## Problem
We hold the layer map for too long on occasion.
## Summary of changes
This should help us identify the places where it's happening from.
Related https://github.com/neondatabase/neon/issues/12182
## Problem
Part of https://github.com/neondatabase/neon/issues/11813
In PostHog UI, we need to create the properties before using them as a
filter. We report all variants automatically when we start the
pageserver. In the future, we can report all real tenants instead of
fake tenants (we do that now to save money + we don't need real tenants
in the UI).
## Summary of changes
* Collect `region`, `availability_zone`, `pageserver_id` properties and
use them in the feature evaluation.
* Report 10 fake tenants on each pageserver startup.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of #11813. This pull request adds misc observability improvements
for the functionality.
## Summary of changes
* Info span for the PostHog feature background loop.
* New evaluate feature flag API.
* Put the request error into the error message.
* Log when feature flag gets updated.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
There is a new API that I plan to use. We generate client from the spec
so it should be in the spec
## Summary of changes
Document the existing API in openAPI format
## Problem
Test coverage of timeline imports is lacking.
## Summary of changes
This PR adds a chaos import test. It runs an import while injecting
various chaos events
in the environment. All the commits that follow the test fix various
issues that were surfaced by it.
Closes https://github.com/neondatabase/neon/issues/10191
Support timeline creations on the storage controller to opt out from
their creation on the safekeepers, introducing the read-only timelines
concept. Read only timelines:
* will never receive WAL of their own, so it's fine to not create them
on the safekeepers
* the property is non-transitive. children of read-only timelines aren't
neccessarily read-only themselves.
This feature can be used for snapshots, to prevent the safekeepers from
being overloaded by empty timelines that won't ever get written to. In
the current world, this is not a problem, because timelines are created
implicitly by the compute connecting to a safekeeper that doesn't have
the timeline yet. In the future however, where the storage controller
creates timelines eagerly, we should watch out for that.
We represent read-only timelines in the storage controller database so
that we ensure that they never touch the safekeepers at all. Especially
we don't want them to cause a mess during the importing process of the
timelines from the cplane to the storcon database.
In a hypothetical future where we have a feature to detach timelines
from safekeepers, we'll either need to find a way to distinguish the
two, or if not, asking safekeepers to list the (empty) timeline prefix
and delete everything from it isn't a big issue either.
This patch will unconditionally hit the new safekeeper timeline creation
path for read-only timelines, without them needing the
`--timelines-onto-safekeepers` flag enabled. This is done because it's
lower risk (no safekeepers or computes involved at all) and gives us
some initial way to verify at least some parts of that code in prod.
https://github.com/neondatabase/cloud/issues/29435https://github.com/neondatabase/neon/issues/11670
## Problem
It is not currently possible to disambiguate a timeline with an
uninitialized PITR cutoff from one that was created within the PITR
window -- both of these have `GcCutoffs::time == Lsn(0)`. For billing
metrics, we need to disambiguate these to avoid accidentally billing the
entire history when a tenant is initially loaded.
Touches https://github.com/neondatabase/cloud/issues/28155.
## Summary of changes
Make `GcCutoffs::time` an `Option<Lsn>`, and only set it to `Some` when
initialized. A `pitr_interval` of 0 will yield `Some(last_record_lsn)`.
This PR takes a conservative approach, and mostly retains the old
behavior of consumers by using `unwrap_or_default()` to yield 0 when
uninitialized, to avoid accidentally introducing bugs -- except in cases
where there is high confidence that the change is beneficial (e.g. for
the `pageserver_pitr_history_size` Prometheus metric and to return early
during GC).
## Problem
The gRPC page service API will require decoupling the `PageHandler` from
the libpq protocol implementation. As preparation for this, avoid
passing in the entire server config to `PageHandler`, and instead
explicitly pass in the relevant fields.
Touches https://github.com/neondatabase/neon/issues/11728.
## Summary of changes
* Change `PageHandler` to take a `GetVectoredConcurrentIo` instead of
the entire config.
* Change `IoConcurrency::spawn_from_conf` to take a
`GetVectoredConcurrentIo`.
## Problem
Lifetime of imported timelines (and implicitly the import background
task) has some shortcomings:
1. Timeline activation upon import completion is tricky. Previously, a
timeline that finished importing
after a tenant detach would not get activated and there's concerns about
the safety of activating
concurrently with shut-down.
2. Import jobs can prevent tenant shut down since they hold the tenant
gate
## Summary of Changes
Track the import tasks in memory and abort them explicitly on tenant
shutdown.
Integrate more closely with the storage controller:
1. When an import task has finished all of its jobs, it notifies the
storage controller, but **does not** mark the import as done in the
index_part. When all shards have finished importing, the storage
controller will call the `/activate_post_import` idempotent endpoint for
all of them. The handler, marks the import complete in index part,
resets the tenant if required and checks if the timeline is active yet.
2. Not directly related, but the import job now gets the starting state
from the storage controller instead of the import bucket. This paves the
way for progress checkpointing.
Related: https://github.com/neondatabase/neon/issues/11568
## 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
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
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>
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
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
`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.
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
close https://github.com/neondatabase/neon/issues/11279
## Summary of changes
* Allow passthrough of other methods in tenant timeline shard0
passthrough of storcon.
* Passthrough mark invisible API in storcon.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
ref https://github.com/neondatabase/neon/issues/11279
Imagine we have a branch with 3 snapshots A, B, and C:
```
base---+---+---+---main
\-A \-B \-C
base=100G, base-A=1G, A-B=1G, B-C=1G, C-main=1G
```
at this point, the synthetic size should be 100+1+1+1+1=104G.
after the deletion, the structure looks like:
```
base---+---+---+
\-A \-B \-C
```
If we simply assume main never exists, the size will be calculated as
size(A) + size(B) + size(C)=300GB, which obviously is not what the user
would expect.
The correct way to do this is to assume part of main still exists, that
is to say, set C-main=1G:
```
base---+---+---+main
\-A \-B \-C
```
And we will get the correct synthetic size of 100G+1+1+1=103G.
## Summary of changes
* Do not generate gc cutoff point for invisible branches.
* Use the same LSN as the last branchpoint for branch end.
* Remove test_api_handler for mark_invisible.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Add an optional `safekeepers` field to `TimelineInfo` which is returned
by the storcon upon timeline creation if the
`--timelines-onto-safekeepers` flag is enabled. It contains the list of
safekeepers chosen.
Other contexts where we return `TimelineInfo` do not contain the
`safekeepers` field, sadly I couldn't make this more type safe like done
in Rust via `TimelineCreateResponseStorcon`, as there is no way of
flattening or inheritance (and I don't that duplicating the entire type
for some minor type safety improvements is worth it).
The storcon side has been done in #11058.
Part of https://github.com/neondatabase/cloud/issues/16176
cc https://github.com/neondatabase/cloud/issues/16796
## Problem
`CompactFlags::NoYield` was a bit inconvenient, since every caller
except for the background compaction loop should generally set it (e.g.
HTTP API calls, tests, etc). It was also inconsistent with
`CompactionOutcome::YieldForL0`.
## Summary of changes
Invert `CompactFlags::NoYield` as `CompactFlags::YieldForL0`. There
should be no behavioral changes.
## Problem
part of https://github.com/neondatabase/neon/issues/11279
## Summary of changes
The invisible flag is used to exclude a timeline from synthetic size
calculation. For the first step, let's persist this flag. Most of the
code are following the `is_archived` modification flow.
Signed-off-by: Alex Chi Z <chi@neon.tech>
The only difference between
- `pageserver_api::models::TenantConfig` and
- `pageserver::tenant::config::TenantConfOpt`
at this point is that `TenantConfOpt` serializes with
`skip_serializing_if = Option::is_none`.
That is an efficiency improvement for all the places that currently
serde `models::TenantConfig` because new serializations will no longer
write `$fieldname: null` for each field that is `None` at runtime.
This should be particularly beneficial for Storcon, which stores
JSON-serialized `models::TenantConfig` in its DB.
# Behavior Changes
This PR changes the serialization behavior: we omit `None` fields
instead of serializing `$fieldname: null`).
So it's a data format change (see section on compatibility below).
And it changes API responses from Storcon and Pageserver.
## API Response Compatibility
Storcon returns the location description.
Afaik it is passed through into
- storcon_cli output
- storcon UI in console admin UI
These outputs will no longer contain `$fieldname: null` values,
which de-bloats the output (good).
But in storcon UI, it also serves as an editor "default", which
will be eliminated after a storcon with this PR is released.
## Data Format Compatibility
Backwards compat: new software reading old serialized data will
deserialize to the same runtime value because all the field types
are exactly the same and `skip_serializing_if` does not affect
deserialization.
Forward compat: old software reading data serialized by new software
will map absence fields in the serialized form to runtime value
`Option::None`. This is serde default behavior, see this playground
to convince yourself:
https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=f7f4e1a169959a3085b6158c022a05eb
The `serde(with="humantime_serde")` however behaves strangely:
if used on an `Option<Duration>`, it still requires the field to be
present,
unlike the serde default behavior shown in the previous paragraph.
The workaround is to set `serde(default)`.
Previously it was set on each individual field, but, we do have the
container attribute, so, set it there.
This requires deriving a `Default` impl, which, because all fields are
`Option`,
is non-magic.
See my notes here:
https://gist.github.com/problame/eddbc225a5d12617e9f2c6413e0cf799
# Future Work
We should have separate types (& crates) for
- runtime types configuration (e.g. PageServerConf::tenant_config,
AttachedLocationConf)
- `config-v1` file pageserver local disk file format
- `mgmt API`
- `pageserver.toml`
Right now they all use the same, which is convenient but makes it hard
to reason about compatibility breakage.
# Refs
- corresponding docs.neon.build PR
https://github.com/neondatabase/docs/pull/470
## Problem
`compaction_l0_first` has already been enabled in production for a
couple of weeks.
## Summary of changes
Enable `compaction_l0_first` by default.
Also set `CompactFlags::NoYield` in `timeline_checkpoint_handler`, to
ensure explicitly requested compaction runs to completion. This endpoint
is mainly used in tests, and caused some flakiness where tests expected
compaction to complete.
## Problem
close https://github.com/neondatabase/neon/issues/10310
## Summary of changes
This patch adds a new behavior for the detach_ancestor API: detach with
multi-level ancestor and no reparenting. Though we can potentially
support multi-level + do reparenting / single-level + no-reparenting in
the future, as it's not required for the recovery/snapshot epic, I'd
prefer keeping things simple now that we only handle the old one and the
new one instead of supporting the full feature matrix.
I only added a test case of successful detaching instead of testing
failures. I'd like to make this into staging and add more tests in the
future.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
This field was retained for backward compat only in
https://github.com/neondatabase/neon/pull/10707.
Once https://github.com/neondatabase/cloud/pull/25233 is released,
nothing external will be reading this field.
Internally, this was a mandatory field so storage controller is still
trying to decode it, so we must do this removal in two steps: this PR
makes the field optional, and after one release we can fully remove it.
Related: https://github.com/neondatabase/cloud/issues/24250
## Summary of changes
- Rename field to `_unused`
- Remove field from swagger
- Make field optional
## Problem
In #11122, we want to split shards once the logical size of the largest
timeline exceeds a split threshold. However, `get_top_tenants` currently
only returns `max_logical_size`, which tracks the max _total_ logical
size of a timeline across all shards.
This is problematic, because the storage controller needs to fetch a
list of N tenants that are eligible for splits, but the API doesn't
currently have a way to express this. For example, with a split
threshold of 1 GB, a tenant with `max_logical_size` of 4 GB is eligible
to split if it has 1 or 2 shards, but not if it already has 4 shards. We
need to express this in per-shard terms, otherwise the `get_top_tenants`
endpoint may end up only returning tenants that can't be split, blocking
splits entirely.
Touches https://github.com/neondatabase/neon/pull/11122.
Touches https://github.com/neondatabase/cloud/issues/22532.
## Summary of changes
Add `TenantShardItem::max_logical_size_per_shard` containing
`max_logical_size / shard_count`, and
`TenantSorting::MaxLogicalSizePerShard` to order and filter by it.
# Refs
- fixes https://github.com/neondatabase/neon/issues/6107
# Problem
`VirtualFile` currently parses the path it is opened with to identify
the `tenant,shard,timeline` labels to be used for the `STORAGE_IO_SIZE`
metric.
Further, for each read or write call to VirtualFile, it uses
`with_label_values` to retrieve the correct metrics object, which under
the hood is a global hashmap guarded by a parking_lot mutex.
We perform tens of thousands of reads and writes per second on every
pageserver instance; thus, doing the mutex lock + hashmap lookup is
wasteful.
# Changes
Apply the technique we use for all other timeline-scoped metrics to
avoid the repeat `with_label_values`: add it to `TimelineMetrics`.
Wrap `TimelineMetrics` into an `Arc`.
Propagate the `Arc<TimelineMetrics>` down do `VirtualFile`, and use
`Timeline::metrics::storage_io_size`.
To avoid contention on the `Arc<TimelineMetrics>`'s refcount atomics
between different connection handlers for the same timeline, we wrap it
into another Arc.
To avoid frequent allocations, we store that Arc<Arc<TimelineMetrics>>
inside the per-connection timeline cache.
Preliminary refactorings to enable this change:
- https://github.com/neondatabase/neon/pull/11001
- https://github.com/neondatabase/neon/pull/11030
# Performance
I ran the benchmarks in
`test_runner/performance/pageserver/pagebench/test_pageserver_max_throughput_getpage_at_latest_lsn.py`
on an `i3en.3xlarge` because that's what we currently run them on.
None of the benchmarks shows a meaningful difference in latency or
throughput or CPU utilization.
I would have expected some improvement in the
many-tenants-one-client-each workload because they all hit that hashmap
constantly, and clone the same `UintCounter` / `Arc` inside of it.
But apparently the overhead is miniscule compared to the remaining work
we do per getpage.
Yet, since the changes are already made, the added complexity is
manageable, and the perf overhead of `with_label_values` demonstrable in
micro-benchmarks, let's have this change anyway.
Also, propagating TimelineMetrics through RequestContext might come in
handy down the line.
The micro-benchmark that demonstrates perf impact of
`with_label_values`, along with other pitfalls and mitigation techniques
around the `metrics`/`prometheus` crate:
- https://github.com/neondatabase/neon/pull/11019
# Alternative Designs
An earlier iteration of this PR stored an `Arc<Arc<Timeline>>` inside
`RequestContext`.
The problem is that this risks reference cycles if the RequestContext
gets stored in an object that is owned directly or indirectly by
`Timeline`.
Ideally, we wouldn't be using this mess of Arc's at all and propagate
Rust references instead.
But tokio requires tasks to be `'static`, and so, we wouldn't be able to
propagate references across task boundaries, which is incompatible with
any sort of fan-out code we already have (e.g. concurrent IO) or future
code (parallel compaction).
So, opt for Arc for now.
## Problem
As part of the disaster recovery tool. Partly for
https://github.com/neondatabase/neon/issues/9114.
## Summary of changes
* Add a new pageserver API to force patch the fields in index_part and
modify the timeline internal structures.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
part of https://github.com/neondatabase/neon/issues/9516
## Summary of changes
Similar to the aux v2 migration, we persist the relv2 migration status
into index_part, so that even the config item is set to false, we will
still read from the v2 storage to avoid loss of data.
Note that only the two variants `None` and
`Some(RelSizeMigration::Migrating)` are used for now. We don't have full
migration implemented so it will never be set to
`RelSizeMigration::Migrated`.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
We intend for cplane to use the heatmap layer download API to warm up
timelines after unarchival. It's tricky for them to recurse in the
ancestors,
and the current implementation doesn't work well when unarchiving a
chain
of branches and warming them up.
## Summary of changes
* Add a `recurse` flag to the API. When the flag is set, the operation
recurses into the parent
timeline after the current one is done.
* Be resilient to warming up a chain of unarchived branches. Let's say
we unarchived `B` and `C` from
the `A -> B -> C` branch hierarchy. `B` got unarchived first. We
generated the unarchival heatmaps
and stash them in `A` and `B`. When `C` unarchived, it dropped it's
unarchival heatmap since `A` and `B`
already had one. If `C` needed layers from `A` and `B`, it was out of
luck. Now, when choosing whether
to keep an unarchival heatmap we look at its end LSN. If it's more
inclusive than what we currently have,
keep it.
Updates storage components to edition 2024. We like to stay on the
latest edition if possible. There is no functional changes, however some
code changes had to be done to accommodate the edition's breaking
changes.
The PR has two commits:
* the first commit updates storage crates to edition 2024 and appeases
`cargo clippy` by changing code. i have accidentially ran the formatter
on some files that had other edits.
* the second commit performs a `cargo fmt`
I would recommend a closer review of the first commit and a less close
review of the second one (as it just runs `cargo fmt`).
part of https://github.com/neondatabase/neon/issues/10918
## Problem
part of https://github.com/neondatabase/neon/issues/9114
## Summary of changes
Add the auto trigger for gc-compaction. It computes two values: L1 size
and L2 size. When L1 size >= initial trigger threshold, we will trigger
an initial gc-compaction. When l1_size / l2_size >=
gc_compaction_ratio_percent, we will trigger the "tiered" gc-compaction.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Read errors during repartition should be a critical error.
## Summary of changes
<del>We only have one call site</del> We have two call sites of
`repartition` where one of them is during the initial image upload
optimization and another is during image layer creation, so I added a
`critical!` here instead of inside `collect_keyspace`.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
The usual workflow for me to debug read path errors in staging is:
download the tenant to my laptop, import, and then run some read tests.
With this patch, we can do this directly over staging pageservers.
## Summary of changes
* Add a new `touchpagelsn` API that does a page read but does not return
page info back.
* Allow read from latest record LSN from get/touchpagelsn
* Add read_debug config in the context.
* The read path will read the context config to decide whether to enable
read path tracing or not.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
We lack an API for warming up attached locations based on the heatmap
contents.
This is problematic in two places:
1. If we manually migrate and cut over while the secondary is still cold
2. When we re-attach a previously offloaded tenant
## Summary of changes
https://github.com/neondatabase/neon/pull/10597 made heatmap generation
additive
across migrations, so we won't clobber it a after a cold migration. This
allows us to implement:
1. An endpoint for downloading all missing heatmap layers on the
pageserver:
`/v1/tenant/:tenant_shard_id/timeline/:timeline_id/download_heatmap_layers`.
Only one such operation per timeline is allowed at any given time. The
granularity is tenant shard.
2. An endpoint to the storage controller to trigger the downloads on the
pageserver:
`/v1/tenant/:tenant_shard_id/timeline/:timeline_id/download_heatmap_layers`.
This works both at
tenant and tenant shard level. If an unsharded tenant id is provided,
the operation is started on
all shards, otherwise only the specified shard.
3. A storcon cli command. Again, tenant and tenant-shard level
granularities are supported.
Cplane will call into storcon and trigger the downloads for all shards.
When we want to rescue a migration, we will use storcon cli targeting
the specific tenant shard.
Related: https://github.com/neondatabase/neon/issues/10541
## Problem
We expose `latest_gc_cutoff` in our API, and callers understandably were
using that to validate LSNs for branch creation. However, this is _not_
the true GC cutoff from a user's point of view: it's just the point at
which we last actually did GC. The actual cutoff used when validating
branch creations and page_service reads is the min() of latest_gc_cutoff
and the planned GC lsn in GcInfo.
Closes: https://github.com/neondatabase/neon/issues/10639
## Summary of changes
- Expose the more useful min() of GC cutoffs as `gc_cutoff_lsn` in the
API, so that the most obviously named field is really the one people
should use.
- Retain the ability to read the LSN at which GC was actually done, in
an `applied_gc_cutoff_lsn` field.
- Internally rename `latest_gc_cutoff_lsn` to `applied_gc_cutoff_lsn`
("latest" was a confusing name, as the value in GcInfo is more up to
date in terms of what a user experiences)
- Temporarily preserve the old `latest_gc_cutoff_lsn` field for compat
with control plane until we update it to use the new field.
---------
Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
## Problem
L0 compaction frequently gets starved out by other background tasks and
image/GC compaction. L0 compaction must be responsive to keep read
amplification under control.
Touches #10694.
Resolves#10689.
## Summary of changes
Use a separate semaphore for the L0-only compaction pass.
* Add a `CONCURRENT_L0_COMPACTION_TASKS` semaphore and
`BackgroundLoopKind::L0Compaction`.
* Add a setting `compaction_l0_semaphore` (default off via
`compaction_l0_first`).
* Use the L0 semaphore when doing an `OnlyL0Compaction` pass.
* Use the background semaphore when doing a regular compaction pass
(which includes an initial L0 pass).
* While waiting for the background semaphore, yield for L0 compaction if
triggered.
* Add `CompactFlags::NoYield` to disable L0 yielding, and set it for the
HTTP API route.
* Remove the old `use_compaction_semaphore` setting and
compaction-scoped semaphore.
* Remove the warning when waiting for a semaphore; it's noisy and we
have metrics.
Avoids compiling the crate and its dependencies into binaries that don't
need them. Shrinks the compute_ctl binary from about 31MB to 28MB in the
release-line-debug-size-lto profile.
## Problem
When a client dropped before a request completed, and a handler returned
an ApiError, we would log that at error severity. That was excessive in
the case of a request erroring on a shutdown, and could cause test
flakes.
example:
https://neon-github-public-dev.s3.amazonaws.com/reports/main/13067651123/index.html#suites/ad9c266207b45eafe19909d1020dd987/6021ce86a0d72ae7/
```
Cancelled request finished with an error: ShuttingDown
```
## Summary of changes
- Log a different info-level on ShuttingDown and ResourceUnavailable API
errors from cancelled requests
## Problem
Timeline bootstrap starts a flush loop, but doesn't reliably shut down
the timeline (incl. waiting for flush loop to exit) before destroying
UninitializedTimeline, and that destructor tries to clean up local
storage. If local storage is still being written to, then this is
unsound.
Currently the symptom is that we see a "Directory not empty" error log,
e.g.
https://neon-github-public-dev.s3.amazonaws.com/reports/main/12966756686/index.html#testresult/5523f7d15f46f7f7/retries
## Summary of changes
- Move fallible IO part of bootstrap into a function (notably, this is
fallible in the case of the tenant being shut down while creation is
happening)
- When that function returns an error, call shutdown() on the timeline
## Problem
Follow-up of the incident, we should not use the same bound on
lower/upper limit of compaction files. This patch adds an upper bound
limit, which is set to 50 for now.
## Summary of changes
Add `compaction_upper_limit`.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Christian Schwarz <christian@neon.tech>
