part of https://github.com/neondatabase/neon/issues/7462
## Summary of changes
This pull request adds two APIs to the pageserver management API:
list_aux_files and ingest_aux_files. The aux file pagebench is intended
to be used on an empty timeline because the data do not go through the
safekeeper. LSNs are advanced by 8 for each ingestion, to avoid
invariant checks inside the pageserver.
For now, I only care about space amplification / read amplification, so
the bench is designed in a very simple way: ingest 10000 files, and I
will manually dump the layer map to analyze.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Part of https://github.com/neondatabase/neon/issues/7462
## Summary of changes
Tenant config is not persisted unless it's attached on the storage
controller. In this pull request, we persist the aux file policy flag in
the `index_part.json`.
Admins can set `switch_aux_file_policy` in the storage controller or
using the page server API. Upon the first aux file gets written, the
write path will compare the aux file policy target with the current
policy. If it is switch-able, we will do the switch. Otherwise, the
original policy will be used. The test cases show what the admins can do
/ cannot do.
The `last_aux_file_policy` is stored in `IndexPart`. Updates to the
persisted policy are done via
`schedule_index_upload_for_aux_file_policy_update`. On the write path,
the writer will update the field.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
## Problem
Currently tenants are only split into multiple shards if a human being
calls the API to do it.
Issue: #7388
## Summary of changes
- Add a pageserver API for returning the top tenants by size
- Add a step to the controller's background loop where if there is no
reconciliation or optimization to be done, it looks for things to split.
- Add a test that runs pgbench on many tenants concurrently, and checks
that splitting happens as expected as tenants grow, without interrupting
the client I/O.
This PR is quite basic: there is a tasklist in
https://github.com/neondatabase/neon/issues/7388 for further work. This
PR is meant to be safe (off by default), and sufficient to enable our
staging environment to run lots of sharded tenants without a human
having to set them up.
## Problem
This is historical baggage from when the pageserver could be run with
local disk only: we had a bunch of places where we had to treat remote
storage as optional.
Closes: https://github.com/neondatabase/neon/issues/6890
## Changes
- Remove Option<> around remote storage (in
https://github.com/neondatabase/neon/pull/7722 we made remote storage
clearly mandatory)
- Remove code for deleting old metadata files: they're all gone now.
- Remove other references to metadata files when loading directories, as
none exist.
I checked last 14 days of logs for "found legacy metadata", there are no
instances.
## Problem
In https://github.com/neondatabase/neon/pull/7531, I had a test flaky
because the GC API endpoint fails if the tenant happens not to be active
yet.
## Summary of changes
While adding that wait for the tenant to be active, I noticed that this
endpoint is kind of strange (spawns a TaskManager task) and has a
comment `// TODO: spawning is redundant now, need to hold the gate`, so
this PR cleans it up to just run the GC inline while holding a gate.
The GC code is updated to avoid assuming it runs inside a task manager
task. Avoiding checking the task_mgr cancellation token is safe, because
our timeline shutdown always cancels Timeline::cancel.
We had accidentally left two endpoints for `tenant`: `/synthetic_size`
and `/size`. Size had the more extensive description but has returned
404 since renaming. Remove the `/size` in favor of the working one and
describe the `text/html` output.
- Rename "filename" types which no longer map directly to a filename
(LayerFileName -> LayerName)
- Add a -v1- part to local layer paths to smooth the path to future
updates (we anticipate a -v2- that uses checksums later)
- Rename methods that refer to the string-ized version of a LayerName to
no longer be called "filename"
- Refactor reconcile() function to use a LocalLayerFileMetadata type
that includes the local path, rather than carrying local path separately
in a tuple and unwrap()'ing it later.
## Problem
In https://github.com/neondatabase/neon/pull/7531, we would like to be
able to rewrite layers safely. One option is to make `Layer` able to
rewrite files in place safely (e.g. by blocking evictions/deletions for
an old Layer while a new one is created), but that's relatively fragile.
It's more robust in general if we simply never overwrite the same local
file: we can do that by putting the generation number in the filename.
## Summary of changes
- Add `local_layer_path` (counterpart to `remote_layer_path`) and
convert all locations that manually constructed a local layer path by
joining LayerFileName to timeline path
- In the layer upload path, construct remote paths with
`remote_layer_path` rather than trying to build them out of a local
path.
- During startup, carry the full path to layer files through
`init::reconcile`, and pass it into `Layer::for_resident`
- Add a test to make sure we handle upgrades properly.
- Comment out the generation part of `local_layer_path`, since we need
to maintain forward compatibility for one release. A tiny followup PR
will enable it afterwards.
We could make this a bit simpler if we bulk renamed existing layers on
startup instead of carrying literal paths through init, but that is
operationally risky on existing servers with millions of layer files. We
can always do a renaming change in future if it becomes annoying, but
for the moment it's kind of nice to have a structure that enables us to
change local path names again in future quite easily.
We should rename `LayerFileName` to `LayerName` or somesuch, to make it
more obvious that it's not a literal filename: this was already a bit
confusing where that type is used in remote paths. That will be a
followup, to avoid polluting this PR's diff.
## Problem
Timelines cannot be deleted if they have children. In many production
cases, a branch or a timeline has been created off the main branch for
various reasons to the effect of having now a "new main" branch. This
feature will make it possible to detach a timeline from its ancestor by
inheriting all of the data before the branchpoint to the detached
timeline and by also reparenting all of the ancestor's earlier branches
to the detached timeline.
## Summary of changes
- Earlier added copy_lsn_prefix functionality is used
- RemoteTimelineClient learns to adopt layers by copying them from
another timeline
- LayerManager adds support for adding adopted layers
-
`timeline::Timeline::{prepare_to_detach,complete_detaching}_from_ancestor`
and `timeline::detach_ancestor` are added
- HTTP PUT handler
Cc: #6994
Co-authored-by: Christian Schwarz <christian@neon.tech>
## Problem
The logic in Service::optimize_all would sometimes choose to migrate a
tenant to a secondary location that was only recently created, resulting
in Reconciler::live_migrate hitting its 5 minute timeout warming up the
location, and proceeding to attach a tenant to a location that doesn't
have a warm enough local set of layer files for good performance.
Closes: #7532
## Summary of changes
- Add a pageserver API for checking download progress of a secondary
location
- During `optimize_all`, connect to pageservers of candidate
optimization secondary locations, and check they are warm.
- During shard split, do heatmap uploads and start secondary downloads,
so that the new shards' secondary locations start downloading ASAP,
rather than waiting minutes for background downloads to kick in.
I have intentionally not implemented this by continuously reading the
status of locations, to avoid dealing with the scale challenge of
efficiently polling & updating 10k-100k locations status. If we
implement that in the future, then this code can be simplified to act
based on latest state of a location rather than fetching it inline
during optimize_all.
extracted (and tested) from
https://github.com/neondatabase/neon/pull/7468, part of
https://github.com/neondatabase/neon/issues/7462.
The current codebase assumes the keyspace is dense -- which means that
if we have a keyspace of 0x00-0x100, we assume every key (e.g., 0x00,
0x01, 0x02, ...) exists in the storage engine. However, the assumption
does not hold any more in metadata keyspace. The metadata keyspace is
sparse. It is impossible to do per-key check.
Ideally, we should not have the assumption of dense keyspace at all, but
this would incur a lot of refactors. Therefore, we split the keyspaces
we have to dense/sparse and handle them differently in the code for now.
At some point in the future, we should assume all keyspaces are sparse.
## Summary of changes
* Split collect_keyspace to return dense+sparse keyspace.
* Do not allow generating image layers for sparse keyspace (for now --
will fix this next week, we need image layers anyways).
* Generate delta layers for sparse keyspace.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Sometimes we have test data in the form of S3 contents that we would
like to run live in a neon_local environment.
## Summary of changes
- Add a storage controller API that imports an existing tenant.
Currently this is equivalent to doing a create with a high generation
number, but in future this would be something smarter to probe S3 to
find the shards in a tenant and find generation numbers.
- Add a `neon_local` command that invokes the import API, and then
inspects timelines in the newly attached tenant to create matching
branches.
As part of https://github.com/neondatabase/neon/pull/7375 and to improve
the current vectored get implementation, we separate the missing key
error out. This also saves us several Box allocations in the get page
implementation.
## Summary of changes
* Create a caching field of layer traversal id for each of the layer.
* Remove box allocations for layer traversal id retrieval and implement
MissingKey error message as before. This should be a little bit faster.
* Do not format error message until `Display`.
* For in-mem layer, the descriptor is different before/after frozen. I'm
using once lock for that.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
We specify a bunch of possible error codes in the pageserver api swagger
spec. This is error prone and annoying to work with.
https://github.com/neondatabase/cloud/pull/11907 introduced generic
error handling on the control plane side, so we can now clean up the
spec.
## Summary of changes
* Remove generic error codes from swagger spec
* Update a couple route handlers which would previously return an error
without a `msg` field in the response body.
Tested via https://github.com/neondatabase/cloud/pull/12340
Related https://github.com/neondatabase/cloud/issues/7238
No functional changes, this is a comments/naming PR.
While merging sharding changes, some cleanup of the shard.rs types was
deferred.
In this PR:
- Rename `is_zero` to `is_shard_zero` to make clear that this method
doesn't literally mean that the entire object is zeros, just that it
refers to the 0th shard in a tenant.
- Pull definitions of types to the top of shard.rs and add a big comment
giving an overview of which type is for what.
Closes: https://github.com/neondatabase/neon/issues/6072
We can currently underflow `pageserver_resident_physical_size_global`,
so the used disk bytes would show `u63::MAX` by mistake. The assumption
of the API (and the documented behavior) was to give the layer files
disk usage.
Switch to reporting numbers that match `df` output.
Fixes: #7336
## Problem
(Follows https://github.com/neondatabase/neon/pull/7237)
Some API users will query a tenant to wait for it to activate.
Currently, we return the current status of the tenant, whatever that may
be. Under heavy load, a pageserver starting up might take a long time to
activate such a tenant.
## Summary of changes
- In `tenant_status` handler, call wait_to_become_active on the tenant.
If the tenant is currently waiting for activation, this causes it to
skip the queue, similiar to other API handlers that require an active
tenant, like timeline creation. This avoids external services waiting a
long time for activation when polling GET /v1/tenant/<id>.
## Problem
This is a refactor.
This PR was a precursor to a much smaller change
e5bd602dc1,
where as I was writing it I found that we were not far from getting rid
of the last non-deprecated code paths that use `mgr::` scoped functions
to get at the TenantManager state.
We're almost done cleaning this up as per
https://github.com/neondatabase/neon/issues/5796. The only significant
remaining mgr:: item is `get_active_tenant_with_timeout`, which is
page_service's path for fetching tenants.
## Summary of changes
- Remove the bool argument to get_attached_tenant_shard: this was almost
always false from API use cases, and in cases when it was true, it was
readily replacable with an explicit check of the returned tenant's
status.
- Rather than letting the timeline eviction task query any tenant it
likes via `mgr::`, pass an `Arc<Tenant>` into the task. This is still an
ugly circular reference, but should eventually go away: either when we
switch to exclusively using disk usage eviction, or when we change
metadata storage to avoid the need to imitate layer accesses.
- Convert all the mgr::get_tenant call sites to use
TenantManager::get_attached_tenant_shard
- Move list_tenants into TenantManager.
## Problem
Currently, we return 409 (Conflict) in two cases:
- Temporary: Timeline creation cannot proceed because another timeline
with the same ID is being created
- Permanent: Timeline creation cannot proceed because another timeline
exists with different parameters but the same ID.
Callers which time out a request and retry should be able to distinguish
these cases.
Closes: #7208
## Summary of changes
- Expose `AlreadyCreating` errors as 429 instead of 409
## Problem
Storage controller had basically no metrics.
## Summary of changes
1. Migrate the existing metrics to use Conrad's
[`measured`](https://docs.rs/measured/0.0.14/measured/) crate.
2. Add metrics for incoming http requests
3. Add metrics for outgoing http requests to the pageserver
4. Add metrics for outgoing pass through requests to the pageserver
5. Add metrics for database queries
Note that the metrics response for the attachment service does not use
chunked encoding like the rest of the metrics endpoints. Conrad has
kindly extended the crate such that it can now be done. Let's leave it
for a follow-up since the payload shouldn't be that big at this point.
Fixes https://github.com/neondatabase/neon/issues/6875
with `immediate_gc` the span only covered the `gc_iteration`, make it
cover the whole needless spawned task, which also does waiting for layer
drops and stray logging in tests.
also clarify some comments while we are here.
Fixes: #6910
## Problem
Followup to https://github.com/neondatabase/neon/pull/6725
In that PR, code for purging local files from a tenant shard was
duplicated.
## Summary of changes
- Refactor detach code into TenantManager
- `spawn_background_purge` method can now be common between detach and
split operations
## Problem
The existing secondary download API relied on the caller to wait as long
as it took to complete -- for large shards that could be a long time, so
typical clients that might have a baked-in ~30s timeout would have a
problem.
## Summary of changes
- Take a `wait_ms` query parameter to instruct the pageserver how long
to wait: if the download isn't complete in this duration, then 201 is
returned instead of 200.
- For both 200 and 201 responses, include response body describing
download progress, in terms of layers and bytes. This is sufficient for
the caller to track how much data is being transferred and log/present
that status.
- In storage controller live migrations, use this API to apply a much
longer outer timeout, with smaller individual per-request timeouts, and
log the progress of the downloads.
- Add a test that injects layer download delays to exercise the new
behavior
Switched the order; doing https://github.com/neondatabase/neon/pull/6139
first then can remove uninit marker after.
## Problem
Previously, existence of a timeline directory was treated as evidence of
the timeline's logical existence. That is no longer the case since we
treat remote storage as the source of truth on each startup: we can
therefore do without this mark file.
The mark file had also been used as a pseudo-lock to guard against
concurrent creations of the same TimelineId -- now that persistence is
no longer required, this is a bit unwieldy.
In #6139 the `Tenant::timelines_creating` was added to protect against
concurrent creations on the same TimelineId, making the uninit mark file
entirely redundant.
## Summary of changes
- Code that writes & reads mark file is removed
- Some nearby `pub` definitions are amended to `pub(crate)`
- `test_duplicate_creation` is added to demonstrate that mutual
exclusion of creations still works.
## Problem
If a pageserver was offline when the storage controller started, there
was no mechanism to update the
storage controller state when the pageserver becomes active.
## Summary of changes
* Add a heartbeater module. The heartbeater must be driven by an
external loop.
* Integrate the heartbeater into the service.
- Extend the types used by the service and scheduler to keep track of a
nodes' utilisation score.
- Add a background loop to drive the heartbeater and update the state
based on the deltas it generated
- Do an initial round of heartbeats at start-up
## Problem
Shard splits worked, but weren't safe against failures (e.g. node crash
during split) yet.
Related: #6676
## Summary of changes
- Introduce async rwlocks at the scope of Tenant and Node:
- exclusive tenant lock is used to protect splits
- exclusive node lock is used to protect new reconciliation process that
happens when setting node active
- exclusive locks used in both cases when doing persistent updates (e.g.
node scheduling conf) where the update to DB & in-memory state needs to
be atomic.
- Add failpoints to shard splitting in control plane and pageserver
code.
- Implement error handling in control plane for shard splits: this
detaches child chards and ensures parent shards are re-attached.
- Crash-safety for storage controller restarts requires little effort:
we already reconcile with nodes over a storage controller restart, so as
long as we reset any incomplete splits in the DB on restart (added in
this PR), things are implicitly cleaned up.
- Implement reconciliation with offline nodes before they transition to
active:
- (in this context reconciliation means something like
startup_reconcile, not literally the Reconciler)
- This covers cases where split abort cannot reach a node to clean it
up: the cleanup will eventually happen when the node is marked active,
as part of reconciliation.
- This also covers the case where a node was unavailable when the
storage controller started, but becomes available later: previously this
allowed it to skip the startup reconcile.
- Storage controller now terminates on panics. We only use panics for
true "should never happen" assertions, and these cases can leave us in
an un-usable state if we keep running (e.g. panicking in a shard split).
In the unlikely event that we get into a crashloop as a result, we'll
rely on kubernetes to back us off.
- Add `test_sharding_split_failures` which exercises a variety of
failure cases during shard split.
The `tenant_id` in `TenantLocationConfigRequest` in the
`location_config` endpoint was only used in the storage
controller/attachment service, and there it was only used for assertions
and the creation part.
## Summary
- Currently we can set stripe size at tenant creation, but it doesn't
mean anything until we have multiple shards
- When onboarding an existing tenant, it will always get a default shard
stripe size, so we would like to be able to pick the actual stripe size
at the point we split.
## Why do this inline with a split?
The alternative to this change would be to have a separate endpoint on
the storage controller for setting the stripe size on a tenant, and only
permit writes to that endpoint when the tenant has only a single shard.
That would work, but be a little bit more work for a client, and not
appreciably simpler (instead of having a special argument to the split
functions, we'd have a special separate endpoint, and a requirement that
the controller must sync its config down to the pageserver before
calling the split API). Either approach would work, but this one feels a
bit more robust end-to-end: the split API is the _very last moment_ that
the stripe size is mutable, so if we aim to set it before splitting, it
makes sense to do it as part of the same operation.
## Problem
Closes: https://github.com/neondatabase/neon/issues/6847
Closes: https://github.com/neondatabase/neon/issues/7006
## Summary of changes
- Pageserver API calls are wrapped in timeout/retry logic: this prevents
a reconciler getting hung on a pageserver API hang, and prevents
reconcilers having to totally retry if one API call returns a retryable
error (e.g. 503).
- Add a cancellation token to `Node`, so that when we mark a node
offline we will cancel any API calls in progress to that node, and avoid
issuing any more API calls to that offline node.
- If the dirty locations of a shard are all on offline nodes, then don't
spawn a reconciler
- In re-attach, if we have no observed state object for a tenant then
construct one with conf: None (which means "unknown"). Then in
Reconciler, implement a TODO for scanning such locations before running,
so that we will avoid spuriously incrementing a generation in the case
of a node that was offline while we started (this is the case that
tripped up #7006)
- Refactoring: make Node contents private (and thereby guarantee that
updates to availability mode reliably update the cancellation token.)
- Refactoring: don't pass the whole map of nodes into Reconciler (and
thereby remove a bunch of .expect() calls)
Some of this was discovered/tested with a new failure injection test
that will come in a separate PR, once it is stable enough for CI.
## Problem
- The storage controller is the source of truth for a tenant's stripe
size, but doesn't currently have a way to propagate that to compute:
we're just using the default stripe size everywhere.
Closes: https://github.com/neondatabase/neon/issues/6903
## Summary of changes
- Include stripe size in `ComputeHookNotifyRequest`
- Include stripe size in `LocationConfigResponse`
The stripe size is optional: it will only be advertised for
multi-sharded tenants. This enables the controller to defer the choice
of stripe size until we split a tenant for the first time.
Add off-by-default support for lazy queued tenant activation on attach.
This should be useful on bulk migrations as some tenants will be
activated faster due to operations or endpoint startup. Eventually all
tenants will get activated by reusing the same mechanism we have at
startup (`PageserverConf::concurrent_tenant_warmup`).
The difference to lazy attached tenants to startup ones is that we leave
their initial logical size calculation be triggered by WalReceiver or
consumption metrics.
Fixes: #6315
Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
## Problem
Callers of the timeline creation API may issue timeline GETs ahead of
creation to e.g. check if their intended timeline already exists, or to
learn the LSN of a parent timeline.
Although the timeline creation API already triggers activation of a
timeline if it's currently waiting to activate, the GET endpoint
doesn't, so such callers will encounter 503 responses for several
minutes after a pageserver restarts, while tenants are lazily warming
up.
The original scope of which APIs will activate a timeline was quite
small, but really it makes sense to do it for any API that needs a
particular timeline to be active.
## Summary of changes
- In the timeline detail GET handler, use wait_to_become_active, which
triggers immediate activation of a tenant if it was currently waiting
for the warmup semaphore, then waits up to 5 seconds for the activation
to complete. If it doesn't complete promptly, we return a 503 as before.
- Modify active_timeline_for_active_tenant to also use
wait_to_become_active, which indirectly makes several other
timeline-scope request handlers fast-activate a tenant when called. This
is important because a timeline creation flow could also use e.g.
get_lsn_for_timestamp as a precursor to creating a timeline.
- There is some risk to this change: an excessive number of timeline GET
requests could cause too many tenant activations to happen at the same
time, leading to excessive queue depth to the S3 client. However, this
was already the case for e.g. many concurrent timeline creations.
fixes https://github.com/neondatabase/neon/issues/6889
# Problem
The failure in the last 3 flaky runs on `main` is
```
test_runner/regress/test_remote_storage.py:460: in test_remote_timeline_client_calls_started_metric
churn("a", "b")
test_runner/regress/test_remote_storage.py:457: in churn
assert gc_result["layers_removed"] > 0
E assert 0 > 0
```
That's this code
cd449d66ea/test_runner/regress/test_remote_storage.py (L448-L460)
So, the test expects GC to remove some layers but the GC doesn't.
# Fix
My impression is that the VACUUM isn't re-using pages aggressively
enough, but I can't really prove that. Tried to analyze the layer map
dump but it's too complex.
So, this PR:
- Creates more churn by doing the overwrite twice.
- Forces image layer creation.
It also drive-by removes the redundant call to timeline_compact,
because, timeline_checkpoint already does that internally.
## Problem
Since the location config API was added, the attach and detach endpoints
are deprecated. Hiding them from consumers of the swagger definition is
a precursor to removing them
Neon's cloud no longer uses this api since
https://github.com/neondatabase/cloud/pull/10538
Fully removing the APIs will implicitly make use of generation numbers
mandatory, and should happen alongside
https://github.com/neondatabase/neon/issues/5388, which will happen once
we're happy that the storage controller is ready for prime time.
## Summary of changes
- Remove /attach and /detach from pageserver's swagger file
PR adds a simple at most 1Hz refreshed informational API for querying
pageserver utilization. In this first phase, no actual background
calculation is performed. Instead, the worst possible score is always
returned. The returned bytes information is however correct.
Cc: #6835
Cc: #5331
Often times the tenants we want to (WAL) DR are the ones which the
pageserver marks as broken. Therefore, we should allow initdb
preservation also for broken tenants.
Fixes#6781.
## Problem
test_sharding_split_unsharded was flaky with log errors from tenants not
being active. This was happening when the split function enters
wait_lsn() while the child shard might still be activating. It's flaky
rather than an outright failure because activation is usually very fast.
This is also a real bug fix, because in realistic scenarios we could
proceed to detach the parent shard before the children are ready,
leading to an availability gap for clients.
## Summary of changes
- Do a short wait_to_become_active on the child shards before proceeding
to wait for their LSNs to advance
---------
Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
## Problem
The ShardCount type has a magic '0' value that represents a legacy
single-sharded tenant, whose TenantShardId is formatted without a
`-0001` suffix (i.e. formatted as a traditional TenantId).
This was error-prone in code locations that wanted the actual number of
shards: they had to handle the 0 case specially.
## Summary of changes
- Make the internal value of ShardCount private, and expose `count()`
and `literal()` getters so that callers have to explicitly say whether
they want the literal value (e.g. for storing in a TenantShardId), or
the actual number of shards in the tenant.
---------
Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
The canonical release artifact of neon.git is the Docker image with all
the binaries in them:
```
docker pull neondatabase/neon:release-4854
docker create --name extract neondatabase/neon:release-4854
docker cp extract:/usr/local/bin/pageserver ./pageserver.release-4854
chmod +x pageserver.release-4854
cp -a pageserver.release-4854 ./target/release/pageserver
```
Before this PR, these artifacts didn't expose the `keyspace` API,
thereby preventing `pagebench get-page-latest-lsn` from working.
Having working pagebench is useful, e.g., for experiments in staging.
So, expose the API, but don't document it, as it's not part of the
interface with control plane.
There is O(n^2) issues due to how we store these directories (#6626), so
it's good to keep an eye on them and ensure the numbers stay low.
The new per-timeline metric `pageserver_directory_entries_count`
isn't perfect, namely we don't calculate it every time we attach
the timeline, but only if there is an actual change.
Also, it is a collective metric over multiple scalars. Lastly,
we only emit the metric if it is above a certain threshold.
However, the metric still give a feel for the general size of the timeline.
We care less for small values as the metric is mainly there to
detect and track tenants with large directory counts.
We also expose the directory counts in `TimelineInfo` so that one can
get the detailed size distribution directly via the pageserver's API.
Related: #6642 , https://github.com/neondatabase/cloud/issues/10273
The smaller changes I found while looking around #6584.
- rustfmt was not able to format handle_timeline_create
- fix Generation::get_suffix always allocating
- Generation was missing a `#[track_caller]` for panicky method
- attach has a lot of issues, but even with this PR it cannot be
formatted by rustfmt
- moved the `preload` span to be on top of `attach` -- it is awaited
inline
- make disconnected panic! or unreachable! into expect, expect_err
## Problem
One doesn't know at tenant creation time how large the tenant will grow.
We need to be able to dynamically adjust the shard count at runtime.
This is implemented as "splitting" of shards into smaller child shards,
which cover a subset of the keyspace that the parent covered.
Refer to RFC: https://github.com/neondatabase/neon/pull/6358
Part of epic: #6278
## Summary of changes
This PR implements the happy path (does not cleanly recover from a crash
mid-split, although won't lose any data), without any optimizations
(e.g. child shards re-download their own copies of layers that the
parent shard already had on local disk)
- Add `/v1/tenant/:tenant_shard_id/shard_split` API to pageserver: this
copies the shard's index to the child shards' paths, instantiates child
`Tenant` object, and tears down parent `Tenant` object.
- Add `splitting` column to `tenant_shards` table. This is written into
an existing migration because we haven't deployed yet, so don't need to
cleanly upgrade.
- Add `/control/v1/tenant/:tenant_id/shard_split` API to
attachment_service,
- Add `test_sharding_split_smoke` test. This covers the happy path:
future PRs will add tests that exercise failure cases.
This PR adds an API to live-reconfigure the VirtualFile io engine.
It also adds a flag to `pagebench get-page-latest-lsn`, which is where I
found this functionality to be useful: it helps compare the io engines
in a benchmark without re-compiling a release build, which took ~50s on
the i3en.3xlarge where I was doing the benchmark.
Switching the IO engine is completely safe at runtime.
I was on-call this week, these would had made me understand more/faster
of the system:
- move stray attaching start logging inside the span it starts, add
generation
- log ancestor timeline_id or bootstrapping in the beginning of timeline
creation
## Problem
The 5 second activation timeout is appropriate for production
environments, where we want to give a prompt response to the cloud
control plane, and if we fail it will retry the call. In tests however,
we don't want every call to e.g. timeline create to have to come with a
retry wrapper.
This issue has always been there, but it is more apparent in sharding
tests that concurrently attach several tenant shards.
Closes: https://github.com/neondatabase/neon/issues/6563
## Summary of changes
When `testing` feature is enabled, make `ACTIVE_TENANT_TIMEOUT` 30
seconds instead of 5 seconds.
