Commit Graph

4728 Commits

Author SHA1 Message Date
Michał Chojnowski
3017dbb204 sstables/trie: add trie traversal routines
`trie::node_reader`, added in a previous series, contains
encoding-aware logic for traversing a single node
(or a batch of nodes) during a trie search.

This commits adds encoding-agnostic functions which drive the
the `trie::node_reader` in a loop to traverse the whole branch.

Together, the added functions (`traverse`, `step`, `step_back`)
and the data structure they modify (`ancestor_trail`) constitute
a trie cursor. We might later wrap them into some `trie_cursor`
class, but regardless of whether we are going to do that,
keeping them (also) as free functions makes them easier to test.

Closes scylladb/scylladb#25396
2025-08-11 19:15:09 +03:00
Botond Dénes
65c770f21a test/boost/row_cache_test: add test for memtable overlap check elision 2025-08-11 17:20:12 +03:00
Botond Dénes
cfac9691ff compaction/compaction_garbage_collector: max_purgeable: add expiry_treshold
Allow possibly avoiding overlap checks in the case where the source of
the min-live timestamp is known to only contain data which was written
*after* expiry treshold. Expiry treshold is the upper bound of
tombstone.deletion_time that was already expired at the time of
obtaining this expiry treshold value. Meaning that any write originating
from after this point in time, was generated at a time when such
tombstone was already expired. Hence these writes are not relevant for
the purposes of overlap checks with the tombstone and so their min-live
timestamp can be ignored.
This is important for MV workloads, where writes generated now can have
timestamps going far back in time, possibly blocking tombstone GC of
much older [shadowable] tombstones.
2025-08-11 17:20:11 +03:00
Patryk Jędrzejczak
e14c5e3890 Merge 'raft: enforce odd number of voters in group0' from Emil Maskovsky
raft: enforce odd number of voters in group0

Implement odd number voter enforcement in the group0 voter calculator to ensure proper Raft consensus behavior. Raft consensus requires a majority of voters to make decisions, and odd numbers of voters is preferred because an even number doesn't add additional reliability but introduces
the risk of scenarios where no group can make progress. If an even number of voters is divided into two groups of equal size during a network
partition, neither group will have majority and both will be unable to commit new entries. With an odd number of voters, such equal partition
scenarios are impossible (unless the network is partitioned into at least three groups).

Fixes: scylladb/scylladb#23266

No backport: This is a new change that is to be only deployed in the new version, so it will not be backported.

Closes scylladb/scylladb#25332

* https://github.com/scylladb/scylladb:
  raft: enforce odd number of voters in group0
  test/raft: adapt test_tablets_lwt.py for odd voter number enforcement
  test/raft: adapt test_raft_no_quorum.py for odd voter enforcement
2025-08-11 15:44:21 +02:00
Benny Halevy
23ac80fc6b utils: stall_free: detect clear_gently method of const payload types
Currently, when a container or smart pointer holds a const payload
type, utils::clear_gently does not detect the object's clear_gently
method as the method is non-const and requires a mutable object,
as in the following example in class tablet_metadata:
```
    using tablet_map_ptr = foreign_ptr<lw_shared_ptr<const tablet_map>>;
    using table_to_tablet_map = std::unordered_map<table_id, tablet_map_ptr>;
```

That said, when a container is cleared gently the elements it holds
are destroyed anyhow, so we'd like to allow to clear them gently before
destruction.

This change still doesn't allow directly calling utils::clear_gently
an const objects.

And respective unit tests.

Fixes #24605

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-11 14:22:01 +03:00
Benny Halevy
cb9db2f396 utils: stall_free: clear gently a foreign shared ptr only when use_count==1
Unlike clear_gently of SharedPtr, clear_gently of a
`foreign_ptr<shared_ptr<T>>` calls clear_gently on the contained object
even if it's still shared and may still be in use.

This change examines the foreign shared pointer's use_count
and calls clear_gently on the shard object only when
its use_count reaches 1.

Fixes #25026

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-11 14:21:32 +03:00
Tomasz Grabiec
f7c001deff Merge 'key: clustering_bounds_comparator: avoid thread_local initialization guard overhead' from Avi Kivity
I noticed clustering_bounds_comparator was running an unnecessary
thread_local initialization guard. This series switches the variable
to constinit initialization, removing the guard.

Performance measurements (perf-simple-query) show an unimpressive
20 instruction per op reduction. However, each instruction counts!

Before:

```
throughput:
	mean=   203642.54 standard-deviation=1102.99
	median= 204328.69 median-absolute-deviation=955.56
	maximum=204624.13 minimum=202222.19
instructions_per_op:
	mean=   42097.59 standard-deviation=40.07
	median= 42111.83 median-absolute-deviation=30.65
	maximum=42139.88 minimum=42044.91
cpu_cycles_per_op:
	mean=   22664.81 standard-deviation=131.28
	median= 22581.10 median-absolute-deviation=111.57
	maximum=22832.30 minimum=22553.24
```

After:

```
throughput:
	mean=   204397.73 standard-deviation=2277.71
	median= 204942.95 median-absolute-deviation=2191.54
	maximum=207588.30 minimum=202162.80
instructions_per_op:
	mean=   42087.21 standard-deviation=27.30
	median= 42092.75 median-absolute-deviation=20.33
	maximum=42108.33 minimum=42041.51
cpu_cycles_per_op:
	mean=   22589.79 standard-deviation=219.24
	median= 22544.82 median-absolute-deviation=191.98
	maximum=22835.11 minimum=22303.52
```

(Very) minor performance improvement, no backport suggestd.

Closes scylladb/scylladb#25259

* github.com:scylladb/scylladb:
  keys: clustering_bounds_comparator: make thread_local _empty_prefix constinit
  keys: make empty creation clustering_key_prefix constexpr
  managed_bytes: make empty managed_bytes constexpr friendly
  keys: clustering_bounds_comparator: make _empty_prefix a prefix
2025-08-11 13:20:38 +02:00
Botond Dénes
ab633590f1 tombstone_gc: introduce tombstone_gc_state_snapshot
Returns gc-before times, identical to what tombstone_gc_state would have
returned at the point of taking the snapshot.
2025-08-11 07:09:14 +03:00
Botond Dénes
614d17347a tombstone_gc: extract shared state into shared_tombstone_gc_state
Instead of storing it partially in tombstone_gc and partially in an
external map. Move all external parts into the new
shared_tombstone_gc_state. This new class is responsible for
keeping and updating the repair history. tombstone_gc_state just keeps
const pointers to the shared state as before and is only responsible for
querying the tombstone gc before times.
This separation makes the code easier to follow and also enables further
patching of tombstone_gc_state.
2025-08-11 07:09:14 +03:00
Botond Dénes
ef7d49cd21 compaction/compaction_garbage_collector: refactor max_purgeable into a class
Make members private, add getters and constructors.
This struct will get more functionality soon, so class is a better fit.
2025-08-11 07:09:13 +03:00
Botond Dénes
c150bdd59c test/boost/row_cache_test: refactor test_populating_reader_tombstone_gc_with_data_in_memtable
This test currently uses gc_grace_seconds=0. The introduction
of memtable overlap elision will break these tests because the
optimization is always active with this tombstone-gc.
Switch the tests to use tombstone-gc=repair, which allows for greater
control over when the memtable overlap elision is triggered.
This requires a move to vnodes, as tombstone-gc=repair doesn't
work with RF=1 currently, and using RF=3 won't work with tablets.
2025-08-11 07:09:13 +03:00
Botond Dénes
c052f2ad1d test: rewrite test_compacting_reader_tombstone_gc_with_data_in_memtable in C++
This test will soon need to be changed to use tombstone-gc=repair. This
cannot work as of now, as the test uses a single-node cluster.
The options are the following:
* Make it use more than one nodes
* Make repair work with single node clusters
* Rewrite in C++ where repair can be done synthetically

We chose the last option, it is the simplest one both in terms of code
and runtime footprint.

The new test is in test/boost/row_cache_test.cc
Two changes were done during the migration
* Change the name to
  test_populating_reader_tombstone_gc_with_data_in_memtable
  to better express which cache component this test is targetting;
* Use NullCompactionStrategy on the table instead of disabling
  auto-compaction.
2025-08-11 07:09:13 +03:00
Botond Dénes
e4c048ada1 test/boost/row_cache_test: refactor cache tombstone GC with memtable overlap tests
These tests currently use tombstone-gc=immediate. The introduction
of memtable overlap elision will break these tests because the
optimization is always active with this tombstone-gc.
Switch the tests to use tombstone-gc=repair, which allows for greater
control over when the memtable overlap elision is triggered.
This requires a move to vnodes, as tombstone-gc=repair doesn't
work with RF=1 currently, and using RF=3 won't work with tablets.
2025-08-11 07:09:13 +03:00
Emil Maskovsky
7c54401d3d raft: enforce odd number of voters in group0
Implement odd number voter enforcement in the group0 voter calculator to
ensure proper Raft consensus behavior. Raft consensus requires a majority
of voters to make decisions, and odd numbers of voters is preferred
because an even number doesn't add additional reliability but introduces
the risk of scenarios where no group can make progress. If an even number
of voters is divided into two groups of equal size during a network
partition, neither group will have majority and both will be unable to
commit new entries. With an odd number of voters, such equal partition
scenarios are impossible (unless the network is partitioned into at least
three groups).

Fixes: scylladb/scylladb#23266
2025-08-08 19:49:20 +02:00
Benny Halevy
0a20834d2a replica: table: get rid of update_sstables_known_generation
It is not needed anymore.
With that database::_sstable_generation_generator can
be a regular member rather than optional and initialized
later.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-08 11:46:21 +03:00
Benny Halevy
42cb25c470 sstables: sstable_directory: stop tracking highest_generation
It is not needed anymore as we always generate
uuid generations.

Convert sstable_directory_test_table_simple_empty_directory_scan
to use the newly added empty() method instead of
checking the highest generation seen.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-08 11:46:21 +03:00
Benny Halevy
b01524c5a3 replica: distributed_loader: stop tracking highest_generation
It is not needed anymore as we always generate
uuid generations.

Move highest_generation_seen(sharded<sstables::sstable_directory>& directory)
to sstables/sstable_directory module.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-08 11:46:21 +03:00
Benny Halevy
6cc964ef16 sstables: sstable_generation: get rid of uuid_identifiers bool class
Now that all call sites enable uuid_identifiers.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-08 11:46:21 +03:00
Raphael S. Carvalho
beaaf00fac test: Add test that compaction doesn't cross logical group boundary
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
2025-08-08 06:58:01 +03:00
Raphael S. Carvalho
d351b0726b replica: Introduce views in compaction_group for incremental repair
Wired the unrepaired, repairing and repaired views into compaction_group.

Also the repaired filter was wired, so tablet_storage_group_manager
can implement the procedure to classify the sstable.

Based on this classifier, we can decide which view a sstable belongs
to, at any given point in time.

Additionally, we made changes changes to compaction_group_view
to return only sstables that belong to the underlying view.

From this point on, repaired, repairing and unrepaired sets are
connected to compaction manager through their views. And that
guarantees sstables on different groups cannot be compacted
together.
Repairing view specifically has compaction disabled on it altogether,
we can revert this later if we want, to allow repairing sstables
to be compacted with one another.

The benefit of this logical approach is having the classifier
as the single source of truth. Otherwise, we'd need to keep the
sstable location consistest with global metadata, creating
complexity

Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
2025-08-08 06:58:00 +03:00
Raphael S. Carvalho
9d3755f276 replica: Futurize retrieval of sstable sets in compaction_group_view
This will allow upcoming work to gently produce a sstable set for
each compaction group view. Example: repaired and unrepaired.

Locking strategy for compaction's sstable selection:
Since sstable retrieval path became futurized, tasks in compaction
manager will now hold the write lock (compaction_state::lock)
when retrieving the sstable list, feeding them into compaction
strategy, and finally registering selected sstables as compacting.
The last step prevents another concurrent task from picking the
same sstable. Previously, all those steps were atomic, but
we have seen stall in that area in large installations, so
futurization of that area would come sooner or later.

Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
2025-08-08 06:58:00 +03:00
Raphael S. Carvalho
2c4a9ba70c treewide: Rename table_state to compaction_group_view
Since table_state is a view to a compaction group, it makes sense
to rename it as so.

With upcoming incremental repair, each replica::compaction_group
will be actually two compaction groups, so there will be two
views for each replica::compaction_group.

Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
2025-08-08 06:51:28 +03:00
Asias He
acc367c522 tests: adjust for incremental repair
The separatation of sstables into the logical repaired and unrepaired
virtual sets, requires some adjustments for certain tests, in particular
for those that look at number of compaction tasks or number of sstables.
The following tests need adjustment:
* test/cluster/tasks/test_tablet_tasks.py
* test/boost/memtable_test.cc

The adjustments are done in such a way that they accomodate both the
case where there is separate repaired/unrepaired states and when there
isn't.
2025-08-08 06:49:17 +03:00
Avi Kivity
8164f72f6e Merge 'Separate local_effective_replication_map from vnode_effective_replication_map' from Benny Halevy
Derive both vnode_effective_replication_map
and local_effective_replication_map from
static_effective_replication_map as both are static and per-keyspace.

However, local_effective_replication_map does not need vnodes
for the mapping of all tokens to the local node.

Refs #22733

* No backport required

Closes scylladb/scylladb#25222

* github.com:scylladb/scylladb:
  locator: abstract_replication_strategy: implement local_replication_strategy
  locator: vnode_effective_replication_map: convert clone_data_gently to clone_gently
  locator: abstract_replication_map: rename make_effective_replication_map
  locator: abstract_replication_map: rename calculate_effective_replication_map
  replica: database: keyspace: rename {create,update}_effective_replication_map
  locator: effective_replication_map_factory: rename create_effective_replication_map
  locator: abstract_replication_strategy: rename vnode_effective_replication_map_ptr et. al
  locator: abstract_replication_strategy: rename global_vnode_effective_replication_map
  keyspace: rename get_vnode_effective_replication_map
  dht: range_streamer: use naked e_r_m pointers
  storage_service: use naked e_r_m pointers
  alternator: ttl: use naked e_r_m pointers
  locator: abstract_replication_strategy: define is_local
2025-08-07 12:51:43 +03:00
Avi Kivity
90eb6e6241 Merge 'sstables/trie: implement BTI node format serialization and traversal' from Michał Chojnowski
This is the next part in the BTI index project.

Overarching issue: https://github.com/scylladb/scylladb/issues/19191
Previous part: https://github.com/scylladb/scylladb/pull/25154
Next part: implementing a trie cursor (the "set to key, step forwards, step backwards" thing) on top of the `node_reader` added here.

The new code added here is not used for anything yet, but it's posted as a separate PR
to keep things reviewably small.

This part implements the BTI trie node encoding, as described in https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/io/sstable/format/bti/BtiFormat.md#trie-nodes.
It contains the logic for encoding the abstract in-memory `writer_node`s (added in the previous PR)
into the on-disk format, and the logic for traversing the on-disk nodes during a read.

New functionality, no backporting needed.

Closes scylladb/scylladb#25317

* github.com:scylladb/scylladb:
  sstables/trie: add tests for BTI node serialization and traversal
  sstables/trie: implement BTI node traversal
  sstables/trie: implement BTI serialization
  utils/cached_file: add get_shared_page()
  utils/cached_file: replace a std::pair with a named struct
2025-08-07 12:15:42 +03:00
Benny Halevy
02b922ac40 test: cql_query_test: add test_sstable_load_mixed_generation_type
Test that we can load sstables with mixed, numerical and uuid
generation types, and verify the expected data.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-07 12:04:23 +03:00
Benny Halevy
9b65856a26 test: sstable_datafile_test: move copy_directory helper to test/lib/test_utils
It's a generic helper that can be used by all tests.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-07 12:04:23 +03:00
Benny Halevy
7c9ce235d7 test: database_test: move table_dir helper to test/lib/test_utils
It's a generic helper that can be used by all tests.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-07 12:04:23 +03:00
Nikos Dragazis
ee92fcc078 encryption_at_rest_test: Preserve tmpdir from failing KMIP tests
The KMIP tests start a local PyKMIP server and configure it to write
logs in the test's temporary directory (`tmpdir`). However, the tmpdir
is a RAII object that deletes the directory once it goes out of scope,
causing PyKMIP server logs to be lost on test failures.

To assist with debugging, preserve the whole directory if the test
failed with an exception. Allow the user to disable this by setting the
SCYLLA_TEST_PRESERVE_TMP_ON_EXCEPTION environment variable.

Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
2025-08-06 16:29:19 +03:00
Benny Halevy
6dbbb80aae locator: abstract_replication_strategy: implement local_replication_strategy
Derive both vnode_effective_replication_map
and local_effective_replication_map from
static_effective_replication_map as both are static and per-keyspace.

However, local_effective_replication_map does not need vnodes
for the mapping of all tokens to the local node.

Note that everywhere_replication_strategy is not abstracted in a similar
way, although it could, since the plan is to get rid of it
once all system keyspaces areconverted to local or tablets replication
(and propagated everywhere if needed using raft group0)

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-06 16:05:11 +03:00
Benny Halevy
babb4a41a8 locator: abstract_replication_map: rename calculate_effective_replication_map
to calculate_vnode_effective_replication_map since
it is specific to vnode-based range calculations.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-06 16:03:53 +03:00
Benny Halevy
cbad497859 locator: abstract_replication_strategy: rename vnode_effective_replication_map_ptr et. al
to static_effective_replication_map_ptr, in preparation
for separating local_effective_replication_map from
vnode_effective_replication_map.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-06 16:03:53 +03:00
Benny Halevy
bd62421c05 keyspace: rename get_vnode_effective_replication_map
to get_static_effective_replication_map, in preparation
for separating local_effective_replication_map from
vnode_effective_replication_map (both are per-keyspace).

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-08-06 13:40:43 +03:00
Pavel Emelyanov
0616407be5 Merge 'rest_api: add endpoint which drops all quarantined sstables' from Taras Veretilnyk
Added a new POST endpoint `/storage_service/drop_quarantined_sstables` to the REST API.
This endpoint allows dropping all quarantined SSTables either globally or
for a specific keyspace and tables.
Optional query parameters `keyspace` and `tables` (comma-separated table names) can be
provided to limit the scope of the operation.

Fixes scylladb/scylladb#19061

Backport is not required, it is new functionality

Closes scylladb/scylladb#25063

* github.com:scylladb/scylladb:
  docs: Add documentation for the nodetool dropquarantinedsstables command
  nodetool: add command for dropping quarantine sstables
  rest_api: add endpoint which drops all quarantined sstables
2025-08-06 11:55:15 +03:00
Karol Nowacki
032e8f9030 test/boost/vector_store_client_test.cc: Fix flaky tests
The vector_store_client_test was observed to be flaky, sometimes hanging while waiting for a response from HTTP server.

Problem:
The default load balancing algorithm (in Seastar's posix_server_socket_impl::accept) could route an incoming connection to a different shard than the one executing the test.
Because the HTTP server is a non-sharded service running only on the test's originating shard, any connection submitted to another shard would never be handled, causing the test client to hang waiting for response.

Solution:
The patch resolves the issue by explicitly setting fixed cpu load balancing algorithm.
This ensures that incoming connections are always handled on the same shard where the HTTP server is running.

Closes scylladb/scylladb#25314
2025-08-06 11:24:51 +03:00
Michał Chojnowski
9930cd59eb sstables/trie: add tests for BTI node serialization and traversal
Adds tests which check that nodes serialized by `bti_node_sink`
are readable by `bti_node_reader` with the right result.

(Note: there are no tests which check compatibility of the encoded nodes
with Cassandra or with handwritten hexdumps. There are only tests
for mutual compatibility between Scylla's writers and readers.
This can be considered a gap in testing.)
2025-08-05 21:48:24 +02:00
Pavel Emelyanov
10056a8c6d Merge 'Simplify credential reload: remove internal expiration checks' from Ernest Zaslavsky
This PR introduces a refinement in how credential renewal is triggered. Previously, the system attempted to renew credentials one hour before their expiration, but the credentials provider did not recognize them as expired—resulting in a no-op renewal that returned existing credentials. This led the timer fiber to immediately retry renewal, causing a renewal storm.

To resolve this, we remove expiration (or any other checks) in `reload` method, assuming that whoever calls this method knows what he does.

Fixes: https://github.com/scylladb/scylladb/issues/25044

Should be backported to 2025.3 since we need this fix for the restore

Closes scylladb/scylladb#24961

* github.com:scylladb/scylladb:
  s3_creds: code cleanup
  s3_creds: Make `reload` unconditional
  s3_creds: Add test exposing credentials renewal issue
2025-08-05 17:49:13 +03:00
Avi Kivity
4c785b31c7 Merge 'List Alternator clients in system.clients virtual table' from Nadav Har'El
Before this series, the "system.clients" virtual table lists active connections (and their various properties, like client address, logged in username and client version) only for CQL requests. This series adds also Alternator clients to system.clients. One of the interesting use cases of this new feature is understanding exactly which SDK a user is using -without inspecting their application code.  Different SDKs pass different "User-Agent" headers in requests, and that User-Agent will be visible in the system.clients entries for Alternator requests as the "driver_name" field.

Unlike CQL where logged in username, driver name, etc. applies to a complete connection, in the Alternator API, different requests can theoretically be signed by different users and carry different headers but still arrive over the same HTTP connection. So instead of listing the currently open Alternator *connections*, we will list the currently active *requests*.

The first three patches introduce utilities that will be useful in the implementation. The fourth patch is the implementation itself (which is quite simple with the utility introduced in the second patch), and the fifth patch a regression test for the new feature. The sixth patch adds documentation, the seventh patch refactors generic_server to use the newly introduced utility class and reduce code duplication, and the eighth patch adds a small check to an existing check of CQL's system.clients.

Fixes #24993

This patch adds a new feature, so doesn't require a backport. Nevertheless, if we want it to get to existing customers more quickly to allow us to better understand their use case by reading the system.clients table, we may want to consider backporting this patch to existing branches. There is some risk involved in this patch, because it adds code that gets run on every Alternator request, so a bug on it can cause problems for every Alternator request.

Closes scylladb/scylladb#25178

* github.com:scylladb/scylladb:
  test/cqlpy: slightly strengthen test for system.clients
  generic_server: use utils::scoped_item_list
  docs/alternator: document the system.clients system table in Alternator
  alternator: add test for Alternator clients in system.clients
  alternator: list active Alternator requests in system.clients
  utils: unit test for utils::scoped_item_list
  utils: add a scoped_item_list utility class
  utils: add "fatal" version of utils::on_internal_error()
2025-08-05 15:55:41 +03:00
Ernest Zaslavsky
e4ebe6a309 s3_creds: Make reload unconditional
Assume that any caller invoking `reload` intends to refresh credentials.
Remove conditional logic that checks for expiration before reloading.
2025-08-03 17:41:35 +03:00
Ernest Zaslavsky
68855c90ca s3_creds: Add test exposing credentials renewal issue
Add a test demonstrating that renewing credentials does not update
their expiration. After requesting credentials again, the expiration
remains unchanged, indicating no actual update occurred.
2025-08-03 17:41:25 +03:00
Avi Kivity
8b1bf46086 Merge 'sstables: introduce trie_writer' from Michał Chojnowski
This is the first part of a larger project meant to implement a trie-based
index format. (The same or almost the same as Cassandra's BTI).

As of this patch, the new code isn't used for anything yet,
but we introduced separately from its users to keep PRs small enough
for reviewability.

This commit introduces trie_writer, a class responsible for turning a
stream of (key, value) pairs (already sorted by key) into a stream of
serializable nodes, such that:

1. Each node lies entirely within one page (guaranteed).
2. Parents are located in the same page as their children (best-effort).
3. Padding (unused space) is minimized (best-effort).

It does mostly what you would expect a "sorted keys -> trie" builder to do.
The hard part is calculating the sizes of nodes (which, in a well-packed on-disk
format, depend on the exact offsets of the node from its children) and grouping
them into pages.

This implementation mostly follows Cassandra's design of the same thing.
There are some differences, though. Notable ones:

1. The writer operates on chains of characters, rather than single characters.

   In Cassandra's implementation, the writer creates one node per character.
   A single long key can be translated to thousands of nodes.
   We create only one node per key. (Actually we split very long keys into
   a few nodes, but that's arbitrary and beside the point).

   For BTI's partition key index this doesn't matter.
   Since it only stores a minimal unique prefix of each key,
   and the trie is very balanced (due to token randomness),
   the average number of new characters added per key is very close to 1 anyway.
   (And the string-based logic might actually be a small pessimization, since
   manipulating a 1-byte string might be costlier than manipulating a single byte).

   But the row index might store arbitrarily long entries, and in that case the
   character-based logic might result in catastrophically bad performance.
   For reference: when writing a partition index, the total processing cost
   of a single node in the trie_writer is on the order of 800 instructions.
   Total processing cost of a single tiny partition during a `upgradesstables`
   operation is on the order of 10000 instructions. A small INSERT is on the
   order of 40000 instructions.

   So processing a single 1000-character clustering key in the trie_writer
   could cost as much as 20 INSERTs, which is scary. Even 100-character keys
   can be very expensive. With extremely long keys like that, the string-based
   logic is more than ~100x cheaper than character-based logic.
   (Note that only *new* characters matter here. If two index entries share a
   prefix, that prefix is only processed once. And the index is only populated
   with the minimal prefix needed to distinguish neighbours. So in practice,
   long chains might not happen often. But still, they are possible).

   I don't know if it makes sense to care about this case, but I figured the
   potential for problems is too big to ignore, so I switched to chain-based logic.

2. In the (assumed to be rare) case when a grouped subtree turns out to be bigger
   than a full page after revising the estimate, Cassandra splits it in a
   different way than us.

For testability, there is some separation between the logic responsible
for turning a stream of keys into a stream of nodes, and the logic
responsible for turning a stream of nodes into a stream of bytes.
This commit only includes the first part. It doesn't implement the target
on-disk format yet.

The serialization logic is passed to trie_writer via a template parameter.

There is only one test added in this commit, which attempts to be exhaustive,
by testing all possible datasets up to some size. The run time of the test
grows exponentially with the parameter size. I picked a set of parameters
which runs fast enough while still being expressive enough to cover all
the logic. (I checked the code coverage). But I also tested it with greater parameters
on my own machine (and with DEVELOPER_BUILD enabled, which adds extra sanitization).

Refs scylladb/scylladb#19191

New functionality, no backporting needed.

Closes scylladb/scylladb#25154

* github.com:scylladb/scylladb:
  sstables: introduce trie_writer
  utils/bit_cast: add object_representation()
2025-08-01 20:23:24 +03:00
Nikos Dragazis
2656fca504 test: Use in-memory SQLite for PyKMIP server
The PyKMIP server uses an SQLite database to store artifacts such as
encryption keys. By default, SQLite performs a full journal and data
flush to disk on every CREATE TABLE operation. Each operation triggers
three fdatasync(2) calls. If we multiply this by 16, that is the number
of tables created by the server, we get a significant number of file
syncs, which can last for several seconds on slow machines.

This behavior has led to CI stability issues from KMIP unit tests where
the server failed to complete its schema creation within the 20-second
timeout (observed on spider9 and spider11).

Fix this by configuring the server to use an in-memory SQLite.

Fixes #24842.

Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>

Closes scylladb/scylladb#24995
2025-08-01 12:11:27 +03:00
Nadav Har'El
20b31987e1 utils: unit test for utils::scoped_item_list
The previous test introduced a new utility class, utils::scoped_item_list.
This patch adds a comprehensive unit test for the new class.

We test basic usage of scoped_item_list, its size() and empty() methods,
how items are removed from the list when their handle goes out of scope,
how a handle's move constructor works, how items can be read and written
through their handles, and finally that removing an item during a
for_each_gently() iteration doesn't break the iteration.

One thing I still didn't figure out how to properly test is how removing
an item during *multiple* iterations that run concurrently fixes
multiple iterators. I believe the code is correct there (we just have a
list of ongoing iterations - instead of just one), but haven't found
yet a way to reproduce this situation in a test.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
2025-08-01 02:15:04 +03:00
Michał Chojnowski
c8682af418 sstables: introduce trie_writer
This is the first part of a larger project meant to implement a trie-based
index format. (The same or almost the same as Cassandra's BTI).

As of this patch, the new code isn't used for anything yet,
but we introduced separately from its users to keep PRs small enough
for reviewability.

This commit introduces trie_writer, a class responsible for turning a
stream of (key, value) pairs (already sorted by key) into a stream of
serializable nodes, such that:

1. Each node lies entirely within one page (guaranteed).
2. Parents are located in the same page as their children (best-effort).
3. Padding (unused space) is minimized (best-effort).

It does mostly what you would expect a "sorted keys -> trie" builder to do.
The hard part is calculating the sizes of nodes (which, in a well-packed on-disk
format, depend on the exact offsets of the node from its children) and grouping
them into pages.

This implementation mostly follows Cassandra's design of the same thing.
There are some differences, though. Notable ones:

1. The writer operates on chains of characters, rather than single characters.

   In Cassandra's implementation, the writer creates one node per character.
   A single long key can be translated to thousands of nodes.
   We create only one node per key. (Actually we split very long keys into
   a few nodes, but that's arbitrary and beside the point).

   For BTI's partition key index this doesn't matter.
   Since it only stores a minimal unique prefix of each key,
   and the trie is very balanced (due to token randomness),
   the average number of new characters added per key is very close to 1 anyway.
   (And the string-based logic might actually be a small pessimization, since
   manipulating a 1-byte string might be costlier than manipulating a single byte).

   But the row index might store arbitrarily long entries, and in that case the
   character-based logic might result in catastrophically bad performance.
   For reference: when writing a partition index, the total processing cost
   of a single node in the trie_writer is on the order of 800 instructions.
   Total processing cost of a single tiny partition during a `upgradesstables`
   operation is on the order of 10000 instructions. A small INSERT is on the
   order of 40000 instructions.

   So processing a single 1000-character clustering key in the trie_writer
   could cost as much as 20 INSERTs, which is scary. Even 100-character keys
   can be very expensive. With extremely long keys like that, the string-based
   logic is more than ~100x cheaper than character-based logic.
   (Note that only *new* characters matter here. If two index entries share a
   prefix, that prefix is only processed once. And the index is only populated
   with the minimal prefix needed to distinguish neighbours. So in practice,
   long chains might not happen often. But still, they are possible).

   I don't know if it makes sense to care about this case, but I figured the
   potential for problems is too big to ignore, so I switched to chain-based logic.

2. In the (assumed to be rare) case when a grouped subtree turns out to be bigger
   than a full page after revising the estimate, Cassandra splits it in a
   different way than us.

For testability, there is some separation between the logic responsible
for turning a stream of keys into a stream of nodes, and the logic
responsible for turning a stream of nodes into a stream of bytes.
This commit only includes the first part. It doesn't implement the target
on-disk format yet.

The serialization logic is passed to trie_writer via a template parameter.

There is only one test added in this commit, which attempts to be exhaustive,
by testing all possible datasets up to some size. The run time of the test
grows exponentially with the parameter size. I picked a set of parameters
which runs fast enough while still being expressive enough to cover all
the logic. (I checked the code coverage). But I also tested it with greater parameters
on my own machine (and with DEVELOPER_BUILD enabled, which adds extra sanitization).
2025-07-31 12:51:37 +02:00
Calle Wilund
43f7eecf9e compress: move compress.cc/hh to sstables/compressor
Fixes #22106

Moves the shared compress components to sstables, and rename to
match class type.

Adjust includes, removing redundant/unneeded ones where possible.

Closes scylladb/scylladb#25103
2025-07-31 13:10:41 +03:00
Pavel Emelyanov
34608450c5 Merge 'qos: don't populate effective service level cache until auth is migrated to raft' from Piotr Dulikowski
Right now, service levels are migrated in one group0 command and auth is migrated in the next one. This has a bad effect on the group0 state reload logic - modifying service levels in group0 causes the effective service levels cache to be recalculated, and to do so we need to fetch information about all roles. If the reload happens after SL upgrade and before auth upgrade, the query for roles will be directed to the legacy auth tables in system_auth - and the query, being a potentially remote query, has a timeout. If the query times out, it will throw an exception which will break the group0 apply fiber and the node will need to be restarted to bring it back to work.

In order to solve this issue, make sure that the service level module does not start populating and using the service level cache until both service levels and auth are migrated to raft. This is achieved by adding the check both to the cache population logic and the effective service level getter - they now look at service level's accessor new method, `can_use_effective_service_level_cache` which takes a look at the auth version.

Fixes: scylladb/scylladb#24963

Should be backported to all versions which support upgrade to topology over raft - the issue described here may put the cluster into a state which is difficult to get out of (group0 apply fiber can break on multiple nodes, which necessitates their restart).

Closes scylladb/scylladb#25188

* github.com:scylladb/scylladb:
  test: sl: verify that legacy auth is not queried in sl to raft upgrade
  qos: don't populate effective service level cache until auth is migrated to raft
2025-07-31 13:05:27 +03:00
Avi Kivity
5c6c944797 managed_bytes: make empty managed_bytes constexpr friendly
Sprinkle constexpr where needed to make the default constructor,
move constructor, and destructor constexpr.

Add a test to verify.

This is needed to make a thread_local variable containing an
empty managed_bytes constinit, reducing thread-local guards.
2025-07-29 23:51:43 +03:00
Botond Dénes
2985c343ed Merge 'repair: Avoid too many fragments in a single repair_row_on_wire' from Asias He
When repairing a partition with many rows, we can store many fragments in a repair_row_on_wire object which is sent as a rpc stream message.

This could cause reactor stalls when the rpc stream compression is turned on, because the compression compresses the whole message without any split and compression.

This patch solves the problem at the higher level by reducing the message size that is sent to the rpc stream.

Tests are added to make sure the message split works.

Fixes #24808

Closes scylladb/scylladb#25002

* github.com:scylladb/scylladb:
  repair: Avoid too many fragments in a single repair_row_on_wire
  repair: Change partition_key_and_mutation_fragments to use chunked_vector
  utils: Allow chunked_vector::erase to work with non-default-constructible type
2025-07-29 17:45:57 +03:00
Piotr Dulikowski
2bb800c004 qos: don't populate effective service level cache until auth is migrated to raft
Right now, service levels are migrated in one group0 command and auth
is migrated in the next one. This has a bad effect on the group0 state
reload logic - modifying service levels in group0 causes the effective
service levels cache to be recalculated, and to do so we need to fetch
information about all roles. If the reload happens after SL upgrade and
before auth upgrade, the query for roles will be directed to the legacy
auth tables in system_auth - and the query, being a potentially remote
query, has a timeout. If the query times out, it will throw
an exception which will break the group0 apply fiber and the node will
need to be restarted to bring it back to work.

In order to solve this issue, make sure that the service level module
does not start populating and using the service level cache until both
service levels and auth are migrated to raft. This is achieved by adding
the check both to the cache population logic and the effective service
level getter - they now look at service level's accessor new method,
`can_use_effective_service_level_cache` which takes a look at the auth
version.

Fixes: scylladb/scylladb#24963
2025-07-29 11:37:37 +02:00
Asias He
266a518e4c repair: Change partition_key_and_mutation_fragments to use chunked_vector
With the change in "repair: Avoid too many fragments in a single
repair_row_on_wire", the

std::list<frozen_mutation_fragment> _mfs;

in partition_key_and_mutation_fragments will not contain large number of
fragments any more. Switch to use chunked_vector.
2025-07-29 13:43:17 +08:00