The current test was just SQL files only, but we also want to test a
remote extension which includes a loadable library. With both extensions
we should cover a larger portion of compute_ctl's remote extension code
paths.
Fixes: https://github.com/neondatabase/neon/issues/11146
Signed-off-by: Tristan Partin <tristan@neon.tech>
## Problem
In https://github.com/neondatabase/neon/pull/11345 coordination of
imports moved to the storage controller.
It involves notifying cplane when the import has been completed by
calling an idempotent endpoint.
If the storage controller shuts down in the middle of finalizing an
import, it would never be retried.
## Summary of changes
Reconcile imports at start-up by fetching the complete imports from the
database and spawning a background
task which notifies cplane.
Closes: https://github.com/neondatabase/neon/issues/11570
## Problem
We saw the following scenario in staging:
1. Pod A starts up. Becomes leader and steps down the previous pod
cleanly.
2. Pod B starts up (deployment).
3. Step down request from pod B to pod A times out. Pod A did not manage
to stop its reconciliations within 10 seconds and exited with return
code 1
([code](7ba8519b43/storage_controller/src/service.rs (L8686-L8702))).
4. Pod B marks itself as the leader and finishes start-up
5. k8s restarts pod A
6. k8s marks pod B as ready
7. pod A sends step down request to pod A - this succeeds => pod A is
now the leader
8. k8s kills pod A because it thinks pod B is healthy and pod A is part
of the old replica set
We end up in a situation where the only pod we have (B) is stepped down
and attempts to forward requests to a leader that doesn't exist. k8s
can't detect that pod B is in a bad state since the /status endpoint
simply returns 200 hundred if the pod is running.
## Summary of changes
This PR includes a number of robustness improvements to the leadership
protocol:
* use a single step down task per controller
* add a new endpoint to be used as k8s liveness probe and check
leadership status there
* handle restarts explicitly (i.e. don't step yourself down)
* increase the step down retry count
* don't kill the process on long step down since k8s will just restart
it
## Problem
Currently, we only report the timestamp of the last moment we think
Postgres was active. The problem is that if Postgres gets completely
unresponsive, we still report some old timestamp, and it's impossible to
distinguish situations 'Postgres is effectively down' and 'Postgres is
running, but no client activity'.
## Summary of changes
Refactor the `compute_ctl`'s compute monitor so that it was easier to
track the connection errors and failed activity checks, and report
- `now() - last_successful_check` as current downtime on any failure
- cumulative Postgres downtime during the whole compute lifetime
After adding a test, I also noticed that the compute monitor may not
reconnect even though queries fail with `connection closed` or `error
communicating with the server: Connection reset by peer (os error 54)`,
but for some reason we do not catch it with `client.is_closed()`, so I
added an explicit reconnect in case of any failures.
Discussion:
https://neondb.slack.com/archives/C03TN5G758R/p1742489426966639
## Problem
Pageservers notify control plane directly when a shard import has
completed.
Control plane has to download the status of each shard from S3 and
figure out if everything is truly done,
before proceeding with branch activation.
Issues with this approach are:
* We can't control shard split behaviour on the storage controller side.
It's unsafe to split
during import.
* Control plane needs to know about shards and implement logic to check
all timelines are indeed ready.
## Summary of changes
In short, storage controller coordinates imports, and, only when
everything is done, notifies control plane.
Big rocks:
1. Store timeline imports in the storage controller database. Each
import stores the status of its shards in the database.
We hook into the timeline creation call as our entry point for this.
2. Pageservers get a new upcall endpoint to notify the storage
controller of shard import updates.
3. Storage controller handles these updates by updating persisted state.
If an update finalizes the import,
then poll pageservers until timeline activation, and, then, notify the
control plane that the import is complete.
Cplane side change with new endpoint is in
https://github.com/neondatabase/cloud/pull/26166
Closes https://github.com/neondatabase/neon/issues/11566
ARM computes are incoming and we need to account for that in remote
extensions. Previously, we just blindly assumed that all computes were
x86_64.
Note that we use the Go architecture naming convention instead of the
Rust one directly to do our best and be consistent across the stack.
Part-of: https://github.com/neondatabase/cloud/issues/23148
Signed-off-by: Tristan Partin <tristan@neon.tech>
In tests and when one safekeeper is down in small regions, we need to
contend with one or two safekeepers. Before, we gave an error in
`safekeepers_for_new_timeline`. Now we just silently allow the timeline
to be created on one or two safekeepers.
Part of #9011
## Problem
test_storage_controller_heartbeats is flaky because of unallowed
reconciler errors (#11625)
## Summary of changes
Allow reconcile errors as in other tests in test_storage_controller.py.
This delivers some additional fixes and improvements to storcon managed
safekeeper timelines:
* use `i32::MAX` for the generation number of timeline deletion
* start the generation for new timelines at 1 instead of 0: this ensures
that the other components actually are generation enabled
* fix database operations we use for metrics
* use join in list_pending_ops to prevent the classical ORM issue where
one does many db queries
* use enums in `test_storcon_create_delete_sk_down`. we are adding a
second parameter, and having two bool parameters is weird.
* extend `test_storcon_create_delete_sk_down` with a test of whole
tenant deletion. this hasn't been tested before.
* remove some redundant logging contexts
* Don't require mutable access to the service lock for scheduling
pending ops in memory. In order to pull this off, create reconcilers
eagerly. The advantage is that we don't need mutable access to the
service lock that way any more.
Part of #9011
---------
Co-authored-by: Arseny Sher <sher-ars@yandex.ru>
## Problem
https://github.com/neondatabase/neon/pull/11531 did not fully fix the
problem because the warning is part of the storcon instead of
pageserver.
## Summary of changes
Allow stale generation error in storcon.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
There are mentions of `ALLOW_BACKWARD_COMPATIBILITY_BREAKAGE` and
`ALLOW_FORWARD_COMPATIBILITY_BREAKAGE`, but in reality, this mechanism
doesn't work, so let's remove it to avoid confusion.
The idea behind it was to allow some breaking changes by adding a
special label to a PR that would `xfail` the test. However, in practice,
this means we would need to carry this label through all subsequent PRs
until the release (and artifact regeneration). This approach isn't
really viable, as it increases the risk of missing a compatibility break
in another PR.
## Summary of changes
- Remove mentions and handling of
`ALLOW_BACKWARD_COMPATIBILITY_BREAKAGE` /
`ALLOW_FORWARD_COMPATIBILITY_BREAKAGE`
## Problem
Test lfc working set approximation becomes flaky after recent changes in
prefetch.
May be it is caused by updating HLL in `lfc_write`, may be by some other
reasons.
## Summary of changes
1. Disable autovacuum in this test (as possible source of extra page
accesses).
2. Increase upper boundary for WS approximation from 12 to 20.
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
This is mostly a documentation update, but a few updates with regard to
neon_local, pageserver, and tests.
17 is our default for users in production, so dropping references to 16
makes sense.
Signed-off-by: Tristan Partin <tristan@neon.tech>
Signed-off-by: Tristan Partin <tristan@neon.tech>
1. Compute may generate WAL on shutdown. The test assumes that after
shutdown,
no further ingest happens. Tweak the compute shutdown to make the
assumption true.
2. Assertion of local layer count post cold migration is not right since
we may have downloaded
layers due to ingest. Remove it.
Closes https://github.com/neondatabase/neon/issues/11587
## Problem
Splits of large tenants (several TB) can cause a huge amount of shard
ancestor compaction work, which can overload Pageservers.
Touches https://github.com/neondatabase/cloud/issues/22532.
## Summary of changes
Add a setting `compaction_shard_ancestor` (default `true`) to disable
shard ancestor compaction on a per-tenant basis.
## Problem
Part of https://github.com/neondatabase/neon/issues/11486
## Summary of changes
50% of the test instability of `test_create_churn_during_restart` are
due to error message gets changed. Allow the new error message.
Still need to fix other errors due to failure to acquire semaphore in
this or the next patch.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Get page batching stops when we encounter requests at different LSNs.
We are leaving batching factor on the table.
## Summary of changes
The goal is to support keys with different LSNs in a single batch and
still serve them with a single vectored get.
Important restriction: the same key at different LSNs is not supported
in one batch. Returning different key
versions is a much more intrusive change.
Firstly, the read path is changed to support "scattered" queries. This
is a conceptually simple step from
https://github.com/neondatabase/neon/pull/11463. Instead of initializing
the fringe for one keyspace,
we do it for multiple at different LSNs and let the logic already
present into the fringe handle selection.
Secondly, page service code is updated to support batching at different
LSNs. Eeach request parsed from the wire determines its effective
request LSN and keeps it in mem for the batcher toinspect. The batcher
allows keys at
different LSNs in one batch as long one key is not requested at
different LSNs.
I'd suggest doing the first pass commit by commit to get a feel for the
changes.
## Results
I used the batching test from [Christian's
PR](https://github.com/neondatabase/neon/pull/11391) which increases the
change of batch breaks. Looking at the logs I think the new code is at
the max batching factor for the workload (we
only break batches due to them being oversized or because the executor
is idle).
```
Main:
Reasons for stopping batching: {'LSN changed': 22843, 'of batch size': 33417}
test_throughput[release-pg16-50-pipelining_config0-30-100-128-batchable {'max_batch_size': 32, 'execution': 'concurrent-futures', 'mode': 'pipelined'}].perfmetric.batching_factor: 14.6662
My branch:
Reasons for stopping batching: {'of batch size': 37024}
test_throughput[release-pg16-50-pipelining_config0-30-100-128-batchable {'max_batch_size': 32, 'execution': 'concurrent-futures', 'mode': 'pipelined'}].perfmetric.batching_factor: 19.8333
```
Related: https://github.com/neondatabase/neon/issues/10765
## Problem
See https://github.com/neondatabase/neon/issues/10652
Neon extension launches 2 BGW which reduce limit for parallel workers
and so affecting parallel_deadlock isolation test.
## Summary of changes
Increase `max_worker_processes` from default 8 to 16 for isolation test.
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
## Problem
Part of #9114
There was a debug-mode verification mode that verifies at every
retain_lsn. However, the code was tangled within the actual history
generation itself and it's hard to reason about correctness. This patch
adds a separate post-verification of the gc-compaction result that redos
logs at every retain_lsn and every record above the GC horizon. This
ensures that all key history we produce with gc-compaction is readable,
and if there're read errors after gc-compaction, it can only be
read-path errors instead of gc-compaction bugs.
## Summary of changes
* Add gc_compaction_verification flag, default to true.
* Implement a post-verification process.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Previously, the structure of the spec file was just the compute spec.
However, the response from the control plane get spec request included
the compute spec and the compute_ctl config. This divergence was
hindering other work such as adding regression tests for compute_ctl
HTTP authorization.
Signed-off-by: Tristan Partin <tristan@neon.tech>
# Refs
- fixes https://github.com/neondatabase/neon/issues/11395
# Problem
Since 2025-03-10, we have observed increased flakiness of
`test_pageserver_getpage_throttle`.
The test is timing-dependent by nature, and was hitting the
```
assert duration_secs >= 10 * actual_smgr_query_seconds, (
"smgr metrics should not include throttle wait time"
)
```
quite frequently.
# Analysis
These failures are not reproducible.
In this PR's history is a commit that reran the test 100 times without
requiring a single retry.
In https://github.com/neondatabase/neon/issues/11395 there is a link to
a query to the test results database.
It shows that the flakiness was not constant, but rather episodic:
2025-03-{10,11,12,13} 2025-03-{19,20,21} 2025-03-31 and 2025-04-01.
To me, this suggests variability in available CPU.
# Solution
The point of the offending assertion is to ensure that most of the
request latency is spent on throttling, because testing of the
throttling mechanism is the point of the test.
The `10` magic number means at most 10% of mean latency may be spent on
request processing.
Ideally we would control the passage of time (virtual clock source) to
make this test deterministic.
But I don't see that happening in our regression test setup.
So, this PR de-flakes the test as follows:
- allot up to 66% of mean latency for request processing
- increase duration from 10s to 20s, hoping to get better protection
from momentary CPU spikes in noisy neighbor tests or VMs on the runner
host
As a drive-by, switch to `pytest.approx` and remove one self-test
assertion I can't make sense of anymore.
## Problem
We need to export some metrics about certs/connections to configure
alerts and make sure that all HTTP requests are gone before turning
https-only mode on.
- Closes: https://github.com/neondatabase/cloud/issues/25526
## Summary of changes
- Add started connection and connection error metrics to http/https
Server.
- Add certificate expiration time and reload metrics to
ReloadingCertificateResolver.
## Problem
The graceful leadership transfer process involves calling step_down on
the old controller, but this was not waiting for shard splits to
complete, and the new controller could therefore end up trying to abort
a shard split while it was still going on.
We mitigated this already in #11256 by avoiding the case where shard
split completion would update the database incorrectly, but this was a
fragile fix because it assumes that is the only problematic part of the
split running concurrently.
Precursors:
- #11290
- #11256Closes: #11254
## Summary of changes
- Hold the reconciler gate from shard splits, so that step_down will
wait for them. Splits should always be fairly prompt, so it is okay to
wait here.
- Defense in depth: if step_down times out (hardcoded 10 second limit),
then fully terminate the controller process rather than letting it
continue running, potentially doing split-brainy things. This makes
sense because the new controller will always declare itself leader
unilaterally if step_down fails, so leaving an old controller running is
not beneficial.
- Tests: extend
`test_storage_controller_leadership_transfer_during_split` to separately
exercise the case of a split holding up step_down, and the case where
the overall timeout on step_down is hit and the controller terminates.
## Problem
`test_location_conf_churn` performs random location updates on
Pageservers. While doing this, it could instruct the compute to connect
to a stale generation and execute queries. This is invalid, and will
fail if a newer generation has removed layer files used by the stale
generation.
Resolves#11348.
## Summary of changes
Only connect to the latest generation when executing queries.
## Problem
Walproposer should get elected and commit WAL on safekeepers specified
by the membership configuration.
## Summary of changes
- Add to wp `members_safekeepers` and `new_members_safekeepers` arrays
mapping configuration members to connection slots. Establish this
mapping (by node id) when safekeeper sends greeting, giving its id and
when mconf becomes known / changes.
- Add to TermsCollected, VotesCollected,
GetAcknowledgedByQuorumWALPosition membership aware logic. Currently it
partially duplicates existing one, but we'll drop the latter eventually.
- In python, rename Configuration to MembershipConfiguration for
clarity.
- Add test_quorum_sanity testing new logic.
ref https://github.com/neondatabase/neon/issues/10851
## Problem
Part of #9114
## Summary of changes
Gc-compaction flag was not correctly set, causing it not getting
preempted by L0.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
`test_location_conf_churn` often fails with `neither image nor delta
layer`, but doesn't say what the file actually is. However, past local
failures have indicated that it might be `.___temp` files.
Touches https://github.com/neondatabase/neon/issues/11348.
## Summary of changes
Ignore `.___temp` files when evicting local layers, and include the file
name in the error message.
## Problem
Now `get_timestamp_of_lsn` returns `404 NotFound` if there is no clog
pages for given LSN, and it's difficult to distinguish from other 404
errors. A separate status code for this error will allow the control
plane to handle this case.
- Closes: https://github.com/neondatabase/neon/issues/11439
- Corresponding PR in control plane:
https://github.com/neondatabase/cloud/pull/27125
## Summary of changes
- Return `412 PreconditionFailed` instead of `404 NotFound` if no
timestamp is fond for given LSN.
I looked briefly through the current error handling code in cloud.git
and the status code change should not affect anything for the existing
code. Change from the corresponding PR also looks fine and should work
with the current PS status code. Additionally, here is OK to merge it
from control plane team:
https://github.com/neondatabase/neon/issues/11439#issuecomment-2789327552
---------
Co-authored-by: John Spray <john@neon.tech>
## Problem
The current stripe size of 256 MB is a bit large, and can cause load
imbalances across shards. A stripe size of 16 MB appears more reasonable
to avoid hotspots, although we don't see evidence of this in benchmarks.
Resolves https://github.com/neondatabase/cloud/issues/25634.
Touches https://github.com/neondatabase/cloud/issues/21870.
## Summary of changes
* Change the default stripe size to 16 MB.
* Remove `ShardParameters::DEFAULT_STRIPE_SIZE`, and only use
`pageserver_api::shard::DEFAULT_STRIPE_SIZE`.
* Update a bunch of tests that assumed a certain stripe size.
## Problem
With the recent improvements to L0 compaction responsiveness,
`test_create_snapshot` now ends up generating 10,000 layer files
(compared to 1,000 in previous snapshots). This increases the snapshot
size by 4x, and significantly slows down tests.
## Summary of changes
Increase the target layer size from 128 KB to 256 KB, and the L0
compaction threshold from 1 to 5. This reduces the layer count from
about 10,000 to 1,000.
## Problem
`tenant_import`, used to import an existing tenant from remote storage
into a storage controller for support and debugging, assumed
`DEFAULT_STRIPE_SIZE` since this can't be recovered from remote storage.
In #11168, we are changing the stripe size, which will break
`tenant_import`.
Resolves#11175.
## Summary of changes
* Add `stripe_size` to the tenant manifest.
* Add `TenantScanRemoteStorageShard::stripe_size` and return from
`tenant_scan_remote` if present.
* Recover the stripe size during`tenant_import`, or fall back to 32768
(the original default stripe size).
* Add tenant manifest compatibility snapshot:
`2025-04-08-pgv17-tenant-manifest-v1.tar.zst`
There are no cross-version concerns here, since unknown fields are
ignored during deserialization where relevant.
Service targeted for storing and retrieving LFC prewarm data.
Can be used for proxying S3 access for Postgres extensions like
pg_mooncake as well.
Requests must include a Bearer JWT token.
Token is validated using a pemfile (should be passed in infra/).
Note: app is not tolerant to extra trailing slashes, see app.rs
`delete_prefix` test for comments.
Resolves: https://github.com/neondatabase/cloud/issues/26342
Unrelated changes: gate a `rename_noreplace` feature and disable it in
`remote_storage` so as `object_storage` can be built with musl
## Problem
`test_scrubber_tenant_snapshot` is flaky with `request was dropped`
errors. More details are in the issue.
- Closes: https://github.com/neondatabase/neon/issues/11278
## Summary of changes
- Disable shard scheduling during pageservers restart
- Add `reconcile_until_idle` in the end of the test
## Problem
If the local file cache is shrunk, so that we punch some holes in the
underlying file, the local_cache view displays the holes incorrectly.
See https://github.com/neondatabase/neon/issues/10770
## Summary of changes
Skip hole tags in the local_cache view.
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
## Problem
Currently, the tenant manifest is only uploaded if there are offloaded
timelines. The checks are also a bit loose (e.g. only checks number of
offloaded timelines). We want to start using the manifest for other
things too (e.g. stripe size).
Resolves#11271.
## Summary of changes
This patch ensures that a tenant manifest always exists. The lifecycle
is:
* During preload, fetch the existing manifest, if any.
* During attach, upload a tenant manifest if it differs from the
preloaded one (or does not exist).
* Upload a new manifest as needed, if it differs from the last-known
manifest (ignoring version number).
* On splits, pre-populate the manifest from the parent.
* During Pageserver physical GC, remove old manifests but keep the
latest 2 generations.
This will cause nearly all existing tenants to upload a new tenant
manifest on their first attach after this change. Attaches are
concurrency-limited in the storage controller, so we expect this will be
fine.
Also updates `make_broken` to automatically log at `INFO` level when the
tenant has been cancelled, to avoid spurious error logs during shutdown.
## Problem
We don't have metrics to exactly quantify the end user impact of
on-demand downloads.
Perf tracing is underway (#11140) to supply us with high-resolution
*samples*.
But it will also be useful to have some aggregate per-timeline and
per-instance metrics that definitively contain all observations.
## Summary of changes
This PR consists of independent commits that should be reviewed
independently.
However, for convenience, we're going to merge them together.
- refactor(metrics): measure_remote_op can use async traits
- impr(pageserver metrics): task_kind dimension for
remote_timeline_client latency histo
- implements https://github.com/neondatabase/cloud/issues/26800
- refs
https://github.com/neondatabase/cloud/issues/26193#issuecomment-2769705793
- use the opportunity to rename the metric and add a _global suffix;
checked grafana export, it's only used in two personal dashboards, one
of them mine, the other by Heikki
- log on-demand download latency for expensive-to-query but precise
ground truth
- metric for wall clock time spent waiting for on-demand downloads
## Refs
- refs https://github.com/neondatabase/cloud/issues/26800
- a bunch of minor investigations / incidents into latency outliers
# Refs
- refs https://github.com/neondatabase/neon/issues/8915
- discussion thread:
https://neondb.slack.com/archives/C033RQ5SPDH/p1742406381132599
- stacked atop https://github.com/neondatabase/neon/pull/11298
- corresponding internal docs update that illustrates how this PR
removes friction: https://github.com/neondatabase/docs/pull/404
# Problem
Rejecting `pageserver.toml`s with unknown fields adds friction,
especially when using `pageserver.toml` fields as feature flags that
need to be decommissioned.
See the added paragraphs on `pageserver_api::models::ConfigToml` for
details on what kind of friction it causes.
Also read the corresponding internal docs update linked above to see a
more imperative guide for using `pageserver.toml` flags as feature
flags.
# Solution
## Ignoring unknown fields
Ignoring is the serde default behavior.
So, just remove `serde(deny_unknown_fields)` from all structs in
`pageserver_api::config::ConfigToml`
`pageserver_api::config::TenantConfigToml`.
I went through all the child fields and verified they don't use
`deny_unknown_fields` either, including those shared with
`pageserver_api::models`.
## Warning about unknown fields
We still want to warn about unknown fields to
- be informed about typos in the config template
- be reminded about feature-flag style configs that have been cleaned up
in code but not yet in config templates
We tried `serde_ignore` (cf draft #11319) but it doesn't work with
`serde(flatten)`.
The solution we arrived at is to compare the on-disk TOML with the TOML
that we produce if we serialize the `ConfigToml` again.
Any key specified in the on-disk TOML but not present in the serialized
TOML is flagged as an ignored key.
The mechanism to do it is a tiny recursive decent visitor on the
`toml_edit::DocumentMut`.
# Future Work
Invalid config _values_ in known fields will continue to fail pageserver
startup.
See
- https://github.com/neondatabase/cloud/issues/24349
for current worst case impact to deployments & ideas to improve.
## Problem
https://github.com/neondatabase/neon/pull/11140 introduces performance
tracing with OTEL
and a pageserver config which configures the sampling ratio of get page
requests.
Enabling a non-zero sampling ratio on a per region basis is too
aggressive and comes with perf
impact that isn't very well understood yet.
## Summary of changes
Add a `sampling_ratio` tenant level config which overrides the
pageserver level config.
Note that we do not cache the config and load it on every get page
request such that changes propagate
timely.
Note that I've had to remove the `SHARD_SELECTION` span to get this to
work. The tracing library doesn't
expose a neat way to drop a span if one realises it's not needed at
runtime.
Closes https://github.com/neondatabase/neon/issues/11392
## Problem
IO metrics for secondary locations do not get deregistered when the
timeline is removed.
## Summary of changes
Stash the request context to be used for downloads in
`SecondaryTimelineDetail`. These objects match the lifetime of the
secondary timeline location pretty well.
When the timeline is removed, deregister the metrics too.
Closes https://github.com/neondatabase/neon/issues/11156
Adds a test `test_storcon_create_delete_sk_down` which tests the
reconciler and pending op persistence if faced with a temporary
safekeeper downtime during timeline creation or deletion. This is in
contrast to `test_explicit_timeline_creation_storcon`, which tests the
happy path.
We also do some fixes:
* timeline and tenant deletion http requests didn't expect a body, but
`()` sent one.
* we got the tenant deletion http request's return type wrong: it's
supposed to be a hash map
* we add some logging to improve observability
* We fix `list_pending_ops` which had broken code meant to make it
possible to restrict oneself to a single pageserver. But diesel doesn't
support that sadly, or at least I couldn't figure out a way to make it
work. We don't need that functionality, so remove it.
* We add an info span to the heartbeater futures with the node id, so
that there is no context-free msgs like "Backoff: waiting 1.1 seconds
before processing with the task" in the storcon logs. we could also add
the full base url of the node but don't do it as most other log lines
contain that information already, and if we do duplication it should at
least not be verbose. One can always find out the base url from the node
id.
Successor of #11261
Part of #9011
## Problem
Previously, if the observed state was refreshed and matching the intent,
we wouldn't send
a compute notification. This is unsafe. There's no guarantee that the
location landed on the
pageserver _and_ a compute notification for it was delivered.
See
https://github.com/neondatabase/neon/issues/11291#issuecomment-2743205411
for one such example.
## Summary of changes
Add a reproducer and notify the compute if the correct observed state
required a refresh.
Closes https://github.com/neondatabase/neon/issues/11291
## Problem
The test_pageserver_gc_compaction_smoke fails rather often due to a
timeout on slow machines.
See https://github.com/neondatabase/neon/issues/11355.
## Summary of changes
Increase the timeout for the test.
