In PR 5b6570be52 we introduced the config option `sstable_compression_user_table_options` to allow adjusting the default compression settings for user tables. However, the new option was hooked into the CQL layer and applied only to CQL base tables, not to the whole spectrum of user tables: CQL auxiliary tables (materialized views, secondary indexes, CDC log tables), Alternator base tables, Alternator auxiliary tables (GSIs, LSIs, Streams).
This gap also led to inconsistent default compression algorithms after we changed the option’s default algorithm from LZ4 to LZ4WithDicts (adf9c426c2).
This series introduces a general “schema initializer” mechanism in `schema_builder` and uses it to apply the default compression settings uniformly across all user tables. This ensures that all base and aux tables take their default compression settings from config.
Fixes#26914.
Backport justification: LZ4WithDicts is the new default since 2025.4, but the config option exists since 2025.2. Based on severity, I suggest we backport only to 2025.4 to maintain consistency of the defaults.
Closesscylladb/scylladb#27204
* github.com:scylladb/scylladb:
db/config: Update sstable_compression_user_table_options description
schema: Add initializer for compression defaults
schema: Generalize static configurators into schema initializers
schema: Initialize static properties eagerly
db: config: Add accessor for sstable_compression_user_table_options
test: Check that CQL and Alternator tables respect compression config
Problem
-------
Secondary indexes are implemented via materialized views under the
hood. The way an index behaves is determined by the configuration
of the view. Currently, it can be modified by performing the CQL
statement `ALTER MATERIALIZED VIEW` on it. However, that raises some
concerns.
Consider, for instance, the following scenario:
1. The user creates a secondary index on a table.
2. In parallel, the user performs writes to the base table.
3. The user modifies the underlying materialized view, e.g. by setting
the `synchronous_updates` to `true` [1].
Some of the writes that happened before step 3 used the default value
of the property (which is `false`). That had an actual consequence
on what happened later on: the view updates were performed
asynchronously. Only after step 3 had finished did it change.
Unfortunately, as of now, there is no way to avoid a situation like
that. Whenever the user wants to configure a secondary index they're
creating, they need to do it in another schema change. Since it's
not always possible to control how the database is manipulated in
the meantime, it leads to problems like the one described.
That's not all, though. The fact that it's not possible to configure
secondary indexes is inconsistent with other schema entities. When
it comes to tables or materialized views, the user always have a means
to set some or even all of the properties during their creation.
Solution
--------
The solution to this problem is extending the `CREATE INDEX` CQL
statement by view properties. The syntax is of form:
```
> CREATE INDEX <index name>
> .. ON <keyspace>.<table> (<columns>)
> .. WITH <properties>
```
where `<properties>` corresponds to both index-specific and view
properties [2, 3]. View properties can only be used with indexes
implemented with materialized views; for example, it will be impossible
to create a vector index when specifying any view property (see
examples below).
When a view property is provided, it will be applied when creating the
underlying materialized view. The behavior should be similar to how
other CQL statements responsible for creating schema entities work.
High-level implementation strategy
----------------------------------
1. Make auxiliary changes.
2. Introduce data structures representing the new set of index
properties: both index-specific and those corresponding to the
underlying view.
3. Extend `CREATE INDEX` to accept view properties.
4. Extend `DESCRIBE INDEX` and other `DESCRIBE` statements to include
view properties in their output.
User documentation is also updated at the steps to reflect the
corresponding changes.
Implementation considerations
-----------------------------
There are a number of schema properties that are now obsolete. They're
accepted by other CQL statements, but they have no effect. They
include:
* `index_interval`
* `replicate_on_write`
* `populate_io_cache_on_flush`
* `read_repair_chance`
* `dclocal_read_repair_chance`
If the user tries to create a secondary index specifying any of those
keywords, the statement will fail with an appropriate error (see
examples below).
Unlike materialized views, we forbid specifying the clustering order
when creating a secondary index [4]. This limitation may be lifted
later on, but it's a detail that may or may not prove troublesome. It's
better to postpone covering it to when we have a better perspective on
the consequences it would bring.
Examples
--------
Good examples
```
> CREATE INDEX idx ON ks.t (v);
> CREATE INDEX idx ON ks.t (v) WITH comment = 'ok view property';
> CREATE INDEX idx ON ks.t (v)
.. WITH comment = 'multiple view properties are ok'
.. AND synchronous_updates = true;
> CREATE INDEX idx ON ks.t (v)
.. WITH comment = 'default value ok'
.. AND synchronous_updates = false;
```
Bad examples
```
> CREATE INDEX idx ON ks.t (v) WITH replicate_on_write = true;
SyntaxException: Unknown property 'replicate_on_write'
> CREATE INDEX idx ON ks.t (v)
.. WITH OPTIONS = {'option1': 'value1'}
.. AND comment = 'some text';
InvalidRequest: Error from server: code=2200 [Invalid query]
message="Cannot specify options for a non-CUSTOM index"
> CREATE CUSTOM INDEX idx ON ks.t (v)
.. WITH OPTIONS = {'option1': 'value1'}
.. AND comment = 'some text';
InvalidRequest: Error from server: code=2200 [Invalid query]
message="CUSTOM index requires specifying the index class"
> CREATE CUSTOM INDEX idx ON ks.t (v)
.. USING 'vector_index'
.. WITH OPTIONS = {'option1': 'value1'}
.. AND comment = 'some text';
InvalidRequest: Error from server: code=2200 [Invalid query]
message="You cannot use view properties with a vector index"
> CREATE INDEX idx ON ks.t (v) WITH CLUSTERING ORDER BY (v ASC);
InvalidRequest: Error from server: code=2200 [Invalid query]
message="Indexes do not allow for specifying the clustering order"
```
and so on. For more examples, see the relevant tests.
References:
[1] https://docs.scylladb.com/manual/branch-2025.4/cql/cql-extensions.html#synchronous-materialized-views
[2] https://docs.scylladb.com/manual/branch-2025.4/cql/secondary-indexes.html#create-index
[3] https://docs.scylladb.com/manual/branch-2025.4/cql/mv.html#mv-options
[4] https://docs.scylladb.com/manual/branch-2025.4/cql/dml/select.html#ordering-clauseFixesscylladb/scylladb#16454
Backport: not needed. This is an enhancement.
Closesscylladb/scylladb#24977
* github.com:scylladb/scylladb:
cql3: Extend DESC INDEX by view properties
cql3: Forbid using CLUSTERING ORDER BY when creating index
cql3: Extend CREATE INDEX by MV properties
cql3/statements/create_index_statement: Allow for view options
cql3/statements/create_index_statement: Rename member
cql3/statements/index_prop_defs: Re-introduce index_prop_defs
cql3/statements/property_definitions: Add extract_property()
cql3/statements/index_prop_defs.cc: Add namespace
cql3/statements/index_prop_defs.hh: Rename type
cql3/statements/view_prop_defs.cc: Move validation logic into file
cql3/statements: Introduce view_prop_defs.{hh,cc}
cql3/statements/create_view_statement.cc: Move validation of ID
schema/schema.hh: Do not include index_prop_defs.hh
In PR 5b6570be52 we introduced the config option
`sstable_compression_user_table_options` to allow adjusting the default
compression settings for user tables. However, the new option was hooked
into the CQL layer and applied only to CQL base tables, not to the whole
spectrum of user tables: CQL auxiliary tables (materialized views,
secondary indexes, CDC log tables), Alternator base tables, Alternator
auxiliary tables (GSIs, LSIs, Streams).
Fix this by moving the logic into the `schema_builder` via a schema
initializer. This ensures that the default compression settings are
applied uniformly regardless of how the table is created, while also
keeping the logic in a central place.
Register the initializer at startup in all executables where schemas are
being used (`scylla_main()`, `scylla_sstable_main()`, `cql_test_env`).
Finally, remove the ad-hoc logic from `create_table_statement`
(redundant as of this patch), remove the xfail markers from the relevant
tests and adjust `test_describe_cdc_log_table_create_statement` to
expect LZ4WithDicts as the default compressor.
Fixes#26914.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Extend the `static_configurator` mechanism to support initialization of
arbitrary schema properties, not only static ones, by passing a
`schema_builder` reference to the configurator interface.
As part of this change, rename `static_configurator` to
`schema_initializer` to better reflect its broader responsibility.
Add a checkpoint/restore mechanism to allow de-registering an
initializer (useful for testing; will be used in the next patch).
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Schemas maintain a set of so-called "static properties". These are not
user-visible schema properties; they are internal values carried by
in-memory `schema` objects for convenience (349bc1a9b6,
https://github.com/scylladb/scylladb/pull/13170#issuecomment-1469848086).
Currently, the initialization of these properties happens when a
`schema_builder` builds a schema (`schema_builder::build()`), by
invoking all registered "static configurators".
This patch moves the initialization of static properties into the
`schema_builder` constructor. With this change, the builder initializes
the properties once, stores them in a data member, and reuses them for
all schema objects that it builds. This doesn't affect correctness as
the values produced by static configurators are "static" by
nature; they do not depend on runtime state.
In the next patch, we will replace the "static configurator" pattern
with a more general pattern that also supports initialization of regular
schema properties, not just static ones. Regular properties cannot be
initialized in `build()` because users may have already explicitly set
values via setters, and there is no way to distinguish between default
values and explicitly assigned ones.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
When learning a schema that has a linked cdc schema, we need to learn
also the cdc schema, and at the end the schema should point to the
learned cdc schema.
This is needed because the linked cdc schema is used for generating cdc
mutations, and when we process the mutations later it is assumed in some
places that the mutation's schema has a schema registry entry.
We fix a scenario where we could end up with a schema that points to a
cdc schema that doesn't have a schema registry entry. This could happen
for example if the schema is loaded before it is learned, so when we
learn it we see that it already has an entry. In that case, we need to
set the cdc schema to the learned cdc schema as well, because it could
have been loaded previously with a cdc schema that was not learned.
Fixesscylladb/scylladb#27610Closesscylladb/scylladb#27704
We're extending the logic of DESCRIBE INDEX to include properties of the
underlying materialized view. Tests are provided to ensure the
implementation works as intended.
One of the upcoming commits will lead to a cyclic dependency
of headers because `schema.hh` includes `index_prop_defs.hh`.
To prevent that, we remove the include and replace it with
a manually added alias.
This is not a perfect solution, but doing it properly would
require comprehensive changes. We can do that in a separate
task.
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
The properties can be directly manipulated by the user
via statements like `ALTER TABLE`. To better organize
the structure of `raw_schema`, we encapsulate that data
in the form of a dedicated struct. This change will be
later used for applying multiple properties to `schema_builder`
in one go.
This patch series re-enables support for speculative retry values `0` and `100`. These values have been supported some time ago, before [schema: fix issue 21825: add validation for PERCENTILE values in speculative_retry configuration. #21879
](https://github.com/scylladb/scylladb/pull/21879). When that PR prevented using invalid `101PERCENTILE` values, valid `100PERCENTILE` and `0PERCENTILE` value were prevented too.
Reproduction steps from [[Bug]: drop schema and all tables after apply speculative_retry = '99.99PERCENTILE' #26369](https://github.com/scylladb/scylladb/issues/26369) are unable to reproduce the issue after the fix. A test is added to make sure the inclusive border values `0` and `100` are supported.
Documentation is updated to give more information to the users. It now states that these border values are inclusive, and also that the precision, with automatic rounding, is 1 decimal digit.
Fixes#26369
This is a bug fix. If at any time a client tries to use value >= 99.5 and < 100, the raft error will happen. Backport is needed. The code which introduced inconsistency is introduced in 2025.2, so no backporting to 2025.1.
Closesscylladb/scylladb#26909
* github.com:scylladb/scylladb:
test: cqlpy: add test case for non-numeric PERCENTILE value
schema: speculative_retry: update exception type for sstring ops
docs: cql: ddl.rst: update speculative-retry-options
test: cqlpy: add test for valid speculative_retry values
schema: speculative_retry: allow 0 and 100 PERCENTILE values
Change speculative_retry::to_sstring and speculative_retry::from_sstring
to throw exceptions::configuration_exception instead of std::invalid_argument.
These errors can be triggered by CQL, so appropriate CQL exception should be
used.
Reference: https://github.com/scylladb/scylladb/issues/24748#issuecomment-3025213304
Refs #26369
This patch allows specifying 0 and 100 PERCENTILE values in speculative_retry.
It was possible to specify these values before #21825. #21825 prevented specifying
invalid values, like -1 and 101, but also prevented using 0 and 100.
On top of that, speculative_retry::to_sstring function did rounding when
formatting the string, which introduced inconsistency.
Fixes#26369
Add to the schema object a member that points to the CDC schema object
that is compatible with this schema, if any.
The compatible CDC schema is created and altered with its base schema in
the same group0 operation.
When generating CDC log mutations for some base mutation we want them to
be created using a compatible schema thas has a CDC column corresponding
to each base column. This change will allow us to find the right CDC
schema given a base mutation.
We also update the relevant structures in the schema registry that are
related to learning about schemas and transporting schemas across
shards or nodes.
When transporting a schema as frozen_schema, we need to transport the
frozen cdc schema as well, and set it again when unfreezing and
reconstructing the schema.
When adding a schema to the registry, we need to ensure its CDC schema
is added to the registry as well.
Currently we always set the CDC schema to nullptr and maintain the
previous behavior. We will change it in a later commit. Until then, we
mark all places where CDC schema is passed clearly so we don't forget
it.
remove the _base_info member from global_schema_ptr, and used the
base_info we have stored in the schema registry entry instead.
Currently when constructing a global_schema_ptr from a schema_ptr it
extracts and stores the base_info from the schema_ptr. Later it uses it
to reconstruct the schema_ptr, together with the frozen schema from the
schema registry entry.
But we can use the base_info that is already stored in the
schema registry entry.
Change the schema loader type in the schema_registry to return a
extended_frozen_schema instead of view_schema_and_base_info, and
remove view_schema_and_base_info which is not used anymore.
The casting between them is trivial.
The schema_registry_entry holds a frozen_schema and a base_info. The
base_info is extracted from the schema_ptr on load of a schema_ptr, and
it is used when unfreezing the schema.
But this is exactly what extended_frozen_schema is doing, so we can
just store an object of this type in the schema_registry_entry.
This makes the code simpler because the schema registry doesn't need to
be aware of the base_info.
Currently we construct a frozen schema with base info in few places, and
the caller is responsible for constructing the frozen schema and extracting
the base info if it's a view table.
We change it to make it simpler and remove the burden from the caller.
The caller can simply pass the schema_ptr, and the constructor for
extended_frozen_schema will construct the frozen schema and extract
the additional info it needs. This will make it easier to add additional
fields, and reduces code duplication.
We also make temporary castings between extended_frozen_schema and
view_schema_and_base_info for the transition, which are trivial, until
they are combined to a single type.
This commit starts a series of refactoring commits of the frozen_schema
to reduce duplication and make it easier to extend.
Currently there are two essentially identical types,
frozen_schema_with_base_info and view_schema_and_base_info in the
schema_registry that hold a frozen_schema together with a base_info for
view schemas.
Their role is to pass around a frozen schema together with additional
info that is extracted from the schema and passed around with it when
transporting it across shards or nodes, and is needed for
reconstructing it, and it is not part of the schema mutations.
Our goal is to combine them to a single type that we will call
extended_frozen_schema.
The namespace usage in this directory is very inconsistent, with files
and classes scattered in:
* global namespace
* namespace compaction
* namespace sstables
With cases, where all three used in the same file. This code used to
live in sstables/ and some of it still retains namespace sstables as a
heritage of that time. The mismatch between the dir (future module) and
the namespace used is confusing, so finish the migration and move all
code in compaction/ to namespace compaction too.
This patch, although large, is mechanic and only the following kind of
changes are made:
* replace namespace sstable {} with namespace compaction {}
* add namespace compaction {}
* drop/add sstables::
* drop/add compaction::
* move around forward-declarations so they are in the correct namespace
context
This refactoring revealed some awkward leftover coupling between
sstables and compaction, in sstables/sstable_set.cc, where the
make_sstable_set() methods of compaction strategies are implemented.
As requested in #22104, moved the files and fixed other includes and build system.
Moved files:
- combine.hh
- collection_mutation.hh
- collection_mutation.cc
- converting_mutation_partition_applier.hh
- converting_mutation_partition_applier.cc
- counters.hh
- counters.cc
- timestamp.hh
Fixes: #22104
This is a cleanup, no need to backport
Closesscylladb/scylladb#25085
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
Closes#25182
Fixes#22106
Moves the shared compress components to sstables, and rename to
match class type.
Adjust includes, removing redundant/unneeded ones where possible.
Closesscylladb/scylladb#25103
As requested in #22102, #22103 and #22105 moved the files and fixed other includes and build system.
Moved files:
- clustering_bounds_comparator.hh
- keys.cc
- keys.hh
- clustering_interval_set.hh
- clustering_key_filter.hh
- clustering_ranges_walker.hh
- compound_compat.hh
- compound.hh
- full_position.hh
Fixes: #22102Fixes: #22103Fixes: #22105Closesscylladb/scylladb#25082
Before for views and indexes it was fetching base schema from db (and
couple other properties). This is a problem once we introduce atomic
tables and views deletion (in the following commit).
Because once we delete table it can no longer be fetched from db object,
and truncation is performed after atomically deleting all relevant
tables/views/indexes.
Now the whole relevant schema will be fetched via global_table_ptr
(table_shards) object.
When describing a table, we need to do it carefully: if some
columns were dropped, we must specify that explicitly by
```
ALTER TABLE {table} DROP {column} USING TIMESTAMP ...
```
in the result of the DESCRIBE statement. Failing to do so
could lead to data resurrection.
However, if a table has been altered many, many times,
we might end up with a huge create statement. Constructing
it could, in turn, trigger an oversized allocation.
Some tests ran into that very problem in fact.
In this commit, we want to mitigate the problem: instead of
allocating a contiguous chunk of memory for the create
statement, we use `fragmented_ostringstream` and `managed_string`
to possibly keep data scattered in memory. It makes handling
`cql3::description` less convenient in the code, but since
the struct is pretty much immediately serialized after
creating it, it's a very good trade-off.
We provide a reproducer. It consistently passes with this commit,
while having about 50% chance of failure before it (based on my
own experiments). Playing with the parameters of the test
doesn't seem to improve that chance, so let's keep it as-is.
Fixesscylladb/scylladb#24018
This commit increases the maximum length of names for keyspaces, tables, materialized views, and indexes from 48 to 192 bytes.
The previous 48-bytes limit was inherited from Cassandra 3 for compatibility. However, this validation was removed in Cassandra 4 and 5 (see CASSANDRA-20389)
and some usage scenarios (such as some feature store workflows generating long table names) now depend on this relaxed constraint.
This change brings ScyllaDB's behavior in line with modern Cassandra versions and better supports these use cases.
The new limit of 192 bytes is derived from underlying filesystem limitations to prevent runtime errors when creating directories for table data.
When a new table is created, ScyllaDB generates a directory for its SSTables. The directory name is constructed from the table name, a dash, and a 32-character UUID.
For a CDC-enabled table, an associated log table is also created, which has the suffix `_scylla_cdc_log` appended to its name.
The directory name for this log table becomes the longest possible representation.
Additionally we reserve 15 bytes for future use, allowing for potential future extensions without breaking existing schemas.
To guarantee that directory creation never fails due to exceeding filesystem name limits, the maximum name length is calculated as follows:
255 bytes (common filesystem limit for a path component)
- 32 bytes (for the 32-character UUID string)
- 1 byte (for the '-' separator)
- 15 bytes (for the '_scylla_cdc_log' suffix)
- 15 bytes (reserved for future use)
----------
= 192 bytes (Maximum allowed name length)
This calculation is similar in principle to the one proposed for Cassandra to fix related directory creation failures (see apache/cassandra/pull/4038).
This patch also updates/adds all associated tests to validate the new 192-byte limit.
The documentation has been updated accordingly.
This reverts commit 0b516da95b, reversing
changes made to 30199552ac. It breaks
cluster.random_failures.test_random_failures.test_random_failures
in debug mode (at least).
Fixes#24513
Before for views and indexes it was fetching base schema from db (and
couple other properties). This is a problem once we introduce atomic
tables and views deletion (in the following commit).
Because once we delete table it can no longer be fetched from db object,
and truncation is performed after atomically deleting all relevant
tables/views/indexes.
Now the whole relevant schema will be fetched via global_table_ptr
(table_shards) object.
This pull request adds support for creating custom indexes (at a metadata level) as long as a supported custom class is provided (currently only vector search).
The patch contains:
- a change in CREATE INDEX statement that allows for the USING keyword to be present as long as one of the supported classes is used
- support for describing custom indexes in the DESCRIBE statement
- unit tests
Co-authored by: @Balwancia
Closesscylladb/scylladb#23720
* github.com:scylladb/scylladb:
test/cqlpy: add custom index tests
index: support storing metadata for custom indices
Added function returning custom index class name.
Added printing custom index class name when using DESCRIBE.
Changed validation to reflect current support of indices.
In the previous commits we made sure that the base info is not dependent
on the base schema version, and the info dependent on the base schema
version is calculated when it's needed. In this patch we remove the
unnecessary re-setting of the base_info.
The set_base_info method isn't removed completely, because it also has
a secondary function - zeroing the view_info fields other than base_info.
Because of this, in this patch we rename it accordingly and limit its
use to the updates caused by a base schema change.
The base info now only contains values which are not reliant on the
base schema version. We remove the the base schema from the base info
to make it immutable regardless of base schema version, at the point
of this patch it's also not needed anywhere - the new base info can
replace the base schema in most places, and in the few (view_updates)
where we need it, we pull the most recent base schema version from
the database.
After this change, the base info no longer changes in a view schema
after creation, so we'll no longer get errors when we try generating
view updates with a base_info that's incompatible with a specific
base schema version.
Fixes#9059Fixes#21292Fixes#22410
In the following patch we plan to remove the base schema from the base_info
to make the base_info immutable. To do that, we first prepare the schema
registry for the change; we need to be able to create view schemas from
frozen schemas there and frozen schemas have no information about the base
table. Unless we do this change, after base schemas are removed from the
base info, we'll no longer be able to load a view schema to the schema registry
without looking up the base schema in the database.
This change also required some updates to schema building:
* we add a method for unfreezing a view schema with base info instead of
a base schema
* we make it possible to use schema_builder with a base info instead of
a base schema
* we add a method for creating a view schema from mutations with a base info
instead of a base schema
* we add a view_info constructor withat base info instead of a base schema
* we update the naming in schema_registry to reflect the usage of base info
instead of base schema
Currently, the base_info may or may not be set in view schemas.
Even when it's set, it may be modified. This necessitates extra
checks when handling view schemas, as well as potentially causing
errors when we forget to set it at some point.
Instead, we want to make the base info an immutable member of view
schemas (inside view_info). The first step towards that is making
sure that all newly created schemas have the base info set.
We achieve that by requiring a base schema when constructing a view
schema. Unfortunately, this adds complexity each time we're making
a view schema - we need to get the base schema as well.
In most cases, the base schema is already available. The most
problematic scenario is when we create a schema from mutations:
- when parsing system tables we can get the schema from the
database, as regular tables are parsed before views
- when loading a view schema using the schema loader tool, we need
to load the base additionally to the view schema, effectively
doubling the work
- when pulling the schema from another node - in this case we can
only get the current version of the base schema from the local
database
Additionally, we need to consider the base schema version - when
we generate view updates the version of the base schema used for
reads should match the version of the base schema in view's base
info.
This is achieved by selecting the correct (old or new) schema in
`db::schema_tables::merge_tables_and_views` and using the stored
base schema in the schema_registry.
schema_extension allows making invisible changes to system_schema
that evade upgrade rollback tests. They appear in system_schema
as an encoded blob which reduces serviceability, as they cannot
be read.
Deprecate it and point users to adding explicit columns in scylla_tables.
We could probably make use of the data structure, after we teach it
to encode its payload into proper named and typed columns instead of
using IDL.
Closesscylladb/scylladb#23151
In this series we implement the UpdateTable operation to add a GSI to an existing table, or remove a GSI from a table. As the individual commit messages will explained, this required changing how Alternator stores materialized view keys - instead of insisting that these key must be real columns (that is **not** the case when adding a GSI to an existing table), the materialized view can now take as its key any Alternator attribute serialized inside the ":attrs" map holding all non-key attributes. Fixes#11567.
We also fix the IndexStatus and Backfilling attributes returned by DescribeTable - as DynamoDB API users use this API to discover when a newly added GSI completed its "backfilling" (what we call "view building") stage. Fixes#11471.
This series should not be backported lightly - it's a new feature and required fairly large and intrusive changes that can introduce bugs to use cases that don't even use Alternator or its UpdateTable operations - every user of CQL materialized views or secondary indexes, as well as Alternator GSI or LSI, will use modified code. **It should be backported to 2025.1**, though - this version was actually branched long after this PR was sent, and it provides a feature that was promised for 2025.1.
Closesscylladb/scylladb#21989
* github.com:scylladb/scylladb:
alternator: fix view build on oversized GSI key attribute
mv: clean up do_delete_old_entry
test/alternator: unflake test for IndexStatus
test/alternator: work around unrelated bug causing test flakiness
docs/alternator: adding a GSI is no longer an unimplemented feature
test/alternator: remove xfail from all tests for issue 11567
alternator: overhaul implementation of GSIs and support UpdateTable
mv: support regular_column_transformation key columns in view
alternator: add new materialized-view computed column for item in map
build: in cmake build, schema needs alternator
build: build tests with Alternator
alternator: add function serialized_value_if_type()
mv: introduce regular_column_transformation, a new type of computed column
alternator: add IndexStatus/Backfilling in DescribeTable
alternator: add "LimitExceededException" error type
docs/alternator: document two more unimplemented Alternator features
This patch removes expansion of "SELECT *" in DESC MATERIALIZED VIEW.
Instead of explicitly printing each column, DESC command will now just
use SELECT *, if view was created with it. Also, adds a correspodning test.
Fixes#21154Closesscylladb/scylladb#21962
This patch adds a new computed column class for materialized views,
extract_from_attrs_column_computation
which is Alternator-specific and knows how to extract a value (of a
known type) from an attribute stored in Alternator's map-of-all-nonkey-
attributes ":attrs".
We'll use this new computed column in the next patch to reimplement GSI.
The new computed-column class is based on regular_column_transformation
introduced in the previous patch. It is not yet wired to anything:
The MV code cannot handle any regular_column_transformation yet, and
Alternator will not yet use it to create a GSI. We'll do those things
in the following patches.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch is to cmake what the previous patch was to configure.py.
In the next patch we want to make schema/schema.o depend on
alternator/executor.o - because when the schema has an Alternator
computed column, the schema code needs to construct the computed column
object (extract_from_attrs_column_computation) and that lives in
alternator/executor.o.
In the cmake-based build, all the schema/* objects are put into one
library "libschema.a". But code that uses this library (e.g., tests)
can't just use that library alone, because it depends on other code
not in schema/. So CMakeLists.txt lists other "libraries" that
libschema.a depends on - including for example "cql3". We now need
to add "alternator" to this dependency list. The dependency is marked
"PRIVATE" - schema needs alternator for its own internal uses, but
doesn't need to export alternator's APIs to its own users.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Unlike with vnodes, each tablet is served only by a single
shard, and it is associated with a memtable that, when
flushed, it creates sstables which token-range is confined
to the tablet owning them.
On one hand, this allows for far better agility and elasticity
since migration of tablets between nodes or shards does not
require rewriting most if not all of the sstables, as required
with vnodes (at the cleanup phase).
Having too few tablets might limit performance due not
being served by all shards or by imbalance between shards
caused by quantization. The number of tabelts per table has to be
a power of 2 with the current design, and when divided by the
number of shards, some shards will serve N tablets, while others
may serve N+1, and when N is small N+1/N may be significantly
larger than 1. For example, with N=1, some shards will serve
2 tablet replicas and some will serve only 1, causing an imbalance
of 100%.
Now, simply allocating a lot more tablets for each table may
theoretically address this problem, but practically:
a. Each tablet has memory overhead and having too many tablets
in the system with many tables and many tablets for each of them
may overwhelm the system's and cause out-of-memory errors.
b. Too-small tablets cause a proliferation of small sstables
that are less efficient to acces, have higher metadata overhead
(due to per-sstable overhead), and might exhaust the system's
open file-descriptors limitations.
The options introduced in this change can help the user tune
the system in two ways:
1. Sizing the table to prevent unnecessary tablet splits
and migrations. This can be done when the table is created,
or later on, using ALTER TABLE.
2. Controlling min_per_shard_tablet_count to improve
tablet balancing, for hot tables.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
This commit addresses issue #21825, where invalid PERCENTILE values for
the `speculative_retry` setting were not properly handled, causing potential
server crashes. The valid range for PERCENTILE is between 0 and 100, as defined
in the documentation for speculative retry options, where values above 100 or
below 0 are invalid and should be rejected.
The added validation ensures that such invalid values are rejected with a clear
error message, improving system stability and user experience.
Fixes#21825Closesscylladb/scylladb#21879
