla_pg.is_running()
+    pg_port = vanilla_pg.default_options["port"]
+
+    out = static_proxy.safe_psql(
+        "select 1",
+        dbname="postgres",
+        sslmode="require",
+        host=f"endpoint--namespace--{pg_port}.local.neon.build",
+        hostaddr="127.0.0.1",
+        port=static_proxy.router_port,
+    )
+    assert out[0][0] == 1

vendor/revisions.json

@@ -5,7 +5,7 @@
   ],
   "v16": [
     "16.8",
-    "05ddf212e2e07b788b5c8b88bdcf98630941f6ae"
+    "d72d76f2cdee4194dd052ce099e9784aca7c794a"
   ],
   "v15": [
     "15.12",