Doing it with format("{}", foo) is correct, but to_string is
a bit more lightweight.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#28630
Compaction and statement groups are carried over on those configs, but
are in fact unused. Drop both.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#28540
There is a handful of places in the code related to dictionary
compression which calls get_units to acquire semaphore units but the
returned future is not awaited, seemingly by mistake. The result of
get_units is assigned to a variable - which is reasonable at a glance
because the semaphore units need to be assigned to a variable in order
to control their scope - but at the same time if co_await is mistakenly
omitted, like here, doing so will silence the nodiscard check of
seastar::future and, effectively, the get_units call will be nearly
useless. Unfortunately, this is an easy mistake to make.
Fix the places in the code that acquire semaphore units via get_units
but never await the future returned by it. I found them by manual code
inspection, so I hope that I didn't miss any.
Closesscylladb/scylladb#28581
All users of it had been updated to get the streaming group elsewhere,
so this getter is no longer needed.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#28527
Add explicit erm-holding variables in all replica-side RPC handlers.
This is required to ensure that tablet migration waits for in-flight
replica requests even if a non-replica coordinator has been fenced out.
Holding erms on the replica side may increase the global-barrier wait
time, since the barrier must drain these requests. We believe this
is acceptable because:
* We already hold erms during replica-side request execution, but in
an ad-hoc, non-systemic way in lower layers of storage_proxy
(e.g. in sp::mutate_locally and do_query_tablets).
* Replica requests are bounded by replica-side timeouts, so the
global-barrier wait time cannot exceed the maximum of these timeouts.
For Paxos verbs, we use token_metadata_guard, which wraps the ERM and
automatically refreshes it when tablet migration does not affect the
current token; see the token_metadata_guard comments for details.
We use this guard only for Paxos verbs because regular reads and writes
already hold raw erms in storage_proxy and on the coordinators.
The erms must be held in all RPC handlers that support fencing — that
is, those with a fencing_token parameter in storage_proxy.idl.
Counter updates already hold erms in
mutate_counter_on_leader_and_replicate.
Fix test_tablets2::test_timed_out_reader_after_cleanup: the tablets
barrier now waits for all nodes. As a result, the replica read
is expected to finish, rather than fail due to the tablet having
moved as it did previously. The test is renamed to
test_tablets_barrier_waits_for_replica_erms to better reflect its
purpose.
Refs scylladb/scylladb#26864
This field is only used to initialize the following _memtable_controller
one. It's simpler just to do the initialization with whatever value the
field itself is initialized and drop the field itself.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#28539
The method was coroutinized by 6df07f7ff7. Back then thecoroutine::switch_to() wasn't available, and the code used with_scheduling_group() to call coroutinized lambdas. Those lambdas were implemented as on-stack variables to solve the capture list lifetime problems. As a result, the code looks like
```
auto flush = [] {
... // do the flushing
auto post_flush = [] {
... // do the post-flushing
}
co_return co_await with_scheduling_group(group_b, post_flush);
};
co_return co_await with_scheduling_group(group_a, flush);
```
which is a bit clumsy. Now we have switch_to() and can make the code flow of this method more readable, like this
```
co_await switch_to(group_a);
... // do the flushing
co_await switch_to(group_b);
... // do the post-flushing
```
Code cleanup, not backporting
Closesscylladb/scylladb#28430
* github.com:scylladb/scylladb:
table: Fix indentation after previous patch
table: Use coroutine::switch_to() in try_flush_memtable_to_sstable()
It allows dropping the local lambdas passed into with_scheduling_group()
calls. Overall the code flow becomes more readable.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Move to `replica/`, drop `flat` from name and drop unused usages as well as unused includes.
Code cleanup, no backport
Closesscylladb/scylladb#28353
* github.com:scylladb/scylladb:
replica/partition_snapshot_reader: remove unused includes
partition_snapshot_reader: remove "flat" from name
mv partition_snapshot_reader.hh -> replica/
When reads arrive, they have to wait for admission on the reader
concurrency semaphore. If the node is overloaded, the reads will
be queued. They can time out while in the queue, but will not time
out once admitted.
Once the shard is sufficiently loaded, it is possible that most
queued reads will time out, because the average time it takes to
for a queued read to be admitted is around that of the timeout.
If a read times out, any work we already did, or are about to do
on it is wasted effort. Therefore, the patch tries to prevent it
by checking if an admitted read has a chance to complete in time
and abort it if not. It uses the following criteria:
if read's remaining time <= read's timeout when arrived to the semaphore * live updateable preemptive_abort_factor;
the read is rejected and the next one from the wait list is considered.
Fixes https://github.com/scylladb/scylladb/issues/14909
Fixes: SCYLLADB-353
Backport is not needed. Better to first observe its impact.
Closesscylladb/scylladb#21649
* github.com:scylladb/scylladb:
reader_concurrency_semaphore: Check during admission if read may timeout
permit_reader::impl: Replace break with return after evicting inactive permit on timeout
reader_concurrency_semaphore: Add preemptive_abort_factor to constructors
config: Add parameters to control reads' preemptive_abort_factor
permit_reader: Add a new state: preemptive_aborted
reader_concurrency_semaphore: validate waiters counter when dequeueing a waiting permit
reader_concurrency_semaphore: Remove cpu_concurrency's default value
The new parameter parametrizes the factor used to reject a read
during admission. Its value shall be between 0.0 and 1.0 where
+ 0.0 means a read will never get rejected during admission
+ 1.0 means a read will immediatelly get rejected during admission
Although passing values outside the interaval is possible, they
will have the exact same effects as they were clamped to [0.0, 1.0].
The commit 59faa6d, introduces a new parameter called cpu_concurrency
and sets its default value to 1 which violates the commit fbb83dd that
removes all default values from constructors but one used by the unit
tests.
The patch removes the default value of the cpu_concurrency parameter
and alters tests to use the test dedicated reader_concurrency_semaphore
constructor wherever possible.
The partition snapshot lives in mutation/, however mutation/ is a lower
level concept than a mutation reader. The next best place for this
reader is the replica/ directory, where the memtable, its main user,
also lives.
Also move the code to the replica namespace.
test/boost/mvcc_test.cc includes this header but doesn't use anything
from it. Instead of updating the include path, just drop the unused
include.
In 8df61f6d99 we changed the requirements for creating materialized
views and MV-based indexes - instead of requiring the
rf_rack_valid_keyspaces flag to be set, we now require the keyspace to
be RF-rack-valid at the time of creation, and it is enforced to remain
RF-rack-valid while the MV exists. This validation is done in the cql
create view/index statements.
The same should be done also for alternator - when creating a table with
GSI or LSI, or when adding a GSI to an existing table, previously we
required the flag rf_rack_valid_keyspaces to be set. Now we change it to
instead check if the keyspace is RF-rack-valid, and if not the operation
fails with an appropriate error.
Fixes https://github.com/scylladb/scylladb/issues/28214
backport to 2025.4 to add RF-rack-valid enforcements in alternator
Closesscylladb/scylladb#28154
* github.com:scylladb/scylladb:
locator: document the exception type of assert_rf_rack_valid_keyspace
alternator: don't require rf_rack flag for indexes, validate instead
In this PR we add a basic implementation of the strongly-consistent tables:
* generate raft group id when a strongly-consistent table is created
* persist it into system.tables table
* start raft groups on replicas when a strongly-consistent tablet_map reaches them
* add strongly-consistent version of the storage_proxy, with the `query` and `mutate` methods
* the `mutate` method submits a command to the tablets raft group, the query method reads the data with `raft.read_barrier()`
* strongly-consistent versions of the `select_statement` and `modification_statement` are added
* a basic `test_strong_consistency.py/test_basic_write_read` is added which to check that we can write and read data in a strongly consistent fashion.
Limitations:
* for now the strongly consistent tables can have tablets only on shard zero. This is because we (ab/re) use the existing raft system tables which live only on shard0. In the next PRs we'll create separate tables for the new tablets raft groups.
* No Scylla-side proxying - the test has to figure out who is the leader and submit the command to the right node. This will be fixed separately.
* No tablet balancing -- migration/split/merges require separate complicated code.
The new behavior is hidden behind `STRONGLY_CONSISTENT_TABLES` feature, which is enabled when the `STRONGLY_CONSISTENT_TABLES` experimental feature flag is set.
Requirements, specs and general overview of the feature can be found [here](https://scylladb.atlassian.net/wiki/spaces/RND/pages/91422722/Strong+Consistency). Short term implementation plan is [here](https://docs.google.com/document/d/1afKeeHaCkKxER7IThHkaAQlh2JWpbqhFLIQ3CzmiXhI/edit?tab=t.0#heading=h.thkorgfek290)
One can check the strongly consistent writes and reads locally via cqlsh:
scylla.yaml:
```
experimental_features:
- strongly-consistent-tables
```
cqlsh:
```
CREATE KEYSPACE IF NOT EXISTS my_ks WITH replication = {'class': 'NetworkTopologyStrategy', 'replication_factor': 1} AND tablets = {'initial': 1} AND consistency = 'local';
CREATE TABLE my_ks.test (pk int PRIMARY KEY, c int);
INSERT INTO my_ks.test (pk, c) VALUES (10, 20);
SELECT * FROM my_ks.test WHERE pk = 10;
```
Fixes SCYLLADB-34
Fixes SCYLLADB-32
Fixes SCYLLADB-31
Fixes SCYLLADB-33
Fixes SCYLLADB-56
backport: no need
Closesscylladb/scylladb#27614
* https://github.com/scylladb/scylladb:
test_encryption: capture stderr
test/cluster: add test_strong_consistency.py
raft_group_registry: disable metrics for non-0 groups
strong consistency: implement select_statement::do_execute()
cql: add select_statement.cc
strong consistency: implement coordinator::query()
cql: add modification_statement
cql: add statement_helpers
strong consistency: implement coordinator::mutate()
raft.hh: make server::wait_for_leader() public
strong_consistency: add coordinator
modification_statement: make get_timeout public
strong_consistency: add groups_manager
strong_consistency: add state_machine and raft_command
table: add get_max_timestamp_for_tablet
tablets: generate raft group_id-s for new table
tablet_replication_strategy: add consistency field
tablets: add raft_group_id
modification_statement: remove virtual where it's not needed
modification_statement: inline prepare_statement()
system_keyspace: disable tablet_balancing for strongly_consistent_tables
cql: rename strongly_consistent statements to broadcast statements
The function assert_rf_rack_valid_keyspace uses the exception type
std::invalid_argument when the RF-rack validation fails. Document it and
change all callers to catch this specific exception type when checking
for RF-rack validation failures, so that other exception types can be
propagated properly.
Add enforce_rack_list option. When the option is set to true,
all tablet keyspaces have rack list replication factor.
When the option is on:
- CREATE STATEMENT always auto-extends rf to rack lists;
- ALTER STATEMENT fails when there is numeric rf in any DC.
The flag is set to false by default and a node needs to be restarted
in order to change its value. Starting a node with enforce_rack_list
option will fail, if there are any tablet keyspaces with numeric rf
in any DC.
enforce_rack_list is a per-node option and a user needs to ensure
that no tablet keyspace is altered or created while nodes in
the cluster don't have the consistent value.
Mark rf_rack_valid_keyspaces as deprecated.
Fixes: https://github.com/scylladb/scylladb/issues/26399.
New feature; no backport needed
Closesscylladb/scylladb#28084
* github.com:scylladb/scylladb:
test: add test for enforce_rack_list option
db: mark rf_rack_valid_keyspaces as deprecated
config: add enforce_rack_list option
Revert "alternator: require rf_rack_valid_keyspaces when creating index"
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>
And keep the options for now in the local_snapshot_writer.
The options will be used by following patches to pass
extra metadata like the snapshot creation time, expiration time, etc.
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>
Strongly consistent writes require knowing the maximum timestamp of
locally applied mutations to guarantee monotonically increasing
timestamps for subsequent writes.
This commit adds a function that returns the maximum timestamp for a
given tablet.
Why it is safe to use this function with deleted cells:
* Tombstones are included in memtable.get_max_timestamp() calculations.
* The maximum timestamp of a memtable is used to initialize the maximum
timestamp of the resulting sstable.
* During compaction, a new sstable’s maximum timestamp is initialized as
the maximum of the contributing sstables.
Add a `raft_group_id` column to `system.tablets` and to the `tablet_map`
class. The column is populated only when the
`strongly_consistent_tables` feature is enabled.
This feature is currently disabled by default and is enabled only when
the user sets the `STRONGLY_CONSISTENT_TABLES` experimental flag.
The `raft_group_id` column is added to `system.tablets` only when this
flag is set. This allows the schema to evolve freely while the feature
is experimental, without requiring complex migrations.
Add enforce_rack_list option. When the option is set to true,
all tablet keyspaces have rack list replication factor.
When the option is on:
- CREATE STATEMENT always auto-extends rf to rack lists;
- ALTER STATEMENT fails when there is numeric rf in any DC.
The flag is set to false by default and a node needs to be restarted
in order to change its value. Starting a node with enforce_rack_list
option will fail, if there are any tablet keyspaces with numeric rf
in any DC.
enforce_rack_list is a per-node option and a user needs to ensure
that no tablet keyspace is altered or created while nodes in
the cluster don't have the consistent value.
do_query() is a coroutine but uses some continuations to take
advantage of exceptions being propagated via future::then() without
being thrown. We can accomplish the same thing with a nested coroutine
and coroutine::try_future(), simplifying the code.
While this area isn't performance intensive, we're not adding allocations.
The coroutine frame may add an allocation, but since read_page()
certainly does not return immediately, the following then() will allocate
as well. Since we eliminated that then(), the change is at least neutral
allocation-wise.
Closesscylladb/scylladb#28258
This PR marks system_replicated_keys as a system keyspace.
It was missing when the keyspace was added.
A side effect of that is that metrics that are not supposed to be reported are.
Fixes#27903Closesscylladb/scylladb#27954
* github.com:scylladb/scylladb:
distributed_loader: system_replicated_keys as system keyspace
replicated_key_provider: make KSNAME public
Use coroutine::as_future() to avoid exceptions taking flight and
triggering expensive stack-unwinding.
Especially bad for common exceptions like timeouts.
Not using coroutine::try_future(), because on the error path, the
querier has to be closed.
Use coroutine::try_future() to avoid exceptions taking flight and
triggering expensive stack-unwinding.
Especially bad for common exceptions like timeouts.
repair: Implement auto repair for tablet repair
This patch implements the basic auto repair support for tablet repair.
It was decided to add no per table configuration for the initial
implementation, so two scylla yaml config options are introduced to set
the default auto repair configs for all the tablet tables.
- auto_repair_enabled_default
Set true to enable auto repair for tablet tables by default. The value
will be overridden by the per keyspace or per table configuration which
is not implemented yet.
- auto_repair_threshold_default_in_seconds
Set the default time in seconds for the auto repair threshold for tablet
tables. If the time since last repair is bigger than the configured
time, the tablet is eligible for auto repair. The value will be
overridden by the per keyspace or per table configuration which is not
implemented yet.
The following metrcis are added:
- auto_repair_needs_repair_nr
The number of tablets with auto repair enabled that needs repair
- auto_repair_enabled_nr
The number of tablets with auto repair enabled
The metrics are useful to tell if auto repair is falling behind.
In the future, more auto repair scheduling will be added, e.g.,
scheduling based on the repaired and unrepaired sstable set size,
tombstone ratio and so on, in addition to the time based scheduling.
Fixes SCYLLADB-99
New feature. No backport.
Closesscylladb/scylladb#27534
* github.com:scylladb/scylladb:
topology_coordinator: Add metrics for tablet repair
repair: Implement auto repair for tablet repair
This patch implements the basic auto repair support for tablet repair.
It was decided to add no per table configuration for the initial
implementation, so two scylla yaml config options are introduced to set
the default auto repair configs for all the tablet tables.
- auto_repair_enabled_default
Set true to enable auto repair for tablet tables by default. The value
will be overridden by the per keyspace or per table configuration which
is not implemented yet.
- auto_repair_threshold_default_in_seconds
Set the default time in seconds for the auto repair threshold for tablet
tables. If the time since last repair is bigger than the configured
time, the tablet is eligible for auto repair. The value will be
overridden by the per keyspace or per table configuration which is not
implemented yet.
The following metrcis are added:
- auto_repair_needs_repair_nr
The number of tablets with auto repair enabled that needs repair
- auto_repair_enabled_nr
The number of tablets with auto repair enabled
The metrics are useful to tell if auto repair is falling behind.
In the future, more auto repair scheduling will be added, e.g.,
scheduling based on the repaired and unrepaired sstable set size,
tombstone ratio and so on, in addition to the time based scheduling.
Fixes SCYLLADB-99
Allow creating materialized views and secondary indexes in a tablets keyspace only if it's RF-rack-valid, and enforce RF-rack-validity while the keyspace has views by restricting some operations:
* Altering a keyspace's RF if it would make the keyspace RF-rack-invalid
* Adding a node in a new rack
* Removing / Decommissioning the last node in a rack
Previously the config option `rf_rack_valid_keyspaces` was required for creating views. We now remove this restriction - it's not needed because we always maintain RF-rack-validity for keyspaces with views.
The restrictions are relevant only for keyspaces with numerical RF. Keyspace with rack-list-based RF are always RF-rack-valid.
Fixesscylladb/scylladb#23345
Fixes https://github.com/scylladb/scylladb/issues/26820
backport to relevant versions for materialized views with tablets since it depends on rf-rack validity
Closesscylladb/scylladb#26354
* github.com:scylladb/scylladb:
docs: update RF-rack restrictions
cql3: don't apply RF-rack restrictions on vector indexes
cql3: add warning when creating mv/index with tablets about rf-rack
service/tablet_allocator: always allow tablet merge of tables with views
locator: extend rf-rack validation for rack lists
test: test rf-rack validity when creating keyspace during node ops
locator: fix rf-rack validation during node join/remove
test: test topology restrictions for views with tablets
test: add test_topology_ops_with_rf_rack_valid
topology coordinator: restrict node join/remove to preserve RF-rack validity
topology coordinator: add validation to node remove
locator: extend rf-rack validation functions
view: change validate_view_keyspace to allow MVs if RF=Racks
db: enforce rf-rack-validity for keyspaces with views
replica/db: add enforce_rf_rack_validity_for_keyspace helper
db: remove enforce parameter from check_rf_rack_validity
test: adjust test to not break rf-rack validity
The comment was added in 83323e155e
Since then, table::seal_active_memtable was improved to guarantee
waiting on oustanding flushes on success (See d55a2ac762), so
we can remove this TODO comment (it also not covered by any issue
so nobody is planned to ever work on it).
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
can_flush might return a different value for each shard
so check it right before deciding whether to flush or clear a memtable
shard.
Note that under normal condition can_flush would always return true
now that it checks only the presence of the seal memtable function
rather than check memtable_list::empty().
Fixes#27639
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Now that we have a unit test proving that it's safe to flush an
empty memtable list there is no need to distinguish between
may_flush and can_flush.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Table needs flush if not all its memtable lists are empty.
To be used in the next patch for a unit test.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
