Commit Graph

395 Commits

Author SHA1 Message Date
Kefu Chai
a33651b03e db, service: do not include unused header
these unused headers were flagged by clang-include-cleaner.

Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>

Closes scylladb/scylladb#23735
2025-04-17 11:49:59 +03:00
Nadav Har'El
fbcf77d134 raft: make group0 Raft operation timeout configurable
A recent commit 370707b111 (re)introduced
a timeout for every group0 Raft operation. This timeout was set to 60
seconds, which, paraphrasing Bill Gates, "ought to be enough for anybody".

However, one of the things we do as a group0 operation is schema
changes, and we already noticed a few years ago, see commit
0b2cf21932, that in some extremely
overloaded test machines where tests run hundreds of times (!) slower
than usual, a single big schema operation - such as Alternator's
DeleteTable deleting a table and multiple of its CDC or view tables -
sometimes takes more than 60 seconds. The above fix changed the
client's timeout to wait for 300 seconds instead of 60 seconds,
but now we also need to increase our Raft timeout, or the server can
time out. We've seen this happening recently making some tests flaky
in CI (issue #23543).

So let's make this timeout configurable, as a new configuration option
group0_raft_op_timeout_in_ms. This option defaults to 60000 (i.e,
60 seconds), the same as the existing default. The test framework
overrides this default with a a higher 300 second timeout, matching
the client-side timeout.

Before this patch, this timeout was already configurable in a strange
way, using injections. But this was a misstep: We already have more
than a dozen timeouts configurable through the normal configration,
and this one should have been configured in the same way. There is
nothing "holy" about the default of 60 seconds we chose, and who
knows maybe in the future we might need to tweek it in the field,
just like we made the other timeouts tweakable. Injections cannot
be used in release mode, but configuration options can.

Fixes #23543

Signed-off-by: Nadav Har'El <nyh@scylladb.com>

Closes scylladb/scylladb#23717
2025-04-15 10:57:39 +03:00
Avi Kivity
ed3e4f33fd Merge 'generic_server: throttle and shed incoming connections according to semaphore limit' from Marcin Maliszkiewicz
Adds new live updatable config: uninitialized_connections_semaphore_cpu_concurrency.

It should help to reduce cpu usage by limiting cpu concurrency for new connections.  As a last resort when those connections are waiting for initial processing too long (over 1m) they are shed.

New connections_shed and connections_blocked metrics are added for tracking.

Testing:
 - manually via simple program creating high number of connection and constantly re-connecting
 - added benchmark

Following are benchmark results:

Before:
```
> build/release/test/perf/perf_generic_server --smp=1
170101.41 tps ( 13.1 allocs/op,   0.0 logallocs/op,   7.0 tasks/op,    4695 insns/op,    3178 cycles/op,        0 errors)
[...]
throughput: mean=173850.06 standard-deviation=1844.48 median=174509.66 median-absolute-deviation=874.23 maximum=175087.49 minimum=170588.54
instructions_per_op: mean=4725.59 standard-deviation=13.35 median=4729.38 median-absolute-deviation=12.49 maximum=4738.61 minimum=4709.96
  cpu_cycles_per_op: mean=3135.08 standard-deviation=32.13 median=3122.68 median-absolute-deviation=22.29 maximum=3179.38 minimum=3103.15
```

After:
```
> build/release/test/perf/perf_generic_server --smp=1
167373.19 tps ( 13.1 allocs/op,   0.0 logallocs/op,   7.0 tasks/op,    4821 insns/op,    3371 cycles/op,        0 errors)
[...]
throughput:
  mean=   171199.55 standard-deviation=2484.58
  median= 171667.06 median-absolute-deviation=2087.63
  maximum=173689.11 minimum=167904.76
instructions_per_op:
  mean=   4801.90 standard-deviation=16.54
  median= 4796.78 median-absolute-deviation=9.32
  maximum=4830.71 minimum=4789.81
cpu_cycles_per_op:
  mean=   3245.26 standard-deviation=32.28
  median= 3230.44 median-absolute-deviation=16.52
  maximum=3297.39 minimum=3215.62
```

The patch adds around 67 insns/op so it's effect on performance should be negligible.

Fixes: https://github.com/scylladb/scylladb/issues/22844

Closes scylladb/scylladb#22828

* github.com:scylladb/scylladb:
  transport: move on_connection_close into connection destructor
  test: perf: make aggregated_perf_results formatting more human readable
  transport: add blocked and shed connection metrics
  generic_server: throttle and shed incoming connections according to semaphore limit
  generic_server: add data source and sink wrappers bookkeeping network IO
  generic_server: coroutinize part of server::do_accepts
  test: add benchmark for generic_server
  test: perf: add option to count multiple ops per time_parallel iteration
  generic_server: add semaphore for limiting new connections concurrency
  generic_server: add config to the constructor
  generic_server: add on_connection_ready handler
2025-04-09 21:41:38 +03:00
Marcin Maliszkiewicz
ed82bede39 generic_server: add semaphore for limiting new connections concurrency
It will be used in following commits.
2025-04-09 10:30:58 +02:00
Botond Dénes
fcdae20fd1 Merge 'Add tablet enforcing option' from Benny Halevy
This series add a new config option: `tablets_mode_for_new_keyspaces` that replaces the existing
`enable_tablets` option. It can be set to the following values:
    disabled: New keyspaces use vnodes by default, unless enabled by the tablets={'enabled':true} option
    enabled:  New keyspaces use tablets by default, unless disabled by the tablets={'disabled':true} option
    enforced: New keyspaces must use tablets. Tablets cannot be disabled using the CREATE KEYSPACE option

`tablets_mode_for_new_keyspaces=disabled` or `tablets_mode_for_new_keyspaces=enabled` control whether
tablets are disabled or enabled by default for new keyspaces, respectively.
In either cases, tablets can be opted-in or out using the `tablets={'enabled':...}`
keyspace option, when the keyspace is created.

`tablets_mode_for_new_keyspaces=enforced` enables tablets by default for new keyspaces,
like `tablets_mode_for_new_keyspaces=enabled`.
However, it does not allow to opt-out when creating
new keyspaces by setting `tablets = {'enabled': false}`

Refs scylladb/scylla-enterprise#4355

* Requires backport to 2025.1

Closes scylladb/scylladb#22273

* github.com:scylladb/scylladb:
  boost/tablets_test: verify failure to create keyspace with tablets and non network replication strategy
  tablets: enforce tablets using tablets_mode_for_new_keyspaces=enforced config option
  db/config: add tablets_mode_for_new_keyspaces option
2025-04-03 16:32:19 +03:00
Radosław Cybulski
c36614e16d alternator: add size check to BatchItemWrite
Add a size check for BatchItemWrite command - if the item count is
bigger than configuration value `alternator_maximum_batch_write_size`,
an error will be raised and no modification will happen.

This is done to synchronize with DynamoDB, where maximum size of
BatchItemWrite is 25. To avoid complaints from clients, who use
our feature of BatchWriteItem being limitless we set default value
to 100.

Fixes #5057

Closes scylladb/scylladb#23232
2025-04-02 14:48:00 +03:00
Pavel Emelyanov
2ee9cec1d3 Merge 'Remove object_storage.yaml and move the endpoints to scylla.yaml' from Robert Bindar
Move `object_storage.yaml` endpoints to `scylla.yaml`

This change also removes the `object_storage.yaml` file
altogether and adds tests for fetching the endpoints
via the `v2/config/object_storage_endpoints` REST api.

Also, `object_storage_config_file` options is moved to a deprecated state as it's no longer needed.

This PR depends on #22951, the reviewers should review patch 393e1ac0ec066475ca94094265a5f88dbbdb1a1f

Refs https://github.com/scylladb/scylladb/issues/22428

Closes scylladb/scylladb#22952

* github.com:scylladb/scylladb:
  Remove db::config::object_storage_config
  Move `object_storage.yaml` endpoints to `scylla.yaml`
2025-04-01 16:01:44 +03:00
Michał Chojnowski
4f0d453acf dict_autotrainer: introduce sstable_dict_autotrainer
Add a fiber responsible for periodic re-training of compression dictionaries
(for tables which opted into dict-aware compression).

As of this patch, it works like this:
every `$tick_period` (15 minutes), if we are the current Raft leader,
we check for dict-aware tables which have no dict, or a dict older
than `$retrain_period`.

For those tables, if they have enough data (>1GiB) for a training,
we train a new dict and check if it's significantly better
than the current one (provides ratio smaller than 95% of current ratio),
and if so, we update the dict.
2025-04-01 00:07:30 +02:00
Michał Chojnowski
30a9d471fa sstables: plug an sstable_compressor_factory into sstables_manager
Create a `sstable_compressor_factory_impl` in `scylla_main`,
and pipe it through constructors into `sstables_manager`.

In next commits, the factory available through the `sstables_manager`
will be used to create compressors for SSTable readers and writers.
2025-04-01 00:07:28 +02:00
Robert Bindar
b647196121 Remove db::config::object_storage_config
That map became redundant once we added
object_storage_endpoints in the config, this patch removes
it and switches all the user code to use the new option.

Signed-off-by: Robert Bindar <robert.bindar@scylladb.com>
2025-03-31 17:15:12 +03:00
Robert Bindar
e3a3508960 Move object_storage.yaml endpoints to scylla.yaml
This change also removes the `object_storage.yaml` file
altogether and adds tests for fetching the endpoints
via the `v2/config/object_storage_endpoints` REST api.

Signed-off-by: Robert Bindar <robert.bindar@scylladb.com>
2025-03-31 13:39:39 +03:00
Benny Halevy
62aeba759b tablets: enforce tablets using tablets_mode_for_new_keyspaces=enforced config option
`tablets_mode_for_new_keyspaces=enforced` enables tablets by default for
new keyspaces, like `tablets_mode_for_new_keyspaces=enabled`.
However, it does not allow to opt-out when creating
new keyspaces by setting `tablets = {'enabled': false}`.

Refs scylladb/scylla-enterprise#4355

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-03-24 15:32:16 +02:00
Benny Halevy
c62865df90 db/config: add tablets_mode_for_new_keyspaces option
The new option deprecates the existing `enable_tablets` option.
It will be extended in the next patch with a 3rd value: "enforced"
while will enable tablets by default for new keyspace but
without the posibility to opt out using the `tablets = {'enabled':
false}` keyspace schema option.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-03-24 14:54:45 +02:00
Avi Kivity
7646e1448a Merge 'cql3: Introduce RF-rack-valid keyspaces' from Dawid Mędrek
This PR is an introductory step towards enforcing
RF-rack-valid keyspaces in Scylla.

The scope of changes:
* defining RF-rack-valid keyspaces,
* introducing a configuration option enforcing RF-rack-valid
  keyspaces,
* restricting the CREATE and ALTER KEYSPACE statements
  so that they never lead to RF-rack invalid keyspaces,
* during the initialization of a node, it verifies that all existing
  keyspaces are RF-rack-valid. If not, the initialization fails.

We provide tests verifying that the changes behave as intended.

---

Note that there are a number of things that still need to be implemented.
That includes, for instance, restricting topology operations too.

---

Implementation strategy (going beyond the scope of this PR):

1. Introduce the new configuration option `rf_rack_valid_keyspaces`.
2. Start enforcing RF-rack-validity in keyspaces if the option is enabled.
3. Adjust the tests: in the tree and out of it. Explicitly enable the option in all tests.
4. Once the tests have been adjusted, change the default value of the option to enabled.
5. Stop explicitly enabling the option in tests.
6. Get rid of the option.

---

Fixes scylladb/scylladb#20356
Fixes scylladb/scylladb#23276
Fixes scylladb/scylladb#23300

---

Backport: this is part of the requirements for releasing 2025.1.

Closes scylladb/scylladb#23138

* github.com:scylladb/scylladb:
  main: Refuse to start node when RF-rack-invalid keyspace exists
  cql3: Ensure that CREATE and ALTER never lead to RF-rack-invalid keyspaces
  db/config: Introduce RF-rack-valid keyspaces
2025-03-20 19:10:36 +02:00
Dawid Mędrek
32879ec0d5 db/config: Introduce RF-rack-valid keyspaces
We introduce a new term in the glossary: RF-rack-valid keyspace.

We also highlight in our user documentation that all keyspaces
must remain RF-rack-valid throughout their lifetime, and failing
to guarantee that may result in data inconsistencies or other
issues. We base that information on our experience with materialized
views in keyspaces using tablets, even though they remain
an experimental feature.

Along with the new term, we introduce a new configuration option
called `rf_rack_valid_keyspaces`, which, when enabled, will enforce
preserving all keyspaces RF-rack-valid. That functionality will be
implemented in upcoming commits. For now, we materialize the
restriction in form of a named requirement: a function verifying
that the passed keyspace is RF-rack-valid.

The option is disabled by default. That will change once we adjust
the existing tests to the new semantics. Once that is done, the option
will first be enabled by default, and then it will be removed.

Fixes scylladb/scylladb#20356
2025-03-19 14:46:35 +01:00
Patryk Jędrzejczak
fd51d7e448 treewide: allow recreating group 0 in the Raft-based recovery procedure
This patch adds support for recreating group 0 after losing
majority. This is the only part of the new Raft-based recovery
procedure that touches Scylla core.

The following steps are necessary to recreate group 0:
1. Determine the new group 0 members. These are alive nodes that
are normal or rebuilding.
2. Choose the recovery leader - the node which will become the
new group 0 leader. This must be one of the nodes with the
latest persistent group 0 state.
3. Remove `raft_group_id` from `system.scylla_local` and truncate
`system.discovery` on each live node.
4. Set the new scylla.yaml parameter - `recovery_leader` - to Host
ID of the recovery leader on each live node.
5. Rolling restart all live nodes, but the recovery leader must be
restarted first.

In the implementation, restarts in step 5 are very similar to normal
restarts with the Raft-based topology enabled. The only differences
are:
1. Steps 3-4 make the restarting node discover the new group 0
in `join_cluster`.
2. The group 0 server is started in `join_group0`, not
`setup_group0_if_exists`.
3. The restarting node joins the new group 0 in `join_topology` using
`legacy_handshaker`. There is no reason to contact the topology
coordinator since the node has already joined the topology.

Unfortunately, this patch creates another execution path for the
starting logic. `join_cluster` becomes even messier. However, there
is nothing we can do about it. Joining group 0 without joining
topology is something completely new. Having a few small changes
without touching other execution paths is the best we can do.
We will start removing the old stuff soon, after making the
Raft-based topology mandatory, and the situation will improve.
2025-03-14 13:52:57 +01:00
Tomasz Grabiec
d01cc16d1e config, disk_space_monitor: Allow overriding capacity via config
Intended for testing, or hot-fixing out-of-space issues in production.

Tablet load balancer uses this information for determining per-shard load
so reducing capacity will cause tablets to be migrated away from the node.
2025-03-06 13:35:37 +01:00
Botond Dénes
5d63ef4d15 Merge 'scylla sstable: Add standard extensions and propagate to schema load ' from Calle Wilund
Fixes #22314

Adds expected schema extensions to the tools extension set (if used). Also uses the source config extensions in schema loader instead of temp one, to ensure we can, for example, load a schema.cql with things like `tombstone_gc` or encryption attributes in them.

Bundles together the setup of "always on" schema extensions into a single call, and uses this from the three (3) init points.
Could have opted for static reg via `configurables`, but since we are moving to a single code base, the need for this is going away, hence explicit init seems more in line.

Closes scylladb/scylladb#22327

* github.com:scylladb/scylladb:
  tools: Add standard extensions and propagate to schema load
  cql_test_env: Use add all extensions instead of inidividually
  main: Move extensions adding to function
  tomstone_gc: Make validate work for tools
2025-02-26 13:52:47 +02:00
Tomasz Grabiec
1a7023c85a config, tablets: Allow tablets_initial_scale_factor to be a fraction
We may want fewer than 1 tablets per shard in large clusters.

The per-table option is a fraction, so for consistency, this should be
too.
2025-02-19 16:29:08 +01:00
Tomasz Grabiec
f1bda8d4c1 tablets: load_balancer: Scale down tablet count to respect per-shard tablet count goal
The limit is enforced by controlling average per-shard tablet replica
count in a given DC, which is controlled by per-table tablet
count. This is effective in respecting the limit on individual shards
as long as tablet replicas are distributed evenly between shards.

There is no attempt to move tablets around in order to enforce limits
on individual shards in case of imbalance between shards.

If the average per-shard tablet count exceeds the limit, all tables
which contribute to it (have replicas in the DC) are scaled down
by the same factor. Due to rounding up to the nearest power of 2,
we may overshoot the per-shard goal by at most a factor of 2.

If different DCs want different scale factors of a given table, the
lowest scale factor is chosen for a given table.

The limit is configurable. It's a global per-cluster config which
controls how many tablet replicas per shard in total we consider to be
still ok. It controls tablet allocator behavior, when choosing initial
tablet count. Even though it's a per-node config, we don't support
different limits per node. All nodes must have the same value of that
config. It's similar in that regard to other scheduler config items
like tablets_initial_scale_factor and target_tablet_size_in_bytes.
2025-02-19 16:29:07 +01:00
Avi Kivity
c212f5a296 db/config: forward-declare boost options_description_easy_init
Reduces large dependency pull from boost.

Closes scylladb/scylladb#22748
2025-02-10 15:08:11 +02:00
Asias He
4018dc7f0d Introduce file stream for tablet
File based stream is a new feature that optimizes tablet movement
significantly. It streams the entire SSTable files without deserializing
SSTable files into mutation fragments and re-serializing them back into
SSTables on receiving nodes. As a result, less data is streamed over the
network, and less CPU is consumed, especially for data models that
contain small cells.

The following patches are imported from the scylla enterprise:

*) Merge 'Introduce file stream for tablet' from Asias He

    This patch uses Seastar RPC stream interface to stream sstable files on
    network for tablet migration.

    It streams sstables instead of mutation fragments. The file based
    stream has multiple advantages over the mutation streaming.

    - No serialization or deserialization for mutation fragments
    - No need to read and process each mutation fragments
    - On wire data is more compact and smaller

    In the test below, a significant speed up is observed.

    Two nodes, 1 shard per node, 1 initial_tablets:

    - Start node 1
    - Insert 10M rows of data with c-s
    - Bootstrap node 2

    Node 1 will migration data to node2 with the file stream.

    Test results:

    1) File stream: bytes on wire = 1132006250 bytes, bw = 836MB/s

    [shard 0:stre] stream_blob - stream_sstables[eadaa8e0-a4f2-4cc6-bf10-39ad1ce106b0]
	Finished sending sstable_nr=2 files_nr=18 files={} range=(-1,9223372036854775807] bytes_sent=1132006250 stream_bw=836MB/s
    [shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 1.08004s seconds

    2) Mutation stream: bytes on wire = 3030004736 bytes, bw = 125410.87 KiB/s = 128MB/s

    [shard 0:stre] stream_session - [Stream #406dc8b0-56b5-11ee-bc2d-000bf4871058]
	Streaming plan for Tablet migration-ks1-index-0 succeeded, peers={127.0.0.1}, tx=0 KiB, 0.00 KiB/s, rx=2958989 KiB, 125410.87 KiB/s
    [shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 23.5992s seconds

    Test Summary:

    File stream v.s. Mutation stream improvements

    - Stream bandwidth = 836 / 128  (MB/s)  = 6.53X

    - Stream time = 23.60 / 1.08  (Seconds) = 21.85X

    - Stream bytes on wire = 3030004736 / 1132006250 (Bytes)= 2.67X

    Closes scylladb/scylla-enterprise#3438

    * github.com:scylladb/scylla-enterprise:
      tests: Add file_stream_test
      streaming: Implement file stream for tablet

*) streaming: Use new take_storage_snapshot interface

    The new take_storage_snapshot returns a file object instead of a file
    name. This allows the file stream sender to read from the file even if
    the file is deleted by compaction.

    Closes scylladb/scylla-enterprise#3728

*) streaming: Protect unsupported file types for file stream

    Currently, we assume the file streamed over the stream_blob rpc verb is
    a sstable file. This patch rejects the unsupported file types on the
    receiver side. This allows us to stream more file types later using the
    current file stream infrastructure without worrying about old nodes
    processing the new file types in the wrong way.

    - The file_ops::noop is renamed to file_ops::stream_sstables to be
      explicit about the file types

    - A missing test_file_stream_error_injection is added to the idl

    Fixes: #3846
    Tests: test_unsupported_file_ops

    Closes scylladb/scylla-enterprise#3847

*) idl: Add service::session_id id to idl

    It will be used in the next patch.

    Refs #3907

*) streaming: Protect file stream with topology_guard

    Similar to "storage_service, tablets: Use session to guard tablet
    streaming", this patch protects file stream with topology_guard.

    Fixes #3907

*) streaming: Take service topology_guard under the try block

    Taking the service::topology_guard could throw. Currently, it throws
    outside the try block, so the rpc sink will not be closed, causing the
    following assertion:

    ```
    scylla: seastar/include/seastar/rpc/rpc_impl.hh:815: virtual
    seastar::rpc::sink_impl<netw::serializer,
    streaming::stream_blob_cmd_data>::~sink_impl() [Serializer =
    netw::serializer, Out = <streaming::stream_blob_cmd_data>]: Assertion
    `this->_con->get()->sink_closed()' failed.
    ```

    To fix, move more code including the topology_guard taking code to the
    try block.

    Fixes https://github.com/scylladb/scylla-enterprise/issues/4106

    Closes scylladb/scylla-enterprise#4110

*) Merge 'Preserve original SSTable state with file based tablet migration' from Raphael "Raph" Carvalho

    We're not preserving the SSTable state across file based migration, so
    staging SSTables for example are being placed into main directory, and
    consequently, we're mixing staging and non-staging data, losing the
    ability to continue from where the old replica left off.
    It's expected that the view update backlog is transferred from old
    into new replica, as migration doesn't wait for leaving replica to
    complete view update work (which can take long). Elasticity is preferred.

    So this fix guarantees that the state of the SSTable will be preserved
    by propagating it in form of subdirectory (each subdirectory is
    statically mapped with a particular state).

    The staging sstables aren't being registered into view update generator
    yet, as that's supposed to be fixed in OSS (more details can be found
    at https://github.com/scylladb/scylladb/issues/19149).

    Fixes #4265.

    Closes scylladb/scylla-enterprise#4267

    * github.com:scylladb/scylla-enterprise:
      tablet: Preserve original SSTable state with file based tablet migration
      sstables: Add get method for sstable state

*) sstable: (Re-)add shareabled_components getter

*) Merge 'File streaming sstables: Use sstable source/sink to transfer snapshots' from Calle Wilund

    Fixes #4246

    Alternative approach/better separation of concern, transport vs. sstable layer. Builds on #4472, but fancier.

    Ensures we transfer and pre-process scylla metadata for streamed
    file blobs first, then properly apply receiving nodes local config
    by using a source and sink layer exported from sstables, which
    handles things like ordering, metadata filtering (on source) as well
    as handling metadata and proper IO paths when writing data on
    receiver node (sink).

    This implementation maintains the statelessness of the current
    design, and the delegated sink side will re-read and re-write the
    metadata for each component processed. This is a little wasteful,
    but the meta is small, and it is less error prone than trying to do
    caching cross-shards etc. The transport is isolated from the
    knowledge.

    This is an alternative/complement to #4436 and #4472, fixing the
    underlying issue. Note that while the layers/API:s here allows easy
    fixing of other fundamental problems in the feature (such as
    destination location etc), these are not included in the PR, to keep
    it as close to the current behaviour as possible.

    Closes scylladb/scylla-enterprise#4646

    * github.com:scylladb/scylla-enterprise:
      raft_tests: Copy/add a topology test with encryption
      file streaming: Use sstable source/sink to transfer snapshots
      sstables: Add source and sink objects + producers for transfering a snapshot
      sstable::types: Add remove accessor for extension info in metadata

*) The change for error injection in merge commit 966ea5955dd8760:

    File streaming now has "stream_mutation_fragments" error injection points
    so test_table_dropped_during_streaming works with file streaming.

*) doc: document file-based streaming

    This commit adds a description of the file-based streaming feature to the documentation.

    It will be displayed in the docs using the scylladb_include_flag directive after
    https://github.com/scylladb/scylladb/pull/20182 is merged, backported to branch-6.0,
    and, in turn, branch-2024.2.

    Refs https://github.com/scylladb/scylla-enterprise/issues/4585
    Refs https://github.com/scylladb/scylla-enterprise/issues/4254

    Closes scylladb/scylla-enterprise#4587

*) doc: move File-based streaming to the Tablets source file-based-streaming

    This commit moves the description of file-based streaming from a common include file
    to the regular doc source file where tablets are described.

    Closes scylladb/scylla-enterprise#4652

*) streaming: sstable_stream_sink_impl: abort: prevent null pointer dereference

Closes scylladb/scylladb#22467
2025-01-26 12:51:59 +02:00
Avi Kivity
59d3a66d18 Revert "Introduce file stream for tablet"
This reverts commit 8208688178. It was
contributed from enterprise, but is too different from the original
for me to merge back.
2025-01-22 09:42:20 +02:00
Nadav Har'El
3e16b80014 Merge 'Reject create table with compact storage' from Benny Halevy
As discussed in
https://github.com/scylladb/scylladb/issues/12263#issuecomment-1853576813,
compact storage tables are deprecated.

Yet, there's is nothing in the code that prevents users
from creating such tables.

This patch adds a live-updateable config option:
`enable_create_table_with_compact_storage`, set to
`false` by default, that require users to opt-in
in order to create new tables WITH COMPACT STORAGE.

Refs scylladb/scylladb#12263, scylladb/scylladb#16375

* Since this guardrail is an enhancement, no backport is needed

Closes scylladb/scylladb#16403

* github.com:scylladb/scylladb:
  docs: ddl: document the deprecation of compact tables
  test: enable_create_table_with_compact_storage for tests that need it
  config: add enable_create_table_with_compact_storage
2025-01-20 22:02:02 +02:00
Asias He
8208688178 Introduce file stream for tablet
File based stream is a new feature that optimizes tablet movement
significantly. It streams the entire SSTable files without deserializing
SSTable files into mutation fragments and re-serializing them back into
SSTables on receiving nodes. As a result, less data is streamed over the
network, and less CPU is consumed, especially for data models that
contain small cells.

The following patches are imported from the scylla enterprise:

*) Merge 'Introduce file stream for tablet' from Asias He

    This patch uses Seastar RPC stream interface to stream sstable files on
    network for tablet migration.

    It streams sstables instead of mutation fragments. The file based
    stream has multiple advantages over the mutation streaming.

    - No serialization or deserialization for mutation fragments
    - No need to read and process each mutation fragments
    - On wire data is more compact and smaller

    In the test below, a significant speed up is observed.

    Two nodes, 1 shard per node, 1 initial_tablets:

    - Start node 1
    - Insert 10M rows of data with c-s
    - Bootstrap node 2

    Node 1 will migration data to node2 with the file stream.

    Test results:

    1) File stream: bytes on wire = 1132006250 bytes, bw = 836MB/s

    [shard 0:stre] stream_blob - stream_sstables[eadaa8e0-a4f2-4cc6-bf10-39ad1ce106b0]
	Finished sending sstable_nr=2 files_nr=18 files={} range=(-1,9223372036854775807] bytes_sent=1132006250 stream_bw=836MB/s
    [shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 1.08004s seconds

    2) Mutation stream: bytes on wire = 3030004736 bytes, bw = 125410.87 KiB/s = 128MB/s

    [shard 0:stre] stream_session - [Stream #406dc8b0-56b5-11ee-bc2d-000bf4871058]
	Streaming plan for Tablet migration-ks1-index-0 succeeded, peers={127.0.0.1}, tx=0 KiB, 0.00 KiB/s, rx=2958989 KiB, 125410.87 KiB/s
    [shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 23.5992s seconds

    Test Summary:

    File stream v.s. Mutation stream improvements

    - Stream bandwidth = 836 / 128  (MB/s)  = 6.53X

    - Stream time = 23.60 / 1.08  (Seconds) = 21.85X

    - Stream bytes on wire = 3030004736 / 1132006250 (Bytes)= 2.67X

    Closes scylladb/scylla-enterprise#3438

    * github.com:scylladb/scylla-enterprise:
      tests: Add file_stream_test
      streaming: Implement file stream for tablet

*) streaming: Use new take_storage_snapshot interface

    The new take_storage_snapshot returns a file object instead of a file
    name. This allows the file stream sender to read from the file even if
    the file is deleted by compaction.

    Closes scylladb/scylla-enterprise#3728

*) streaming: Protect unsupported file types for file stream

    Currently, we assume the file streamed over the stream_blob rpc verb is
    a sstable file. This patch rejects the unsupported file types on the
    receiver side. This allows us to stream more file types later using the
    current file stream infrastructure without worrying about old nodes
    processing the new file types in the wrong way.

    - The file_ops::noop is renamed to file_ops::stream_sstables to be
      explicit about the file types

    - A missing test_file_stream_error_injection is added to the idl

    Fixes: #3846
    Tests: test_unsupported_file_ops

    Closes scylladb/scylla-enterprise#3847

*) idl: Add service::session_id id to idl

    It will be used in the next patch.

    Refs #3907

*) streaming: Protect file stream with topology_guard

    Similar to "storage_service, tablets: Use session to guard tablet
    streaming", this patch protects file stream with topology_guard.

    Fixes #3907

*) streaming: Take service topology_guard under the try block

    Taking the service::topology_guard could throw. Currently, it throws
    outside the try block, so the rpc sink will not be closed, causing the
    following assertion:

    ```
    scylla: seastar/include/seastar/rpc/rpc_impl.hh:815: virtual
    seastar::rpc::sink_impl<netw::serializer,
    streaming::stream_blob_cmd_data>::~sink_impl() [Serializer =
    netw::serializer, Out = <streaming::stream_blob_cmd_data>]: Assertion
    `this->_con->get()->sink_closed()' failed.
    ```

    To fix, move more code including the topology_guard taking code to the
    try block.

    Fixes https://github.com/scylladb/scylla-enterprise/issues/4106

    Closes scylladb/scylla-enterprise#4110

*) Merge 'Preserve original SSTable state with file based tablet migration' from Raphael "Raph" Carvalho

    We're not preserving the SSTable state across file based migration, so
    staging SSTables for example are being placed into main directory, and
    consequently, we're mixing staging and non-staging data, losing the
    ability to continue from where the old replica left off.
    It's expected that the view update backlog is transferred from old
    into new replica, as migration doesn't wait for leaving replica to
    complete view update work (which can take long). Elasticity is preferred.

    So this fix guarantees that the state of the SSTable will be preserved
    by propagating it in form of subdirectory (each subdirectory is
    statically mapped with a particular state).

    The staging sstables aren't being registered into view update generator
    yet, as that's supposed to be fixed in OSS (more details can be found
    at https://github.com/scylladb/scylladb/issues/19149).

    Fixes #4265.

    Closes scylladb/scylla-enterprise#4267

    * github.com:scylladb/scylla-enterprise:
      tablet: Preserve original SSTable state with file based tablet migration
      sstables: Add get method for sstable state

*) sstable: (Re-)add shareabled_components getter

*) Merge 'File streaming sstables: Use sstable source/sink to transfer snapshots' from Calle Wilund

    Fixes #4246

    Alternative approach/better separation of concern, transport vs. sstable layer. Builds on #4472, but fancier.

    Ensures we transfer and pre-process scylla metadata for streamed
    file blobs first, then properly apply receiving nodes local config
    by using a source and sink layer exported from sstables, which
    handles things like ordering, metadata filtering (on source) as well
    as handling metadata and proper IO paths when writing data on
    receiver node (sink).

    This implementation maintains the statelessness of the current
    design, and the delegated sink side will re-read and re-write the
    metadata for each component processed. This is a little wasteful,
    but the meta is small, and it is less error prone than trying to do
    caching cross-shards etc. The transport is isolated from the
    knowledge.

    This is an alternative/complement to #4436 and #4472, fixing the
    underlying issue. Note that while the layers/API:s here allows easy
    fixing of other fundamental problems in the feature (such as
    destination location etc), these are not included in the PR, to keep
    it as close to the current behaviour as possible.

    Closes scylladb/scylla-enterprise#4646

    * github.com:scylladb/scylla-enterprise:
      raft_tests: Copy/add a topology test with encryption
      file streaming: Use sstable source/sink to transfer snapshots
      sstables: Add source and sink objects + producers for transfering a snapshot
      sstable::types: Add remove accessor for extension info in metadata

*) The change for error injection in merge commit 966ea5955dd8760:

    File streaming now has "stream_mutation_fragments" error injection points
    so test_table_dropped_during_streaming works with file streaming.

*) doc: document file-based streaming

    This commit adds a description of the file-based streaming feature to the documentation.

    It will be displayed in the docs using the scylladb_include_flag directive after
    https://github.com/scylladb/scylladb/pull/20182 is merged, backported to branch-6.0,
    and, in turn, branch-2024.2.

    Refs https://github.com/scylladb/scylla-enterprise/issues/4585
    Refs https://github.com/scylladb/scylla-enterprise/issues/4254

    Closes scylladb/scylla-enterprise#4587

*) doc: move File-based streaming to the Tablets source file-based-streaming

    This commit moves the description of file-based streaming from a common include file
    to the regular doc source file where tablets are described.

    Closes scylladb/scylla-enterprise#4652

*) streaming: sstable_stream_sink_impl: abort: prevent null pointer dereference

Closes scylladb/scylladb#22034
2025-01-20 16:43:21 +02:00
Benny Halevy
0110eb0506 config: add enable_create_table_with_compact_storage
As discussed in
https://github.com/scylladb/scylladb/issues/12263#issuecomment-1853576813,
compact storage tables are deprecated.

Yet, there's is nothing in the code that prevents users
from creating such tables.

This patch adds a live-updateable config option:
`enable_create_table_with_compact_storage` that require users
to opt-in in order to create new tables WITH COMPACT STORAGE.

The option is currently set to `true` by default in db/config
to reduce the churn to tests and to `false` in scylla.yaml,
for new clusters.

TODO: once regressions tests that use compact storage
are converted to enable the option, change the default in
db/config to false.

A unit test was added to test/cql-pytest that
checks that the respective cql query fails as expected
with the default option or when it is explicitly set to `false`,
and that the query succeeds when the option is set to `true`.

Note that `check_restricted_table_properties` already
returns an optional warning, but it is only logged
but not returned in the `prepared_statement`.
Fixing that is out of the scope of this patch.
See https://github.com/scylladb/scylladb/issues/20945

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2025-01-20 08:03:25 +02:00
Calle Wilund
4aaf3df45e main: Move extensions adding to function
Easily called from elsewhere. The extensions we should always include (oxymoron?)
2025-01-15 12:07:39 +00:00
Paweł Zakrzewski
384641194a audit: Add the audit subsystem
This change introduces a new audit subsystem that allows tracking and logging of database operations for security and compliance purposes. Key features include:

- Configurable audit logging to either syslog or a dedicated system table (audit.audit_log)
- Selective auditing based on:
  - Operation categories (QUERY, DML, DDL, DCL, AUTH, ADMIN)
  - Specific keyspaces
  - Specific tables
- New configuration options:
  - audit: Controls audit destination (none/syslog/table)
  - audit_categories: Comma-separated list of operation categories to audit
  - audit_tables: Specific tables to audit
  - audit_keyspaces: Specific keyspaces to audit
  - audit_unix_socket_path: Path for syslog socket
  - audit_syslog_write_buffer_size: Buffer size for syslog writes

The audit logs capture details including:
- Operation timestamp
- Node and client IP addresses
- Operation category and query
- Username
- Success/failure status
- Affected keyspace and table names
2025-01-15 11:10:35 +01:00
Benny Halevy
8d2ff8a915 utils: add disk_space_monitor
Instantiated only on shard 0.
Currently, only subscribe from unit test

Manual unit test using loop mount was added.
Note that the test requires sudo access
and root access to /dev/loop, so it cannot
run in rootless podman instance, and it'd
fail with Permission denied.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>

Closes scylladb/scylladb#21523
2025-01-12 14:51:15 +02:00
Piotr Smaron
288f9b2b15 Introduce LDAP role manager & saslauthd authenticator
This PR extends authentication with 2 mechanisms:
- a new role_manager subclass, which allows managing users via
LDAP server,
- a new authenticator, which delegates plaintext authentication
to a running saslauthd daemon.

The features have been ported from the enterprise repository
with their test.py tests and the documentation as part of
changing license to source available.

Fixes: scylladb/scylla-enterprise#5000
Fixes: scylladb/scylla-enterprise#5001

Closes scylladb/scylladb#22030
2025-01-12 14:50:29 +02:00
Wojciech Mitros
d04f376227 mv: add an experimental feature for creating views using tablets
We still have a number of issues to be solved for views with tablets.
Until they are fixed, we should prevent users from creating them,
and use the vnode-based views instead.

This patch prepares the feature for enabling views with tablets. The
feature is disabled by default, but currently it has no effect.
After all tests are adjusted to use the feature, we should depend
on the feature for deciding whether we can create materialized views
in tablet-enabled keyspaces.

The unit tests are adjusted to enable this feature explicitly, and it's
also added to the scylla sstable tool config - this tool treats all
tables as if they were tablet-based (surprisingly, with SimpleStrategy),
so for it to work on views, the new feature must be enabled.

Refs scylladb/scylladb#21832

Closes scylladb/scylladb#21833
2025-01-07 15:52:36 +01:00
Michał Chojnowski
fdb2d2209c messaging_service: use advanced_rpc_compression::tracker for compression
This patch sets up an `alien_worker`, `advanced_rpc_compression::tracker`,
`dict_sampler` and `dictionary_service` in `main()`, and wires them to each other
and to `messaging_service`.

`messaging_service` compresses its network traffic with compressors managed by
the `advanced_rpc_compression::tracker`. All this traffic is passed as a single
merged "stream" through `dict_sampler`.

`dictionary_service` has access to `dict_sampler`.
On chosen nodes (by default: the Raft leader), it uses the sampler to maintain
a random multi-megabyte sample of the sampler's stream. Every several minutes,
it copies the sample, trains a compression dictionary on it (by calling zstd's
training library via the `alien_worker` thread) and publishes the new dictionary
to `system.dicts` via Raft.

This update triggers a callback into `advanced_rpc_compression::tracker` on all nodes,
which updates the dictionary used by the compressors it manages.
2024-12-27 10:17:58 +01:00
Avi Kivity
f3eade2f62 treewide: relicense to ScyllaDB-Source-Available-1.0
Drop the AGPL license in favor of a source-available license.
See the blog post [1] for details.

[1] https://www.scylladb.com/2024/12/18/why-were-moving-to-a-source-available-license/
2024-12-18 17:45:13 +02:00
Botond Dénes
34a8b492be Merge 'materialized view: make flow-control maximum delay configurable' from Piotr Dulikowski
This pull request is continuation of scylladb/scylladb#20688 - contents of the main commit are the same, the only change is the additional commit with a test.

Until this patch, the materialized view flow-control algorithm (https://www.scylladb.com/2018/12/04/worry-free-ingestion-flow-control/) used a constant delay_limit_us hard-coded to one second, which means that when the size of view-update backlog reached the maximum (10% of memory), we delay every request by an additional second - while smaller amounts of backlog will result in smaller delays.

This hard-coded one maximum second delay was considered *huge* - it will slow down a client with concurrency 1000 to just 1000 requests per second - but we already saw some workloads where it was not enough - such as a test workload running very slow reads at high concurrency on a slow machine, where a latency of over one second was expected for each read, so adding a one second latecy for writes wasn't having any noticable affect on slowing down the client.

So this patch replaces the hard-coded default with a live-updateable configuration parameter, `view_flow_control_delay_limit_in_ms`, which defaults to 1000ms as before.

Another useful way in which the new `view_flow_control_delay_limit_in_ms` can be used is to set it to 0. In that case, the view-update flow control always adds zero delay, and in effect - does absolutely nothing. This setting can be used in emergency situations where it is suspected that the MV flow control is not behaving properly, and the user wants to disable it.

The new parameter's help string mentions both these use cases of the parameter.

Fixes #18187

This is new functionality, no need to backport to any open source release.

Closes scylladb/scylladb#21647

* github.com:scylladb/scylladb:
  materialized views: test for the MV delay configuration parameter
  service: add injection for skipping view update backlog
  materialized view: make flow-control maximum delay configurable
2024-12-16 14:20:33 +02:00
Nadav Har'El
49f11f655c materialized view: make flow-control maximum delay configurable
Until this patch, the materialized view flow-control algorithm
(https://www.scylladb.com/2018/12/04/worry-free-ingestion-flow-control/)
used a constant delay_limit_us hard-coded to one second, which means
that when the size of view-update backlog reached the maximum (10%
of memory), we delay every request by an additional second - while
smaller amounts of backlog will result in smaller delays.

This hard-coded one maximum second delay was considered *huge* - it will
slow down a client with concurrency 1000 to just 1000 requests per
second - but we already saw some workloads where it was not enough -
such as a test workload running very slow reads at high concurrency
on a slow machine, where a latency of over one second was expected
for each read, so adding a one second latecy for writes wasn't having
any noticable affect on slowing down the client.

So this patch replaces the hard-coded default with a live-updateable
configuration parameter, `view_flow_control_delay_limit_in_ms`, which
defaults to 1000ms as before.

Another useful way in which the new `view_flow_control_delay_limit_in_ms`
can be used is to set it to 0. In that case, the view-update flow
control always adds zero delay, and in effect - does absolutely
nothing. This setting can be used in emergency situations where it
is suspected that the MV flow control is not behaving properly, and
the user wants to disable it.

The new parameter's help string mentions both these use cases of
the parameter.

Fixes #18187

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
2024-12-05 09:51:56 +01:00
Botond Dénes
ccb433d767 Merge 'tasks: add api_task_ttl for tasks started with API' from Aleksandra Martyniuk
When users start an operation asynchronously with API, they are expected to check the operation's status. Hence, the status should be kept in task manager for reasonable time after the operation is done. The operations that are started internally usually don't need to stay in task manager for that long.

Add api_task_ttl that will be used for tasks started with API. By default it's 1 hour. The time for which non-API tasks stay in task manager isn't changed.

Fixes: #21499.
Refs: #21425.

No backport needed - previous versions may use task_ttl

Closes scylladb/scylladb#21505

* github.com:scylladb/scylladb:
  test: add test to check user_task_ttl
  tasks: api: move make_task method
  docs: nodetool: update backup and restore commands docs
  docs: update task manager docs
  nodetool: add nodetool tasks user-ttl command
  node_ops: use user task ttl for node ops virtual task
  tasks: use user_task_ttl for tasks started by user
  api: task_manager: add /task_manager/user_ttl to get and set user task ttl
  tasks: add task_manager::task::is_user_task method
  tasks: keep updateable_value of task_ttl in task manager
  db: config: add user_task_ttl_seconds named value
2024-11-27 09:57:57 +02:00
Aleksandra Martyniuk
1bf073704c db: config: add user_task_ttl_seconds named value
Add user_task_ttl_seconds config option and keep the value in task manager.
In the following patches tasks started by user will be kept in task
manager for user_task_ttl_seconds after they are finished.
2024-11-25 14:16:06 +01:00
Asias He
9ace191616 repair: Enable small table optimization for RBNO bootstrap and decommission
The non local strategy system keyspaces usually contain very litte data.
All the tables within them have to be repaired for all the token ranges,
which could be large in clusters with a large number of nodes. In multiple
DC setup, the repair in RBNO is dominated by the network latency. As a
result, it takes a long time to repair those tables even if they are
almost empty.

To speed up the RBNO bootstrap, especially for starting empty clusters,
this patch enables small table optimization for RBNO for system tables.
We could enable it for small user tables as a follow up.

Tests:

1) A 5ms latency is added to simulate cross dc network delay, 256 tokens
per node, 10 nodes:

- Before

  topology_custom dev topology_custom.test_boot_time.1 1287.06s

- After

  topology_custom dev topology_custom.test_boot_time.1 12.48s

The test shows 100X boot time improvement

2) A SCT test to bootstrap 3 DCs, 3 nodes in each DC.

- Before

  Time to bootstrap = 1h23m

- After

  Time to bootstrap = 13m

The test shows 6X bootstrap time improvement

Fixes #19131
2024-11-25 13:46:17 +08:00
Botond Dénes
a248520201 db/config: introduce repair_multishard_reader_enable_read_ahead
Not used yet.
2024-11-07 02:47:54 -05:00
Botond Dénes
3c25e6fcb4 db/config: introduce enable_repair_multishard_reader_buffer_hint
Allows enabling/disabling the multishard reader buffer hint
optimization. Not wired yet.
2024-11-06 08:51:00 -05:00
Asias He
b3b3e880d3 repair: Reduce hints and batchlog flush
The hints and batchlog flush requests are issued to all nodes for each
repair request when tombstone_gc repair mode is used.

The amount of such flush requests is high when all nodes in the cluster
run repair. It is observed it takes a long time, up to 15s, for a repair
request to finish such a flush request.

To reduce overhead of the flush, each node caches the flush and only
executes the real flush when the cahce time has passed. It is safe to do
so because the real flush_time is returned. Repair uses the smallest
flush_time returned from peers as the repair time.

The nice thing about the cache on the receiver side is that all senders
can hit the cache. It is better than cache on the sender side.

A slightly smaller flush_time compared to the real flush time will be
used with the benefits of significantly dropped hints and batchlog
flush. The trade-off looks reasonable.

Tests: 2 nodes, with 1s batchlog delay:

Before:
   Repair nr_repairs=20 cache_time_in_ms=0 total_repair_duration=40.04245328903198

After:
   Repair nr_repairs=20 cache_time_in_ms=5000 total_repair_duration=1.252073049545288

Fixes #20259
2024-10-30 11:07:57 +08:00
Botond Dénes
1635525526 db/config: introduce batchlog_replay_cleanup_after_replays
Not used yet.
2024-10-30 11:07:57 +08:00
Nadav Har'El
5fd3177057 Merge 'mv: add a dedicated read concurrency semaphore for view update read before writes' from Wojciech Mitros
When writing to some tables with materialized views, we need to read from the base table first to perform a delete of the old view row. When doing so, the memory used for the read is tracked by the user read concurrency semaphore. When we have a large number of such reads, we may use up all of the semaphore units, causing the following reads to be queued. When we have some user reads coming at the same time, these reads can have very high latency due to the write workload on the base table. We want to avoid this, so that the write workload doesn't have a high impact on the latency of the read workload.

This is fixed in this patch by adding a separate read concurrency semaphore just for view update read-before-writes. With the new semaphore, even if there are many view update read-before-writes, they will be queued on a different semaphore than the user reads, and they won't impact their latency.

The second issue fixed by this patch is the concurrency of the view updates that is currently unlimited. Because of that view updates may take up so much memory that they we may run out of memory.

This is fixed by using the read admission on the view update concurrency semaphore.
This limits the number of concurrent view update reads to
max_count_concurrent_view_update_reads, all other incoming view update reads are
queued using just a small chunk of memory. Without this, the reads would also get
queued after exceeding view_update_reader_concurrency_semaphore_serialize_limit_multiplier, but they would take much more memory while staying in the queue.

The new semaphore has half the capacity of the regular user read concurrency semahpore and is currently used only for user writes - is't used independently of the scheduling group on which we base the read semaphore selection, but we use a different code path for streaming (not database::do_apply) and we shouldn't have view updates in system writes or during compaction.

This patch also adds a test to confirm that the view update workload doesn't impact the read latency, as well as a test which confirms that we do not run out of memory even under heavy view udpate workload.

The issue of view updates causing increased latencies most often occurs in the following scenario:
* we have a medium to high write workload to a table with a materialized view which requires reading from the base table before sending the update to delete the old rows
* we have any read workload
* one replica is slower or is handling more writes due to an imbalance of data distribution
* we write with a cl<ALL, the mentioned replica is replying to write requests slower while new ones keep being sent to it.
* each write performs a read first taking resources from the user read concurrency semaphore, so when enough writes accumulate the reads using the semaphore start getting queued
* the queue is shared by regular reads and view update reads. When there's enough view update reads in the queue, regular reads start getting increased latencies

An sct test (perf-regression-latency-mv-read-concurrency) was prepared to somewhat resemble this scenario:
* the tables were prepared satisfying the conditions above
* we use a medium write workload and a very low read workload
* the imbalance is achieved by writing to just a few (10) partitions - some replicas (and shards) can have twice or more used partitions than others. We also keep writing to a limited (though high) number of rows, to cause overwrites which require reading before sending the view update
* to minimize the test case, we use a cluster of 3 nodes and rf=2, we write with cl=ONE to have background replica writes and read with cl=ALL to wait for the slower replica to respond.

In the test above:
* without the fix, the latency of reads increases over 50s
* with the fix, the latency of reads stays below 20ms

Fixes https://github.com/scylladb/scylladb/issues/8873
Fixes https://github.com/scylladb/scylladb/issues/15805

The patch is not that small and it isn't fixing a regression, so no backports

Closes scylladb/scylladb#20887

* github.com:scylladb/scylladb:
  test: add test for high view update concurrency causing bad_allocs
  test: add test for high view update concurrency degrading read latency
  mv: add a dedicated read concurrency semaphore for view update read before writes
2024-10-22 22:17:23 +03:00
Wojciech Mitros
242079d70b mv: add a dedicated read concurrency semaphore for view update read before writes
When writing to some tables with materialized views, we need to read from the base
table first to perform a delete of the old view row. When doing so, the memory used
for the read is tracked by the user read concurrency semaphore. When we have a large
number of such reads, we may use up all of the semaphore units, causing the following
reads to be queued. When we have some user reads coming at the same time, these reads
can have very high latency due to the write workload on the base table. We want to avoid
this, so that the write workload doesn't have a high impact on the latency of the
read workload.

This is fixed in this patch by adding a separate read concurrency semaphore just for
view update read-before-writes. With the new semaphore, even if there are many view
update read-before-writes, they will be queued on a different semaphore than the user
reads, and they won't impact their latency.

The second issue fixed by this patch is the concurrency of the view updates that is
currently unlimited. Because of that view updates may take up so much memory that
they we may run out of memory.

This is fixed by using the read admission on the view update concurrency semaphore.
This limits the number of concurrent view update reads to
max_count_concurrent_view_update_reads, all other incoming view update reads are
queued using just a small chunk of memory. Without this, the reads would also get
queued after exceeding view_update_reader_concurrency_semaphore_serialize_limit_multiplier,
but they would take much more memory while staying in the queue.

The new semaphore has half the capacity of the regular user read concurrency semahpore
and is currently used only for user writes - is't used independently of the scheduling
group on which we base the read semaphore selection, but we use a different code path
for streaming (not database::do_apply) and we shouldn't have view updates in system
writes or during compaction.

Fixes https://github.com/scylladb/scylladb/issues/8873
Fixes https://github.com/scylladb/scylladb/issues/15805
2024-10-21 11:02:06 +02:00
Emil Maskovsky
a03e98d6e8 raft: fast tombstone GC for group0-managed tables
Set the tombstone GC time for group0-managed tables to the minimal state
id of the group0 nodes.

The check is being done based on a timer, iterating through each node
(according to the group0 topology configuration) and taking the minimum
across all nodes.

This miminum timestamp is then be used to set the tombstone GC time
for the tombstone GC of all the group0-managed tables.

Fixes: scylladb/scylla#15607
2024-10-08 21:07:30 +02:00
Kefu Chai
ee36358a60 db: remove unused includes
these unused includes are identified by clang-include-cleaner.
after auditing the source files, all of the reports have been
confirmed.

please note, since we have `using seastar::shared_ptr` in
`seastarx.h`, this renders `#include <seastar/core/shared_ptr.hh>`
unnecessary if we don't need the full definition of `seastar::shared_ptr`.

so, in this change, all the unused includes are removed. but there are
some headers which are actually used, while still being identified by
this tool. these includes are marked with "IWYU pragma: keep".

Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
2024-10-04 20:48:18 +08:00
Sergey Zolotukhin
3b9033423d utils: Optimizations for utils::split_comma_separated_list and usage of host_id_or_endpoint lists
- utils::split_comma_separated_list now accepts a reference to sstring instead
  of a copy to avoid extra memory allocations. Additionally, the results of
  trimming are moved to the resulting vector instead of being copied.
- service/storage_service removenode, raft_removenode, find_raft_nodes_from_hoeps,
  parse_node_list and api/storage_service::set_storage_service were changed to use
  std::vector<host_id_or_endpoint> instead of std::list<host_id_or_endpoint> as
  std::vector is a more cache-friendly structure,  resulting in better performance.
2024-10-02 11:56:59 +02:00
Calle Wilund
238a0236e5 features/config: Add feature for fragmented commitlog entries
Hides the functionality behind a cluster feature, i.e. postspones
using it until an upgrade is complete etc. This to allow rolling back
even with dirty nodes, at least until a cluster is commited.

Feature can also be disabled by scylla option, just in case. This will
lock it out of whole cluster, but this is probably good, because depending
on off or on, certain schema/raft ops might fail or succeed (due to large
mutations), and this should probably be equivalent across nodes.
2024-09-03 16:38:28 +00:00
Avi Kivity
ea8441dfa3 cql3: add option to not unify bind variables with the same name
Bind variables in CQL have two formats: positional (`?`) where a
variable is referred to by its relative position in the statement,
and named (`:var`), where the user is expected to supply a
name->value mapping.

In 19a6e69001 we identified the case where a named bind variable
appears twice in a query, and collapsed it to a single entry in the
statement metadata. Without this, a driver using the named variable
syntax cannot disambiguate which variable is referred to.

However, it turns out that users can use the positional call form
even with the named variable syntax, by using the positional
API of the driver. To support this use case, we add a configuration
variable to disable the same-variable detection.

Because the detection has to happen when the entire statement is
visible, we have to supply the configuration to the parser. We
call it the `dialect` and pass it from all callers. The alternative
would be to add a pre-prepare call similar to fill_prepare_context that
rewrites all expressions in a statement to deduplicate variables.

A unit test is added.

Fixes #15559
2024-09-01 17:27:48 +03:00
Łukasz Paszkowski
b270097f1f config: drop reversed_reads_auto_bypass_cache
Reverse reads have already been with us for a while, thus this back
door option to bypass in-memory data cache for reversed queries can
be retired.
2024-08-13 10:02:42 +02:00