Currently we do not allow tablet merge if either of the tablets contain
a tablet repair request. This could block the tablet merge for a very
long time if the repair requests could not be scheduled and executed.
We can actually merge the repair tasks in most of the cases. This is
because most of the time all tablets are requested to be repaired by a
single API request, so they share the same task_id, request_type and
other parameters. We can merge the repair task info and executes the
repair after the merge. If they do not share the task info, we could
not merge and have to wait for the repair before merge, which is both
rare and ok.
Another case is that one of the tablet has a repair task info (t1) while
the other tablet (t2) does not have, it is possible the t2 has finished
repair by the same repair request or t2 is not requested to be repaired
at all. We allow merge in this case too to avoid blocking the tablet
merge, with the price of reparing a bit more.
Fixes#26844Closesscylladb/scylladb#26922
This PR extends the restore API so that it accepts primary_replica_only as parameter and it combines the concepts of primary-replica-only with scoped streaming so that with:
- `scope=all primary_replica_only=true` The restoring node will stream to the global primary replica only
- `scope=dc primary_replica_only=true` The restoring node will stream to the local primary replica only.
- `scope=rack primary_replica_only=true` The restoring node will stream only to the primary replica from within its own rack (with rf=#racks, the restoring node will stream only to itself)
- `scope=node primary_replica_only=true` is not allowed, the restoring node will always stream only to itself so the primary_replica_only parameter wouldn't make sense.
The PR also adjusts the `nodetool refresh` restriction on running restore with both primary_replica_only and scope, it adds primary_replica_only to `nodetool restore` and it adds cluster tests for primary replica within scope.
Fixes#26584Closesscylladb/scylladb#26609
* github.com:scylladb/scylladb:
Add cluster tests for checking scoped primary_replica_only streaming
Improve choice distribution for primary replica
Refactor cluster/object_store/test_backup
nodetool restore: add primary-replica-only option
nodetool refresh: Enable scope={all,dc,rack} with primary_replica_only
Enable scoped primary replica only streaming
Support primary_replica_only for native restore API
This patch fixes a bug with tablet size migration in load_stats.
has_tablet_size() lambda in topology_coordinator::migrate_tablet_size()
was returning false in all cases due to incorrect search iterator
comparison after a table and tablet saeach.
This change moves load_stats migrate_tablet_sizes() functionaility
into a separate method of load_stats.
I noticed during tests that `maybe_get_primary_replica`
would not distribute uniformly the choice of primary replica
because `info.replicas` on some shards would have an order whilst
on others it'd be ordered differently, thus making the function choose
a node as primary replica multiple times when it clearly could've
chosen a different nodes.
This patch sorts the replica set before passing it through the
scope filter.
Signed-off-by: Robert Bindar <robert.bindar@scylladb.com>
This change adds the ability to move tablets sizes in load_stats after a tablet migration or table resize (split/merge). This is needed because the size based load balancer needs to have tablet size data which is as accurate as possible, in order to work on fresh tablet size distribution and issue correct tablet migrations.
This is the second part of the size based load balancing changes:
- First part for tablet size collection via load_stats: #26035
- Second part reconcile load_stats: #26152
- The third part for load_sketch changes: #26153
- The fourth part which performs tablet load balancing based on tablet size: #26254
This is a new feature and backport is not needed.
Closesscylladb/scylladb#26152
* github.com:scylladb/scylladb:
load_balancer: load_stats reconcile after tablet migration and table resize
load_stats: change data structure which contains tablet sizes
Auto-exands numeric RF in CREATE/ALTER KEYSPACE statements for
new DCs specified in the statement.
Doesn't auto-expand existing options, as the rack choice may not be in
line with current replica placement. This requires co-locating tablet
replicas, and tracking of co-location state, which is not implemented yet.
Signed-off-by: Tomasz Grabiec <tgrabiec@scylladb.com>
This change adds the ability to move tablets sizes in load_stats after a
tablet migration or table resize (split/merge). This is needed because
the size based load balancer needs to have tablet size data which is as
accurate as possible, in order to issue migrations which improve
load balance.
Currently, tablet_sstable_streamer::get_primary_endpoints is out of
sync with tablet_map::get_primary_replica. The get_primary_replica
optimizes the choice of the replica so that the work is fairly
distributes among nodes. Meanwhile, get_primary_endpoints always
chooses the first replica.
Use get_primary_replica for get_primary_endpoints.
Fixes: https://github.com/scylladb/scylladb/issues/21883.
Closesscylladb/scylladb#26385
This patch changes the tablet size map in load_stats. Previously, this
data structure was:
std::unordered_map<range_based_tablet_id, uint64_t> tablet_sizes;
and is changed into:
std::unordered_map<table_id, std::unordered_map<dht::token_range, uint64_t>> tablet_sizes;
This allows for improved performance of tablet tablet size reconciliation.
Using the name regular as the incremental mode could be confusing, since
regular might be interpreted as the non-incremental repair. It is better
to use incremental directly.
Before:
- regular (standard incremental repair)
- full (full incremental repair)
- disabled (incremental repair disabled)
After:
- incremental (standard incremental repair)
- full (full incremental repair)
- disabled (incremental repair disabled)
Fixes#26503Closesscylladb/scylladb#26504
This commit extend the TABLE_LOAD_STATS RPC with data about the tablet
replica sizes and effective disk capacity.
Effective disk capacity of a node is computed as a sum of the sizes of
all tablet replicas on a node and available disk space.
This is the first change in the size based load balancing series.
Closesscylladb/scylladb#26035
Consider the following:
1) balancer emits split decision
2) split compaction starts
3) split decision is revoked
4) emits merge decision
5) completes merge, before compaction in step 2 finishes
After last step, split compaction initiated in step 2 can fail because it works with the global tablet map, rather than the map when the compaction started. With the global state changing under its feet, on merge, the mutation splitting writer will think it's going backwards since sibling tablets are merged.
This problem was also seen when running load-and-stream, where split initiated by the sstable writer failed, split completed, and the unsplit sstable is left in the table dir, causing problems in the restart.
To fix this, let's make split compaction always work with the state when it started, not a global state.
Fixes#24153.
All 2025.* versions are vulnerable, so fix must be backported to them.
Closesscylladb/scylladb#25690
* github.com:scylladb/scylladb:
replica: Fix split compaction when tablet boundaries change
replica: Futurize split_compaction_options()
This patch introduces a new `incremental_mode` parameter to the tablet
repair REST API, providing more fine-grained control over the
incremental repair process.
Previously, incremental repair was on and could not be turned off. This
change allows users to select from three distinct modes:
- `regular`: This is the default mode. It performs a standard
incremental repair, processing only unrepaired sstables and skipping
those that are already repaired. The repair state (`repaired_at`,
`sstables_repaired_at`) is updated.
- `full`: This mode forces the repair to process all sstables, including
those that have been previously repaired. This is useful when a full
data validation is needed without disabling the incremental repair
feature. The repair state is updated.
- `disabled`: This mode completely disables the incremental repair logic
for the current repair operation. It behaves like a classic
(pre-incremental) repair, and it does not update any incremental
repair state (`repaired_at` in sstables or `sstables_repaired_at` in
the system.tablets table).
The implementation includes:
- Adding the `incremental_mode` parameter to the
`/storage_service/repair/tablet` API endpoint.
- Updating the internal repair logic to handle the different modes.
- Adding a new test case to verify the behavior of each mode.
- Updating the API documentation and developer documentation.
Fixes#25605Closesscylladb/scylladb#25693
Consider the following:
1) balancer emits split decision
2) split compaction starts
3) split decision is revoked
4) emits merge decision
5) completes merge, before compaction in step 2 finishes
After last step, split compaction initiated in step 2 can fail
because it works with the global tablet map, rather than the
map when the compaction started. With the global state changing
under its feet, on merge, the mutation splitting writer will
think it's going backwards since sibling tablets are merged.
This problem was also seen when running load-and-stream, where
split initiated by the sstable writer failed, split completed,
and the unsplit sstable is left in the table dir, causing
problems in the restart.
To fix this, let's make split compaction always work with
the state when it started, not a global state.
Fixes#24153.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
This commit extends the TABLE_LOAD_STATS RPC with information whether
a node operates in the critical disk utilization mode.
This information will be needed to distict between the causes why
a table migration/repair was interrupted.
This patch addes incremental_repair support in compaction.
- The sstables are split into repaired and unrepaired set.
- Repaired and unrepaired set compact sperately.
- The repaired_at from sstable and sstables_repaired_at from
system.tablets table are used to decide if a sstable is repaired or
not.
- Different compactions tasks, e.g., minor, major, scrub, split, are
serialized with tablet repair.
As they are wasteful in many cases, it is better
to move the tablet_map if possible, or clone
it gently in an async fiber.
Add clone() and clone_gently() methods to
allow explicit copies.
* minor optimization, no backport needed
Closesscylladb/scylladb#24978
* github.com:scylladb/scylladb:
tablets: prevent accidental copy of tablets_map
locator: tablets: get rid of synchronous mutate_tablet_map
The `token_metadata_impl` stores the sorted tokens in an `std::vector`.
With a large number of nodes, the size of this vector can grow quickly,
and updating it might lead to oversized allocations.
This commit changes `_sorted_tokens` to a `chunked_vector` to avoid such
issues. It also updates all related code to use `chunked_vector` instead
of `std::vector`.
Fixes#24876
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Closesscylladb/scylladb#25027
As they are wasteful in many cases, it is better
to move the tablet_map if possible, or clone
it gently in an async fiber.
Add clone() and clone_gently() methods to
allow explicit copies.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
It is currently used only by tests that could very well
do with mutate_tablet_map_async.
This will simplify the following patch to prevent
accidental copy of the tablet_map, provding explicit
clone/clone_gently methods.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
The method all_tables in tablet_metadata is used for iterating over all
tables in the tablet metadata with their tablet maps.
Now that we have co-located tables we need to make the distinction on
which tables we want to iterate over. In some cases we want to iterate
over each group of co-located tables, treating them as one unit, and in
other cases we want to iterate over all tables, doesn't matter if they
are part of a co-located group and have a base table.
We replace all_tables with new methods that can be used for each of the
cases.
Modify tablet_metadata to be able to represent co-located tables.
The new method set_colocated_table adds to tablet_metadata a table which
is co-located with another table. A co-located table shares the tablet
map object with the base table, so we just create a copy of the shared
tablet map pointer and store it as the co-located table's tablet map.
Whenever a tablet map is modified we update the pointer for all the
co-located tables accordingly, so the tablet map remains shared.
We add some data structures to tablet_metadata to be able to work with
co-located table groups efficiently:
* `_table_groups` maps every base table to all tables in its
co-location group. This is convenient for iterating over all table
groups, or finding all tables in some group.
* `_base_table` maps a co-located table to its base table.
When a tablet is migrated and cleaned up, deallocate the tablet storage
group state on `end_migration` stage, instead of `cleanup` stage:
* When the stage is updated from `cleanup` to `end_migration`, the
storage group is removed on the leaving replica.
* When the table is initialized, if the tablet stage is `end_migration`
then we don't allocate a storage group for it. This happens for
example if the leaving replica is restarted during tablet migration.
If it's initialized in `cleanup` stage then we allocate a storage
group, and it will be deallocated when transitioning to
`end_migration`.
This guarantees that the storage group is always deallocated on the
leaving replica by `end_migration`, and that it is always allocated if
the tablet wasn't cleaned up fully yet.
It is a similar case also for the pending replica when the migration is
aborted. We deallocate the state on `revert_migration` which is the
stage following `cleanup_target`.
Previously the storage group would be allocated when the tablet is
initialized on any of the tablet replicas - also on the leaving replica,
and when the tablet stage is `cleanup` or `end_migration`, and
deallocated during `cleanup`.
This fixes the following issue:
1. A migrating tablet enters cleanup stage
2. the tablet is cleaned up successfuly
3. The leaving replica is restarted, and allocates storage group
4. tablet cleanup is not called because it was already cleaned up
4. the storage group remains allocated on the leaving replica after the
migration is completed - it's not cleaned up properly.
Fixesscylladb/scylladb#23481
Support for TTL-based data removal when using tablets.
The essence of this commit is a separate code path for finding token
ranges owned by the current shard for the cases when tablets are used
and not vnodes. At the same time, the vnodes-case is not touched not to
cause any regressions.
The TTL-caused data removal is normally performed by the primary
replica (both when using vnodes and tablets). For the tablets case,
the already-existing method tablet_map::get_primary_replica(tablet_id)
is used to know if a shard execuring the TTL-related data removal is
the primary replica for each tablet.
A new method tablet_map::get_secondary_replica(tablet_id) has been
added. It is needed by the data invalidation procedure to remove data
when the primary replica node is down - the data is then removed by the
secondary replica node. The mechanism is the same as in the vnodes case.
Since alternator now supports TTL, the test
`test_ttl_enable_error_with_tablets` has been removed.
Also, tests in the test_ttl.py have been made to run twice, once with
vnodes and once with tablets. When run with tablets, the due to lack of
support for LWT with tablets (#18068), tests use
'system:write_isolation' of 'unsafe_rmw'. This approach allows early
regression testing with tablets and is meant only as a tentative
solution.
Fixesscylladb/scylladb#16567Closesscylladb/scylladb#23662
To simplify future usage in
network_topology_strategy::add_tablets_in_dc() which invokes
populate() for a given table, which may be both new and preexisitng.
Currently, in the streaming stage of rebuild tablet transition,
we stream tablet data from all replicas.
This patch series splits the streaming stage into two phases:
- repair phase, where we repair the tablet;
- streaming phase, where we stream tablet data from one replica.
rebuild_repair is a stage that will be used to perform the repair
phase. It executes the tablet repair on tablet_info::replicas.
A primary replica out of migration_streraming_info::read_from is
the repair master. If the repair succeeds, we move to streaming
tablet transition stage, and to cleanup_target - if it fails.
The repair bypasses the tablet repair scheduler and it does not update
the repair_time.
A transition to the rebuild_repair stage will be added in the following
patches.
Currently, in the streaming stage of rebuild tablet transition,
we stream tablet data from all replicas.
This patch series splits the streaming stage into two phases:
- repair phase, where we repair the tablet;
- streaming phase, where we stream tablet data from one replica.
To differentiate the two streaming methods, a new tablet transition
kind - rebuild_v2 - is added.
The transtions and stages for rebuild_v2 transition kind will be
added in the following patches.
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 series achieves two things:
1) changes default number of tablet replicas per shard to be 10 in order to reduce load imbalance between shards
This will result in new tables having at least 10 tablet replicas per
shard by default.
We want this to reduce tablet load imbalance due to differences in
tablet count per shard, where some shards have 1 tablet and some
shards have 2 tablets. With higher tablet count per shard, this
difference-by-one is less relevant.
Fixes https://github.com/scylladb/scylladb/issues/21967
2) introduces a global goal for tablet replica count per shard and adds logic to tablet scheduler to respect it by controlling per-table tablet count
The per-shard goal is enforced by controlling average per-shard tablet replica
count in a given DC, which is controlled by per-table tablet
count. This is effective in respecting the limit on individual shards
as long as tablet replicas are distributed evenly between shards.
There is no attempt to move tablets around in order to enforce limits
on individual shards in case of imbalance between shards.
If the average per-shard tablet count exceeds the limit, all tables
which contribute to it (have replicas in the DC) are scaled down
by the same factor. Due to rounding up to the nearest power of 2,
we may overshoot the per-shard goal by at most a factor of 2.
The scaling is applied after computing desired tablet count due to
all other factors: per-table tablet count hints, defaults, average tablet size.
If different DCs want different scale factors of a given table, the
lowest scale factor is chosen for a given table.
When creating a new table, its tablet count is determined by tablet
scheduler using the scheduler logic, as if the table was already created.
So any scaling due to per-shard tablet count goal is reflected immediately
when creating a table. It may however still take some time for the system
to shrink existing tables. We don't reject requests to create new tables.
Fixes#21458Closesscylladb/scylladb#22522
* github.com:scylladb/scylladb:
config, tablets: Allow tablets_initial_scale_factor to be a fraction
test: tablets_test: Test scaling when creating lots of tables
test: tablets_test: Test tablet count changes on per-table option and config changes
test: tablets_test: Add support for auto-split mode
test: cql_test_env: Expose db config
config: Make tablets_initial_scale_factor live-updateable
tablets: load_balancer: Pick initial_scale_factor from config
tablets, load_balancer: Fix and improve logging of resize decisions
tablets, load_balancer: Log reason for target tablet count
tablets: load_balancer: Move hints processing to tablet scheduler
tablets: load_balancer: Scale down tablet count to respect per-shard tablet count goal
tablets: Use scheduler's make_sizing_plan() to decide about tablet count of a new table
tablets: load_balancer: Determine desired count from size separately from count from options
tablets: load_balancer: Determine resize decision from target tablet count
tablets: load_balancer: Allow splits even if table stats not available
tablets: load_balancer: Extract make_sizing_plan()
tablets: Add formatter for resize_decision::way_type
tablets: load_balancer: Simplify resize_urgency_cmp()
tablets: load_balancer: Keep config items as instance members
locator: network_topology_strategy: Simplify calculate_initial_tablets_from_topology()
tablets: Change the meaning of initial_scale to mean min-avg-tablets-per-shard
tablets: Set default initial tablet count scale to 10
tablets: network_topology_stragy: Coroutinize calculate_initial_tablets_from_topology()
tablets: load_balancer: Extract get_schema_and_rs()
tablets: load_balancer: Drop test_mode
The split monitor wasn't handling the scenario where the table being
split is dropped. The monitor would be unable to find the tablet map
of such a table, and the error would be treated as a retryable one
causing the monitor to fall into an endless retry loop, with sleeps
in between. And that would block further splits, since the monitor
would be busy with the retries. The fix is about detecting table
was dropped and skipping to the next candidate, if any.
Fixes#21859.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closesscylladb/scylladb#22933
Resize plan making will now happen in two stages:
1) Determine desired tablet counts per table (sizing plan)
2) Schedule resize decisions
We need intermediate step in the resize plan making, which gives us
the planned tablet counts, so that we can plug this part of the
algorithm into initial tablet allocation on table construction.
We want decisisons made by the scheduler to be consistent with
decisions made on table creation. We want to avoid over-allocation of
tablets when table is created, which would then be reduced by the
scheduler. Not just to avoid wasteful migrations post table creation,
but to respect the per-shard goal. To respect the per-shard goal, the
algorithm will no longer be as simple as looking at hints, and we want
to share the algorithm between the scheduler and initial tablet
allocator.
Also, this sizing plan will be later plugged into a virtual table for
observability.
Currently, the tablet repair scheduler repairs all replicas of a tablet.
It does not support hosts or DCs selection. It should be enough for most
cases. However, users might still want to limit the repair to certain
hosts or DCs in production. #21985 added the preparation work to add the
config options for the selection. This patch adds the hosts or DCs
selection support.
Fixes#22417
Do not merge tablets if that would drop the tablet_count
below the minimum provided by hints.
Split tablets if the current tablet_count is less than
the minimum tablet count calculated using the table's tablet options.
TODO: override min_tablet_count if the tablet count per shard
is greater than the maximum allowed. In this case
the tables tablet counts should be scaled down proportionally.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
In this change, tablet_virtual_task starts supporting tablet
resize (i.e. split and merge).
Users can see running resize tasks - finished tasks are not
presented with the task manager API.
A new task state "suspended" is added. If a resize was revoked,
it will appear to users as suspended. We assume that the resize was revoked
when the tablet number didn't change.
Fixes: #21366.
Fixes: #21367.
No backport, new feature
Closesscylladb/scylladb#21891
* github.com:scylladb/scylladb:
test: boost: check resize_task_info in tablet_test.cc
test: add tests to check revoked resize virtual tasks
test: add tests to check the list of resize virtual tasks
test: add tests to check spilt and merge virtual tasks status
test: test_tablet_tasks: generalize functions
replica: service: add split virtual task's children
replica: service: pass parent info down to storage_group::split
tasks: children of virtual tasks aren't internal by default
tasks: initialize shard in task_info ctor
service: extend tablet_virtual_task::abort
service: retrun status_helper struct from tablet_virtual_task::get_status_helper
service: extend tablet_virtual_task::wait
tasks: add suspended task state
service: extend tablet_virtual_task::get_status
service: extend tablet_virtual_task::contains
service: extend tablet_virtual_task::get_stats
service: add service::task_manager_module::get_nodes
tasks: add task_manager::get_nodes
tasks: drop noexcept from module::get_nodes
replica: service: add resize_task_info static column to system.tablets
locator: extend tablet_task_info to cover resize tasks
They will be useful for hosts and DCs selection for the repair
scheduler. It is not implemented yet. Adding it earlier, so we do not
need to change the system tabler later.
Closesscylladb/scylladb#21985
Add resize_task_info static column to system.tablets. Set or delete
resize_task_info value when the resize_decision is changed.
Reflect the column content in tablet_map.
Add migration_task_info column to system.tablets. Set migration_task_info
value on migration request if the feature is enabled in the cluster.
Reflect the column content in tablet_metadata.
