If a keyspace has a numeric replication factor in a DC and rf < #racks,
then the replicas of tablets in this keyspace can be distributed among
all racks in the DC (different for each tablet). With rack list, we need all
tablet replicas to be placed on the same racks. Hence, the conversion
requires tablet co-location.
After this series, the conversion can be done using ALTER KEYSPACE
statement. The statement that does this conversion in any DC is not
allowed to change a rf in any DC. So, if we have dc1 and dc2 with 3 racks
each and a keyspace ks then with a single ALTER KEYSPACE we can do:
- {dc1 : 2} -> {dc1 : [r1, r2]};
- {dc1 : 2, dc2: 2} -> {dc1 : [r1, r2], dc2: [r2,r3]};
- {dc1 : 2, dc2: 2} -> {dc1 : [r1, r2], dc2: 2}
- {dc1 : 2} -> {dc1 : 2, dc2 : [r1]}
But we cannot do:
- {dc1 : 2} -> {dc1 : [r1, r2, r3]};
- {dc1 : 1, dc2 : [r1, r2] → dc1: [r1], dc2: [r1].
In order to do the co-locations rf change request is paused. Tablet
load balancer examines the paused rf change requests and schedules
necessary tablet migrations. During the process of co-location, no other
cross-rack migration is allowed.
Load balancer checks whether any paused rf change request is
ready to be resumed. If so, it puts the request back to global topology
request queue.
While an rf change request for a keyspace is running, any other rf change
of this keyspace will fail.
Fixes: #26398.
New feature, no backport
Closesscylladb/scylladb#27279
* github.com:scylladb/scylladb:
test: add est_rack_list_conversion_with_two_replicas_in_rack
test: test creating tablet_rack_list_colocation_plan
test: add test_numeric_rf_to_rack_list_conversion test
tasks: service: add global_topology_request_virtual_task
cql3: statements: allow altering from numeric rf to rack list
service: topology_coordinator: pause keyspace_rf_change request
service: implement make_rack_list_colocation_plan
service: add tablet_rack_list_colocation_plan
cql3: reject concurrent alter of the same keyspace
test: check paused rf change requests persistence
db: service: add paused_rf_change_requests to system.topology
service: pass topology and system_keyspace to load_balancer ctor
service: tablet_allocator: extract load updates
service: tablet_allocator: extract ensure_node
tasks, system_keyspace: Introduce get_topology_request_entry_opt()
node_ops: Drop get_pending_ids()
node_ops: Drop redundant get_status_helper()
Allow altering from numeric replication factor to rack list. Ensure
that a single ALTER KEYSPACE statement doesn't try to both convert
to rack list and change rf.
Reject ALTER KEYSPACE request if there is unfinished (queued, pending,
or paused) alter request of the same keyspace.
This is required as in the following changes, global request queue
will contain rf change requests meant to be resumed.
We currently allow restrictions on single column primary key,
but we ignore the restriction and return all results.
This can confuse the users. We change it so such a restriction
will throw an error and add a test to validate it.
Fixes: VECTOR-331
Closesscylladb/scylladb#27143
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.
The rf_rack_valid_keyspaces option needs to be turned on in order to
allow creating materialized views in tablet keyspaces with numeric RF
per DC. This is also necessary for secondary indexes because they use
materialized views underneath. However, this option is _not_ necessary
for vector store indexes because those use the external vector store
service for querying the list of keys to fetch from the main table, they
do not create a materialized view. The rf_rack_valid_keyspaces was, by
accident, required for vector indexes, too.
Remove the restriction for vector store indexes as it is completely
unnecessary.
Fixes: SCYLLADB-81
Closesscylladb/scylladb#27447
The PRUNE MATERALIZED VIEW statement is performed as follows:
1. Perform a range scan of the view table from the view replicas based
on the ranges specified in the statement.
2. While reading the paged scan above, for each view row perform a read
from all base replicas at the corresponding primary key. If a discrepancy
is detected, delete the row in the view table.
When reading multiple rows, this is very slow because for each view row
we need to performe a single row query on multiple replicas.
In this patch we add an option to speed this up by performing many of the
single base row reads concurrently, at the concurrency specified in the
USING CONCURRENCY clause.
Aside from the unit test, I checked manually on a 3-node cluster with 10M rows, using vnodes. There were actually no ghost rows in the test, but we still had to iterate over all view rows and read the corresponding base rows. And actual ghost rows, if there are any, should be a tiny fraction of all rows. I compared concurrencies 1,2,10,100 and the results were:
* Pruning with concurrency 1 took total 1416 seconds
* Pruning with concurrency 2 took total 731 seconds
* Pruning with concurrency 10 took total 234 seconds
* Pruning with concurrency 100 took total 171 seconds
So after a concurrency of 10 or so we're hitting diminishing returns (at least in this setup). At that point we may be no longer bottlenecked by the reads, but by CPU on the shard that's handling the PRUNE
Fixes https://github.com/scylladb/scylladb/issues/27070Closesscylladb/scylladb#27097
* github.com:scylladb/scylladb:
mv: allow setting concurrency in PRUNE MATERIALIZED VIEW
cql: add CONCURRENCY to the USING clause
This PR introduces two key improvements to the robustness and resource management of vector search:
Proper Abort on CQL Timeout: Previously, when a CQL query involving a vector search timed out
, the underlying ANN query to the vector store was not aborted and would continue to run. This has been fixed by ensuring the abort source is correctly signaled, terminating the ANN request when its parent CQL query expires and preventing unnecessary resource consumption.
Faster Failure Detection: The connection and keep-alive timeouts for vector store nodes were excessively long (2 and 11 minutes, respectively), causing significant delays in detecting and recovering from unreachable nodes. These timeouts are now aligned with the request_timeout_in_ms setting, allowing for much faster failure detection and improving high availability by failing over from unresponsive nodes more quickly.
Fixes: SCYLLADB-76
This issue affects the 2025.4 branch, where similar HA recovery delays have been observed.
Closesscylladb/scylladb#27377
* github.com:scylladb/scylladb:
vector_search: Fix ANN query abort on CQL timeout
vector_search: Reduce connection and keep-alive timeouts
When a CQL vector search request timed out, the underlying ANN query was
not aborted and continued to run. This happened because the abort source
was not being signaled upon request expiration.
This commit ensures the ANN query is aborted when the CQL request times out
preventing unnecessary resource consumption.
Before this commit, any attempt to create, alter, attach, or drop
the default service level would result in a syntax error whose
error message was unclear:
```
cqlsh> attach service level default to cassandra;
SyntaxException: line 1:21 no viable alternative at input 'default'
```
The error stems from the grammar not being able to parse `default`
as a correct service level name. To fix that, we cover it manually.
This way, the grammar accepts it and we can process it in Scylla.
The reason why we'd like to cover the default service level is that
it's an actual service level that the user should reference. Getting
a syntax error is not what should happen. Hence this fix.
We validate the input and if the given role is really the default
service level, we reject the query and provide an informative error
message.
Two validation tests are provided.
Fixesscylladb/scylladb#26699Closesscylladb/scylladb#27162
The PRUNE MATERALIZED VIEW statement is performed as follows:
1. Perform a range scan of the view table from the view replicas based
on the ranges specified in the statement.
2. While reading the paged scan above, for each view row perform a read
from all base replicas at the corresponding primary key. If a discrepancy
is detected, delete the row in the view table.
When reading multiple rows, this is very slow because for each view row
we need to performe a single row query on multiple replicas.
In this patch we add an option to speed this up by performing many of the
single base row reads concurrently, at the concurrency specified in the
USING CONCURRENCY clause.
Fixes https://github.com/scylladb/scylladb/issues/27070
This patch enforces that vector indexes can only be created on keyspaces
that use tablets. During index validation, `check_uses_tablets()` verifies
the base keyspace configuration and rejects creation otherwise.
To support this, the `custom_index::validate()` API now receives a
`const data_dictionary::database&` parameter, allowing index
implementations to access keyspace-level settings during DDL validation.
Fixes https://scylladb.atlassian.net/browse/VECTOR-322Closesscylladb/scylladb#26786
For tables of special types that can be located: MV, CDC, and paxos
table, we should not use tombstone_gc=repair mode because colocated
tablets are never repaired, hence they will not have repair_time set and
will never be GC'd using 'repair' mode.
In ALTER KEYSPACE, when a datacenter name is omitted, its replication
factor is implicitly set to zero with vnodes, while with tablets,
it remains unchanged.
ALTER KEYSPACE should behave the same way for tablets as it does
for vnodes. However, this can be dangerous as we may mistakenly
drop the whole datacenter.
Reject ALTER KEYSPACE if it changes replication factor, but omits
a datacenter that currently contains tablet replicas.
Fixes: https://github.com/scylladb/scylladb/issues/25549.
Closesscylladb/scylladb#25731
Currently, the PRUNE MATERIALIZED VIEW statement performs all its
reads and writes in a single, continous sequence. This takes too
much time even for a moderate amount of 'PRUNED' data.
Instead, we want to make it possible to set a concurrency of the
reads and writes performed while processing the PRUNE statement,
so that if the user so desires, it may finish the PRUNING quicker
at the cost of adding more load on the cluster.
In this patch we add the CONCURRENCY setting to the USING clause
in cql. In the next patch, we'll be using it to actually set the
concurrency of PRUNE MATERIALIZED VIEW.
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
Closesscylladb/scylladb#26617
Currently we do not support paging for vector search queries.
When we get such a query with paging enabled we ignore the paging
and return the entire result. This behavior can be confusing for users,
as there is no warning about paging not working with vector search.
This patch fixes that by adding a warning to the result of ANN queries
with paging enabled.
Closesscylladb/scylladb#26384
The polymorphic abstract_type class serves as an interface and should not be copied.
To prevent accidental and unsafe copies, make it explicitly uncopyable.
When deserializing a vector whose elements are collections (e.g., set, list),
the operation raises a `std::bad_cast` exception.
This was caused by type slicing due to an incorrect assignment of a
polymorphic type by value instead of by reference. This resulted in a
failed `dynamic_cast` even when the underlying type was correct.
When creating a keyspace with tablets, a warning is shown with all the
unsupported features for tablets, which is only counters currently.
Now that counters is also supported with tablets, we can remove this
warning entirely.
Now that counters work with tablets, allow to create a table with
counters in a tablets-enabled keyspace, and remove the warning about
counters not being supported when creating a keyspace with tablets.
We allow to use counters with tablets only when all nodes are upgraded
and support counters with tablets. We add a new feature flag to
determine if this is the case.
Fixesscylladb/scylladb#18180
`sstable_compression_user_table_options` allows configuring a node-global SSTable compression algorithm for user tables via scylla.yaml. The current default is LZ4Compressor (inherited from Cassandra).
Make LZ4WithDictsCompressor the new default. Metrics from real datasets in the field have shown significant improvements in compression ratios.
If the dictionary compression feature is not enabled in the cluster (e.g., during an upgrade), fall back to the `LZ4Compressor`. Once the feature is enabled, flip the default back to the dictionary compressor using with a listener callback.
Fixes#26610.
Closesscylladb/scylladb#26697
* github.com:scylladb/scylladb:
test/cluster: Add test for default SSTable compressor
db/config: Change default SSTable compressor to LZ4WithDictsCompressor
db/config: Deprecate sstable_compression_dictionaries_allow_in_ddl
boost/cql_query_test: Get expected compressor from config
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#26397Closesscylladb/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
Auto-exands numeric RF in CREATE/ALTER KEYSPACE statements for
new DCs specified in the statement.
Doesn't auto-expand existing options, as the rack choice may not be in
line with current replica placement. This requires co-locating tablet
replicas, and tracking of co-location state, which is not implemented yet.
Signed-off-by: Tomasz Grabiec <tgrabiec@scylladb.com>
Tests expect this failure in some scenarios, but later changes make us
fail ealier due to topology constraints.
As a rule, more general validation should come before more specific
validation. So syntax validation before topology validation.
The option is a knob that allows to reject dictionary-aware compressors
in the validation stage of CREATE/ALTER statements, and in the
validation of `sstable_compression_user_table_options`. It was
introduced in 7d26d3c7cb to allow the admins of Scylla Cloud to
selectively enable it in certain clusters. For more details, check:
https://github.com/scylladb/scylla-enterprise/issues/5435
As of this series, we want to start offering dictionary compression as
the default option in all clusters, i.e., treat it as a generally
available feature. This makes the knob redundant.
Additionally, making dictionary compression the default choice in
`sstable_compression_user_table_options` creates an awkward dependency
with the knob (disabling the knob should cause
`sstable_compression_user_table_options` to fall back to a non-dict
compressor as default). That may not be very clear to the end user.
For these reasons, mark the option as "Deprecated", remove all relevant
tests, and adjust the business logic as if dictionary compression is
always available.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
cql3: Refactor vector search select impl into a dedicated class
The motivation for this change is crash fixed in https://github.com/scylladb/scylladb/pull/25500.
This commit refactors how ANN ordered select statements are handled to prevent a potential null pointer dereference and improve code organization.
Previously, vector search selects were managed by `indexed_table_select_statement`, which unconditionally dereferenced a `view_ptr`. This assumption is invalid for vector search indexes where no view exists, creating a risk of crashes.
To address this, the refactoring introduces the following changes:
- A new `vector_indexed_table_select_statement` class is created to specifically handle ANN-ordered selects. This class operates without a view_ptr, resolving the null pointer risk.
- The `indexed_table_select_statement` is renamed to `view_indexed_table_select_statement` to more accurately reflect its function with view-based indexes.
- An assertion has been added to `indexed_table_select_statement` constructor to ensure view_ptr is not null, preventing similar issues in the future.
Fixes: VECTOR-162
No backport is needed, as this is refactoring.
Closesscylladb/scylladb#25798
* github.com:scylladb/scylladb:
cql3: Rename indexed_table_select_statement
cql3: Move vector search select to dedicated class
We currently allow creating multiple vector indexes on one column.
This doesn't make much sense as we do not support picking one when
making ann queries.
To make this less confusing and to make our behavior similar
to Cassandra we disallow the creation of multiple vector indexes
on one column.
We also add a test that checks this behavior.
Fixes: VECTOR-254
Fixes: #26672Closesscylladb/scylladb#26508
To align with `vector_indexed_table_select_statement`, this commit renames
`indexed_table_select_statement` to `view_indexed_table_select_statement`
to clarify its usage with materialized views.
The execution of SELECT statements with ANN ordering (vector search) was
previously implemented within `indexed_table_select_statement`. This was
not ideal, as vector search logic is independent of secondary index selects.
This resulted in unnecessary complexity because vector search queries don't
use features like aggregates or paging. More importantly,
`indexed_table_select_statement` assumed a non-null `view_schema` pointer,
which doesn't hold for vector indexes (where `view_ptr` is null).
This caused null pointer dereferences during ANN ordered selects, leading
to crashes (VECTOR-179). Other parts of the class still dereference
`view_schema` without null checks.
Moving the vector search select logic out of
`indexed_table_select_statement` simplifies the code and prevents these
null pointer dereferences.
Before this commit, when the underlying materialized view was created,
it didn't have the property `tombstone_gc` set to any value. We fix the
bug in this PR.
Implementation strategy:
1. Move code responsible for producing the schema
of a secondary index to the file that handles
`CREATE INDEX`.
2. Set the property when creating the view.
3. Add reproducer tests.
Fixesscylladb/scylladb#26542
Backport: we can discuss it.
Closesscylladb/scylladb#26543
* github.com:scylladb/scylladb:
index: Set tombstone_gc when creating secondary index
index: Make `create_view_for_index` method of `create_index_statement`
index: Move code for creating MV of secondary index to cql3
db, cql3: Move creation of underlying MV for index
Currently when a null vector is passed to an ANN query we fail with a
quite confusing error ("NoHostAvailable: ('Unable to complete the
operation against any hosts', {<Host: 127.0.0.1:9042 datacenter1>:
<Error from server: code=0000 [Server error] message="to_bytes() called
on raw value that is null">})").
This patch fixes that by throwing an InvalidRequestException with an
appropriate message instead.
We also add a test case that validates this behavior.
Fixes: VECTOR-257
Closesscylladb/scylladb#26510
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.
Closesscylladb/scylladb#26482
This patch implements the changes required by the Vector Store authorization, as described in https://scylladb.atlassian.net/wiki/spaces/RND/pages/107085899/Vector+Store+Authentication+And+Authorization+To+ScyllaDB, that is:
- adding a new permission VECTOR_SEARCH_INDEXING, grantable only on ALL KEYSPACES
- allowing users with that permission to perform SELECT queries, but only on tables with a vector index
- increasing the number of scheduling groups by one to allow users to create a service level for a vector store user
- adjusting the tests and documentation
These changes are needed, as the vector indexes are managed by the external service, Vector Store, which needs to read the tables to create the indexes in its memory. We would like to limit the privileges of that service to a minimum to maintain the principle of least privilege, therefore a new permission, one that allows the SELECTs conditional on the existence of a vector_index on the table.
Fixes: VECTOR-201
Backport reasoning:
Backport to 2025.4 required as this can make upgrading clusters more difficult if we add it in 2026.1. As for now Scylla Cloud requires version 2025.4 to enable vector search and permission is set by orchestrator so there is no chance that someone will try to add this permission during upgrade. In 2026.1 it will be more difficult.
Closesscylladb/scylladb#25976
* github.com:scylladb/scylladb:
docs: adjust docs for VS auth changes
test: add tests for VECTOR_SEARCH_INDEXING permission
cql: allow VECTOR_SEARCH_INDEXING users to select
auth: add possibilty to check for any permission in set
auth: add a new permission VECTOR_SEARCH_INDEXING
Before this commit, when the underlying materialized view was created,
it didn't have the property `tombstone_gc` set to any value. That
was a bug and we fix it now.
Two reproducer tests is added for validation. They reproduce the problem
and don't pass before this commit.
Fixesscylladb/scylladb#26542
We move the code responsible for creating the schema for the underlying
materialized view of a secondary index from `index/` to `cql3/` so that
it's close to that responsible for performing `CREATE INDEX`. That's in
line with how other CQL statements are designed.
Note that the moved method is still a method of `secondary_index_manager`.
We'll make it a method of `create_index_statement` in the following
commit.
The main goal of this patch is to give more control over the creation
of the underlying view on an index to `create_index_statement.cc`.
That goal is in line with how the other statements are executed:
the schema is built in the cql3 module and only the ready schema_ptr
is passed further. That should also make the code cleaner and easier
to understand.
There are a few important things to note here:
* A call to `service::prepare_new_view_announcement` appears out of nowhere.
Aside from some validation checks and logging, that function does pretty
much the same as the pre-existing code we remove:
a. It creates Raft mutations based on the passed `view_ptr`.
b. It creates Raft mutations responsible for view building tasks.
c. It notifies about a new column family.
* We seemingly get rid of the code that creates view building tasks. That's not
true: we still do that via `service::prepare_new_view_announcement`.
That should explain why the change doesn't remove any relevant logic.
On the other hand, it might be more difficult to explain why moving the
code is correct. I'll touch on it below.
Before that, it may also be important to highlight that this commit only
affects the logic responsible for creating an index. There should be no
effect on any other part of how Scylla behaves.
---
Proving the correctness of the solution would take quite a lot of space,
so I'll only summarize it. It relies on a few things:
1. Two schema changes cannot happen in one operation. We allow for more
but only when those changes are dependent on each other and when
the additional ones are internal for Scylla, e.g. creating an index
leads to creating the underlying materialized view.
2. There are no entities or components that rely on indexes.
3. Each index is uniquely defined by the keyspace it belongs to
and the name of the index.
4. There is a bijection between rows in `system_schema.indexes`
and the currently existing indexes.
5. The name of an unnamed index depends on the name of the base table
and the names of the indexed columns. The name of an unnamed index
may have a number attached to it, but that number only depends on
the state of the schema at the time of creation of the index, and
it never changes later on. There are no other things the name of
an unnamed index depends on.
6. Scylla doesn't allow for changing any column in the base table
that has an index depending on it.
Based on that, we conclude that every existing index has exactly one
entry in `system_schema.indexes`, and the primary key of that entry
never changes.
The columns of `system_schema.indexes` that are not part of the primary
key are: `kind` and `options`. Both values are only decided at the time
of creation of an index, and currently there's no way to modify them.
That implies that there are only two events when an entry in the system
table can change: when creating an index and when dropping an index.
---
When we consider the previous place of the logic that this commit moves
to `cql3/statements/create_index_statement.cc`, it works like this:
1. We compare the sets of indexes defined on a specific table
(in the form of a structure called `index_metadata`) before and
after an operation.
2. We divide the entries into three sets: those present in both sets
and those present in only one of them.
3. We handle each of those three sets separately.
The structure `index_metadata` is a reflection of entries in
`system_schema.indexes`. It stores one more parameter -- `local` --
but its value depends on the other values of an entry, so we can ignore
it in this reasoning.
Because an index cannot be modified -- it can only be created or dropped
-- there are at most two non-empty sets: the set of new indexes and the
set of dropped indexes. Those sets are only non-empty during an operation
like `CREATE INDEX`, `DROP INDEX`, `DROP TABLE (base table)`,
`DROP KEYSPACE`. Note that it's impossible to drop an index by dropping
the underlying materialized view -- Scylla doesn't allow for that.
However, the code in `migration_manager.cc` we call
(`prepare_column_family_update_announcement`) and the code that we call
in `schema_tables.cc` (`make_update_table_mutations`) is only triggered
by *updates* related to the base table. In the context of `DROP TABLE`
or `DROP KEYSPACE`, we'd call `prepare_column_family_drop_announcement`
instead. In other words, we're only concerned with `CREATE INDEX` and
`DROP INDEX`.
---
A conclusion from this reasoning is that we only need to consider those
two situations when talking about correctness of this change. The impact
of this commit is that we may have potentially reordered mutations in the
resulting vector that will be applied to the Raft log.
The only mutations we may have reordered are the mutations responsible for
creating the underlying view and the mutations responsible for updating
columns in the base table. It's clear then that this commit brings no change
at all: we only give `cql3/statements/create_index_statement.cc` more
control over creating the underlying view.
---
We leave a remnant of the code in `db/schema_tables.cc` responsible
for dropping an index along with its underlying view. It would require
changing a bit more of the logic, and we don't need it for the rest
of this sequence of changes.
Refs scylladb/scylladb#16454
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.
Closesscylladb/scylladb#26116
* github.com:scylladb/scylladb:
schema: Allow configuring consistency setting for a keyspace
db: experimental consistent-tablets option
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.
The C++ test `test_indexing_paging_and_aggregation` is one of the slowest tests in test/boost. The reason for its slowness is that it needs a table with more rows than SELECT's "DEFAULT_COUNT_PAGE_SIZE" which was hard-coded to 10,000, so the test needed to write and read tens of thousands of rows, and did it multiple times.
It turns out the code actually had an ad-hoc mechanism to override DEFAULT_COUNT_PAGE_SIZE in a C++ test, but both this mechanism and the test itself were so opaque I didn't find it until I fixed it in a different way: What I ended up doing in this pull request is the following (each step in a separate patch):
1. Rewrite this test in Python, in the test/cqlpy framework. This was straightforward, as this test only used CQL and not internal interfaces. The reason why this test wasn't written in Python in the first place is that it was written in 2019, a year before cqlpy existed. A added extensive comments to the new tests, and I finally understood what it was doing :-)
2. I replaced the ad-hoc C++-test-only mechanism of overriding DEFAULT_COUNT_PAGE_SIZE by a bona-fide configuration parameter, `select_internal_page_size`.
3. Finally, the Python test can temporarily lower `select_internal_page_size` and use a table with much fewer rows.
After this series, the test `test_indexing_paging_and_aggregation` (which is now in Python instead of C++) takes around half a second, 20 times faster than before. I expect the speedup to be even more dramatic for the debug build.
Closesscylladb/scylladb#25368
* github.com:scylladb/scylladb:
cql: make SELECT's "internal page size" configurable
secondary index: translate test_indexing_paging_and_aggregation to Python
In some uses of SELECT, such as aggregation (sum() et al.), GROUP BY or
secondary index, it needs to perform internal scans. It uses an "internal
page size" which before this patch was always DEFAULT_COUNT_PAGE_SIZE = 10000.
There was an ad-hoc and undocumented way to override this default in C++
tests, using functions in test/lib/select_statement_utils.hh, but it
was so non-obvious that the test that most needed to override this
default - the very slow test test_indexing_paging_and_aggregation which
would have been must faster with a lower setting - never used it.
So in this patch we replace the ad-hoc configuration functions by a
bona-fide Scylla configuration option named "select_internal_page_size".
The few C++ tests that used the old configuration functions were
modified to use the new configuration parameters. The slow test
test_indexing_paging_and_aggregation still doesn't use the new
configuration to become faster - we'll do this in the next patch.
Another benefit of having this "internal page size" as a configuration
option is that one day a user might realize that the default choice
10,000 is bad for some reason (which I can't envision right now), so
having it configurable might come it handy.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
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/26121Closesscylladb/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
This change extends the CQL replication options syntax so the replication factor can be stated as a list of rack names.
For example: { 'mydatacenter': [ 'myrack1', 'myrack2', 'myrack4' ] }
Rack-list based RF can coexist with the old numerical RF, even in the same keyspace for different DCs.
Specifying the rack list also allows to add replicas on the specified racks (increasing the replication factor), or decommissioning certain racks from their replicas (by omitting them from the current datacenter rack-list). This will allow us to keep the keyspace rf-rack-valid, maintaining guarantees, while allowing adding/removing racks. In particular, this will allow us to add a new DC, which happens by incrementally increasing RF in that DC to cover existing racks.
Migration from numerical RF to rack-list is not supported yet. Migration from rack-list to numerical RF is not planned to be supported.
New feature, no backport required.
Co-authored with @bhalevy
Fixes https://github.com/scylladb/scylladb/issues/25269
Fixes https://github.com/scylladb/scylladb/issues/23525Closesscylladb/scylladb#26358
* github.com:scylladb/scylladb:
tablets: load_balancer: Recognize that tablets are confined to racks when computing desired tablet count
locator: Make hasher for endpoint_dc_rack globally accessible
test: tablets: Add test for replica allocation on rack list changes
test: lib: topology_builder: generate unique rack names
test: Add tests for rack list RF
doc: Document rack-list replication factor
topology_coordinator: Restore formatting
topology_coordinator: Cancel keyspace alter on broader set of errors
topology_coordinator: Make keyspace alter process options through as_ks_metadata_update()
cql3: ks_prop_defs: Preserve old options
cql3: ks_prop_defs: Introduce flattened()
locator: Recognize rack list RF as valid in assert_rf_rack_valid_keyspace()
tablet_allocator: Respect binding replicas to racks
locator: network_topology_strategy: Respect rack list when reallocating tablets
cql3: ks_prop_defs: Fail with more information when options are not in expected format
locator, cql3: Support rack lists in replication options
cql3: Fail early on vnode/tablet flavor alter
cql3: Extract convert_property_map() out of Cql.g
schema: Use definition from the header instead of open-coding it
locator: Abstract obtaining the number of replicas from replication_strategy_config_option
cql3, locator: Use type aliases for option maps
locator: Add debug logging
locator: Pass topology to replication strategy constructor
abstract_replication_strategy, network_topology_strategy: add replication_factor_data class
Materialized views are currently in the experimental phase and using them
in tablet-based keyspaces requires starting Scylla with an experimental feature,
`views-with-tablets`. Any attempts to create a materialized view or secondary
index when it's not enabled will fail with an appropriate error.
After considerable effort, we're drawing close to bringing views out of the
experimental phase, and the experimental feature will no longer be needed.
However, materialized views in tablet-based keyspaces will still be restricted,
and creating them will only be possible after enabling the configuration option
`rf_rack_valid_keyspaces`. That's what we do in this PR.
In this patch, we adjust existing tests in the tree to work with the new
restriction. That shouldn't have been necessary because we've already seemingly
adjusted all of them to work with the configuration option, but some tests hid
well. We fix that mistake now.
After that, we introduce the new restriction. What's more, when starting Scylla,
we verify that there is no materialized view that would violate the contract.
If there are some that do, we list them, notify the user, and refuse to start.
High-level implementation strategy:
1. Name the restrictions in form of a function.
2. Adjust existing tests.
3. Restrict materialized views by both the experimental feature
and the configuration option. Add validation test.
4. Drop the requirement for the experimental feature. Adjust the added test
and add a new one.
5. Update the user documentation.
Fixesscylladb/scylladb#23030
Backport: 2025.4, as we are aiming to support materialized views for tablets from that version.
Closesscylladb/scylladb#25802
* github.com:scylladb/scylladb:
view: Stop requiring experimental feature
db/view: Verify valid configuration for tablet-based views
db/view: Require rf_rack_valid_keyspaces when creating view
test/cluster/random_failures: Skip creating secondary indexes
test/cluster/mv: Mark test_mv_rf_change as skipped
test/cluster: Adjust MV tests to RF-rack-validity
test/boost/schema_loader_test.cc: Explicitly enable rf_rack_valid_keyspaces
db/view: Name requirement for views with tablets
