Counters are now supported in tablet-enabled keyspaces, so remove
the documentation that listed counters as an unsupported feature
and the note warning users about the limitation.
We modify the requirements for using materialized views in tablet-based
keyspaces. Before, it was necessary to enable the configuration option
`rf_rack_valid_keyspaces`, having the cluster feature `VIEWS_WITH_TABLETS`
enabled, and using the experimental feature `views-with-tablets`.
We drop the last requirement.
We adjust code to that change and provide a new validation test.
We also update the user documentation to reflect the changes.
Fixesscylladb/scylladb#23030
This change adds the documentation section which explains the algorithm
to compute the absolute number of tablets a table has.
Fixes: #25740Closesscylladb/scylladb#25741
initial implementation to support CDC in tablets-enabled keyspaces.
The design is described in https://docs.google.com/document/d/1qO5f2q5QoN5z1-rYOQFu6tqVLD3Ha6pphXKEqbtSNiU/edit?usp=sharing
It is followed closely for the most part except "Deciding when to change streams" - instead, streams are changed synchronously with tablet split / merge.
Instead of the stream switching algorithm with the double writes, we use a scheme similar to the previous method for vnodes - we add the new streams with timestamp that is sufficiently far into the future.
In this PR we:
* add new group0-based internal system tables for tablet stream metadata and loading it into in-memory CDC metadata
* add virtual tables for CDC consumers
* the write coordinator chooses a stream by looking up the appropriate stream in the CDC metadata
* enable creating tables with CDC enabled in tablets-enabled keyspaces. tablets are allocated for the CDC table, and a stream is created per each tablet.
* on tablet resize (split / merge), the topology coordinator creates a new stream set with a new stream for each new tablet.
* the cdc tablets are co-located with the base tablets
Fixes https://github.com/scylladb/scylladb/issues/22576
backport not needed - new feature
update dtests: https://github.com/scylladb/scylla-dtest/pull/5897
update java cdc library: https://github.com/scylladb/scylla-cdc-java/pull/102
update rust cdc library: https://github.com/scylladb/scylla-cdc-rust/pull/136Closesscylladb/scylladb#23795
* github.com:scylladb/scylladb:
docs/dev: update CDC dev docs for tablets
doc: update CDC docs for tablets
test: cluster_events: enable add_cdc and drop_cdc
test/cql: enable cql cdc tests to run with tablets
test: test_cdc_with_alter: adjust for cdc with tablets
test/cqlpy: adjust cdc tests for tablets
test/cluster/test_cdc_with_tablets: introduce cdc with tablets tests
cdc: enable cdc with tablets
topology coordinator: change streams on tablet split/merge
cdc: virtual tables for cdc with tablets
cdc: generate_stream_diff helper function
cdc: choose stream in tablets enabled keyspaces
cdc: rename get_stream to get_vnode_stream
cdc: load tablet streams metadata from tables
cdc: helper functions for reading metadata from tables
cdc: colocate cdc table with base
cdc: remove streams when dropping CDC table
cdc: create streams when allocating tablets
migration_listener: add on_before_allocate_tablet_map notification
cdc: notify when creating or dropping cdc table
cdc: move cdc table creation to pre_create
cdc: add internal tables for cdc with tablets
cdc: add cdc_with_tablets feature flag
cdc: add is_log_schema helper
Capacity based balancing was introduced in 2025.1. It computes balance
based on a node's capacity: the number of tablets located on a node
should be directly proportional to that node's storage capacity.
This change adds this explanation to the docs.
Fixes: #25686Closesscylladb/scylladb#25687
`tablets_mode_for_new_keyspaces=enforced` enables tablets by default for
new keyspaces, like `tablets_mode_for_new_keyspaces=enabled`.
However, it does not allow to opt-out when creating
new keyspaces by setting `tablets = {'enabled': false}`.
Refs scylladb/scylla-enterprise#4355
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
The new option deprecates the existing `enable_tablets` option.
It will be extended in the next patch with a 3rd value: "enforced"
while will enable tablets by default for new keyspace but
without the posibility to opt out using the `tablets = {'enabled':
false}` keyspace schema option.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
We introduce a new term in the glossary: RF-rack-valid keyspace.
We also highlight in our user documentation that all keyspaces
must remain RF-rack-valid throughout their lifetime, and failing
to guarantee that may result in data inconsistencies or other
issues. We base that information on our experience with materialized
views in keyspaces using tablets, even though they remain
an experimental feature.
Along with the new term, we introduce a new configuration option
called `rf_rack_valid_keyspaces`, which, when enabled, will enforce
preserving all keyspaces RF-rack-valid. That functionality will be
implemented in upcoming commits. For now, we materialize the
restriction in form of a named requirement: a function verifying
that the passed keyspace is RF-rack-valid.
The option is disabled by default. That will change once we adjust
the existing tests to the new semantics. Once that is done, the option
will first be enabled by default, and then it will be removed.
Fixesscylladb/scylladb#20356
This commit adds a link to the Limitations section on the Tablets page
to the CQL pag, the tablets option.
This is actually the place where the user will need the information:
when creating a keyspace.
In addition, I've reorganized the section for better readability
(otherwise, the section about limitations was easy to miss)
and moved the section up on the page.
Note that I've removed the updated content from the `_common` folder
(which I deleted) to the .rst page - we no longer split OSS and Enterprise,
so there's no need to keep using the `scylladb_include_flag` directive
to include OSS- and Ent-specific content.
Fixes https://github.com/scylladb/scylladb/issues/22892
Fixes https://github.com/scylladb/scylladb/issues/22940Closesscylladb/scylladb#22939
File based stream is a new feature that optimizes tablet movement
significantly. It streams the entire SSTable files without deserializing
SSTable files into mutation fragments and re-serializing them back into
SSTables on receiving nodes. As a result, less data is streamed over the
network, and less CPU is consumed, especially for data models that
contain small cells.
The following patches are imported from the scylla enterprise:
*) Merge 'Introduce file stream for tablet' from Asias He
This patch uses Seastar RPC stream interface to stream sstable files on
network for tablet migration.
It streams sstables instead of mutation fragments. The file based
stream has multiple advantages over the mutation streaming.
- No serialization or deserialization for mutation fragments
- No need to read and process each mutation fragments
- On wire data is more compact and smaller
In the test below, a significant speed up is observed.
Two nodes, 1 shard per node, 1 initial_tablets:
- Start node 1
- Insert 10M rows of data with c-s
- Bootstrap node 2
Node 1 will migration data to node2 with the file stream.
Test results:
1) File stream: bytes on wire = 1132006250 bytes, bw = 836MB/s
[shard 0:stre] stream_blob - stream_sstables[eadaa8e0-a4f2-4cc6-bf10-39ad1ce106b0]
Finished sending sstable_nr=2 files_nr=18 files={} range=(-1,9223372036854775807] bytes_sent=1132006250 stream_bw=836MB/s
[shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 1.08004s seconds
2) Mutation stream: bytes on wire = 3030004736 bytes, bw = 125410.87 KiB/s = 128MB/s
[shard 0:stre] stream_session - [Stream #406dc8b0-56b5-11ee-bc2d-000bf4871058]
Streaming plan for Tablet migration-ks1-index-0 succeeded, peers={127.0.0.1}, tx=0 KiB, 0.00 KiB/s, rx=2958989 KiB, 125410.87 KiB/s
[shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 23.5992s seconds
Test Summary:
File stream v.s. Mutation stream improvements
- Stream bandwidth = 836 / 128 (MB/s) = 6.53X
- Stream time = 23.60 / 1.08 (Seconds) = 21.85X
- Stream bytes on wire = 3030004736 / 1132006250 (Bytes)= 2.67X
Closes scylladb/scylla-enterprise#3438
* github.com:scylladb/scylla-enterprise:
tests: Add file_stream_test
streaming: Implement file stream for tablet
*) streaming: Use new take_storage_snapshot interface
The new take_storage_snapshot returns a file object instead of a file
name. This allows the file stream sender to read from the file even if
the file is deleted by compaction.
Closes scylladb/scylla-enterprise#3728
*) streaming: Protect unsupported file types for file stream
Currently, we assume the file streamed over the stream_blob rpc verb is
a sstable file. This patch rejects the unsupported file types on the
receiver side. This allows us to stream more file types later using the
current file stream infrastructure without worrying about old nodes
processing the new file types in the wrong way.
- The file_ops::noop is renamed to file_ops::stream_sstables to be
explicit about the file types
- A missing test_file_stream_error_injection is added to the idl
Fixes: #3846
Tests: test_unsupported_file_ops
Closesscylladb/scylla-enterprise#3847
*) idl: Add service::session_id id to idl
It will be used in the next patch.
Refs #3907
*) streaming: Protect file stream with topology_guard
Similar to "storage_service, tablets: Use session to guard tablet
streaming", this patch protects file stream with topology_guard.
Fixes#3907
*) streaming: Take service topology_guard under the try block
Taking the service::topology_guard could throw. Currently, it throws
outside the try block, so the rpc sink will not be closed, causing the
following assertion:
```
scylla: seastar/include/seastar/rpc/rpc_impl.hh:815: virtual
seastar::rpc::sink_impl<netw::serializer,
streaming::stream_blob_cmd_data>::~sink_impl() [Serializer =
netw::serializer, Out = <streaming::stream_blob_cmd_data>]: Assertion
`this->_con->get()->sink_closed()' failed.
```
To fix, move more code including the topology_guard taking code to the
try block.
Fixes https://github.com/scylladb/scylla-enterprise/issues/4106Closesscylladb/scylla-enterprise#4110
*) Merge 'Preserve original SSTable state with file based tablet migration' from Raphael "Raph" Carvalho
We're not preserving the SSTable state across file based migration, so
staging SSTables for example are being placed into main directory, and
consequently, we're mixing staging and non-staging data, losing the
ability to continue from where the old replica left off.
It's expected that the view update backlog is transferred from old
into new replica, as migration doesn't wait for leaving replica to
complete view update work (which can take long). Elasticity is preferred.
So this fix guarantees that the state of the SSTable will be preserved
by propagating it in form of subdirectory (each subdirectory is
statically mapped with a particular state).
The staging sstables aren't being registered into view update generator
yet, as that's supposed to be fixed in OSS (more details can be found
at https://github.com/scylladb/scylladb/issues/19149).
Fixes#4265.
Closesscylladb/scylla-enterprise#4267
* github.com:scylladb/scylla-enterprise:
tablet: Preserve original SSTable state with file based tablet migration
sstables: Add get method for sstable state
*) sstable: (Re-)add shareabled_components getter
*) Merge 'File streaming sstables: Use sstable source/sink to transfer snapshots' from Calle Wilund
Fixes#4246
Alternative approach/better separation of concern, transport vs. sstable layer. Builds on #4472, but fancier.
Ensures we transfer and pre-process scylla metadata for streamed
file blobs first, then properly apply receiving nodes local config
by using a source and sink layer exported from sstables, which
handles things like ordering, metadata filtering (on source) as well
as handling metadata and proper IO paths when writing data on
receiver node (sink).
This implementation maintains the statelessness of the current
design, and the delegated sink side will re-read and re-write the
metadata for each component processed. This is a little wasteful,
but the meta is small, and it is less error prone than trying to do
caching cross-shards etc. The transport is isolated from the
knowledge.
This is an alternative/complement to #4436 and #4472, fixing the
underlying issue. Note that while the layers/API:s here allows easy
fixing of other fundamental problems in the feature (such as
destination location etc), these are not included in the PR, to keep
it as close to the current behaviour as possible.
Closesscylladb/scylla-enterprise#4646
* github.com:scylladb/scylla-enterprise:
raft_tests: Copy/add a topology test with encryption
file streaming: Use sstable source/sink to transfer snapshots
sstables: Add source and sink objects + producers for transfering a snapshot
sstable::types: Add remove accessor for extension info in metadata
*) The change for error injection in merge commit 966ea5955dd8760:
File streaming now has "stream_mutation_fragments" error injection points
so test_table_dropped_during_streaming works with file streaming.
*) doc: document file-based streaming
This commit adds a description of the file-based streaming feature to the documentation.
It will be displayed in the docs using the scylladb_include_flag directive after
https://github.com/scylladb/scylladb/pull/20182 is merged, backported to branch-6.0,
and, in turn, branch-2024.2.
Refs https://github.com/scylladb/scylla-enterprise/issues/4585
Refs https://github.com/scylladb/scylla-enterprise/issues/4254Closesscylladb/scylla-enterprise#4587
*) doc: move File-based streaming to the Tablets source file-based-streaming
This commit moves the description of file-based streaming from a common include file
to the regular doc source file where tablets are described.
Closesscylladb/scylla-enterprise#4652
*) streaming: sstable_stream_sink_impl: abort: prevent null pointer dereference
Closesscylladb/scylladb#22467
File based stream is a new feature that optimizes tablet movement
significantly. It streams the entire SSTable files without deserializing
SSTable files into mutation fragments and re-serializing them back into
SSTables on receiving nodes. As a result, less data is streamed over the
network, and less CPU is consumed, especially for data models that
contain small cells.
The following patches are imported from the scylla enterprise:
*) Merge 'Introduce file stream for tablet' from Asias He
This patch uses Seastar RPC stream interface to stream sstable files on
network for tablet migration.
It streams sstables instead of mutation fragments. The file based
stream has multiple advantages over the mutation streaming.
- No serialization or deserialization for mutation fragments
- No need to read and process each mutation fragments
- On wire data is more compact and smaller
In the test below, a significant speed up is observed.
Two nodes, 1 shard per node, 1 initial_tablets:
- Start node 1
- Insert 10M rows of data with c-s
- Bootstrap node 2
Node 1 will migration data to node2 with the file stream.
Test results:
1) File stream: bytes on wire = 1132006250 bytes, bw = 836MB/s
[shard 0:stre] stream_blob - stream_sstables[eadaa8e0-a4f2-4cc6-bf10-39ad1ce106b0]
Finished sending sstable_nr=2 files_nr=18 files={} range=(-1,9223372036854775807] bytes_sent=1132006250 stream_bw=836MB/s
[shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 1.08004s seconds
2) Mutation stream: bytes on wire = 3030004736 bytes, bw = 125410.87 KiB/s = 128MB/s
[shard 0:stre] stream_session - [Stream #406dc8b0-56b5-11ee-bc2d-000bf4871058]
Streaming plan for Tablet migration-ks1-index-0 succeeded, peers={127.0.0.1}, tx=0 KiB, 0.00 KiB/s, rx=2958989 KiB, 125410.87 KiB/s
[shard 0:stre] storage_service - Streaming for tablet migration of a4f68900-568a-11ee-b7b9-c2b13945eed2:1 took 23.5992s seconds
Test Summary:
File stream v.s. Mutation stream improvements
- Stream bandwidth = 836 / 128 (MB/s) = 6.53X
- Stream time = 23.60 / 1.08 (Seconds) = 21.85X
- Stream bytes on wire = 3030004736 / 1132006250 (Bytes)= 2.67X
Closes scylladb/scylla-enterprise#3438
* github.com:scylladb/scylla-enterprise:
tests: Add file_stream_test
streaming: Implement file stream for tablet
*) streaming: Use new take_storage_snapshot interface
The new take_storage_snapshot returns a file object instead of a file
name. This allows the file stream sender to read from the file even if
the file is deleted by compaction.
Closes scylladb/scylla-enterprise#3728
*) streaming: Protect unsupported file types for file stream
Currently, we assume the file streamed over the stream_blob rpc verb is
a sstable file. This patch rejects the unsupported file types on the
receiver side. This allows us to stream more file types later using the
current file stream infrastructure without worrying about old nodes
processing the new file types in the wrong way.
- The file_ops::noop is renamed to file_ops::stream_sstables to be
explicit about the file types
- A missing test_file_stream_error_injection is added to the idl
Fixes: #3846
Tests: test_unsupported_file_ops
Closesscylladb/scylla-enterprise#3847
*) idl: Add service::session_id id to idl
It will be used in the next patch.
Refs #3907
*) streaming: Protect file stream with topology_guard
Similar to "storage_service, tablets: Use session to guard tablet
streaming", this patch protects file stream with topology_guard.
Fixes#3907
*) streaming: Take service topology_guard under the try block
Taking the service::topology_guard could throw. Currently, it throws
outside the try block, so the rpc sink will not be closed, causing the
following assertion:
```
scylla: seastar/include/seastar/rpc/rpc_impl.hh:815: virtual
seastar::rpc::sink_impl<netw::serializer,
streaming::stream_blob_cmd_data>::~sink_impl() [Serializer =
netw::serializer, Out = <streaming::stream_blob_cmd_data>]: Assertion
`this->_con->get()->sink_closed()' failed.
```
To fix, move more code including the topology_guard taking code to the
try block.
Fixes https://github.com/scylladb/scylla-enterprise/issues/4106Closesscylladb/scylla-enterprise#4110
*) Merge 'Preserve original SSTable state with file based tablet migration' from Raphael "Raph" Carvalho
We're not preserving the SSTable state across file based migration, so
staging SSTables for example are being placed into main directory, and
consequently, we're mixing staging and non-staging data, losing the
ability to continue from where the old replica left off.
It's expected that the view update backlog is transferred from old
into new replica, as migration doesn't wait for leaving replica to
complete view update work (which can take long). Elasticity is preferred.
So this fix guarantees that the state of the SSTable will be preserved
by propagating it in form of subdirectory (each subdirectory is
statically mapped with a particular state).
The staging sstables aren't being registered into view update generator
yet, as that's supposed to be fixed in OSS (more details can be found
at https://github.com/scylladb/scylladb/issues/19149).
Fixes#4265.
Closesscylladb/scylla-enterprise#4267
* github.com:scylladb/scylla-enterprise:
tablet: Preserve original SSTable state with file based tablet migration
sstables: Add get method for sstable state
*) sstable: (Re-)add shareabled_components getter
*) Merge 'File streaming sstables: Use sstable source/sink to transfer snapshots' from Calle Wilund
Fixes#4246
Alternative approach/better separation of concern, transport vs. sstable layer. Builds on #4472, but fancier.
Ensures we transfer and pre-process scylla metadata for streamed
file blobs first, then properly apply receiving nodes local config
by using a source and sink layer exported from sstables, which
handles things like ordering, metadata filtering (on source) as well
as handling metadata and proper IO paths when writing data on
receiver node (sink).
This implementation maintains the statelessness of the current
design, and the delegated sink side will re-read and re-write the
metadata for each component processed. This is a little wasteful,
but the meta is small, and it is less error prone than trying to do
caching cross-shards etc. The transport is isolated from the
knowledge.
This is an alternative/complement to #4436 and #4472, fixing the
underlying issue. Note that while the layers/API:s here allows easy
fixing of other fundamental problems in the feature (such as
destination location etc), these are not included in the PR, to keep
it as close to the current behaviour as possible.
Closesscylladb/scylla-enterprise#4646
* github.com:scylladb/scylla-enterprise:
raft_tests: Copy/add a topology test with encryption
file streaming: Use sstable source/sink to transfer snapshots
sstables: Add source and sink objects + producers for transfering a snapshot
sstable::types: Add remove accessor for extension info in metadata
*) The change for error injection in merge commit 966ea5955dd8760:
File streaming now has "stream_mutation_fragments" error injection points
so test_table_dropped_during_streaming works with file streaming.
*) doc: document file-based streaming
This commit adds a description of the file-based streaming feature to the documentation.
It will be displayed in the docs using the scylladb_include_flag directive after
https://github.com/scylladb/scylladb/pull/20182 is merged, backported to branch-6.0,
and, in turn, branch-2024.2.
Refs https://github.com/scylladb/scylla-enterprise/issues/4585
Refs https://github.com/scylladb/scylla-enterprise/issues/4254Closesscylladb/scylla-enterprise#4587
*) doc: move File-based streaming to the Tablets source file-based-streaming
This commit moves the description of file-based streaming from a common include file
to the regular doc source file where tablets are described.
Closesscylladb/scylla-enterprise#4652
*) streaming: sstable_stream_sink_impl: abort: prevent null pointer dereference
Closesscylladb/scylladb#22034
With the tablets feature always enabled (Unless gossip toopology
changes are forced), the enable_tablets option now controls only
the default for newly created keyspaces.
Even when set to `false`, tablets are still enabled as a
feature and the user may explicitly enable tablets
using `CREATE KEYSPACE <name> WITH tablets = {'enabled': true}`
Note: best viewed with `git show -w`
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
This reverts commit c286434e4c, reversing
changes made to 6712fcc316.
The commit causes memtable_test to be very flaky in debug mode.
Specifically, subtests test_exceptions_in_flush_on_sstable_open
and test_exceptions_in_flush_on_sstable_write).
With the tablets feature always enabled (Unless gossip toopology
changes are forced), the enable_tablets option now controls only
the default for newly created keyspaces.
Even when set to `false`, tablets are still enabled as a
feature and the user may explicitly enable tablets
using `CREATE KEYSPACE <name> WITH tablets = {'enabled': true}`
Note: best viewed with `git show -w`
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
This commit adds the main description of tablets and their
benefits.
The article can be used as a reference in other places
across the docs where we mention tablets.
Closesscylladb/scylladb#18619
