## Problem
After a shard split, the pageserver leaves the ancestor shard's content
in place. It may be referenced by child shards, but eventually child
shards will de-reference most ancestor layers as they write their own
data and do GC. We would like to eventually clean up those ancestor
layers to reclaim space.
## Summary of changes
- Extend the physical GC command with `--mode=full`, which includes
cleaning up unreferenced ancestor shard layers
- Add test `test_scrubber_physical_gc_ancestors`
- Remove colored log output: in testing this is irritating ANSI code
spam in logs, and in interactive use doesn't add much.
- Refactor storage controller API client code out of storcon_client into
a `storage_controller/client` crate
- During physical GC of ancestors, call into the storage controller to
check that the latest shards seen in S3 reflect the latest state of the
tenant, and there is no shard split in progress.
We're removing the usage of this long-meaningless config field in
https://github.com/neondatabase/aws/pull/1599
Once that PR has been deployed to staging and prod, we can merge this
PR.
Successor of #8288 , just enable zstd in tests. Also adds a test that
creates easily compressable data.
Part of #5431
---------
Co-authored-by: John Spray <john@neon.tech>
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
## Problem
Ahead of enabling eviction in the field, where it will become the
normal/default mode, let's enable it by default throughout our tests in
case any issues become visible there.
## Summary of changes
- Make default `extra_opts` for safekeepers enable offload & deletion
- Set low timeouts in `extra_opts` so that tests running for tens of
seconds have a chance to hit some of these background operations.
## Problem
These tests time out ~1 in 50 runs when in debug mode.
There is no indication of a real issue: they're just wrappers that have
large numbers of individual tests contained within on pytest case.
## Summary of changes
- Bump pg_regress timeout from 600 to 900s
- Bump test_isolation timeout from 300s (default) to 600s
In future it would be nice to break out these tests to run individual
cases (or batches thereof) as separate tests, rather than this monolith.
## Problem
This test would occasionally fail its metric check. This could happen in
the rare case that the nodes had all been restarted before their most
recent eviction.
The metric check was added in
https://github.com/neondatabase/neon/pull/8348
## Summary of changes
- Check metrics before each restart, accumulate into a bool that we
assert on at the end of the test
When `NeonEnv.from_repo_dir` was introduced, storage controller stored
its
state exclusively `attachments.json`.
Since then, it has moved to using Postgres, which stores its state in
`storage_controller_db`.
But `NeonEnv.from_repo_dir` wasn't adjusted to do this.
This PR rectifies the situation.
Context for this is failures in
`test_pageserver_characterize_throughput_with_n_tenants`
CF:
https://neondb.slack.com/archives/C033RQ5SPDH/p1721035799502239?thread_ts=1720901332.293769&cid=C033RQ5SPDH
Notably, `from_repo_dir` is also used by the backwards- and
forwards-compatibility.
Thus, the changes in this PR affect those tests as well.
However, it turns out that the compatibility snapshot already contains
the `storage_controller_db`.
Thus, it should just work and in fact we can remove hacks like
`fixup_storage_controller`.
Follow-ups created as part of this work:
* https://github.com/neondatabase/neon/issues/8399
* https://github.com/neondatabase/neon/issues/8400
## Problem
We lack insight into:
- How much of a tenant's physical size is image vs. delta layers
- Average sizes of image vs. delta layers
- Total layer counts per timeline, indicating size of index_part object
As well as general observability love, this is motivated by
https://github.com/neondatabase/neon/issues/6738, where we need to
define some sensible thresholds for storage amplification, and using
total physical size may not work well (if someone does a lot of DROPs
then it's legitimate for the physical-synthetic ratio to be huge), but
the ratio between image layer size and delta layer size may be a better
indicator of whether we're generating unreasonable quantities of image
layers.
## Summary of changes
- Add pageserver_layer_bytes and pageserver_layer_count metrics,
labelled by timeline and `kind` (delta or image)
- Add & subtract these with LayerInner's lifetime.
I'm intentionally avoiding using a generic metric RAII guard object, to
avoid bloating LayerInner: it already has all the information it needs
to update metric on new+drop.
This test reproduces the case of a writer creating a deep stack of L0
layers. It uses realistic layer sizes and writes several gigabytes of
data, therefore runs as a performance test although it is validating
memory footprint rather than performance per se.
It acts a regression test for two recent fixes:
- https://github.com/neondatabase/neon/pull/8401
- https://github.com/neondatabase/neon/pull/8391
In future it will demonstrate the larger improvement of using a k-merge
iterator for L0 compaction (#8184)
This test can be extended to enforce limits on the memory consumption of
other housekeeping steps, by restarting the pageserver and then running
other things to do the same "how much did RSS increase" measurement.
## Problem
The `evictions_with_low_residence_duration` is used as an indicator of
cache thrashing. However, there are situations where it is quite
legitimate to only have a short residence during compaction, where a
delta is downloaded, used to generate an image layer, and then
discarded. This can lead to false positive alerts.
## Summary of changes
- Only track low residence duration for layers that have been accessed
at least once (compaction doesn't count as an access). This will give us
a metric that indicates thrashing on layers that the _user_ is using,
rather than those we're downloading for housekeeping purposes.
Once we add "layer visibility" as an explicit property of layers, this
can also be used as a cleaner condition (residence of non-visible layers
should never be alertable)
As described in #8385, the likely source for flakiness in
test_tenant_creation_fails is the following sequence of events:
1. test instructs the storage controller to create the tenant
2. storage controller adds the tenant and persists it to the database.
issues a creation request
3. the pageserver restarts with the failpoint disabled
4. storage controller's background reconciliation still wants to create
the tenant
5. pageserver gets new request to create the tenant from background
reconciliation
This commit just avoids the storage controller entirely. It has its own
set of issues, as the re-attach request will obviously not include the
tenant, but it's still useful to test for non-existence of the tenant.
The generation is also not optional any more during tenant attachment.
If you omit it, the pageserver yields an error. We change the signature
of `tenant_attach` to reflect that.
Alternative to #8385Fixes#8266
Right now timeline detach ancestor reports an error (409, "no ancestor")
on a new attempt after successful completion. This makes it troublesome
for storage controller retries. Fix it to respond with `200 OK` as if
the operation had just completed quickly.
Additionally, the returned timeline identifiers in the 200 OK response
are now ordered so that responses between different nodes for error
comparison are done by the storage controller added in #8353.
Design-wise, this PR introduces a new strategy for accessing the latest
uploaded IndexPart:
`RemoteTimelineClient::initialized_upload_queue(&self) ->
Result<UploadQueueAccessor<'_>, NotInitialized>`. It should be a more
scalable way to query the latest uploaded `IndexPart` than to add a
query method for each question directly on `RemoteTimelineClient`.
GC blocking will need to be introduced to make the operation fully
idempotent. However, it is idempotent for the cases demonstrated by
tests.
Cc: #6994
## Problem
Pageserver GC uses a size-based condition (GC "horizon" in addition to
time-based "PITR").
Eventually we plan to retire the size-based condition:
https://github.com/neondatabase/neon/issues/6374
Currently, we always apply the more conservative of the two, meaning
that tenants always retain at least 64MB of history (default horizon),
even after a very long time has passed. This is particularly acute in
cases where someone has dropped tables/databases, and then leaves a
database idle: the horizon can prevent GCing very large quantities of
historical data (we already account for this in synthetic size by
ignoring gc horizon).
We're not entirely removing GC horizon right now because we don't want
to 100% rely on standby_horizon for robustness of physical replication,
but we can tweak our logic to avoid retaining that 64MB LSN length
indefinitely.
## Summary of changes
- Rework `Timeline::find_gc_cutoffs`, with new logic:
- If there is no PITR set, then use `DEFAULT_PITR_INTERVAL` (1 week) to
calculate a time threshold. Retain either the horizon or up to that
thresholds, whichever requires less data.
- When there is a PITR set, and we have unambiguously resolved the
timestamp to an LSN, then ignore the GC horizon entirely. For typical
PITRs (1 day, 1 week), this will still easily retain enough data to
avoid stressing read only replicas.
The key property we end up with, whether a PITR is set or not, is that
after enough time has passed, our GC cutoff on an idle timeline will
catch up with the last_record_lsn.
Using `DEFAULT_PITR_INTERVAL` is a bit of an arbitrary hack, but this
feels like it isn't really worth the noise of exposing in TenantConfig.
We could just make it a different named constant though. The end-end
state will be that there is no gc_horizon at all, and that tenants with
pitr_interval=0 would truly retain no history, so this constant would go
away.
Currently storage controller does not support forwarding timeline detach
ancestor requests to pageservers. Add support for forwarding `PUT
.../:tenant_id/timelines/:timeline_id/detach_ancestor`. Implement the
support mostly as is, because the timeline detach ancestor will be made
(mostly) idempotent in future PR.
Cc: #6994
## Problem
Right now if there are too many running xacts to be restored from CLOG
at replica startup,
then replica is not trying to restore them and wait for non-overflown
running-xacs WAL record from primary.
But if primary is not active, then replica will not start at all.
Too many running xacts can be caused by transactions with large number
of subtractions.
But right now it can be also cause by two reasons:
- Lack of shutdown checkpoint which updates `oldestRunningXid` (because
of immediate shutdown)
- nextXid alignment on 1024 boundary (which cause loosing ~1k XIDs on
each restart)
Both problems are somehow addressed now.
But we have existed customers with "sparse" CLOG and lack of
checkpoints.
To be able to start RO replicas for such customers I suggest to add GUC
which allows replica to start even in case of subxacts overflow.
## Summary of changes
Add `neon.running_xacts_overflow_policy` with the following values:
- ignore: restore from CLOG last N XIDs and accept connections
- skip: do not restore any XIDs from CXLOGbut still accept connections
- wait: wait non-overflown running xacts record from primary node
## Checklist before requesting a review
- [ ] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
## Checklist before merging
- [ ] Do not forget to reformat commit message to not include the above
checklist
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
## Problem
This test would sometimes violate the min resident size during disk
eviction and fail due to the generate warning log.
Disk usage candidate collection only takes into account active tenants.
However, the statvfs call takes into account the entire tenants
directory, which includes tenants which haven't become active yet.
After re-starting the pageserver, disk usage eviction may kick in
*before* both tenants have become active. Hence, the logic will try to satisfy
thedisk usage requirements by evicting everything belonging to the active
tenant, and hence violating the tenant minimum resident size.
## Summary of changes
Allow the warning
## Problem
We already back off on compaction retries, but the impact of a failing
compaction can be so great that backing off up to 300s isn't enough. The
impact is consuming a lot of I/O+CPU in the case of image layer
generation for large tenants, and potentially also leaking disk space.
Compaction failures are extremely rare and almost always indicate a bug,
frequently a bug that will not let compaction to proceed until it is
fixed.
Related: https://github.com/neondatabase/neon/issues/6738
## Summary of changes
- Introduce a CircuitBreaker type
- Add a circuit breaker for compaction, with a policy that after 5
failures, compaction will not be attempted again for 24 hours.
- Add metrics that we can alert on: any >0 value for
`pageserver_circuit_breaker_broken_total` should generate an alert.
- Add a test that checks this works as intended.
Couple notes to reviewers:
- Circuit breakers are intrinsically a defense-in-depth measure: this is
not the solution to any underlying issues, it is just a general
mitigation for "unknown unknowns" that might be encountered in future.
- This PR isn't primarily about writing a perfect CircuitBreaker type:
the one in this PR is meant to be just enough to mitigate issues in
compaction, and make it easy to monitor/alert on these failures. We can
refine this type in future as/when we want to use it elsewhere.
## Problem
I need `neon_superuser` to be allowed to create snapshots for
replication tests
## Summary of changes
Adds a migration that grants these functions to neon_superuser
## Problem
In anticipation of later adding a really nice drain+delete API, I
initially only added an intentionally basic `/drop` API that is just
about usable for deleting nodes in a pinch, but requires some ugly
storage controller restarts to persuade it to restart secondaries.
## Summary of changes
I started making a few tiny fixes, and ended up writing the delete
API...
- Quality of life nit: ordering of node + tenant listings in storcon_cli
- Papercut: Fix the attach_hook using the wrong operation type for
reporting slow locks
- Make Service::spawn tolerate `generation_pageserver` columns that
point to nonexistent node IDs. I started out thinking of this as a
general resilience thing, but when implementing the delete API I
realized it was actually a legitimate end state after the delete API is
called (as that API doesn't wait for all reconciles to succeed).
- Add a `DELETE` API for nodes, which does not gracefully drain, but
does reschedule everything. This becomes safe to use when the system is
in any state, but will incur availability gaps for any tenants that
weren't already live-migrated away. If tenants have already been
drained, this becomes a totally clean + safe way to decom a node.
- Add a test and a storcon_cli wrapper for it
This is meant to be a robust initial API that lets us remove nodes
without doing ugly things like restarting the storage controller -- it's
not quite a totally graceful node-draining routine yet. There's more
work in https://github.com/neondatabase/neon/issues/8333 to get to our
end-end state.
## Problem
Follow up to https://github.com/neondatabase/neon/pull/8335, to improve
observability of how many evict/restores we are doing.
## Summary of changes
- Add `safekeeper_eviction_events_started_total` and
`safekeeper_eviction_events_completed_total`, with a "kind" label of
evict or restore. This gives us rates, and also ability to calculate how
many are in progress.
- Generalize SafekeeperMetrics test type to use the same helpers as
pageserver, and enable querying any metric.
- Read the new metrics at the end of the eviction test.
`trace_read_requests` is a per `Tenant`-object option.
But the `handle_pagerequests` loop doesn't know which
`Tenant` object (i.e., which shard) the request is for.
The remaining use of the `Tenant` object is to check `tenant.cancel`.
That check is incorrect [if the pageserver hosts multiple
shards](https://github.com/neondatabase/neon/issues/7427#issuecomment-2220577518).
I'll fix that in a future PR where I completely eliminate the holding
of `Tenant/Timeline` objects across requests.
See [my code RFC](https://github.com/neondatabase/neon/pull/8286) for
the
high level idea.
Note that we can always bring the tracing functionality if we need it.
But since it's actually about logging the `page_service` wire bytes,
it should be a `page_service`-level config option, not per-Tenant.
And for enabling tracing on a single connection, we can implement
a `set pageserver_trace_connection;` option.
## Problem
- The condition for eviction is not time-based: it is possible for a
timeline to be restored in response to a client, that client times out,
and then as soon as the timeline is restored it is immediately evicted
again.
- There is no delay on eviction at startup of the safekeeper, so when it
starts up and sees many idle timelines, it does many evictions which
will likely be immediately restored when someone uses the timeline.
## Summary of changes
- Add `eviction_min_resident` parameter, and use it in
`ready_for_eviction` to avoid evictions if the timeline has been
resident for less than this period.
- This also implicitly delays evictions at startup for
`eviction_min_resident`
- Set this to a very low number for the existing eviction test, which
expects immediate eviction.
The default period is 15 minutes. The general reasoning for that is that
in the worst case where we thrash ~10k timelines on one safekeeper,
downloading 16MB for each one, we should set a period that would not
overwhelm the node's bandwidth.
## Problem
This test incorrectly assumed that a post-split compaction would only
drop content. This was easily destabilized by any changes to image
generation rules.
## Summary of changes
- Before split, do a full image layer generation pass, to guarantee that
post-split compaction should only drop data, never create it.
- Fix the force_image_layer_creation mode of compaction that we use from
tests like this: previously it would try and generate image layers even
if one already existed with the same layer key, which caused compaction
to fail.
I want to fix bugs in `page_service`
([issue](https://github.com/neondatabase/neon/issues/7427)) and the
`import basebackup` / `import wal` stand in the way / make the
refactoring more complicated.
We don't use these methods anyway in practice, but, there have been some
objections to removing the functionality completely.
So, this PR preserves the existing functionality but moves it into the
HTTP management API.
Note that I don't try to fix existing bugs in the code, specifically not
fixing
* it only ever worked correctly for unsharded tenants
* it doesn't clean up on error
All errors are mapped to `ApiError::InternalServerError`.
## Summary of changes
Increase the `assert_size_approx_equal` threshold to avoid flakiness of
`test_lsn_lease_size`. Still needs more investigation to fully resolve
#8293.
- Also set `autovacuum=off` for the endpoint we are running in the test.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
## Problem
`test_timeline_size_quota_on_startup` assumed that writing data beyond
the size limit would always be blocked. This is not so: the limit is
only enforced if feedback makes it back from the pageserver to the
safekeeper + compute.
Closes: https://github.com/neondatabase/neon/issues/6562
## Summary of changes
- Modify the test to wait for the pageserver to catch up. The size limit
was never actually being enforced robustly, the original version of this
test was just writing much more than 30MB and about 98% of the time
getting lucky such that the feedback happened to arrive before the tests
for loop was done.
- If the test fails, log the logical size as seen by the pageserver.
## Problem
Debug-mode runs of test_pg_regress are rather slow since
https://github.com/neondatabase/neon/pull/8105, and occasionally exceed
their 600s timeout.
## Summary of changes
- Use 8MiB layer files, avoiding large ephemeral layers
On a hetzner AX102, this takes the runtime from 230s to 190s. Which
hopefully will be enough to get the runtime on github runners more
reliably below its 600s timeout.
This has the side benefit of exercising more of the pageserver stack
(including compaction) under a workload that exercises a more diverse
set of postgres functionality than most of our tests.
These tests will help verify that replication, both physical and
logical, works as expected in Neon.
Co-authored-by: Sasha Krassovsky <sasha@neon.tech>
Allows a process to run without blocking program execution, which can be
useful for certain test scenarios.
Co-authored-by: Sasha Krassovsky <sasha@neon.tech>
## Problem
test_subscriber_restart has quit large failure rate'
https://neonprod.grafana.net/d/fddp4rvg7k2dcf/regression-test-failures?orgId=1&var-test_name=test_subscriber_restart&var-max_count=100&var-restrict=false
I can be caused by too small timeout (5 seconds) to wait until changes
are propagated.
Related to #8097
## Summary of changes
Increase timeout to 30 seconds.
## Checklist before requesting a review
- [ ] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
## Checklist before merging
- [ ] Do not forget to reformat commit message to not include the above
checklist
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
## Problem
We want to be able to test how our infrastructure reacts on segfaults in
Postgres (for example, we collect cores, and get some required
logs/metrics, etc)
## Summary of changes
- Add `trigger_segfauls` function to `neon_test_utils` to trigger a
segfault in Postgres
- Add `trigger_panic` function to `neon_test_utils` to trigger SIGABRT
(by using `elog(PANIC, ...))
- Fix cleanup logic in regression tests in endpoint crashed
## Problem
This test directly manages locations on pageservers and configuration of
an endpoint. However, it did not switch off the parts of the storage
controller that attempt to do the same: occasionally, the test would
fail in a strange way such as a compute failing to accept a
reconfiguration request.
## Summary of changes
- Wire up the storage controller's compute notification hook to a no-op
handler
- Configure the tenant's scheduling policy to Stop.
## Problem
See #7466
## Summary of changes
Implement algorithm descried in
https://hal.science/hal-00465313/document
Now new GUC is added:
`neon.wss_max_duration` which specifies size of sliding window (in
seconds). Default value is 1 hour.
It is possible to request estimation of working set sizes (within this
window using new function
`approximate_working_set_size_seconds`. Old function
`approximate_working_set_size` is preserved for backward compatibility.
But its scope is also limited by `neon.wss_max_duration`.
Version of Neon extension is changed to 1.4
## Checklist before requesting a review
- [ ] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
## Checklist before merging
- [ ] Do not forget to reformat commit message to not include the above
checklist
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
Co-authored-by: Matthias van de Meent <matthias@neon.tech>
Part of #7497, closes#8071. (accidentally closed#8208, reopened here)
## Problem
After the changes in #8084, we need synthetic size to also account for
leased LSNs so that users do not get free retention by running a small
ephemeral endpoint for a long time.
## Summary of changes
This PR integrates LSN leases into the synthetic size calculation. We
model leases as read-only branches started at the leased LSN (except it
does not have a timeline id).
Other changes:
- Add new unit tests testing whether a lease behaves like a read-only
branch.
- Change `/size_debug` response to include lease point in the SVG
visualization.
- Fix `/lsn_lease` HTTP API to do proper parsing for POST.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
Co-authored-by: Christian Schwarz <christian@neon.tech>
## Problem
When generations were new, these messages were an important way of
noticing if something unexpected was going on. We found some real issues
when investigating tests that unexpectedly tripped them.
At time has gone on, this code is now pretty battle-tested, and as we do
more live migrations etc, it's fairly normal to see the occasional
message from a node with a stale generation.
At this point the cognitive load on developers to selectively allow-list
these logs outweighs the benefit of having them at warn severity.
Closes: https://github.com/neondatabase/neon/issues/8080
## Summary of changes
- Downgrade "Dropped remote consistent LSN updates" and "Dropping stale
deletions" messages to INFO
- Remove all the allow-list entries for these logs.
