Analysis of customer stalls revealed that the function `detail::hash_with_salt` (invoked by `passwords::check`) often blocks the reactor. Internally, this function uses the external `crypt_r` function to compute password hashes, which is CPU-intensive.
This PR addresses the issue in two ways:
1) `sha-512` is now the only password hashing scheme for new passwords (it was already the common-case).
2) `passwords::check` is moved to a dedicated alien thread.
Regarding point 1: before this change, the following hashing schemes were supported by `identify_best_supported_scheme()`: bcrypt_y, bcrypt_a, SHA-512, SHA-256, and MD5. The reason for this was that the `crypt_r` function used for password hashing comes from an external library (currently `libxcrypt`), and the supported hashing algorithms vary depending on the library in use. However:
- The bcrypt schemes never worked properly because their prefixes lack the required round count (e.g. `$2y$` instead of `$2y$05$`). Moreover, bcrypt is slower than SHA-512, so it not good idea to fix or use it.
- SHA-256 and SHA-512 both belong to the SHA-2 family. Libraries that support one almost always support the other, so it’s very unlikely to find SHA-256 without SHA-512.
- MD5 is no longer considered secure for password hashing.
Regarding point 2: the `passwords::check` call now runs on a shared alien thread created at database startup. An `std::mutex` synchronizes that thread with the shards. In theory this could introduce a frequent lock contention, but in practice each shard handles only a few hundred new connections per second—even during storms. There is already `_conns_cpu_concurrency_semaphore` in `generic_server` limits the number of concurrent connection handlers.
Fixes https://github.com/scylladb/scylladb/issues/24524
Backport not needed, as it is a new feature.
Closesscylladb/scylladb#24924
* github.com:scylladb/scylladb:
main: utils: add thread names to alien workers
auth: move passwords::check call to alien thread
test: wait for 3 clients with given username in test_service_level_api
auth: refactor password checking in password_authenticator
auth: make SHA-512 the only password hashing scheme for new passwords
auth: whitespace change in identify_best_supported_scheme()
auth: require scheme as parameter for `generate_salt`
auth: check password hashing scheme support on authenticator start
(cherry picked from commit c762425ea7)
This patch fixes an error-path bug in the base-64 decoding code in
utils/base64.cc, which among other things is used in Alternator to decode
blobs in JSON requests.
The base-64 decoding code has a lookup table, which was wrongly sized 255
bytes, but needed to be 256 bytes. This meant that if the byte 255 (0xFF)
was included in an invalid base-64 string, instead of detecting that this
is an invalid byte (since the only valid bytes in a base-64 string are
A-Z,a-z,0-9,+,/ and =), the code would either think it's valid with a
nonsense 6-bit part, or even crash on an out-of-bounds read.
Besides the trivial fix, this patch also includes a reproducing test,
which tries to write a blob as a supposedly base-64 encoded string with
a 0xFF byte in it. The test fails before this patch (the write succeeds,
unexpectedly), and passes after this patch (the write fails as
expected). The test also passes on DynamoDB.
Fixes#25701
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#25705
(cherry picked from commit ff91027eac)
Closesscylladb/scylladb#25767
The following steps are performed in sequence as part of the
Raft-based recovery procedure:
- set `recovery_leader` to the host ID of the recovery leader in
`scylla.yaml` on all live nodes,
- send the `SIGHUP` signal to all Scylla processes to reload the config,
- perform a rolling restart (with the recovery leader being restarted
first).
These steps are not intuitive and more complicated than they could be.
In this PR, we simplify these steps. From now on, we will be able to
simply set `recovery_leader` on each node just before restarting it.
Apart from making necessary changes in the code, we also update all
tests of the Raft-based recovery procedure and the user-facing
documentation.
Fixes scylladb/scylladb#25015
The Raft-based procedure was added in 2025.2. This PR makes the
procedure simpler and less error-prone, so it should be backported
to 2025.2 and 2025.3.
- (cherry picked from commit ec69028907)
- (cherry picked from commit 445a15ff45)
- (cherry picked from commit 23f59483b6)
- (cherry picked from commit ba5b5c7d2f)
- (cherry picked from commit 9e45e1159b)
- (cherry picked from commit f408d1fa4f)
Parent PR: #25032Closesscylladb/scylladb#25335
* https://github.com/scylladb/scylladb:
docs: document the option to set recovery_leader later
test: delay setting recovery_leader in the recovery procedure tests
gossip: add recovery_leader to gossip_digest_syn
db: system_keyspace: peers_table_read_fixup: remove rows with null host_id
db/config, gms/gossiper: change recovery_leader to UUID
db/config, utils: allow using UUID as a config option
Assume that any caller invoking `reload` intends to refresh credentials.
Remove conditional logic that checks for expiration before reloading.
(cherry picked from commit e4ebe6a309)
`protocol_exception` is thrown in several places. This has become a performance issue, especially when starting/restarting a server. To alleviate this issue, throwing the exception has to be replaced with returning it as a result or an exceptional future.
This PR replaces throws in the `transport/server` module. This is achieved by using result_with_exception, and in some places, where suitable, just by creating and returning an exceptional future.
There are four commits in this PR. The first commit introduces tests in `test/cqlpy`. The second commit refactors transport server `handle_error` to not rethrow exceptions. The third commit refactors reusable buffer writer callbacks. The fourth commit replaces throwing `protocol_exception` to returning it.
Based on the comments on an issue linked in https://github.com/scylladb/scylladb/issues/24567, the main culprit from the side of protocol exceptions is the invalid protocol version one, so I tested that exception for performance.
In order to see if there is a measurable difference, a modified version of `test_protocol_version_mismatch` Python is used, with 100'000 runs across 10 processes (not threads, to avoid Python GIL). One test run consisted of 1 warm-up run and 5 measured runs. First test run has been executed on the current code, with throwing protocol exceptions. Second test urn has been executed on the new code, with returning protocol exceptions. The performance report is in https://github.com/scylladb/scylladb/pull/24738#issuecomment-3051611069. It shows ~10% gains in real, user, and sys time for this test.
Testing
Build: `release`
Test file: `test/cqlpy/test_protocol_exceptions.py`
Test name: `test_protocol_version_mismatch` (modified for mass connection requests)
Test arguments:
```
max_attempts=100'000
num_parallel=10
```
Throwing `protocol_exception` results:
```
real=1:26.97 user=10:00.27 sys=2:34.55 cpu=867%
real=1:26.95 user=9:57.10 sys=2:32.50 cpu=862%
real=1:26.93 user=9:56.54 sys=2:35.59 cpu=865%
real=1:26.96 user=9:54.95 sys=2:32.33 cpu=859%
real=1:26.96 user=9:53.39 sys=2:33.58 cpu=859%
real=1:26.95 user=9:56.85 sys=2:34.11 cpu=862% # average
```
Returning `protocol_exception` as `result_with_exception` or an exceptional future:
```
real=1:18.46 user=9:12.21 sys=2:19.08 cpu=881%
real=1:18.44 user=9:04.03 sys=2:17.91 cpu=869%
real=1:18.47 user=9:12.94 sys=2:19.68 cpu=882%
real=1:18.49 user=9:13.60 sys=2:19.88 cpu=883%
real=1:18.48 user=9:11.76 sys=2:17.32 cpu=878%
real=1:18.47 user=9:10.91 sys=2:18.77 cpu=879% # average
```
This PR replaced `transport/server` throws of `protocol_exception` with returns. There are a few other places where protocol exceptions are thrown, and there are many places where `invalid_request_exception` is thrown. That is out of scope of this single PR, so the PR just refs, and does not resolve issue #24567.
Refs: #24567Fixes: #25271
This PR improves performance in cases when protocol exceptions happen, for example during connection storms. It will require backporting.
* (cherry picked from commit 7aaeed012e)
* (cherry picked from commit 30d424e0d3)
* (cherry picked from commit 9f4344a435)
* (cherry picked from commit 5390f92afc)
* (cherry picked from commit 4a6f71df68)
Parent PR: #24738Closesscylladb/scylladb#25117
* github.com:scylladb/scylladb:
test/cqlpy: add cpp exception metric test conditions
transport/server: replace protocol_exception throws with returns
utils/reusable_buffer: accept non-throwing writer callbacks via result_with_exception
transport/server: avoid exception-throw overhead in handle_error
test/cqlpy: add protocol_exception tests
Make make_bytes_ostream and make_fragmented_temporary_buffer accept
writer callbacks that return utils::result_with_exception instead of
forcing them to throw on error. This lets callers propagate failures
by returning an error result rather than throwing an exception.
Introduce buffer_writer_for, bytes_ostream_writer, and fragmented_buffer_writer
concepts to simplify and document the template requirements on writer callbacks.
This patch does not modify the actual callbacks passed, except for the syntax
changes needed for successful compilation, without changing the logic.
Refs: #24567Fixes: #25271
(cherry picked from commit 9f4344a435)
Enhance and fix error handling in the `chunked_download_source` to prevent errors seeping from the request callback. Also stop retrying on seastar's side since it is going to break the integrity of data which maybe downloaded more than once for the same range.
Fixes: https://github.com/scylladb/scylladb/issues/25043
Should be backported to 2025.3 since we have an intention to release native backup/restore feature
- (cherry picked from commit d53095d72f)
- (cherry picked from commit b7ae6507cd)
- (cherry picked from commit ba910b29ce)
- (cherry picked from commit fc2c9dd290)
Parent PR: #24883Closesscylladb/scylladb#25137
* github.com:scylladb/scylladb:
s3_client: Disable Seastar-level retries in HTTP client creation
s3_test: Validate handling of non-`aws_error` exceptions
s3_client: Improve error handling in chunked_download_source
aws_error: Add factory method for `aws_error` from exception
This patch fixes one cause of oversized allocations - and therefore
potentially stalls and increased tail latencies - in Alternator.
Alternator's Scan or Query operation return a page of results. When the
number of items is not limited by a "Limit" parameter, the default is
to return a 1 MB page. If items are short, a large number of them can
fit in that 1MB. The test test_query.py::test_query_large_page_small_rows
has 30,000 items returned in a single page.
In the response JSON, all these items are returned in a single array
"Items". Before this patch, we build the full response as a RapidJSON
object before sending it. The problem is that unfortunately, RapidJSON
stores arrays as contiguous allocations. This results in large
contiguous allocations in workloads that scan many small items, and
large contiguous allocations can also cause stalls and high tail
latencies. For example, before this patch, running
test/alternator/run --runveryslow \
test_query.py::test_query_large_page_small_rows
reports in the log:
oversized allocation: 573440 bytes.
After this patch, this warning no longer appears.
The patch solves the problem by collecting the scanned items not in a
RapidJSON array, but rather in a chunked_vector<rjson::value>, i.e,
a chunked (non-contiguous) array of items (each a JSON value).
After collecting this array separately from the response object, we
need to print its content without actually inserting it into the object -
we add a new function print_with_extra_array() to do that.
The new separate-chunked-vector technique is used when a large number
(currently, >256) of items were scanned. When there is a smaller number
of items in a page (this is typical when each item is longer), we just
insert those items in the object and print it as before.
Beyond the original slow test that demonstrated the oversized allocation
(which is now gone), this patch also includes a new test which
exercises the new code with a scan of 700 (>256) items in a page -
but this new test is fast enough to be permanently in our test suite
and not a manual "veryslow" test as the other test.
Fixes#23535
(cherry picked from commit 2385fba4b6)
Prevent Seastar from retrying HTTP requests to avoid buffer double-feed
issues when an entire request is retried. This could cause data
corruption in `chunked_download_source`. The change is global for every
instance of `s3_client`, but it is still safe because:
* Seastar's `http_client` resets connections regardless of retry behavior
* `s3_client` retry logic handles all error types—exceptions, HTTP errors,
and AWS-specific errors—via `http_retryable_client`
(cherry picked from commit fc2c9dd290)
Inject exceptions not wrapped in `aws_error` from request callback
lambda to verify they are properly caught and handled.
(cherry picked from commit ba910b29ce)
Create aws_error from raised exceptions when possible and respond
appropriately. Previously, non-aws_exception types leaked from the
request handler and were treated as non-retryable, causing potential
data corruption during download.
(cherry picked from commit b7ae6507cd)
Move `aws_error` creation logic out of `retryable_http_client` and
into the `aws_error` class to support reuse across components.
(cherry picked from commit d53095d72f)
Introduce a test that injects a non-retryable error and verifies
that the chunked download source throws an exception as expected.
(cherry picked from commit acf15eba8e)
Handle case where the download loop exits after consuming all data,
but before receiving an empty buffer signaling EOF. Without this, the
next request is sent with a non-zero offset and zero length, resulting
in "Range request cannot be satisfied" errors. Now, an empty buffer is
pushed to indicate completion and exit the fiber properly.
(cherry picked from commit 49e8c14a86)
Disable retries for S3 requests in the chunked download source to
prevent duplicate chunks from corrupting the buffer queue. The
response handler now throws an exception to bypass the retry
strategy, allowing the next range to be attempted cleanly.
This exception is only triggered for retryable errors; unretryable
ones immediately halt further requests.
(cherry picked from commit d2d69cbc8c)
Relocated logging to occur after determining the `current_range`,
ensuring more relevant output during S3 client operations.
(cherry picked from commit f1d0690194)
We move a `seastar::promise` on the external worker thread,
after the matching `seastar::future` was returned to the shard.
That's illegal. If the `promise` move occurs concurrently with some
operation (move, await) on the `future`, it becomes a data race
which could cause various kinds of corruption.
This patch fixes that by keeping the promise at a stable address
on the shard (inside a coroutine frame) and only passing through
the worker.
Fixes#24751Closesscylladb/scylladb#24752
(cherry picked from commit a29724479a)
Closesscylladb/scylladb#24780
The exponent of a big decimal string is parsed as an int32, adjusted for
the removed fractional part, and stored as an int32. When parsing values
like `1.23E-2147483647`, the unscaled value becomes `123`, and the scale
is adjusted to `2147483647 + 2 = 2147483649`. This exceeds the int32
limit, and since the scale is stored as an int32, it overflows and wraps
around, losing the value.
This patch fixes that the by parsing the exponent as an int64 value and
then adjusting it for the fractional part. The adjusted scale is then
checked to see if it is still within int32 limits before storing. An
exception is thrown if it is not within the int32 limits.
Note that strings with exponents that exceed the int32 range, like
`0.01E2147483650`, were previously not parseable as a big decimal. They
are now accepted if the final adjusted scale fits within int32 limits.
For the above value, unscaled_value = 1 and scale = -2147483648, so it
is now accepted. This is in line with how Java's `BigDecimal` parses
strings.
Fixes: #24581
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Closesscylladb/scylladb#24640
It solves the issue, where in some cases a timeout exceptions in CAS operations are logged incorrectly as a general failure.
Fixes#24591Closesscylladb/scylladb#24619
If the object returned from observe() is destructured,
it stops observing, potentially causing subtle bugs.
Typically, the observer object is retained as a class member.
It just std::move-s a buffer and a semaphore_units objects, both moves
are noexcept, so is the constructor itself.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#24552
Revamped the `range` class to actively manage its state by enforcing validation on all modifications. This prevents overflow, invalid states, and ensures the object size does not exceed the 5TiB limit in S3. This should address and prevent future problems related to this issue https://github.com/minio/minio/issues/21333
No backport needed since this problem related only to this change https://github.com/scylladb/scylladb/pull/23880Closesscylladb/scylladb#24312
* github.com:scylladb/scylladb:
s3_client: headers cleanup
s3_client: Refactor `range` class for state validation
Refs #24447
Patch adding this somehow managed to leave out the thread_local
specifier. While gnutls cert object can be shared across shards
just fine, the actual shared_ptr here cannot, thus we could
cause memory errors.
Closesscylladb/scylladb#24514
Revamped the `range` class to actively manage its state by enforcing validation on all modifications. This prevents overflow, invalid states, and ensures the object size does not exceed the 5TiB limit in S3.
Revise how we report statistics for `chunked_download_source`. Ensure
metrics for downloaded but unconsumed data are visible, as they do not
contribute to read amplification, which is tracked separately.
Closesscylladb/scylladb#24491
The existing `download_source` implementation optimizes performance
by keeping the connection to S3 open and draining data directly from
the socket. While this eliminates the overhead (60-100ms) of repeatedly
establishing new connections, it leads to rapid exhaustion of client-
side connections.
On a single shard, two `mx_readers` for load and stream are enough to
trigger this issue. Since each client typically holds two connections,
readers keeping index and data sources open can cause deadlocks where
processes stall due to unavailable connections.
Introduce `chunked_download_source`, a new S3 download method built on
`download_source`, to dynamically manage connections:
- Buffers data in 5MiB chunks using a producer-consumer model
- Closes connections once buffers reach capacity, returning them to
the pool for other clients
- Uses a filling fiber that resumes fetching once buffers are
consumed from the queue
Performance remains comparable to `download_source`, achieving
95MiB/s for sequential 1GiB downloads from S3. However, preloading
large chunks may cause read amplification.
Fixes: https://github.com/scylladb/scylladb/issues/23785Closesscylladb/scylladb#23880
Fixes#24447
This factory type, which is really more a data holder/connection producer
per connection instance, creates, if using https, a new certificate_credentials
on every instance. Which when used by S3 client is per client and
scheduling groups.
Which eventually means that we will do a set_system_trust + "cold" handshake
for every tls connection created this way.
This will cause both IO and cold/expensive certificate checking -> possible
stalls/wasted CPU. Since the credentials object in question is literally a
"just trust system", it could very well be shared across the shard.
This PR adds a thread local static cached credentials object and uses this
instead. Could consider moving this to seastar, but maybe this is too much.
Closesscylladb/scylladb#24448
Register the current space_source_fn in an RAII
object that resets monitor._space_source to the
previous function when the RAII object is destroyed.
Use space_source_registration in database_test::
mutation_dump_generated_schema_deterministic_id_version
to prevent use-after-stack-return in the test.
Fixes#24314
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#24342
Fixed#24296
While the HTTP client used for REST calls in AWS/GCP KMS integration (EAR)
is not general enough to be called a HTTP client as such, it is general
enough to be called a REST client (limited to stateless, single-op REST
calls).
Other code, like general auth integrations (hello Azure) and similar
could reuse this to lessen code duplication.
This patch simply moves the httpclient class from encryption to "rest"
namespace, and explicitly "limits" it to such usage. Making an alias
in encryption to avoid touching more files than needed.
Closesscylladb/scylladb#24297
This series fixes the only known violation of logalloc's allocation size limits (in `chunked_managed_vector`), and then it make those limits hard.
Before the series, LSA handles overly-large allocations by forwarding them to the standard allocator. After the series, an attempt to do an overly large allocations via LSA will trigger an `on_internal_error` instead.
We do this because the allocator fallback logic turned out to have subtle and problematic accounting bugs.
We could fix them, or we can remove the mechanism altogether.
It's hard to say which choice is better. This PR arbitrarily makes the choice to remove the mechanism.
This makes the logic simpler, at the risk of escalating some allocation size bugs to crashes.
See the descriptions of individual commits for more details.
Fixesscylladb/scylladb#23850Fixesscylladb/scylladb#23851Fixesscylladb/scylladb#23854
I'm not sure if any of this should be backported or not.
The `chunked_managed_vector` fix could be backported, because it's a bugfix. It's an old bug, though, and we have never observed problems related to it.
The changes to `logalloc` aren't supposed to be fixing any observable problem, so a backport probably has more risk than benefit in this case.
Closesscylladb/scylladb#23944
* github.com:scylladb/scylladb:
utils/logalloc: enforce LSA allocation size limits
utils/lsa/chunked_managed_vector: fix the calculation of max_chunk_capacity()
In order to guarantee a decent upper limit on fragmentation,
LSA only handles allocations smaller than 0.1 of a segment.
Allocations larger than this limit are permitted, but they are
not placed in LSA segments. Instead, they are forwarded to
the standard allocator.
We don't really have any use case for this "fallback".
As far as I can tell, it only exists for "historical"
reasons, from times where there were some data structures
which weren't fully adapted to LSA yet.
We don't the fallback to be used.
Long-lived standard allocations are undesirable.
They have higher internal fragmentation than LSA
allocations, and they can cause external fragmentation
in the standard allocator. So we want to eliminate them all.
The only reason to keep the fallback is to soften the impact
if some bug results in limit-exceeding LSA allocations happening
in production. In principle, the fallback turns a crash
(or something similarly drastic) into just a performance problem.
However, it turns out that the fallback is buggy.
Recently we had a bug which caused limit-exceeding LSA allocations
to happen.
And then it turned out that LSA reclaim doesn't deal fully correctly
with evictable non-LSA allocations, and the dirty_memory_manager
accounting for non-LSA allocations is completely wrong.
This resulted in subtle, serious, and hard to understand stability
problems in production.
Arguably the biggest problem is that the "fallback" allocations
weren't reported in any way. They were happening in some tests,
but they were silently permitted, so nobody noticed that they
should be eliminated. If we just had a rate-limited error log
that reports fallback allocations, they would have never got
into a release.
So maybe we could fix the fallback, add more tests for it,
add a warning for when it's used, and keep it.
But this PR instead opts for removing the fallback mechanism
altogether and failing fast. After the patch, if a non-conforming
allocation happens, it will trigger an `on_internal_error`.
With this, we risk a greater impact if some non-conforming allocations
happen in production, but we make the system simpler.
It's hard to say if it's a good tradeoff.
The default and recommended way to use zstd compressors is to let
zstd allocate and free memory for compressors on its own.
That's what we did for zstd compressors used in RPC compression.
But it turns out that it generates allocation patterns we dislike.
We expected zstd not to generate allocations after the context object
is initialized, but it turns out that it tries to downsize the context
sometimes (by reallocation). We don't want that because the allocations
generated by zstd are large (1 MiB with the parameters we use),
so repeating them periodically stresses the reclaimer.
We can avoid this by using the "static context" API of zstd,
in which the memory for context is allocated manually by the user
of the library. In this mode, zstd doesn't allocate anything
on its own.
The implementation details of this patch adds a consideration for
forward compatibility: later versions of Scylla can't use a
window size greater than the one we hardcoded in this patch
when talking to the old version of the decompressor.
(This is not a problem, since those compressors are only used
for RPC compression at the moment, where cross-version communication
can be prevented by bumping COMPRESSOR_NAME. But it's something
that the developer who changes the window size must _remember_ to do).
Fixes#24160Fixes#24183Closesscylladb/scylladb#24161
Inserts an iterator range at some position.
Again we insert the range at the end and use std::rotate() to
move the newly inserted elements into place, forgoing possible
optimizations.
Unit tests are added.
chunked_vector is only implemented for types with a
non-throwing move constructor; this greatly simplifies
the implementation.
We have a static_assert to enforce it (should really
be a constraint, but chunked_vector predates C++ concepts).
This static_assert prevents forward declarations from compiling:
class forward_declared;
using a = utils::chunked_vector<forward_declared>;
`a` won't compile since the static_assert will be instantiated
and will fail since forward_declared is an incomplete type. Using
a constraint has the same problem.
Fix by moving the static_assert to the destructor. The destructor
won't be instantiated by the forward declaration, so it won't
trigger. It will trigger when someone destroys the vector; at this
point the types are no longer forward declared.
Implement using std::rotate() and resize(). The elements to be erased
are rotated to the end, then resized out of existence.
Again we defer optimization for trivially copyable types.
Unit tests are added.
Needed for range_streamer with token_ranges using chunked_vector.
partition_range_compat's unwrap() needs insert if we are to
use it for chunked_vector (which we do).
Implement using push_back() and std::rotate().
emplace(iterator, args) is also implemented, though the benefit
is diluted (it will be moved after construction).
The implementation isn't optimal - if T is trivially copyable
then using std::memmove() will be much faster that std::rotate(),
but this complex optimization is left for later.
Unit tests are added.
Interval map is very susceptible to quadratic space behavior when it's flooded with many entries overlapping all (or most of) intervals, since each such entry will have presence on all intervals it overlaps with.
A trigger we observed was memtable flush storm, which creates many small "L0" sstables that spans roughly the entire token range.
Since we cannot rely on insertion order, solution will be about storing sstables with such wide ranges in a vector (unleveled).
There should be no consequence for single-key reads, since upper layer applies an additional filtering based on token of key being queried.
And for range scans, there can be an increase in memory usage, but not significant because the sstables span an wide range and would have been selected in the combined reader if the range of scan overlaps with them.
Anyway, this is a protection against storm of memtable flushes and shouldn't be the common scenario.
It works both with tablets and vnodes, by adjusting the token range spanned by compaction group accordingly.
Fixes#23634.
We can backport this into 2024.2, 2025.1, but we should let this cook in master for 1 month or so.
Closesscylladb/scylladb#23806
* github.com:scylladb/scylladb:
test: Verify partitioned set store split and unsplit correctly
sstables: Fix quadratic space complexity in partitioned_sstable_set
compaction: Wire table_state into make_sstable_set()
compaction: Introduce token_range() to table_state
dht: Add overlap_ratio() for token range
The loading_cache has a periodic timer which acquires the
_timer_reads_gate. The stop() method first closes the gate and then
cancels the timer - this order is necessary because the timer is
re-armed under the gate. However, the timer callback does not check
whether the gate was closed but tries to acquire it, which might result
in unhandled exception which is logged with ERROR severity.
Fix the timer callback by acquiring access to the gate at the beginning
and gracefully returning if the gate is closed. Even though the gate
used to be entered in the middle of the callback, it does not make sense
to execute the timer's logic at all if the cache is being stopped.
Fixes: scylladb/scylladb#23951Closesscylladb/scylladb#23952
