## 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
new clippy warnings on nightly.
## Summary of changes
broken up each commit by warning type.
1. Remove some unnecessary refs.
2. In edition 2024, inference will default to `!` and not `()`.
3. Clippy complains about doc comment indentation
4. Fix `Trait + ?Sized` where `Trait: Sized`.
5. diesel_derives triggering `non_local_defintions`
## 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.
Implement decompression of images for vectored reads.
This doesn't implement support for still treating blobs as uncompressed
with the bits we reserved for compression, as we have removed that
functionality in #8300 anyways.
Part of #5431
We need to pass on the configured compression param during image layer
generation.
This was an oversight of #8106, and the likely cause why #8288 didn't
bring any interesting regressions.
Part of https://github.com/neondatabase/neon/issues/5431
## 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
Rewrite streaming vectored read planner to be a separate struct. The API
is designed to produce batches around `max_read_size` instead of exactly
less than that so that `handle_XX` returns one batch a time.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## 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.
## Problem
SeqWait::would_wait_for returns Ok in the case when we would not wait
for the sequence number and Err otherwise.
ReconcilerWaiter::get_status uses it the wrong way around. This can
cause the storage controller to go into a busy loop
and make it look unavailable to the k8s controller.
## Summary of changes
Use `SeqWait::would_wait_for` correctly.
`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.
Set core rmilit to ulimited in compute_ctl, so that all child processes
inherit it. We could also set rlimit in relevant startup script, but
that way we would depend on external setup and might inadvertently
disable it again (core dumping worked in pods, but not in VMs with
inittab-based startup).
## 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.
Part of https://github.com/neondatabase/neon/issues/8002. This pull
request adds a k-merge iterator for bottom-most compaction.
## Summary of changes
* Added back lsn_range / key_range in delta layer inner. This was
removed due to https://github.com/neondatabase/neon/pull/8050, but added
back because iterators need that information to process lazy loading.
* Added lazy-loading k-merge iterator.
* Added iterator wrapper as a unified iterator type for image+delta
iterator.
The current status and test should cover the use case for L0 compaction
so that the L0 compaction process can bypass page cache and have a fixed
amount of memory usage. The next step is to integrate this with the new
bottom-most compaction.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Christian Schwarz <christian@neon.tech>
Removes the `ImageCompressionAlgorithm::DisabledNoDecompress` variant.
We now assume any blob with the specific bits set is actually a
compressed blob.
The `ImageCompressionAlgorithm::Disabled` variant still remains and is
the new default.
Reverts large parts of #8238 , as originally intended in that PR.
Part of #5431
## 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.
## Problem
#7809 - we do not support sslnegotiation=direct
#7810 - we do not support negotiating down the protocol extensions.
## Summary of changes
1. Same as postgres, check the first startup packet byte for tls header
`0x16`, and check the ALPN.
2. Tell clients using protocol >3.0 to downgrade
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`.
## Problem
Slack thread:
https://neondb.slack.com/archives/C033RQ5SPDH/p1720511577862519
We're seeing OOMs in staging on a pageserver that has
l0_flush.mode=Direct enabled.
There's a strong correlation between jumps in `maxrss_kb` and
`pageserver_timeline_ephemeral_bytes`, so, it's quite likely that
l0_flush.mode=Direct is the culprit.
Notably, the expected max memory usage on that staging server by the
l0_flush.mode=Direct is ~2GiB but we're seeing as much as 24GiB max RSS
before the OOM kill.
One hypothesis is that we're dropping the semaphore permit before all
the dirtied pages have been flushed to disk. (The flushing to disk
likely happens in the fsync inside the `.finish()` call, because we're
using ext4 in data=ordered mode).
## Summary of changes
Hold the permit until after we're done with `.finish()`.
part of https://github.com/neondatabase/cloud/issues/14024, k8s does not
always have a volume available for logging, and I'm running into weird
permission errors... While I could spend time figuring out how to create
temp directories for logging, I think it would be better to just disable
file logging as k8s containers are ephemeral and we cannot retrieve
anything on the fs after the container gets removed.
## Summary of changes
`PAGESERVER_DISABLE_FILE_LOGGING=1` -> file logging disabled
Signed-off-by: Alex Chi Z <chi@neon.tech>
This tweaks the rows-to-JSON rendering logic in order to avoid
allocating 0-sized temporary vectors and later growing them
to insert elements.
As the exact size is known in advance, both vectors can be built
with an exact capacity upfront. This will avoid further vector
growing/reallocation in the rendering hotpath.
Signed-off-by: Luca BRUNO <lucab@lucabruno.net>
## Problem
In https://github.com/neondatabase/neon/pull/8161, we changed the path
to Neon artefacts by adding commit sha to it, but we missed adding these
changes to `promote-compatibility-data` job that we use for
backward/forward- compatibility testing.
## Summary of changes
- Add commit sha to `promote-compatibility-data`
## 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.
## Problem
We currently use 'immediate' mode in the most commonly used shutdown
path, when the control plane calls a `compute_ctl` API to terminate
Postgres inside compute without waiting for the actual pod / VM
termination. Yet, 'immediate' shutdown doesn't create a shutdown
checkpoint and ROs have bad times figuring out the list of running xacts
during next start.
## Summary of changes
Use 'fast' mode, which creates a shutdown checkpoint that is important
for ROs to get a list of running xacts faster instead of going through
the CLOG. On the control plane side, we poll this `compute_ctl`
termination API for 10s, it should be enough as we don't really write
any data at checkpoint time. If it times out, we anyway switch to the
slow k8s-based termination.
See https://www.postgresql.org/docs/current/server-shutdown.html for the
list of modes and signals.
The default VM shutdown hook already uses `fast` mode, see [1]
[1]
c9fd8d7693/vm-image-spec.yaml (L30-L31)
Related to #6211
## Problem
LSN Leases introduced in #8084 is a new API that is made shard-aware
from day 1. To support ephemeral endpoint in #7994 without linking
Postgres C API against `compute_ctl`, part of the sharding needs to
reside in `utils`.
## Summary of changes
- Create a new `shard` module in utils crate.
- Move more interface related part of tenant sharding API to utils and
re-export them in pageserver_api.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
## Problem
Rarely, a dbdir entry can exist with no `relmap_file_key` data. This
causes compaction to fail, because it assumes that if the database
exists, then so does the relmap file.
Basebackup already handled this using a boolean to record whether such a
key exists, but `collect_keyspace` didn't.
## Summary of changes
- Respect the flag for whether a relfilemap exists in collect_keyspace
- The reproducer for this issue will merge separately in
https://github.com/neondatabase/neon/pull/8232
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
- Resident memory on long running pageserver processes tends to climb:
memory fragmentation is suspected.
- Total resident memory may be a limiting factor for running on smaller
nodes.
## Summary of changes
- As a low-energy experiment, switch the pageserver to use jemalloc (not
a net-new dependency, proxy already use it)
- Decide at end of week whether to revert before next release.
