## Problem
follow-up on https://github.com/neondatabase/neon/pull/11601
## Summary of changes
- serialize the start/end time using rfc3339 time string
- compute the size ratio of the compaction
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
`Tenant` isn't really a whole tenant: it's just one shard of a tenant.
## Summary of changes
- Automated rename of Tenant to TenantShard
- Followup commit to change references in comments
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>
## Problem
We currently only have gc-compaction statistics for each single
sub-compaction job.
## Summary of changes
Add meta statistics across all sub-compaction jobs scheduled.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
During shard ancestor compaction, we currently recompress all page
images as we move them into a new layer file. This is expensive and
unnecessary.
Resolves#11562.
Requires #11607.
## Summary of changes
Pass through compressed page images in `ImageLayerInner::filter()`.
## Problem
To avoid recompressing page images during layer filtering, we need
access to the raw header and data from vectored reads such that we can
pass them through to the target layer.
Touches #11562.
## Summary of changes
Adds `VectoredBlob::raw_with_header()` to return a raw view of the
header+data, and updates `read()` to track it.
Also adds `blob_io::Header` with header metadata and decode logic, to
reuse for tests and assertions. This isn't yet widely used.
## 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
close https://github.com/neondatabase/neon/issues/11486, proceeding
https://github.com/neondatabase/neon/pull/11531
## Summary of changes
This patch fixes the rest 50% of instability of
`test_create_churn_during_restart`. During tenant warmup, we'll request
logical size; however, if the startup gets cancelled, we won't be able
to spawn the initial logical size calculation task that sets the
`cancel_wait_for_background_loop_concurrency_limit_semaphore`.
Therefore, we check `cancelled` before proceeding to get
`cancel_wait_for_background_loop_concurrency_limit_semaphore`. There
will still be a race if the timeline shutdown happens after L5710 and
before L5711, but it should be enough to reduce the flakiness of the
test.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
When doing power-of-two shard splits (i.e. 4 → 8 → 16), we end up
rewriting all layers since half of the pages will be local due to
striping. This causes a lot of resource usage when splitting large
tenants.
## Summary of changes
Drop the threshold of local/total pages to 30%, to reduce the amount of
layer rewrites after splits.
## Problem
Shard ancestor compaction can be very expensive following shard splits
of large tenants. We currently rewrite garbage layers after shard splits
as well, which can be a significant amount of data.
Touches https://github.com/neondatabase/cloud/issues/22532.
## Summary of changes
Don't rewrite invisible layers after shard splits.
## Problem
https://github.com/neondatabase/neon/pull/11515 introduced a bug that
some key history cannot be verified.
If a key only exists above the horizon, the verification will fail for
its first occurrence because the history does not exist at that point.
As gc-compaction skips a key range whenever an error occurs, it might be
doing some wasted work in staging/prod now. But I'm not planning a
hotfix this week as the bug doesn't affect correctness/performance.
## Summary of changes
Allow keys with only above horizon history in the verification.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Shard ancestor compaction doesn't currently log any global progress
information, only for the current batch.
## Summary of changes
Log the number of layers checked for eligibility this iteration, and the
total number of layers to check. This will indicate how far along the
total shard ancestor compaction has gotten for this iteration.
## Problem
Every time we make changes to the read path to fix a bug or add a
feature,
we end up adding another incomprehensible test.
## Summary of changes
Add some generic infrastructure for generating a layer map from a type
spec
and use that for a read path test. The test is randomized but uses a
fixed seed
by default. A fuzzing mode is available for confidence building.
See [Notion
page](https://www.notion.so/neondatabase/Read-Path-Unit-Testing-Fuzzing-1d1f189e0047806c8e5cd37781b0a350?pvs=4)
for a diagram of the layer map
used.
Just for fun I tried removing [this
commit](9990199cb4)
from https://github.com/neondatabase/neon/pull/11494
and it caught the bug in the normal mode (no fuzzing required).
## Problem
https://github.com/neondatabase/neon/pull/11494 changes the batching
logic, but we don't have a way to evaluate it.
## Summary of changes
This PR introduces a global and per timeline metric which tracks the
reason for
which a batch was broken.
In #10063 we will switch BlobWriter to use the owned buffers IO buffered
writer, which implements double-buffering by virtue of a background task
that performs the flushing.
That task's lifecylce must be contained within the Timeline lifecycle,
so, it must hold the timeline gate open and respect Timeline::cancel.
This PR does the noisy plumbing to reduce the #10063 diff.
Refs
- extracted from https://github.com/neondatabase/neon/pull/10063
- epic https://github.com/neondatabase/neon/issues/9868
## 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
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>
## Problem
Shard ancestor compaction does not yield for L0 compaction, potentially
starving it.
close https://github.com/neondatabase/neon/issues/11125
## Summary of changes
* Yield for L0 during shard ancestor compaction.
* Return `CompactionOutcome::Pending` when limited by `rewrite_max`, for
eager rescheduling.
Introduces a `WalIngestError` struct together with a
`WalIngestErrorKind` enum, to be used for walingest related failures and
errors.
* the enum captures backtraces, so we don't regress in comparison to
`anyhow::Error`s (backtraces might be a bit shorter if we use one of the
`anyhow::Error` wrappers)
* it explicitly lists most/all of the potential cases that can occur.
I've originally been inspired to do this in #11496, but it's a
longer-term TODO.
## Problem
Shard ancestor compaction always logs "starting shard ancestor
compaction", even if there is no work to do. This is very spammy (every
20 seconds for every shard). It also has limited progress logging.
## Summary of changes
* Only log "starting shard ancestor compaction" when there's work to do.
* Include details about the amount of work.
* Log progress messages for each layer, and when waiting for uploads.
* Log when compaction is completed, with elapsed duration and whether
there is more work for a later iteration.
## 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
This test is slow to execute, particularly if you're on a slow
environment like vscode in a browser. Might have got much slower when we
switched to direct IO?
## Summary of changes
- Reduce the scale of the test by 10x, since there was nothing special
about the original size.
## Problem
Part of https://github.com/neondatabase/neon/issues/10395
## Summary of changes
Add a test case to ensure gc-compaction doesn't fire any critical errors
if the key history is invalid due to partial GC.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Page service doesn't use TLS for incoming requests.
- Closes: https://github.com/neondatabase/cloud/issues/27236
## Summary of changes
- Add option `enable_tls_page_service_api` to pageserver config
- Propagate `tls_server_config` to `page_service` if the option is
enabled
No integration tests for now because I didn't find out how to call page
service API from python and AFAIK computes don't support TLS yet
## 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
In some cases gc-compaction doesn't respond to the L0 compaction yield
notifier. I suspect it's stuck on getting the first item, and if so, we
probably need to let L0 yield notifier preempt `next_with_trace`.
## Summary of changes
- Add `time_to_first_kv_pair` to gc-compaction statistics.
- Inverse the ratio so that smaller ratio -> better compaction ratio.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Not a complete fix for https://github.com/neondatabase/neon/issues/11492
but should work for a short term.
Our current retry strategy for walredo is to retry every request exactly
once. This retry doesn't make sense because it retries all requests
exactly once and each error is expected to cause process restart and
cause future requests to fail. I'll explain it with a scenario of two
threads requesting redos: one with an invalid history (that will cause
walredo to panic) and another that has a correct redo sequence.
First let's look at how we handle retries right now in
do_with_walredo_process. At the beginning of the function it will spawn
a new process if there's no existing one. Then it will continue to redo.
If the process fails, the first process that encounters the error will
remove the walredo process object from the OnceCell, so that the next
time it gets accessed, a new process will be spawned; if it is the last
one that uses the old walredo process, it will kill and wait the process
in `drop(proc)`. I'm skeptical whether this works under races but I
think this is not the root cause of the problem. In this retry handler,
if there are N requests attached to a walredo process and the i-th
request fails (panics the walredo), all other N-i requests will fail and
they need to retry so that they can access a new walredo process.
```
time ---->
proc A None B
request 1 ^-----------------^ fail
uses A for redo replace with None
request 2 ^-------------------- fail
uses A for redo
request 3 ^----------------^ fail
uses A for redo last ref, wait for A to be killed
request 4 ^---------------
None, spawn new process B
```
The problem is with our retry strategy. Normally, for a system that we
want to retry on, the probability of errors for each of the requests are
uncorrelated. However, in walredo, a prior request that panics the
walredo process will cause all future walredo on that process to fail
(that's correlated).
So, back to the situation where we have 2 requests where one will
definitely fail and the other will succeed and we get the following
sequence, where retry attempts = 1,
* new walredo process A starts.
* request 1 (invalid) being processed on A and panics A, waiting for
retry, remove process A from the process object.
* request 2 (valid) being processed on A and receives pipe broken /
poisoned process error, waiting for retry, wait for A to be killed --
this very likely takes a while and cannot finish before request 1 gets
processed again
* new walredo process B starts.
* request 1 (invalid) being processed again on B and panics B, the whole
request fail.
* request 2 (valid) being processed again on B, and get a poisoned error
again.
```
time ---->
proc A None B None
request 1 ^-----------------^--------------^--------------------^
spawn A for redo fail spawn B for redo fail
request 2 ^--------------------^-------------------------^------------^
use A for redo fail, wait to kill A B for redo fail again
```
In such cases, no matter how we set n_attempts, as long as the retry
count applies to all requests, this sequence is bound to fail both
requests because of how they get sequenced; while we could potentially
make request 2 successful.
There are many solutions to this -- like having a separate walredo
manager for compactions, or define which errors are retryable (i.e.,
broken pipe can be retried, while real walredo error won't be retried),
or having a exclusive big lock over the whole redo process (the current
one is very fine-grained). In this patch, we go with a simple approach:
use different retry attempts for different types of requests.
For gc-compaction, the attempt count is set to 0, so that it never
retries and consequently stops the compaction process -- no more redo
will be issued from gc-compaction. Once the walredo process gets
restarted, the normal read requests will proceed normally.
## Summary of changes
Add redo_attempt for each reconstruct value request to set different
retry policies.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Erik Grinaker <erik@neon.tech>
I like to run nightly clippy every so often to make our future rust
upgrades easier. Some notable changes:
* Prefer `next_back()` over `last()`. Generic iterators will implement
`last()` to run forward through the iterator until the end.
* Prefer `io::Error::other()`.
* Use implicit returns
One case where I haven't dealt with the issues is the now
[more-sensitive "large enum variant"
lint](https://github.com/rust-lang/rust-clippy/pull/13833). I chose not
to take any decisions around it here, and simply marked them as allow
for now.
## Problem
We wish to improve pageserver batching such that one batch can contain
requests for
pages at different LSNs. The current shape of the code doesn't lend
itself to the change.
## Summary of changes
Refactor the read path such that the fringe gets initialized upfront.
This is where the multi LSN
change will plug in. A couple other small changes fell out of this.
There should be NO behaviour change here. If you smell one, shout!
I recommend reviewing commits individually (intentionally made them as
small as possible).
Related: https://github.com/neondatabase/neon/issues/10765
## 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>
The timeline stopping state is set much earlier than the cancellation
token is fired, so by checking for the stopping state, we can prevent
races with timeline shutdown where we issue a cancellation error but the
cancellation token hasn't been fired yet.
Fix#11427.
## 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.
## Problem
For future gc-compaction tests when we support
https://github.com/neondatabase/neon/issues/10395
## Summary of changes
Add a new type of neon test WAL record that is conditionally applied
(i.e., only when image == the specified value). We can use this to mock
the situation where we lose some records in the middle, firing an error,
and see how gc-compaction reacts to it.
Signed-off-by: Alex Chi Z <chi@neon.tech>
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
Fix various small issues discovered during gc-compaction rollout.
## Summary of changes
- Log level changes: if errors are from gc-compaction, fire a warning
instead of errors or critical errors.
- Yield to L0 compaction more aggressively. Instead of checking every 1k
keys, we check on every key. Sometimes a single key reconstruct takes a
long time.
---------
Signed-off-by: Alex Chi Z <chi@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
If a tenant is cancelled (e.g. due to Pageserver shutdown) during
attach, it is set to `Broken`. This results both in error log spam and
500 responses for clients -- shutdown is supposed to return 503
responses which can be retried.
This becomes more likely to happen with #11328, where we perform tenant
manifest downloads/uploads during attach.
## Summary of changes
Set tenant state to `Stopping` when attach fails and the tenant is
cancelled, downgrading the log messages to INFO. This introduces two
variants of `Stopping` -- with and without a caller barrier -- where the
latter is used to signal attach cancellation.
## 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
Current perf tracing fields do not allow answering the question what a
specific Postgres backend was waiting for.
# Background
For Pageserver logs, we set the backend PID as the libpq
`application_name` on the compute side, and funnel that into the a
tracing field for the spans that emit to the global tracing subscriber.
# Solution
Funnel `application_name`, and the other fields that we use in the
logging spans, into the root span for perf tracing.
# Refs
- fixes https://github.com/neondatabase/neon/issues/11393
- stacked atop https://github.com/neondatabase/neon/pull/11433
- epic: https://github.com/neondatabase/neon/issues/9873
## 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
## Problem
There are some places in the code where we create `reqwest::Client`
without providing SSL CA certs from `ssl_ca_file`. These will break
after we enable TLS everywhere.
- Part of https://github.com/neondatabase/cloud/issues/22686
## Summary of changes
- Support `ssl_ca_file` in storage scrubber.
- Add `use_https_safekeeper_api` option to safekeeper to use https for
peer requests.
- Propagate SSL CA certs to storage_controller/client, storcon's
ComputeHook, PeerClient and maybe_forward.
## Problem
Part of https://github.com/neondatabase/neon/issues/11318
It's not 100% safe for now to run gc-compaction over the sparse
keyspace. It might cause deleted file to re-appear if a specific
sequence of operations are done as in the issue, which in reality
doesn't happen due to how we split delta/image layers based on the key
range.
A long-term fix would be either having a separate gc-compaction code
path for metadata keys (as how we have a different code path for
metadata image layer generation), or let the compaction process aware of
the information of "there's an image layer that doesn't contain a key"
so that we can skip the keys.
## Summary of changes
* gc-compaction auto trigger only triggers compaction over the normal
data range.
* do not hold gc_block_guard across the full compaction job, only hold
it during each subcompaction.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Based on https://github.com/neondatabase/neon/pull/11139
## Problem
We want to export performance traces from the pageserver in OTEL format.
End goal is to see them in Grafana.
## Summary of changes
https://github.com/neondatabase/neon/pull/11139 introduces the
infrastructure required to run the otel collector alongside the
pageserver.
### Design
Requirements:
1. We'd like to avoid implementing our own performance tracing stack if
possible and use the `tracing` crate if possible.
2. Ideally, we'd like zero overhead of a sampling rate of zero and be a
be able to change the tracing config for a tenant on the fly.
3. We should leave the current span hierarchy intact. This includes
adding perf traces without modifying existing tracing.
To satisfy (3) (and (2) in part) a separate span hierarchy is used.
`RequestContext` gains an optional `perf_span` member
that's only set when the request was chosen by sampling. All perf span
related methods added to `RequestContext` are no-ops for requests that
are not sampled.
This on its own is not enough for (3), so performance spans use a
separate tracing subscriber. The `tracing` crate doesn't have great
support for this, so there's a fair amount of boilerplate to override
the subscriber at all points of the perf span lifecycle.
### Perf Impact
[Periodic
pagebench](https://neonprod.grafana.net/d/ddqtbfykfqfi8d/e904990?orgId=1&from=2025-02-08T14:15:59.362Z&to=2025-03-10T14:15:59.362Z&timezone=utc)
shows no statistically significant regression with a sample ratio of 0.
There's an annotation on the dashboard on 2025-03-06.
### Overview of changes:
1. Clean up the `RequestContext` API a bit. Namely, get rid of the
`RequestContext::extend` API and use the builder instead.
2. Add pageserver level configs for tracing: sampling ratio, otel
endpoint, etc.
3. Introduce some perf span tracking utilities and expose them via
`RequestContext`. We add a `tracing::Span` wrapper to be used for perf
spans and a `tracing::Instrumented` equivalent for it. See doc comments
for reason.
4. Set up OTEL tracing infra according to configuration. A separate
runtime is used for the collector.
5. Add perf traces to the read path.
## Refs
- epic https://github.com/neondatabase/neon/issues/9873
---------
Co-authored-by: Christian Schwarz <christian@neon.tech>
## Problem
There are some cases where traditional gc might collect some layer files
causing gc-compaction cannot read the full history of the key. This
needs to be resolved in the long-term by improving the compaction
process. For now, let's simply avoid such errors triggering the circuit
breaker.
## Summary of changes
* Move the place where we trigger the circuit breaker. We only trigger
it during compactions other than L0 compactions. We added the trigger a
year ago due to file cleanup concerns in image layer compaction.
* For gc-compaction, only return errors to the upper
compaction_iteration if it's a shutdown error. Otherwise, just log it
and skip the compaction for a key range.
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Christian Schwarz <christian@neon.tech>
