There are several reasons we want to do that.
One is that it will give us more flexibility in distributing the
load. We can subdivide tablets at any token, and achieve more
evenly-sized tablets. In particular, we can isolate large partitions
into separate tablets.
We can also split and merge incrementally individual tablets.
Currently, we do it for the whole table or nothing, which makes
splits and merges take longer and cause wide swings of the count.
This is not implemented in this PR yet, we still split/merge the whole table.
Another reason is vnode to tablets migration. We now could construct a
tablet map which matches exactly the vnode boundaries, so migration
can happen transparently from CQL-coordinator point of view.
Tablet count is still a power-of-two by default for newly created tables.
It may be different if tablet map is created by non-standard means,
or if per-table tablet option "pow2_count" is set to "false".
build/release/scylla perf-tablets:
Memory footprint for 131k tablets increased from 56 MiB to 58.1 MiB (+3.5%)
Before:
```
Generating tablet metadata
Total tablet count: 131072
Size of tablet_metadata in memory: 57456 KiB
Copied in 0.014346 [ms]
Cleared in 0.002698 [ms]
Saved in 1234.685303 [ms]
Read in 445.577881 [ms]
Read mutations in 299.596313 [ms] 128 mutations
Read required hosts in 247.482742 [ms]
Size of canonical mutations: 33.945053 [MiB]
Disk space used by system.tablets: 1.456761 [MiB]
Tablet metadata reload:
full 407.69ms
partial 2.65ms
```
After:
```
Generating tablet metadata
Total tablet count: 131072
Size of tablet_metadata in memory: 59504 KiB
Copied in 0.032475 [ms]
Cleared in 0.002965 [ms]
Saved in 1093.877441 [ms]
Read in 387.027100 [ms]
Read mutations in 255.752121 [ms] 128 mutations
Read required hosts in 211.202805 [ms]
Size of canonical mutations: 33.954453 [MiB]
Disk space used by system.tablets: 1.450162 [MiB]
Tablet metadata reload:
full 354.50ms
partial 2.19ms
```
Closesscylladb/scylladb#28459
* github.com:scylladb/scylladb:
test: boost: tablets: Add test for merge with arbitrary tablet count
tablets, database: Advertise 'arbitrary' layout in snapshot manifest
tablets: Introduce pow2_count per-table tablet option
tablets: Prepare for non-power-of-two tablet count
tablets: Implement merged tablet_map constructor on top of for_each_sibling_tablets()
tablets: Prepare resize_decision to hold data in decisions
tablets: table: Make storage_group handle arbitrary merge boundaries
tablets: Make stats update post-merge work with arbitrary merge boundaries
locator: tablets: Support arbitrary tablet boundaries
locator: tablets: Introduce tablet_map::get_split_token()
dht: Introduce get_uniform_tokens()
This series allows creating multiple vector indexes on the same column so users can rebuild an index without losing query availability.
The intended flow is:
1. Create a new vector index on a column that already has one.
2. Keep serving ANN queries from the old index while the new one is being built.
3. Verify the new index is ready.
4. Automatically switch to the remaining index.
5. Drop the old index.
To make that deterministic, `index_version` is changed from the base table schema version to a real creation timeuuid. When multiple vector indexes exist on the same column, ANN query planning now picks the index according to the routing implemented in Vector Store (newest serving index). This keeps queries on the old index until it the new one is up and ready.
This patch also removes the create-time restriction that rejected a second vector index on the same column. Name collisions are still rejected as before.
Test coverage is updated accordingly:
- Scylla now verifies that two vector indexes can coexist on the same column.
- Cassandra/SAI behavior is still covered and is still expected to reject duplicate indexes on the same column.
Fixes: VECTOR-610
Closesscylladb/scylladb#29407
* github.com:scylladb/scylladb:
docs: document vector index metadata and duplicate handling
test/cqlpy: cover vector index duplicate creation rules
vector_index: allow multiple named indexes on one column
vector_index: store `index_version` as creation timeuuid
Commit 234f905 (sstables: scylla_metadata: add schema member) added a
new Schema subcomponent (tag 11) to scylla_metadata. Document it in the
sstable Scylla format reference:
- Add schema to the subcomponent grammar enumeration
- Add a summary entry describing the subcomponent (tag 11) and its purpose
- Add a detailed ## schema subcomponent section with the binary grammar,
covering table_id, table_schema_version, keyspace_name, table_name and
the column_description array (column_kind, column_name, column_type)
Fixes https://github.com/scylladb/scylladb/issues/27960
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Closesscylladb/scylladb#28983
The enable_logstor configuration option is redundant with the 'logstor'
experimental feature flag. Consolidate to a single gate: use the
experimental feature to control both whether logstor is available for
table creation and whether it is initialized at database startup.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#29427
Currently, the manifest advertises "powof2", which is wrong for
arbitrary count and boundaries.
Introduce a new kind of layout called "arbitrary", and produce it if
the tablet map doesn't conform to "powof2" layout.
We should also produce tablet boundaries in this case, but that's
worked on in a different PR: https://github.com/scylladb/scylladb/pull/28525
Document the new vector index behavior in the user-facing and developer
docs.
Describe `index_version` as a creation timeuuid stored in
`system_schema.indexes`, clarify that recreating an index changes it
while ALTER TABLE does not, and document that Scylla allows multiple
named vector indexes on the same column while still rejecting unnamed
duplicates.
implement tablet split, tablet merge and tablet migration for tables that use the experimental logstor storage engine.
* tablet merge simply merges the histograms of segments of one compaction group with another.
* for tablet split we take the segments from the source compaction group, read them and write all live records to separate segments according to the split classifier, and move separated segments to the target compaction groups.
* for tablet migration we use stream_blob, similarly to file streaming of sstables. we add a new op type for streaming a logstor segment. on the source we take a snapshot of the segments with an input stream that reads the segment, and on the target we create a sink that allocates a new segment on the target shard and writes to it.
* we also do some improvements for recovery and loading of segments. we add a segment header that contains useful information for non-mixed segments, such as the table and token range.
Refs SCYLLADB-770
no backport - still a new and experimental feature
Closesscylladb/scylladb#29207
* github.com:scylladb/scylladb:
test: logstor: additional logstor tests
docs/dev: add logstor on-disk format section
logstor: add version and crc to buffer header
test: logstor: tablet split/merge and migration
logstor: enable tablet balancing
logstor: streaming of logstor segments using stream_blob
logstor: add take_logstor_snapshot
logstor: segment input/output stream
logstor: implement compaction_group::cleanup
logstor: tablet split
logstor: tablet merge
logstor: add compaction reenabler
logstor: add segment header
logstor: serialize writes to active segment
replica: extend compaction_group functions for logstor
replica: add compaction_group_for_logstor_segment
logstor: code cleanup
For counter updates, use a counter ID that is constructed from the
node's rack instead of the node's host ID.
A rack can have at most two active tablet replicas at a time: a single
normal tablet replica, and during tablet migration there are two active
replicas, the normal and pending replica. Therefore we can have two
unique counter IDs per rack that are reused by all replicas in the rack.
We construct the counter ID from the rack UUID, which is constructed
from the name "dc:rack". The pending replica uses a deterministic
variation of the rack's counter ID by negating it.
This improves the performance and size of counter cells by having less
unique counter IDs and less counter shards in a counter cell.
Previously the number of counter shards was the number of different
host_id's that updated the counter, which can be typically the number of
nodes in the cluster and continue growing indefinitely when nodes are
replaced. with the rack-based counter id the number of counter shards
will be at most twice the number of different racks (including removed
racks, which should not be significant).
Fixes SCYLLADB-356
backport not needed - an enhancement
Closesscylladb/scylladb#28901
* github.com:scylladb/scylladb:
docs/dev: add counters doc
counters: reuse counter IDs by rack
Every time someone modifies the build system — adding a source file, changing a compilation flag, or wiring a new test — the change tends to land in only one of our two build systems (configure.py or CMake). Over time this causes three classes of problems:
1. **CMake stops compiling entirely.** Missing defines, wrong sanitizer flags, or misplaced subdirectory ordering cause hard build failures that are only discovered when someone tries to use CMake (e.g. for IDE integration).
2. **Missing build targets.** Tests or binaries present in configure.py are never added to CMake, so `cmake --build` silently skips them. This PR fixes several such cases (e.g. `symmetric_key_test`, `auth_cache_test`, `sstable_tablet_streaming`).
3. **Missing compilation units in targets.** A `.cc` file is added to a test binary in one system but not the other, causing link errors or silently omitted test coverage.
To fix the existing drift and prevent future divergence, this series:
**Adds a build-system comparison script**
(`scripts/compare_build_systems.py`) that configures both systems into a temporary directory, parses their generated `build.ninja` files, and compares per-file compilation flags, link target sets, and per-target libraries. configure.py is treated as the baseline; CMake must match it. The script supports a `--ci` mode suitable for gating PRs that touch
build files.
**Fixes all current mismatches** found by the script:
- Mode flag alignment in `mode.common.cmake` and `mode.Coverage.cmake`
(sanitizer flags, `-fno-lto`, stack-usage warnings, coverage defines).
- Global define alignment (`SEASTAR_NO_EXCEPTION_HACK`, `XXH_PRIVATE_API`,
`BOOST_ALL_DYN_LINK`, `SEASTAR_TESTING_MAIN` placement).
- Seastar build configuration (shared vs static per mode, coverage
sanitizer link options).
- Abseil sanitizer flags (`-fno-sanitize=vptr`).
- Missing test targets in `test/boost/CMakeLists.txt`.
- Redundant per-test flags now covered by global settings.
- Lua library resolution via a custom `cmake/FindLua.cmake` using
pkg-config, matching configure.py's approach.
**Adds documentation** (`docs/dev/compare-build-systems.md`) describing how to run the script and interpret its output.
No backport needed — this is build infrastructure improvement only.
Closesscylladb/scylladb#29273
* github.com:scylladb/scylladb:
scripts: remove lua library rename workaround from comparison script
cmake: add custom FindLua using pkg-config to match configure.py
test/cmake: add missing tests to boost test suite
test/cmake: remove per-test LTO disable
cmake: add BOOST_ALL_DYN_LINK and strip per-component defines
cmake: move SEASTAR_TESTING_MAIN after seastar and abseil subdirs
cmake: add -fno-sanitize=vptr for abseil sanitizer flags
cmake: align Seastar build configuration with configure.py
cmake: align global compile defines and options with configure.py
cmake: fix Coverage mode in mode.Coverage.cmake
cmake: align mode.common.cmake flags with configure.py
configure.py: add sstable_tablet_streaming to combined_tests
docs: add compare-build-systems.md
scripts: add compare_build_systems.py to compare ninja build files
Add a documentation of the counters feature implementation in
docs/dev/counters.md.
The documentation is taken from the wiki and updated according to the
current state of the code - legacy details are removed, and a section
about the counter id is added.
Fixes#29043 with the following docs changes:
- docs/dev/system-keyspaces.md: Added a new file that documents all keyspaces created internally
Closesscylladb/scylladb#29044
This commit removes references ScyllaDB versions ("Since x.y")
from the ScyllaDB documentation on Docker Hub, as they are
redundant and confusing (some versions are super ancient).
Fixes SCYLLADB-1212
Closesscylladb/scylladb#29204
Queries against local vector indexes were failing with the error:
```ANN ordering by vector requires the column to be indexed using 'vector_index'```
This was a regression introduced by 15788c3734, which incorrectly
assumed the first column in the targets list is always the vector column.
For local vector indexes, the first column is the partition key, causing
the failure.
Previously, serialization logic for the target index option was shared
between vector and secondary indexes. This is no longer viable due to
the introduction of local vector indexes and vector indexes with filtering
columns, which have different target format.
This commit introduces a dedicated JSON-based serialization format for
vector index targets, identifying the target column (tc), filtering
columns (fc), and partition key columns (pk). This ensures unambiguous
serialization and deserialization for all vector index types.
This change is backward compatible for regular vector indexes. However,
it breaks compatibility for local vector indexes and vector indexes with
filtering columns created in version 2026.1.0. To mitigate this, usage
of these specific index types will be blocked in the 2026.1.0 release
by failing ANN queries against them in vector-store service.
Fixes: SCYLLADB-895
Backport to 2026.1 is required as this issue occurs also on this branch.
Closesscylladb/scylladb#28862
* github.com:scylladb/scylladb:
index: fix DESC INDEX for vector index
vector_search: test: refactor boilerplate setup
vector_search: fix SELECT on local vector index
index: test: vector index target option serialization test
index: test: secondary index target option serialization test
This PR introduces the vnodes-to-tablets migration procedure, which enables converting an existing vnode-based keyspace to tablets.
The migration is implemented as a manual, operator-driven process executed in several stages. The core idea is to first create tablet maps with the same token boundaries and replica hosts as the vnodes, and then incrementally convert the storage of each node to the tablets layout. At a high level, the procedure is the following:
1. Create tablet maps for all tables in the keyspace.
2. Sequentially upgrade all nodes from vnodes to tablets:
1. Mark a node for upgrade in the topology state.
2. Restart the node. During startup, while the node is offline, it reshards the SSTables on vnode boundaries and switches to a tablet ERM.
3. Wait for the node to return online before proceeding to the next node.
4. Finalize the migration:
1. Update the keyspace schema to mark it as tablet-based.
2. Clear the group0 state related to the migration.
From the client's perspective, the migration is online; the cluster can still serve requests on that keyspace, although performance may be temporarily degraded.
During the migration, some nodes use vnode ERMs while others use tablet ERMs. Cluster-level algorithms such as load balancing will treat the keyspace's tables as vnode-based. Once migration is finalized, the keyspace is permanently switched to tablets and cannot be reverted back to vnodes. However, a rollback procedure is available before finalization.
The patch series consists of:
* Load balancer adjustments to ignore tablets belonging to a migrating keyspace.
* A new vnode-based resharding mode, where SSTables are segregated on vnode boundaries rather than with the static sharder.
* A new per-node `intended_storage_mode` column in `system.topology`. Represents migration intent (whether migration should occur on restart) and direction.
* Four new REST endpoints for driving the migration (start, node upgrade/downgrade, finalize, status), along with `nodetool` wrappers. The finalization is implemented as a global topology request.
* Wiring of the migration process into the startup logic: the `distributed_loader` determines a migrating table's ERM flavor from the `intended_storage_mode` and the ERM flavor determines the `table_populator`'s resharding mode. Token metadata changes have been adjusted to preserve the ERM flavor.
* Cluster tests for the migration process.
Fixes SCYLLADB-722.
Fixes SCYLLADB-723.
Fixes SCYLLADB-725.
Fixes SCYLLADB-779.
Fixes SCYLLADB-948.
New feature, no backport is needed.
Closesscylladb/scylladb#29065
* github.com:scylladb/scylladb:
docs: Add ops guide for vnodes-to-tablets migration
test: cluster: Add test for migration of multiple keyspaces
test: cluster: Add test for error conditions
test: cluster: Add vnodes->tablets migration test (rollback)
test: cluster: Add vnodes->tablets migration test (1 table, 3 nodes)
test: cluster: Add vnodes->tablets migration test (1 table, 1 node)
scylla-nodetool: Add migrate-to-tablets subcommand
api: Add REST endpoint for vnode-to-tablet migration status
api: Add REST endpoint for migration finalization
topology_coordinator: Add `finalize_migration` request
database: Construct migrating tables with tablet ERMs
api: Add REST endpoint for upgrading nodes to tablets
api: Add REST endpoint for starting vnodes-to-tablets migration
topology_state_machine: Add intended_storage_mode to system.topology
distributed_loader: Wire vnode-based resharding into table populator
replica: Pick any compaction group for resharding
compaction: resharding_compaction: add vnodes_resharding option
storage_service: Preserve ERM flavor of migrating tables
tablet_allocator: Exclude migrating tables from load balancing
feature_service: Add vnodes_to_tablets_migrations feature
As discussed with @ScyllaPiotr in
https://github.com/scylladb/scylladb/pull/29232, the doc about to be
removed is just:
> Looking at history, I think this audit.md is a design doc: scylladb/scylla-enterprise@87a5c19, for which the feature has been implemented differently, eventually, and was created around the time when design docs, apparently, where stored within the repository itself. So for me it's some trash (sorry for strong language) that can be safely removed.
Closesscylladb/scylladb#29316
Queries against local vector indexes were failing with the error:
"ANN ordering by vector requires the column to be indexed using 'vector_index'"
This was a regression introduced by 15788c3734, which incorrectly
assumed the first column in the targets list is always the vector column.
For local vector indexes, the first column is the partition key, causing
the failure.
Previously, serialization logic for the target index option was shared
between vector and secondary indexes. This is no longer viable due to
the introduction of local vector indexes and vector indexes with filtering
columns, which have different target format.
This commit introduces a dedicated JSON-based serialization format for
vector index targets, identifying the target column (tc), filtering
columns (fc), and partition key columns (pk). This ensures unambiguous
serialization and deserialization for all vector index types.
This change is backward compatible for regular vector indexes. However,
it breaks compatibility for local vector indexes and vector indexes with
filtering columns created in version 2026.1.0. To mitigate this, usage
of these specific index types will be blocked in the 2026.1.0 release
by failing ANN queries against them in vector-store service.
Fixes: SCYLLADB-895
Target option serialization must remain stable for backward compatibility.
The index is restored from this property on startup, so unintentional
changes to the serialization schema can break indexes after upgrade.
Document the purpose, usage, and examples for
scripts/compare_build_systems.py which compares the configure.py
and CMake build systems by parsing their ninja build files.
Part of the vnodes-to-tablets migration is to reshard the SSTables of
each node on vnode boundaries. Resharding is a heavy operation that
runs on startup while the node is offline. Since nodes can restart
for unexpected reasons, we need a flag to do it in a controllable way.
We also need the ability to roll back the migration, which requires
resharding in the opposite direction. This means a node must be aware of
the intended migration direction.
To address both requirements, this patch introduces a new column,
intended_storage_mode, in system.topology. A non-null value indicates
that a node should perform a migration and specifies the migration
direction.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
This pull request adds support for calculation and storing CRC32 digests for all SSTable components.
This change replaces plain file_writer with crc32_digest_file_writer for all SSTable components that should be checksummed. The resulting component digests are stored in the sstable structure
and later persisted to disk as part of the Scylla metadata component during writer::consume_end_of_stream.
Several test cases where introduced to verify expected behaviour.
Additionally, this PR adds new rewrite component mechanism for safe sstable component rewriting.
Previously, rewriting an sstable component (e.g., via rewrite_statistics) created a temporary file that was renamed to the final name after sealing. This allowed crash recovery by simply removing the temporary file on startup.
However, with component digests stored in scylla_metadata (#20100),
replacing a component like Statistics requires atomically updating both the component
and scylla_metadata with the new digest - impossible with POSIX rename.
The new mechanism creates a clone sstable with a fresh generation:
- Hard-links all components from the source except the component being rewritten and scylla_metadata
- Copies original sstable components pointer and recognized components from the source
- Invokes a modifier callback to adjust the new sstable before rewriting
- Writes the modified component along with updated scylla_metadata containing the new digest
- Seals the new sstable with a temporary TOC
- Replaces the old sstable atomically, the same way as it is done in compaction
This is built on the rewrite_sstables compaction framework to support batch operations (e.g., following incremental repair).
In case of any failure durning the whole process, sstable will be automatically deleted on the node startup due to
temporary toc persistence.
Backport is not required, it is a new feature
Fixes https://github.com/scylladb/scylladb/issues/20100, https://github.com/scylladb/scylladb/issues/27453Closesscylladb/scylladb#28338
* github.com:scylladb/scylladb:
docs: document components_digests subcomponent and trailing digest in Scylla.db
sstable_compaction_test: Add tests for perform_component_rewrite
sstable_test: add verification testcases of SSTable components digests persistance
sstables: store digest of all sstable components in scylla metadata
sstables: replace rewrite_statistics with new rewrite component mechanism
sstables: add new rewrite component mechanism for safe sstable component rewriting
compaction: add compaction_group_view method to specify sstable version
sstables: add null_data_sink and serialized_checksum for checksum-only calculation
sstables: extract default write open flags into a constant
sstables: Add write_simple_with_digest for component checksumming
sstables: Extract file writer closing logic into separate methods
sstables: Implement CRC32 digest-only writer
Document the new `components_digests` subcomponent (tag 12) added to the
Scylla.db metadata component, which stores CRC32 digests of all checksummed
SSTable component files. Also document the trailing CRC32 digest that
stores digest of the scylla metadata itself.
In this series we introduce new system tables and use them for storing the raft metadata
for strongly consistent tables. In contrast to the previously used raft group0 tables, the
new tables can store data on any shard. The tables also allow specifying the shard where
each partition should reside, which enables the tablets of strongly consistent tables to have
their raft group metadata co-located on the same shard as the tablet replica.
The new tables have almost the same schemas as the raft group0 tables. However, they
have an additional column in their partition keys. The additional column is the shard
that specifies where the data should be located. While a tablet and its corresponding
raft group server resides on some shard, it now writes and reads all requests to the
metadata tables using its shard in addition to the group_id.
The extra partition key column is used by the new partitioner and sharder which allow
this special shard routing. The partitioner encodes the shard in the token and the
sharder decodes the shard from the token. This approach for routing avoids any
additional lookups (for the tablet mapping) during operations on the new tables
and it also doesn't require keeping any state. It also doesn't interact negatively
with resharding - as long as tablets (and their corresponding raft metadata) occupy
some shard, we do not allow starting the node with a shard count lower than the
id of this shard. When increasing the shard count, the routing does not change,
similarly to how tablet allocation doesn't change.
To use the new tables, a new implementation of `raft::persistence` is added. Currently,
it's almost an exact copy of the `raft_sys_table_storage` which just uses the new tables,
but in the future we can modify it with changes specific to metadata (or mutation)
storage for strongly consistent tables. The new storage is used in the `groups_manager`,
which combined with the removal of some `this_shard_id() == 0` checks, allows strongly
consistent tables to be used on all shards.
This approach for making sure that the reads/writes to the new tables end up on the correct shards
won in the balance of complexity/usability/performance against a few other approaches we've considered.
They include:
1. Making the Raft server read/write directly to the database, skipping the sharder, on its shard, while using
the default partitioner/sharder. This approach could let us avoid changing the schema and there should be
no problems for reads and writes performed by the Raft server. However, in this approach we would input
data in tables conflicting with the placement determined by the sharder. As a result, any read going through
the sharder could miss the rows it was supposed to read. Even when reading all shards to find a specific value,
there is a risk of polluting the cache - the rows loaded on incorrect shards may persist in the cache for an unknown
amount of time. The cache may also mistakenly remember that a row is missing, even though it's actually present,
just on an incorrect shard.
Some of the issues with this approach could be worked around using another sharder which always returns
this_shard_id() when asked about a shard. It's not clear how such a sharder would implement a method like
`token_for_next_shard`, and how much simpler it would be compared to the current "identity" sharder.
2. Using a sharder depending on the current allocation of tablets on the node. This approach relies on the
knowledge of group_id -> shard mapping at any point in time in the cluster. For this approach we'd also
need to either add a custom partitioner which encodes the group_id in the token, or we'd need to track the
token(group_id) -> shard mapping. This approach has the benefit over the one used in the series of keeping
the partition key as just group_id. However, it requires more logic, and the access to the live state of the node
in the sharder, and it's not static - the same token may be sharded differently depending on the state of the
node - it shouldn't occur in practice, but if we changed the state of the node before adjusting the table data,
we would be unable to access/fix the stale data without artificially also changing the state of the node.
3. Using metadata tables co-located to the strongly consistent tables. This approach could simplify the
metadata migrations in the future, however it would require additional schema management of all co-located
metadata tables, and it's not even obvious what could be used as the partition key in these tables - some
metadata is per-raft-group, so we couldn't reuse the partition key of the strongly consistent table for it. And
finding and remembering a partition key that is routed to a specific shard is not a simple task. Finally, splits
and merges will most likely need special handling for metadata anyway, so we wouldn't even make use of
co-located table's splits and merges.
Fixes [SCYLLADB-361](https://scylladb.atlassian.net/browse/SCYLLADB-361)
[SCYLLADB-361]: https://scylladb.atlassian.net/browse/SCYLLADB-361?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQClosesscylladb/scylladb#28509
* github.com:scylladb/scylladb:
docs: add strong consistency doc
test/cluster: add tests for strongly-consistent tables' metadata persistence
raft: enable multi-shard raft groups for strongly consistent tablets
test/raft: add unit tests for raft_groups_storage
raft: add raft_groups_storage persistence class
db: add system tables for strongly consistent tables' raft groups
dht: add fixed_shard_partitioner and fixed_shard_sharder
raft: add group_id -> shard mapping to raft_group_registry
schema: add with_sharder overload accepting static_sharder reference
Fixes issue #12818 with the following docs changes:
docs/dev/system_keyspace.md: Added missing system tables, added table of contents (TOC), added categories
Closesscylladb/scylladb#27789
Introduced a new max_tablet_count tablet option that caps the maximum number of tablets a table can have. This feature is designed primarily for backup and restore workflows.
During backup, when load balancing is disabled for snapshot consistency, the current tablet count is recorded in the backup manifest.
During restore, max_tablet_count is set to this recorded value, ensuring the restored table's tablet count never exceeds the original snapshot's tablet distribution.
This guarantee enables efficient file-based SSTable streaming during restore, as each SSTable remains fully contained within a single tablet boundary.
Closesscylladb/scylladb#28450
Add a new docs/dev document for the strongly consistent tables feature.
For now, it only contains information about the Raft metadata persistence,
but it should be updated as more of the strong-consistency components are
added.
https://github.com/scylladb/scylladb/pull/25746 added a new column to `system.clients`: `client_options frozen<map<text, text>>`. This column stores all options sent by the client in the `STARTUP` message.
This PR also added `CLIENT_OPTIONS` to the list of values sent in `SUPPORTED` message, and documented that drivers can send their configuration (as JSON) in `STARTUP` under this key.
Documentation for the new column was not added to the description of `system.clients` table, and documentation about the new `STARTUP` key was added in `protocol-extensions.md`, but in the section about shard awareness extension.
This PR adds missing `system.clients` column description, moves the documentation of `CLIENT_OPTIONS` into its own section, and expands it a bit.
Backport: none, because this fixes internal documentation.
Closesscylladb/scylladb#28126
* github.com:scylladb/scylladb:
protocol-extensions.md: Fix client_options docs
system_keyspace.md: Add client_options column
system_keyspace.md: Fix order in system.clients
This commit replaces the previous approach of running pytest inside
GDB’s Python interpreter. Instead, tests are executed by driving a
persistent GDB process externally using pexpect.
- pexpect: Python library for controlling interactive programs
(used here to send commands to GDB and capture its output)
- persistent GDB: keep one GDB session alive across multiple tests
instead of starting a new process for each test
Tests can now be executed via `./test.py gdb` or with
`pytest test/scylla_gdb`. This improves performance and
makes failures easier to debug since pytest no longer runs
hidden inside GDB subprocesses.
Closesscylladb/scylladb#24804
A permit gets into the preemptive_aborted state when:
- times out;
- gets rejected from execution due to high chance its execution would
not finalize on time;
Being in this state means a permit was removed from the wait list,
its internal timer was canceled and semaphore's statistic
`total_reads_shed_due_to_overload` increased.
Allows other topology operations to execute while tablets are being
drained on decommission. In particular, bootstrap on scale-out. This
is important for elasticity.
Allows multiple decommission/removenode to happen in parallel, which
is important for efficiency.
Flow of decommission/removenode request:
1) pending and paused, has tablet replicas on target node.
Tablet scheduler will start draining tablets.
2) No tablets on target node, request is pending but not paused
3) Request is scheduled, node is in transition
4) Request is done
Nodes are considered draining as soon as there is a leave or remove
request on them. If there are tablet replicas present on the target
node, the request is in a paused state and will not be picked by
topology coordinator. The paused state is computed from topology state
automatically on reload.
When request is not paused, its execution starts in
write_both_read_old state. The old tablet_draining state is not
entered (it's deprecated now).
Tablet load balancing will yield the state machine as soon as some
request is no longer paused and ready to be scheduled, based on
standard preemption mechanics.
Fixes#21452Closesscylladb/scylladb#24129
* https://github.com/scylladb/scylladb:
docs: Document parallel decommission and removenode and relevant task API
test: Add tests for parallel decommission/removenode
test: util: Introduce ensure_group0_leader_on()
test: tablets: Check that there are no migrations scheduled on draining nodes
test: lib: topology_builder: Introduce add_draining_request()
topology_coordinator, tablets: Fail draining operations when tablet migration fails due to critical disk utilization
tablets: topology_coordinator: Refactor to propagate reason for migration rollback
tablet_allocator: Skip co-location on draining nodes
node_ops: task_manager_module: Populate entity field also for active requests
tasks: node_ops: Put node id in the entity field
tasks, node_ops: Unify setting of task_stats in get_status() and get_stats()
topology: Protect against empty cancelation reason
tasks, topology: Make pending node operations abortable
doc: topology-over-raft.md: Fix diagram for replacing, tablet_draining is not engaged
raft_topology, tablets: Drain tablets in parallel with other topology operations
virtual_tables: Show draining and excluded fields in system.cluster_status and system.load_by_node
locator: topology: Add "draining" flag to a node
topology_coordinator: Extract generate_cancel_request_update()
storage_service: Drop dependency in topology_state_machine.hh in the header
locator: Extract common code in assert_rf_rack_valid_keyspace()
topology_coordinator, storage_service: Validate node removal/decommission at request submission time
Adds a "sstables" array member to manifest.json.
For each sstables, keep the following metadata:
id - a uuid for the sstable (the sstable identifier
if the use-sstable-identifier option was used, otherwise
the sstable uuid generation)
toc_name - the name of the TOC.txt file
data_size and index_size - in bytes
first_token and last_token - of the sstable first and last keys.
Fixes: SCYLLADB-196
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Add a table member to manifest.json with the keyspace_name,
table_name, table_id, tablets_type, and, for tablets-enabled tables, get
tablet_count on each shard and write the minimum to manifest.json.
For vnodes-based tables, tablet_count=0.
For now, `tablets_type` may be either `none` for vnodes tables, or
`powof2` for tablets tables. In the future, when we support arbitrary
tablt boundaries, this will be reflected here, and it is likely we
would backup the whole tablets map sperately to get all tablet boundaries.
Fixes SCYLLADB-195
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Add metadata about the node: host_id, datacenter, and rack.
This enables dc- or rack- aware restore.
Today this information is "encoded" into the snapshot hierarchy
prefixes, but if all manifest files would be stored in a flat
directory, we'd need to encode that metadata in the object name,
but it'd be better for the manifest contents to be self descriptive.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Add metadata about the manifest itself:
A version and the manifest scope (currently "node",
but in the future, may also be "shard", or "tablet")
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Validate the manifest.json format by loading it using rjson::parse
and then validate its contents to ensure it lists exactly the
SSTables present in the snapshot directory.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Allows other topology operations to execute while tablets are being
drained on decommission. In particular, bootstrap on scale-out. This
is important for elasticity.
Allows multiple decommission/removenode to happen in parallel, which
is important for efficiency.
Flow of decommission/removenode request:
1) pending and paused, has tablet replicas on target node.
Tablet scheduler will start draining tablets.
2) No tablets on target node, request is pending but not paused
3) Request is scheduled, node is in transition
4) Request is done
Nodes are considered draining as soon as there is a leave or remove
request on them. If there are tablet replicas present on the target
node, the request is in a paused state and will not be picked by
topology coordinator. The paused state is computed from topology state
automatically on reload.
When request is not paused, its execution starts in
write_both_read_old state. The old tablet_draining state is not
entered (it's deprecated now).
Tablet load balancing will yield the state machine as soon as some
request is no longer paused and ready to be scheduled, based on
standard preemption mechanics.
The test case test_explicit_tablet_movement_during_decommission is
removed. It verifies that tablet move API works during tablet draining
transition. After this PR, we no longer enter this transition, so the
test doesn't work. It loses its purpose, because movement during
normal tablet balancing is not special and tested elsewhere.
0ede8d154b introduced the dev doc for size
based load balancing, but also added spelling errors.
This PR fixed these errors.
Closesscylladb/scylladb#28196
To configure S3 storage, one needs to do
```
object_storage_endpoints:
- name: s3.us-east-1.amazonaws.com
port: 443
https: true
aws_region: us-east-1
```
and for GCS it's
```
object_storage_endpoints:
- name: https://storage.googleapis.com:433
type: gs
credentials_file: <gcp account credentials json file>
```
This PR updates the S3 part to look like
```
object_storage_endpoints:
- name: https://s3.us-east-1.amazonaws.com:443
aws_region: us-east-1
```
fixes: #26570
This is 2nd attempt, previous one (#27360) was reverted because it reported endpoint configs in new format via API and CQL always, even if the endpoint was configured in the old way. This "broke" scylla manager and some dtests. This version has this bug fixed, and endpoints are reported in the same format as they were configured with.
About correctness of the changes.
No modifications to existing tests are made here, so old format is respected correctly (as far as it's covered by tests). To prove the new format works the the test_get_object_store_endpoints is extended to validate both options. Some preparations to this test to make this happen come on their own with the PR #28111 to show that they are valid and pass before changing the core code.
Enhancing the way configuration is made, likely no need to backport.
Closesscylladb/scylladb#28112
* github.com:scylladb/scylladb:
test: Validate S3 endpoints new format works
docs: Update docs according to new endpoints config option format
object_storage: Create s3 client with "extended" endpoint name
s3/storage: Tune config updating
sstable: Shuffle args for s3_client_wrapper
test: Rename badconf variable into objconf
test: Split the object_store/test_get_object_store_endpoints test
When this column and relevant SUPPORTED key were added, the
documentation was mistakenly put in the section about shard awareness
extension. This commit moves the documentation into a dedicated section.
I also expended it to describe both the new column and the new SUPPORTED
key.
Since Scylla 6.0, service levels are manged by Raft group0.
This patch updates table name used by service levels and adds a
paragraph describing service levels on raft.
Fixesscylladb/scylladb#18177Closesscylladb/scylladb#26556
