Commit Graph

996 Commits

Author SHA1 Message Date
Petr Gusev
f00f7976c1 alternator/executor.cc: avoid cross-shard free
This commit is an optimization: avoiding destruction of
foreign objects on the wrong shard. Releasing objects allocated on a
different shard causes their ::free calls to be executed remotely,
which adds unnecessary load to the SMP subsystem.

Before this patch, a std::vector could be moved
to another shard. When the vector was eventually destroyed,
its ::free had to be marshalled back to the shard where the memory had
originally been allocated. This change avoids that overhead by passing
the vector by const reference instead.

The referenced objects lifetime correctness reasoning:
* the put_or_delete_item refs usages in put_or_delete_item_cas_request
are bound to its lifetime
* cas_request lifetime is bound to storage_proxy::cas future
* we don't release put_or_delete_item-s untill all storage_proxy::cas
calls are done.
2025-12-07 16:14:56 +01:00
Petr Gusev
c428645d16 storage_proxy: cas: take cas_request by raw reference
In the next commit we want to add an optimization that relies on
precise control over the lifetime of cas_request. In particular, we
want the implementation of this interface in Alternator to operate on
raw references that are guaranteed to remain valid only until the
cas() future is resolved. We already depend on the same lifetime
assumptions in cas_request when used by modification_statement.
However, these assumptions are not clearly expressed in the current
interface: cas_request is taken by shared_ptr, and nothing prevents
cas() from storing that pointer inside paxos_response_handler, which
may outlive the cas() future.

This commit fixes that by taking cas_request by raw reference. This
makes it explicit that cas() does not assume ownership of the object.
Callers must ensure that the referenced object remains valid until
the returned future is resolved.
2025-12-07 16:14:56 +01:00
Nadav Har'El
350cbd1d66 alternator: fix typo of BatchWriteItem in comments
The DynamoDB API's "BatchWriteItem" operation is spelled like this, in
singular. Some comments incorrectly referred to as BatchWriteItems - in
plural. This patch fixes those mistakes.

There are no functional changes here or changes to user-facing documents -
these mistakes were only in code comments.

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

Closes scylladb/scylladb#27446
2025-12-05 15:08:58 +02:00
Avi Kivity
ce2a403f18 Merge 'alternator: implement gzip-compressed requests' from Nadav Har'El
In this series we implement Alternator's support for gzip-compressed
requests, i.e., requests with the "Content-Encoding: gzip" header,
other uncompressed header, and a gzip-compressed body.

The server needs to verify the signature of the *compressed* content,
and then uncompress the body before running the request.

We only support gzip compression because this is what DynamoDB supports.
But in the future we can easily add support for other compression
algorithms like lz4 or zstd.

This series Refs #5041 but doesn't "Fixes" it because it only implements
compressed requests (Content-Encoding), *not* compressed responses
(Accept-Encoding).

In addition to the code changes, the series also contains tests for this
feature that make sure it behaves like DynamoDB.

Note that while we will have now support in our server for compressed
requests, just like DynamoDB does, the clients (AWS SDKs) will probably
NOT make use of it because they do not enable request compression by
default. For example, see the tests for some hoops one needs to jump
through in boto3 (the Python SDK) to send compressed requests. However,
we are hoping that in the future Alternator's modified clients will
use compressed requests and enjoy this feature.

Closes scylladb/scylladb#27080

* github.com:scylladb/scylladb:
  test/alternator: enable, and add, tests for gzip'ed requests
  alternator: implement gzip-compressed requests
2025-11-30 13:27:46 +02:00
Piotr Dulikowski
44c605e59c Merge 'Fix the types of change events in Alternator Streams' from Piotr Wieczorek
This patch increases the compatibility with DynamoDB Streams by integrating the DynamoDB's event type rules (described in https://github.com/scylladb/scylladb/issues/6918) into Alternator. The main changes are:
- introduce a new flag `alternator_streams_strict_compatibility`, meant as a guard of performance-intensive operations that increase the compatibility with DynamoDB Streams. If enabled, Alternator always performs a RBW before a data-modifying operation, and propagates its result to CDC. Then, the old item is compared to the new one, to determine the mutation type (INSERT vs MODIFY). This option is a no-op for tables with disabled Alternator Streams,
- reduce splitting of simple Alternator mutations,
- correctly distinguish event types described in #6918, except for item deletes. Deleting a missing item with DeleteItem, BatchWriteItem, or a missing field with UpdateItem still emit REMOVEs.

To summarize, the emitted events of the data manipulation operations should be as follows:
- DeleteItem/BatchWriteItem.DeleteItem of existing item: REMOVE (OK)
- DeleteItem of nonexistent item: nothing (OK)
- BatchWriteItem.DeleteItem of nonexistent item: nothing (OK)
- PutItem/UpdateItem/BatchWriteItem.PutItem of existing and not equal item: MODIFY (OK)
- PutItem/UpdateItem/BatchWriteItem.PutItem of existing and equal item: nothing (OK)
- PutItem/UpdateItem/BatchWriteItem.PutItem of nonexistent item: INSERT (OK)

No backport is necessary.

Refs https://github.com/scylladb/scylladb/pull/26149
Refs https://github.com/scylladb/scylladb/pull/26396
Refs https://github.com/scylladb/scylladb/issues/26382
Fixes https://github.com/scylladb/scylladb/issues/6918

Closes scylladb/scylladb#26121

* github.com:scylladb/scylladb:
  test/alternator: Enable the tests failing because of #6918
  alternator, cdc: Don't emit events for no-op removes
  alternator, cdc: Don't emit an event for equal items
  alternator/streams, cdc: Differentiate item replace and item update in CDC
  alternator: Change the return type of rmw_operation_return
  config: Add alternator_streams_strict_compatibility flag
  cdc: Don't split a row marker away from row cells
2025-11-30 07:20:22 +01:00
Radosław Cybulski
b54a9f4613 Fix use-after-free in encode_paging_state in Alternator
Fix unlikely use-after-free in `encode_paging_state`. The function
incorrectly assumes that current position to encode will always have
data for all clustering columns the schema defines. It's possible to
encounter current position having less than all columns specified, for
eample in case of range tombstone. Those don't happen in Alternator
tables as DynamoDB doesn't allow range deletions and clustering key
might be of size at most 1. Alternator api can be used to read
scylla system tables and those do have range tombstones with more
than single clustering column.

The fix is to stop trying to encode columns, that don't have the value -
they are not needed anyway, as there's no possible position with those
values (range tombstone made sure of that).

Fixes #27001
Fixes #27125

Closes scylladb/scylladb#26960
2025-11-28 16:51:15 +03:00
Wojciech Mitros
3c376d1b64 alternator: use storage_proxy from the correct shard in executor::delete_table
When we delete a table in alternator, the schema change is performed on shard 0.
However, we actually use the storage_proxy from the shard that is handling the
delete_table command. This can lead to problems because some information is
stored only on shard 0 and using storage_proxy from another shard may make
us miss it.
In this patch we fix this by using the storage_proxy from shard 0 instead.

Fixes https://github.com/scylladb/scylladb/issues/27223

Closes scylladb/scylladb#27224
2025-11-25 18:56:31 +01:00
Nadav Har'El
4c7c5f4af7 alternator: implement gzip-compressed requests
In this patch we implement Alternator's support for gzip-compressed
requests, i.e., requests with the "Content-Encoding: gzip" header,
other uncompressed headers, and a gzip-compressed body.

The server needs to verify the signature of the *compressed* content,
and then uncompress the body before running the request.

We only support gzip compression because this is what DynamoDB supports.
But in the future we can easily add support for other compression
algorithms like lz4 or zstd.

This patch Refs #5041 but doesn't "Fixes" it because it only implements
compressed requests (Content-Encoding), *not* compressed responses
(Accept-Encoding).

The next patch will enable several tests for this feature and make sure
it behaves like DynamoDB.

Note that while we will have now support in our server for compressed
requests, just like DynamoDB does, the clients (AWS SDKs) will probably
NOT make use of it because they do not enable request compression by
default. For example, see the tests for some hoops one needs to jump
through in boto3 (the Python SDK) to send compressed requests. However,
we are hoping that in the future Alternator's modified clients will
use compressed requests and enjoy this feature.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
2025-11-25 17:46:44 +02:00
Radosław Cybulski
d589e68642 Add precompiled headers to CMakeLists.txt
Add precompiled header support to CMakeLists.txt and configure.py -
it improves compilation time by approximately 10%.

New header `stdafx.hh` is added, don't include it manually -
the compiler will include it for you. The header contains includes from
external libraries used by Scylla - seastar, standard library,
linux headers and zlib.

The feature is enabled by default, use CMake option `Scylla_USE_PRECOMPILED_HEADER`
or configure.py --disable-precompiled-header to disable.

The feature should be disabled, when trying to check headers - otherwise
you might get false negatives on missing includes from seastar / abseil and so on.

Note: following configuration needs to be added to ccache.conf:

    sloppiness = pch_defines,time_macros,include_file_mtime,include_file_ctime

Closes scylladb/scylladb#26617
2025-11-21 12:27:41 +02:00
Nadav Har'El
64a075533b alternator: fix update of stats from wrong shard
In commit 51186b2 (PR #25457) we introduced new statistics for
authentication errors, and among other places we modified
executor::create_table() to update them when necessary.

This function runs its real work (create_table_on_shard0()) on shard
0, but incorrectly updates "_stats" from the original shard. It doesn't
really matter which shard's stats we update - but it does matter that
code running on shard 0 shouldn't touch some other shard's objects.
Since all we do on these stats is to increment an integer, the risk
of updating it on the wrong shard is minimal to non-existant, but it's
still wrong and can cause bigger trouble in the future as the code
continues to evolve.

The fix is simple - we should pass to create_table_on_shard0() the
_stats object from the acutal shard running it (shard 0).

Fixes #26942

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

Closes scylladb/scylladb#26944
2025-11-21 11:53:06 +02:00
Radosław Cybulski
ce8db6e19e Add table name to tracing in alternator
Add a table name to Alternator's tracing output, as some clients would
like to consistently receive this information.

- add missing `tracing::add_table_name` in `executor::scan`
- add emiting tables' names in `trace_state::build_parameters_map`
- update tests, so when tracing is looked for it is filtered by table's
  name, which confirms table is being outputed.
- change `struct one_session_records` declaration to `class one_session_records`,
  as `one_session_records` is later defined as class.

Refs #26618
Fixes #24031

Closes scylladb/scylladb#26634
2025-11-21 09:33:40 +02:00
Pavel Emelyanov
02513ac2b8 alternator: Get feature service from proxy directly
The executor::add_stream_options() obtains local database reference from
proxy just to get feature service from it.

Similar chain is used in executor::update_time_to_live().

It's shorter to get features from proxy itself.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>

Closes scylladb/scylladb#26973
2025-11-18 08:17:16 +02:00
Pavel Emelyanov
f47f2db710 Merge 'Support local primary-replica-only for native restore' from Robert Bindar
This PR extends the restore API so that it accepts primary_replica_only as parameter and it combines the concepts of primary-replica-only with scoped streaming so that with:
- `scope=all primary_replica_only=true` The restoring node will stream to the global primary replica only
- `scope=dc primary_replica_only=true` The restoring node will stream to the local primary replica only.
- `scope=rack primary_replica_only=true` The restoring node will stream only to the primary replica from within its own rack (with rf=#racks, the restoring node will stream only to itself)
- `scope=node primary_replica_only=true` is not allowed, the restoring node will always stream only to itself so the primary_replica_only parameter wouldn't make sense.

The PR also adjusts the `nodetool refresh` restriction on running restore with both primary_replica_only and scope, it adds primary_replica_only to `nodetool restore` and it adds cluster tests for primary replica within scope.

Fixes #26584

Closes scylladb/scylladb#26609

* github.com:scylladb/scylladb:
  Add cluster tests for checking scoped primary_replica_only streaming
  Improve choice distribution for primary replica
  Refactor cluster/object_store/test_backup
  nodetool restore: add primary-replica-only option
  nodetool refresh: Enable scope={all,dc,rack} with primary_replica_only
  Enable scoped primary replica only streaming
  Support primary_replica_only for native restore API
2025-11-13 12:11:18 +03:00
Robert Bindar
817fdadd49 Improve choice distribution for primary replica
I noticed during tests that `maybe_get_primary_replica`
would not distribute uniformly the choice of primary replica
because `info.replicas` on some shards would have an order whilst
on others it'd be ordered differently, thus making the function choose
a node as primary replica multiple times when it clearly could've
chosen a different nodes.

This patch sorts the replica set before passing it through the
scope filter.

Signed-off-by: Robert Bindar <robert.bindar@scylladb.com>
2025-11-11 09:18:01 +02:00
Nadav Har'El
c03081eb12 alternator: improve error in tablets_mode_for_new_keyspaces=enforced
When in tablets_mode_for_new_keyspaces=enforced mode, Alternator is
supposed to fail when CreateTable asks explicitly for vnodes. Before
this patch, this error was an ugly "Internal Server Error" (an
exception thrown from deep inside the implementation), this patch
checks for this case in the right place, to generate a proper
ValidationException with a proper error message.

We also enable the test test_tablets_tag_vs_config which should have
caught this error, but didn't because it was marked xfail because
tablets_mode_for_new_keyspaces had not been live-updatable. Now that
it is, we can enable the test. I also improved the test to be slightly
faster (no need to change the configuration so many times) and also
check the ordinary case - where the schema doesn't choose neither
vnodes nor tablets explicitly and we should just use the default.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
2025-11-09 12:52:29 +02:00
Nadav Har'El
b34f28dae2 alternator: improve comment about non-hidden system tags
The previous patches added a somewhat misleading comment in front of
system:initial_tablets, which this patch improves.

That tag is NOT where Alternator "stores" table properties like the
existing comment claimed. In fact, the whole point is that it's the
opposite - Alternator never writes to this tag - it's a user-writable
tag which Alternator *reads*, to configure the new table. And this is
why it obviously can't be hidden from the user.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
2025-11-09 12:52:29 +02:00
Piotr Szymaniak
63897370cb alternator: Fix tag name to request vnodes
The tag was lately renamed from `experimental:initial_tablets` to
`system::initial_tablets`. This commit fixes both the tests as well as
the exceptions sent to the user instructing how to create table with
vnodes.
2025-11-09 12:52:29 +02:00
Piotr Szymaniak
376a2f2109 alternator: Support tablets_mode_for_new_keyspaces config flag
Until now, tablets in Alternator were experimental feature enabled only
when a TAG "experimental:initial_tablets" was present when creating a
table and associated with a numeric value.

After this patch, Alternator honours the value of
`tablets_mode_for_new_keyspaces` config flag.

Each table can be overriden to use tablets or not by supplying a new TAG
"system:initial_tablets". The rules stay the same as with the earlier,
experimental tag: when supplied with a numeric value, the table will use
tablets (as long as they are supported). When supplied with something
else (like a string "none"), the table will use vnodes, provided that
tablets are not `enforced` by the config flag.

Fixes #22463
2025-11-09 12:52:17 +02:00
Pavel Emelyanov
59019bc9a9 Merge 'Alternator: allow warning on auth errors before enabling enforcement' from Nadav Har'El
An Alternator user was recently "bit" when switching `alternator_enforce_authorization` from "false" to "true": ְְְAfter the configuration change, all application requests suddenly failed because unbeknownst to the user, their application used incorrect secret keys.

This series introduces a solution for users who want to **safely** switch `alternator_enforce_authorization`  from "false" to "true": Before switching from "false" to "true", the user can temporarily switch a new option, `alternator_warn_authorization`, to true. In this "warn" mode, authentication and authorization errors are counted in metrics (`scylla_alternator_authentication_failures` and `scylla_alternator_authorization_failures`) and logged as WARNings, but the user's application continues to work. The user can use these metrics or log messages to learn of errors in their application's setup, fix them, and only do the switch of `alternator_enforce_authorization` when the metrics or log messages show there are no more errors.

The first patch is the implementation of the the feature - the new configuration option, the metrics and the log messages,  the second patch is a test for the new feature, and the third patch is documentation recommending how to use the warn mode and the associated metrics or log messages to safely switch `alternaor_enforce_authorization` from false to true.

Fixes #25308

This is a feature that users need, so it should probably be backported to live branches.

Closes scylladb/scylladb#25457

* github.com:scylladb/scylladb:
  docs/alternator: explain alternator_warn_authorization
  test/alternator: tests for new auth failure metrics and log messages
  alternator: add alternator_warn_authorization config
2025-11-05 10:45:17 +03:00
Avi Kivity
04a289cae6 Merge 'Auto expand to rack list' from Tomasz Grabiec
We want to move towards rack-list based replication factor for tablets being the default mode, and in the future the only supported mode. This PR is a step towards that. We auto-expand numeric RF to rack list on keyspace creation and ALTER when rf_rack_valid_keyspaces option is enabled.

The PR is mostly about adjusting tests. The main logic change is in the last patch, which modifies option post-processing in ks_prop_defs.

Fixes #26397

Closes scylladb/scylladb#26692

* github.com:scylladb/scylladb:
  cql3: ks_prop_defs: Expand numeric RF to rack list
  locator: Move rack_list to topology.hh
  alternator: Do not set RF for zero-token DCs
  alternator: Switch keyspace creation to use ks_prop_defs
  test: alternator: Adjust for rack lists
  cql3: Move validation of invalid ALTER KEYSPACE earlier, to ks_prop_defs
  test: cqlpy: Mark tests using rack lists as scylla-only
  test: Switch to rack-list based RF
  test: Generalize tests to work with both numeric RF and rack lists
  test: cluster: test_zero_token_nodes_multidc: Adjust to rack list RF
  test: Prepare for handling errors specific to rack list path
  test: cluster: dtest: alternator: Force RF=1 in test_putitem_contention
  test: Create cluster with multiple racks in multi-dc setups
  test: boost: network_topology_strategy_test: Adjust to rack-list RF
  test: tablets: Adjust to rack list
  test: cluster: test_group0_schema_versioning: Use smaller RF to respect rf-rack-validness
  test: tablets_test: Convert test_per_shard_goal_mixed_dc_rf to be rack-valid
  test: object_store: test_backup: Adjust for rack lists
  test: cluster: tablets: Do not move tablet across racks in test_tablet_transition_sanity
  test: cluster: mv: Do not move tablets across racks
  test: cluster: util: Fix docstring for parse_replication_options()
  tablets, topology_coordinator: Skip tablet draining on replace
2025-10-30 21:54:08 +02:00
Piotr Wieczorek
8c2f60f111 alternator/streams, cdc: Differentiate item replace and item update in CDC
This commit improves compatibility with DynamoDB streams by changing the
emitted events when creating/updating an item. Replace/update operations
of an existing item emit a MODIFY, whereas replacing/updating a missing
item results in an INSERT. If the state of the item doesn't change after
applying the operation, no event is emitted.

This commit handles the following cases:
- `PutItem/UpdateItem/BatchWriteItem.PutItem of an existing and not equal item: MODIFY`
- `PutItem/UpdateItem/BatchWriteItem.PutItem of a nonexistent item: INSERT`

Refs https://github.com/scylladb/scylladb/issues/6918
2025-10-30 07:40:31 +01:00
Piotr Wieczorek
4f6aeb7b6b alternator: Change the return type of rmw_operation_return
Change the type from future<executor::request_return_type> to
executor::request_return_type, because the method isn't async and one
out of two callers unwraps the future immediately. This simplifies the
code a little and probably saves a few instructions, since we suspect
that moving a future<X> is more expensive than just moving X.
2025-10-30 07:40:31 +01:00
Piotr Wieczorek
e3fde8087a cdc: Don't split a row marker away from row cells
CDC log table records a mutation as a sequence of log rows that record
an atomic change (i.e. a row marker, tombstones, etc.), whereas a
mutation in Alternator Streams always appears as a single log row. The
type of operation is determined based on the type of the last log row in
CDC.

As a result, updates that create a row always appeared to Alternator
Streams as an update (row marker + data), rather than an insert. This
commit makes them a single log row. Its operation type is insert if it
contains a row marker, and an update otherwise, which gives results
consistent with DynamoDB Streams.
2025-10-30 07:40:31 +01:00
Tomasz Grabiec
f6dfea2fb1 alternator: Do not set RF for zero-token DCs
That will fail with tablets because it won't be able to allocate
replicas.
2025-10-29 23:32:58 +01:00
Tomasz Grabiec
21db21af7e alternator: Switch keyspace creation to use ks_prop_defs
So that we get the same validation and option post-processing as
during regular keyspace creation.
RF auto-expansion logic happens in ks_prop_defs, and we want that
for tablets.
2025-10-29 23:32:58 +01:00
Nadav Har'El
aa34f0b875 alternator: fix CDC events for TTL expiration
In commit a3ec6c7d1d we supposedly
implemented the feature of telling TTL experation events from regular
user-sent deletions. However, that implementation did not actually work
at all... It had two bugs:

 1. It created an null rjson::value() instead of an empty dictionary
    rjson::empty_object(), so GetRecords failed every time such a
    TTL expiration event was generated.
 2. In the output, it used lowercase field names "type" and "principalId"
    instead of the uppercase "Type" and "PrincipalId". This is not the
    correct capitalization, and when boto3 recieves such incorrect
    fields it silently deletes them and never passes them to the user's
    get_records() call.

This patch fixes those two bugs, and importantly - enables a test for
this feature. We did already have such a test but it was marked as
"veryslow" so doesn't run in CI and apparently not even run once to
check the new feature. This test is not actually very long on Alternator
when the TTL period is set very low (as we do in our tests), so I replaced
the "veryslow" marker by "waits_for_expiration". The latter marker means
that the test is still very slow - as much as half an hour - on DynamoDB -
but runs quickly on Scylla in our test setup, and enabled in CI by
default.

The enabled test failed badly before this patch (a server error during
GetRecords), and passes with this patch.

Also, the aforementioned commit forgot to remove the paragraph in
Alternator's compatibility.md that claims we don't have that feature yet.
So we do it now.

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

Closes scylladb/scylladb#26633
2025-10-29 17:08:20 +01:00
Nadav Har'El
51186b2f2c alternator: add alternator_warn_authorization config
Before this patch, the configuration alternator_enforce_authorization
is a boolean: true means enforce authentication checks (i.e., each
request is signed by a valid user) and authorization checks (the user
who signed the request is allowed by RBAC to perform this request).

This patch adds a second boolean configuration option,
alternator_warn_authorization. When alternator_enforce_authorization
is false but alternator_warn_authorization is true, authentication and
authorization checks are performed as in enforce mode, but failures
are ignored and counted in two new metrics:

    scylla_alternator_authentication_failures
    scylla_alternator_authorization_failures

additionally,also each authentication or authorization error is logged as
a WARN-level log message. Some users prefer those log messages over
metrics, as the log messages contain additional information about the
failure that can be useful - such as the address of the misconfigured
client, or the username attempted in the request.

All combinations of the two configuration options are allowed:
 * If just "enforce" is true, auth failures cause a request failure.
   The failures are counted, but not logged.
 * If both "enforce" and "warn" are true, auth failures cause a request
   failure. The failures are both counted and logged.
 * If just "warn" is true, auth failures are ignored (the request
   is allowed to compelete) but are counted and logged.
 * If neither "enforce" nor "warn" are true, no authentication or
   authorization check are done at all. So we don't know about failures,
   so naturally we don't count them and don't log them.

This patch is fairly straightforward, doing mainly the following
things:

1. Add an alternator_warn_authorization config parameter.

2. Make sure alternator_enforce_authorization is live-updatable (we'll
   use this in a test in the next patch). It "almost" was, but a typo
   prevented the live update from working properly.

3. Add the two new metrics, and increment them in every type of
   authentication or authorization error.
   Some code that needs to increment these new metrics didn't have
   access to the "stats" object, so we had to pass it around more.

4. Add log messages when alternator_warn_authorization is true.

5. If alternator_enforce_authorization is false, allow the auth check
   to allow the request to proceed (after having counted and/or logged
   the auth error).

A separate patch will follow and add documentation suggesting to users
how to use the new "warn" options to safely switch between non-enforcing
to enforcing mode. Another patch will add tests for the new configuration
options, new metrics and new log messages.

Fixes #25308.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
2025-10-29 11:16:26 +02:00
Nadav Har'El
c3593462a4 alternator: improve protection against oversized requests
Following DynamoDB, Alternator also places a 16 MB limit on the size of
a request. Such a limit is necessary to avoid running out of memory -
because the AWS message authentication protocol requires reading the
entire request into memory before its signature can be verified.

Our implementation for this limit used Seastar's HTTP server's
content_length_limit feature. However, this Seastar feature is
incomplete - it only works when the request uses the Content-Length
header, and doesn't do anything if the request doesn't have a
Content-Length (it may use chunked encoding, or have no length at all).
So malicious users can cause Scylla to OOM by sending a huge request
without a Content-Length.

So in this patch we stop using the incomplete Seastar feature, and
implement the length limit in Scylla in a way that works correctly with
or without Content-Length: We read from the input stream and if we go
over 16MB, we generate an error.

Because we dropped Seastar's protection against a long Content-Length,
we also need to fix a piece of code which used Content-Length to reserve
some semaphore units to prevent reading many large requests in parallel.
We fix two problems in the code:
1. If Content-Length is over the limit, we shouldn't attempt to reserve
   semaphore units - this should just be a Payload Too Large error.
2. If Content-Length is missing, the existing code did nothing and had
   a TODO that we should. In this patch we implement what was suggested
   in that TODO: We temporarily reserve the whole 16 MB limit, and
   after reading the actual request, we return part of the reservation
   according to the real request size.

That last fix is important, because typically the largest requests will be
BatchWriteItem where a well-written client would want to use chunked
encoding, not Content-Length, to avoid materializing the entire request
up-front. For such clients, the memory use semaphore did nothing, and
now it does the right thing.

Note that this patch does *not* solve the problem #12166 that existed
with Seastar's length-limiting implementation but still exists in the
new in-Scylla length-limiting implementation: The fact we send an
error response in the middle of the request and then close the
connection, while the client continues to send the request, can lead
to an RST being sent by the server kernel. Usually this will be fine -
well-written client libraries will be able to read the response before
the RST. But even with a well-written library in some rare timings
the client may get the RST before the response, and will miss the
response, and get an empty or partial response or "connection reset
by peer". This issue existed before this patch, and still exists, but
is probably of minor impact.

Fixes #8196

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

Closes scylladb/scylladb#23434
2025-10-28 15:24:46 +03:00
Radosław Cybulski
ea6b22f461 Add max trace size output configuration variable
In #24031 users complained, that trace message is truncated, namely it's
no longer json parsable and table name might not be part of the output.
This path enables users to configure maximum size of trace message.
In case user wanted `table` name, but didn't care about message size,
 #26634 will help.

- add configuration varable `alternator_max_users_query_size_in_trace_output`
   with default value of 4096 (4 times old default value).
- modify `truncated_content_view` function to use new configuration
  variable for truncation limit
- update `truncated_content_view` to consistently truncate at given
  size, previously trunctation would also happen when data arrived in
  more than one chunk
- update `truncated_content_view` to better handle truncated value
  (limit number of copies)
- fix `scylla_config_read` call - call to `query` for a configuration
  name that is not existing will return `Items` array empty
  (but present) - this would raise array access exception few lines
  below.
- add test

Refs #26634
Refs #24031

Closes scylladb/scylladb#26618
2025-10-28 13:29:15 +03:00
Nadav Har'El
7c9f5ef59e Merge 'alternator/executor: instantly mark view as built when creating it with base table' from Michał Jadwiszczak
`CreateTable` request creates GSI/LSI together with the base table,
the base table is empty and we don't need to actually build the view.

In tablet-based keyspaces we can just don't create view building tasks
and mark the view build status as SUCCESS on all nodes. Then, the view
building worker on each node will mark the view as built in
`system.built_views` (`view_building_worker::update_built_views()`).

Vnode-based keyspaces will use the "old" logic of view builder, which
will process the view and mark it as built.

Fixes scylladb/scylladb#26615

This fix should be backported to 2025.4.

Closes scylladb/scylladb#26657

* github.com:scylladb/scylladb:
  test/alternator/test_tablets: add test for GSI backfill with tablets
  test/alternator/test_tablets: add reproducer for GSI with tablets
  alternator/executor: instantly mark view as built when creating it with base table
2025-10-22 10:44:28 +03:00
Michał Jadwiszczak
8fbf122277 alternator/executor: instantly mark view as built when creating it with base table
`CreateTable` request creates GSI/LSI together with the base table,
the base table is empty and we don't need to actually build the view.

In tablet-based keyspaces we can just don't create view building tasks
and mark the view build status as SUCCESS on all nodes. Then, the view
building worker on each node will mark the view as built in
`system.built_views` (`view_building_worker::update_built_views()`).

Vnode-based keyspaces will use the "old" logic of view builder, which
will process the view and mark it as built.

Fixes scylladb/scylladb#26615
2025-10-22 00:05:40 +02:00
Michał Hudobski
5c957e83cb vector_search: remove dependence on cql3
This patch removes the dependence of vector search module
on the cql3 module by moving the contents of cql3/type_json.hh
to types/json_utils.hh and removing the usage of cql3 primary_key
object in vector_store_client. We also make the needed adjustments
to files that were previously using the afformentioned type_json.hh
file.

This fixes the circular dependency cql3 <-> vector_search.

Closes scylladb/scylladb#26482
2025-10-21 17:41:55 +03:00
Piotr Wieczorek
a3ec6c7d1d alternator/streams: Support userIdentity field for TTL deletions
UserIdentity is a map of two fields in GetRecords responses, which
always has the same value. It may be missing, or contain a constant
object with value `{"type": "Service", "principalId":
"dynamodb.amazonaws.com"}`. Currently, the latter is set only for
`REMOVE`s triggered by TTL.

This commit introduces two new CDC operation types: `service_row_delete`
and `service_partition_delete`, emitted in place of `row_delete` and
`partition_delete`. Alternator Streams treats them as regular `REMOVE`s,
but in addition adds the `userIdentity` field to the record.

This change may break existing Scylla libraries for reading raw CDC
tables, but we doubt that anybody has this use case.

Refs https://github.com/scylladb/scylladb/pull/26149
Refs https://github.com/scylladb/scylladb/pull/26121
Fixes https://github.com/scylladb/scylladb/issues/11523

Closes scylladb/scylladb#26460
2025-10-20 17:15:59 +02:00
Piotr Dulikowski
a716fab125 Merge 'alternator/metrics: Log operation sizes to histograms' from Piotr Wieczorek
This PR adds operation per-table histograms to Alternator with item sizes involved in an operation, for each of the operations: `GetItem`, `PutItem`, `DeleteItem`, `UpdateItem`, `BatchGetItem`, `BatchWriteItem`. If read-before-write wasn't performed (i.e. it was not needed by the operation and the flag `alternator_force_read_before_write` was disabled), then we log sizes of the items that are in the request. Also, `UpdateItem` logs the maximum of the update size and the existing item size. We'll change it in a next PR.

Fixes: #25143

Closes scylladb/scylladb#25529

* github.com:scylladb/scylladb:
  alternator: Add UpdateItem and BatchWriteItem response size metrics
  alternator: Add PutItem and DeleteItem response size metrics
  alternator: Add BatchGetItem response size metrics
  alternator: Add GetItem response size metrics
  alternator/test: Add more context to test_metrics.py asserts
2025-10-20 10:03:31 +03:00
Piotr Wieczorek
a2b9d7eed5 alternator: Split update_item_operation::apply into smaller methods
This is a minor refactoring aimed at reducing cognitive complexity of
`update_item_operation::apply`. The logic remains unchanged.

Closes scylladb/scylladb#25887
2025-10-17 09:51:05 +02:00
Tomasz Grabiec
c4a87453a2 Merge 'Add experimental feature flag for strongly consistent tables and extend kesypace creation syntax to allow specifying consistency mode.' from Gleb Natapov
The series adds an experimental flag for strongly consistent tables  and extends "CREATE KEYSPACE" ddl with `consistency` option that allows specifying the consistency mode for the keyspace.

Closes scylladb/scylladb#26116

* github.com:scylladb/scylladb:
  schema: Allow configuring consistency setting for a keyspace
  db: experimental consistent-tablets option
2025-10-16 21:48:06 +02:00
Piotr Wieczorek
caa522a29d alternator: Add UpdateItem and BatchWriteItem response size metrics
This commit bundle introduces metrics on item sizes for Alternator operations.

The new metrics are:
- `operation_size_kib op=UpdateItem`: Tracks the size of an `UpdateItem`
  operation. This is calculated as the sum of the existing item's size
  plus the estimated size of the updated fields.
- `operation_size_kib op=BatchWriteItem`: Tracks the total size of items
  within a `BatchWriteItem` request, aggregated on a per-table basis. If
  an item already exists, the logged size is the maximum of the old and
  the new item size.

NOTE: Both metrics rely on read-before-write, so if the
`alternator_force_read_before_write` option is disabled, these metrics
may be incomplete and report inaccurate sizes.
2025-10-16 19:17:27 +02:00
Piotr Wieczorek
5ca42b3baf alternator: Add PutItem and DeleteItem response size metrics
This commit bundle introduces metrics on item sizes for Alternator
operations. Specifically, this commit adds `operation_size_kb`
histograms for sizes of items created or replaced by the `PutItem`
operation, and sizes of items deleted by `DeleteItem` requests. The
latter needs a read-before-write, so the metrics may be incomplete if
`alternator_force_read_before_write` is disabled.
2025-10-16 19:17:26 +02:00
Piotr Wieczorek
5c72fd9ea3 alternator: Add BatchGetItem response size metrics
This commit bundle introduces metrics on item sizes for Alternator
operations. Specifically, this commit adds a `operation_size_kb`
per-table histogram, which contains item sizes in BatchGetItem requests.

A size of a BatchGetItem is the sum of the sizes of all items in the
operation grouped by table. In other words, a single BatchGetItem, and
BatchWriteItem for that matter, updates the histograms for each table
that it has items in.
2025-10-16 19:16:57 +02:00
Piotr Wieczorek
1aa3819b57 alternator: Add GetItem response size metrics
This commit bundle introduces metrics on item sizes for Alternator
operations. Specifically, this commit adds a per-table
`operation_size_kb` histogram, recording the sizes of the items
contained in GetItem responses.
2025-10-16 19:04:55 +02:00
Gleb Natapov
c255740989 schema: Allow configuring consistency setting for a keyspace
We want to add strongly consistent tables as an option. We will have
two kind of strongly consistent tables: globally consistent and locally
consistent. The former means that requests from all DCs will be globally
linearisable while the later - only requests to the same DCs will be
linearisable.  To allow configuring all the possibilities the patch
adds new parameter to a keyspace definition "consistency" that can be
configured to be `eventual`, `global` or `local`. Non eventual setting
is supported for tablets enabled keyspaces only. Since we want to start
with implementing local consistency configuring global consistency will
result in an error for now.
2025-10-16 13:34:49 +03:00
Piotr Dulikowski
61662bc562 Merge 'alternator: Make CDC use preimages from LWT for Alternator' from Piotr Wieczorek
This patch adds a struct `per_request_options` used to communicate between CDC and upper abstraction layers. We need this for better compatibility with DynamoDB Streams in Alternator (https://github.com/scylladb/scylladb/issues/6918) to change operation types of log rows. This patch also adds a way to conditionally forward the item read by LWT to CDC and use it as a preimage. For now, only Alternator uses this feature.

The main changes are:
- add a struct `cdc::per_request_options` to pass information between CDC and upper abstraction layers,
- add the struct to `cas_request::apply`'s signature,
- add a possibility to provide a preimage fetched by an upper abstraction layer (to propagate a row read by Alternator to CDC's preimage). This reduces the number of reads-before-write by 1 for some **Alternator** requests and it is always safe. It's possible to use this feature also in CQL.

No backport, it's a feature.

Refs https://github.com/scylladb/scylladb/issues/6918
Refs https://github.com/scylladb/scylladb/pull/26121

Closes scylladb/scylladb#26149

* github.com:scylladb/scylladb:
  alternator, cdc: Re-use the row read by LWT as a CDC preimage
  cdc: Support prefetched preimages
  storage: Add cdc options to cas_request::apply
  cdc, storage: Add a struct to pass per-mutation options to CDC
  cdc: Move operations enum to the top of the namespace
2025-10-15 12:30:29 +02:00
Piotr Wieczorek
28eda0203e alternator: Small cleanup, removing unnecessary statements, etc.
Tiny code cleanup to improve readability without changing behavior.

Changes:
- remove unused variables and imports,
- remove redundant whitespaces, and a duplicated `public:` access
  specifier,
- use `is_aws` function to check if running in AWS
  test/alternator/test_metrics.py,
- other trivial changes.

Closes scylladb/scylladb#26423
2025-10-15 12:05:20 +02:00
Piotr Wieczorek
5ff2d2d6ab alternator, cdc: Re-use the row read by LWT as a CDC preimage
Propagates the row read by CAS to CDC's preimage to save one
read-before-write.

As of now, a preimage in Alternator Streams always contains the entire
item (see previous_item_read_command in executor.cc), so the resulting
preimage should stay the same. In other words, this change should be
transparent to users.
2025-10-14 07:52:40 +02:00
Piotr Wieczorek
a55c5e9ec7 alternator: Correct RCU undercount in BatchGetItem
The `describe_multi_item` function treated the last reference-captured
argument as the number of used RCU half units. The caller
`batch_get_item`, however, expected this parameter to hold an item size.
This RCU value was then passed to
`rcu_consumed_capacity_counter::get_half_units`, treating the
already-calculated RCU integer as if it were a size in bytes.

This caused a second conversion that undercounted the true RCU. During
conversion, the number of bytes is divided by `RCU_BLOCK_SIZE_LENGTH`
(=4KB), so the double conversion divided the number of bytes by 16 MB.

The fix removes the second conversion in `describe_multi_item` and
changes the API of `describe_multi_item`.

Fixes: https://github.com/scylladb/scylladb/pull/25847

Closes scylladb/scylladb#25842
2025-10-12 10:42:32 +03:00
Piotr Wieczorek
b54ad9e22f storage: Add cdc options to cas_request::apply 2025-10-09 12:28:10 +02:00
Tomasz Grabiec
91e51a5dd1 cql3, locator: Use type aliases for option maps
In preparation for changing their structure.

1) std::map<sstring, sstring> -> replication_strategy_config_options

  Parsed options. Values will become std::variant<sstring, rack_list>

2) std::map<sstring, sstring> -> property_definitions::map_type

  Flattened map of options, as stored system tables.
2025-10-01 16:06:51 +02:00
Benny Halevy
da6e2fdb1b locator: Pass topology to replication strategy constructor 2025-10-01 16:06:28 +02:00
Piotr Wieczorek
4be0bdbc07 alternator: Don't emit a redundant REMOVE event in Alternator Streams for PutItem calls
Until now, every PutItem operation appeared in the Alternator Streams as
two events - a REMOVE and a MODIFY. DynamoDB Streams emits only INSERT
or MODIFY, depending on whether a row was replaced, or created anew. A
related issue scylladb#6918 concerns distinguishing the mutation type properly.

This was because each call to PutItem emitted the two CDC rows, returned
by GetRecords. Since this patch, we use a collection tombstone for the
`:attrs` column, and a separate tombstone for each regular column in the
table's schema. We don't expect that new tables would have any other
regular column, except for the `:attrs` and keys, but we may encounter
them in in upgraded tables which had old GSIs or LSIs.

Fixes: scylladb#6930.

Closes scylladb/scylladb#24991
2025-09-30 13:12:16 +03:00
Ernest Zaslavsky
debc756794 treewide: Move transport related files to a transport directory As requested in #22112, moved the files and fixed other includes and build system.
Moved files:
- generic_server.hh
- generic_server.cc
- protocol_server.hh

Fixes: #22112

This is a cleanup, no need to backport

Closes scylladb/scylladb#25090
2025-09-29 11:46:06 +03:00