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>
For example, nodes which are being decommissioned should not be
consider as available capacity for new tables. We don't allocate
tablets on such nodes.
Would result in higher per-shard load then planned.
Closesscylladb/scylladb#22657
The repair_time in system.tablets will be updated when repair runs
successfully. We can now use it to update the repair time for tombstone
gc, i.e, when the system.tablets.repair_time is propagated, call
gc_state.update_repair_time() on the node that is the owner of the
tablet.
Since b3b3e880d3 ("repair: Reduce hints and batchlog flush"), the
repair time that could be used for tombstone gc might be smaller than
when the repair is started, so the actual repair time for tombstone gc
is returned by the repair rpc call from the repair master node.
Fixes#17507
New feature. No backport is needed.
Closesscylladb/scylladb#21896
* github.com:scylladb/scylladb:
repair: Stop using rpc to update repair time for repairs scheduled by scheduler
repair: Wire repair_time in system.tablets for tombstone gc
test: Disable flush_cache_time for two tablet repair tests
test: Introduce guarantee_repair_time_next_second helper
repair: Return repair time for repair_service::repair_tablet
service: Add tablet_operation.hh
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 If a resize was revoked,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 We assume that the resize was revoked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
The repair_time in system.tablets will be updated when repair runs
successfully. We can now use it to update the repair time for tombstone
gc, i.e, when the system.tablets.repair_time is propagated, call
gc_state.update_repair_time() on the node that is the owner of the
tablet.
Since b3b3e880d3 ("repair: Reduce hints and batchlog flush"), the
repair time that could be used for tombstone gc might be smaller than
when the repair is started, so the actual repair time for tombstone gc
is returned by the repair rpc call from the repair master node.
Fixes#17507
Pass task_info down to storage_group::split.
In the following patches, it will be used to set the parent
of offstrategy_compaction_task_executor and split_compaction_task_executor
running as a part of the split. The task_info param will contain task
info of a split virtual task.
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.
these unused includes were identifier by clang-include-cleaner. after
auditing these source files, all of the reports have been confirmed.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22199
Main problem:
If we're draining the last node in a DC, we won't have a chance to
evaluate candidates and notice that constraints cannot be satisfied (N
< RF). Draining will succeed and node will be removed with replicas
still present on that node. This will cause later draining in the same
DC to fail when we will have 2 replicas which need relocaiton for a
given tablet.
The expected behvior is for draining to fail, because we cannot keep
the RF in the DC. This is consistent, for example, with what happens
when removing a node in a 2-node cluster with RF=2.
Fixes#21826
Secondary problem:
We allowed tablet_draining transition to be exited with undrained nodes, leaving replicas on nodes in the "left" state.
Third problem:
We removed DOWN nodes from the candidate node set, even when draining. This is not safe because it may lead to overload. This also makes the "main problem" more likely by extending it to the scenario when the DC is DOWN.
The overload part in not a problem in practice currently, since migrations will block on global topology barrier if there are DOWN nodes.
Closesscylladb/scylladb#21928
* github.com:scylladb/scylladb:
tablets: load_balancer: Fail when draining with no candidate nodes
tablets: load_balancer: Ignore skip_list when draining
tablets: topology_coordinator: Keep tablet_draining transition if nodes are not drained
To reduce test executable size and speed up compilation time, compile unit
tests into a single executable.
Here is a file size comparison of the unit test executable:
- Before applying the patch
$ du -h --exclude='*.o' --exclude='*.o.d' build/release/test/boost/ build/debug/test/boost/
11G build/release/test/boost/
29G build/debug/test/boost/
- After applying the patch
du -h --exclude='*.o' --exclude='*.o.d' build/release/test/boost/ build/debug/test/boost/
5.5G build/release/test/boost/
19G build/debug/test/boost/
It reduces executable sizes 5.5GB on release, and 10GB on debug.
Closes#9155Closesscylladb/scylladb#21443
If we're draining the last node in a DC, we won't have a chance to
evaluate candidates and notice that constraints cannot be satisfied (N
< RF). Draining will succeed and node will be removed with replicas
still present on that node. This will cause later draining in the same
DC to fail when we will have 2 replicas which need relocaiton for a
given tablet.
The expected behvior is for draining to fail, because we cannot keep
the RF in the DC. This is consistent, for example, with what happens
when removing a node in a 2-node cluster with RF=2.
Fixes#21826
When doing normal load balancing, we can ignore DOWN nodes in the node
set and just balance the UP nodes among themselves because it's ok to
equalize load just in that set, it improves the situation.
It's dangerous to do that when draining because that can lead to
overloading of the UP nodes. In the worst case, we can have only one
non-drained node in the UP set, which would receive all the tablets of
the drained node, doubling its load.
It's safer to let the drain fail or stall. This is decided by topology
coordinator, currently we will fail (on barrier) and rollback.
When tablet scheduler drains nodes, it chooses target location based
on "badness" metric. Nodes with lowest score are preferred. Before the
patch, the score which was used was the number of tablets on that node
post-movement. This way we populate least-loaded node first. But this
works only if nodes have equal number of shards. If nodes have different
capacity, then number of tablets is not a good metric, because we don't
aim to equalize per-node count, but per-shard count. We assume that each
shard has equal capacity.
Because of this bug, during decommission, the nodes with fewer shards
would be preferred to receive replicas, which may lead to overloading
of those nodes. This imbalance would be later fixed by the normal load
balancing logic, but it's still problematic.
Fixes#21783Closesscylladb/scylladb#21860
The goal of merge is to reduce the tablet count for a shrinking table. Similar to how split increases the count while the table is growing. The load balancer decision to merge is implemented today (came with infrastructure introduced for split), but it wasn't handled until now.
Initial tablet count is respected while the table is in "growing mode". For example, the table leaves it if there was a need to split above the initial tablet count. After the table leaves the mode, the average size can be trusted to determine that the table is shrinking. Merge decision is emitted if the average tablet size is 50% of the target. Hysteresis is applied to avoid oscillations between split and merges.
Similar to split, the decision to merge is recorded in tablet map's resize_type field with the string "merge". This is important in case of coordinator failover, so new coordinator continues from where the old left off.
Unlike split, the preparation phase during merge is not done by the replica (with split compactions), but rather by the coordinator by co-locating sibling tablets in the same node's shard. We can define sibling tablets as tablets that have contiguous range and will become one after merge. The concept is based on the power-of-two constraint and token contiguity. For example, in a table with 4 tablets, tablets of ids 0 and 1 are siblings, 2 and 3 are also siblings.
The algorithm for co-locating sibling tablets is very simple. The balancer is responsible for it, and it will emit migrations so that "odd" tablet will follow the "even" one. For example, tablet 1 will be migrated to where tablet 0 lives. Co-location is low in priority, it's not the end of the world to delay merge, but it's not ideal to delay e.g. decommission or even regular load balancing as that can translate into temporary unbalancing, impacting the user activities. So co-location migrations will happen when there is no more important work to do.
While regular balancing is higher in priority, it will not undo the co-location work done so far. It does that by treating co-located tablets as if they were already merged. The load inversion convergence check was adjusted so balancer understand when two tablets are being migrated instead of one, to avoid oscillations.
When balancer completes co-location work for a table undergoing merge, it will put the id of the table into the resize_plan, which is about communicating with the topology coordinator that a table is ready for it. With all sibling tablets co-located, the coordinator can resize the tablet map (reduce it by a factor of 2) and record the new map into group0. All the replicas will react to it (on token metadata update) by merging the storage (memtable(s) + sstables) of sibling tablets into one.
Fixes#18181.
system test details:
test: https://github.com/pehala/scylla-cluster-tests/blob/tablets_split_merge/tablets_split_merge_test.py
yaml file: https://github.com/pehala/scylla-cluster-tests/blob/tablets_split_merge/test-cases/features/tablets/tablets-split-merge-test.yaml
instance type: i3.8xlarge
nodes: 3
target tablet size: 0.5G (scaled down by 10, to make it easier to trigger splits and merges)
description: multiple cycles of growing and shrinking the data set in order to trigger splits and merges.
data_set_size: ~100G
initial_tablets: 64, so it grew to 128 tablets on split, and back to 64 on merge.
latency of reads and writes that happened in parallel to split and merge:
```
$ for i in scylla-bench*; do cat $i | grep "Mode\|99th:\|99\.9th:"; done
Mode: write
99.9th: 3.145727ms
99th: 1.998847ms
99.9th: 3.145727ms
99th: 2.031615ms
Mode: read
99.9th: 3.145727ms
99th: 2.031615ms
99.9th: 3.145727ms
99th: 2.031615ms
Mode: write
99.9th: 3.047423ms
99th: 1.933311ms
99.9th: 3.047423ms
99th: 1.933311ms
Mode: read
99.9th: 3.145727ms
99th: 1.900543ms
99.9th: 3.145727ms
99th: 1.900543ms
Mode: write
99.9th: 5.079039ms
99th: 3.604479ms
99.9th: 35.389439ms
99th: 25.624575ms
Mode: write
99.9th: 3.047423ms
99th: 1.998847ms
99.9th: 3.047423ms
99th: 1.998847ms
Mode: read
99.9th: 3.080191ms
99th: 2.031615ms
99.9th: 3.112959ms
99th: 2.031615ms
```
Closesscylladb/scylladb#20572
* github.com:scylladb/scylladb:
docs: Document tablet merging
tests/boost: Add test to verify correctness of balancer decisions during merge
tests/topology_experimental_raft: Add tablet merge test
service: Handle exception when retrying split
service: Co-locate sibling tablets for a table undergoing merge
gms: Add cluster feature for tablet merge
service: Make merge of resize plan commutative
replica: Implement merging of compaction groups on merge completion
replica: Handle tablet merge completion
service: Implement tablet map resize for merge
locator: Introduce merge_tablet_info()
service: Rename topology::transition_state::tablet_split_finalization
service: Respect initial_tablet_count if table is in growing mode
service: Wire migration_tablet_set into the load balancer
locator: Add tablet_map::sibling_tablets()
service: Introduce sorted_replicas_for_tablet_load()
locator/tablets: Extend tablet_replica equality comparator to three-way
service: Introduce alias to per-table candidate map type
service: Add replication constraint check variant for migration_tablet_set
service: Add convergence check variant for migration_tablet_set
service: Add migration helpers for migration_tablet_set
service/tablet_allocator: Introduce migration_tablet_set
service: Introduce migration_plan::add(migrations_vector)
locator/tablets: Introduce tablet_map::for_each_sibling_tablets()
locator/tablets: Introduce tablet_map::needs_merge()
locator/tablets: Introduce resize_decision::initial_decision()
locator/tablets: Fix return type of three-way comparison operators
service: Extract update of node load on migrations
service: Extract converge check for intra-node migration
service: Extract erase of tablet replicas from candidate list
scripts/tablet-mon: Allow visualization of tablet id
This implements the ability for the balancer to co-locate sibling
tablets on the same shard. Co-location is low in priority, so
regular load balancer is preferred over it. Previous changes
allowed balancer to move co-located sibling tablets together,
to not undo the co-location work done so far.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
This transition state will be reused by merge completion, so let's
rename it to tablet_resize_finalization.
The completion handling path will also be reused, so let's rename
functions involved similarly.
The old name "tablet split finalization" is deprecated but still
recognized and points to the correct transition. Otherwise, the
reverse lookup would fail when populating topology system table
which last state was split finalization.
NOTE:
I thought of adding a new tablet_merge_finalization, but it would
complicate things since more than one table could be ready for
either split or merge, so you need a generic transition state
for handling resize completion.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
"
This rather large patch series moves storage proxy and some adjacent
services (like migration manager) to use host ids to identify nodes rather
than ips. Messaging service gains a capability to address nodes by host
ids (which allows dropping translations from topology coordinator code
that worked on host ids already) and also makes sure that a node with
incorrect host id will reject a message (can happen during address
changes).
The series gets rid of the raft address map completely and replaces it with
the gossiper address map which is managed by the gossiper since translation
is now done in the layer below raft.
Fixes: scylladb/scylladb#6403
perf-simple-query -- smp 1 -m 1G output
Before:
enable-cache=1
Running test with config: {partitions=10000, concurrency=100, mode=read, frontend=cql, query_single_key=no, counters=no}
Disabling auto compaction
Creating 10000 partitions...
64336.82 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 41291 insns/op, 24485 cycles/op, 0 errors)
62669.58 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 41277 insns/op, 24695 cycles/op, 0 errors)
69172.12 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.2 tasks/op, 41326 insns/op, 24463 cycles/op, 0 errors)
56706.60 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 41143 insns/op, 24513 cycles/op, 0 errors)
56416.65 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 41186 insns/op, 24851 cycles/op, 0 errors)
throughput: mean=61860.35 standard-deviation=5395.48 median=62669.58 median-absolute-deviation=5153.75 maximum=69172.12 minimum=56416.65
instructions_per_op: mean=41244.62 standard-deviation=76.90 median=41276.94 median-absolute-deviation=58.55 maximum=41326.19 minimum=41142.80
cpu_cycles_per_op: mean=24601.35 standard-deviation=167.39 median=24512.64 median-absolute-deviation=116.65 maximum=24851.45 minimum=24462.70
After:
enable-cache=1
Running test with config: {partitions=10000, concurrency=100, mode=read, frontend=cql, query_single_key=no, counters=no}
Disabling auto compaction
Creating 10000 partitions...
65237.35 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.2 tasks/op, 40733 insns/op, 23145 cycles/op, 0 errors)
59283.09 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 40624 insns/op, 23948 cycles/op, 0 errors)
70851.03 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 40625 insns/op, 23027 cycles/op, 0 errors)
70549.61 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 40650 insns/op, 23266 cycles/op, 0 errors)
68634.96 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 40622 insns/op, 22935 cycles/op, 0 errors)
throughput: mean=66911.21 standard-deviation=4814.60 median=68634.96 median-absolute-deviation=3638.40 maximum=70851.03 minimum=59283.09
instructions_per_op: mean=40650.89 standard-deviation=47.55 median=40624.60 median-absolute-deviation=27.11 maximum=40733.37 minimum=40622.33
cpu_cycles_per_op: mean=23264.16 standard-deviation=402.12 median=23145.29 median-absolute-deviation=237.63 maximum=23947.96 minimum=22934.59
CI: https://jenkins.scylladb.com/job/scylla-master/job/scylla-ci/13531/
SCT (longevity-100gb-4h with nemesis_selector: ['topology_changes']): https://jenkins.scylladb.com/view/staging/job/scylla-staging/job/gleb/job/move-to-host-id/3/
Tested mixed cluster manually.
"
* 'gleb/move-to-host-id-v2' of github.com:scylladb/scylla-dev: (55 commits)
group0: drop unused field from replace_info struct
test: rename raft_address_map_test to address_map_test and move if from raft tests
raft_address_map: remove raft address map
topology coordinator: do not modify expire state for left/new nodes any more in raft address map
topology coordinator: drop expiring entries in gossiper address map on error injections since raft one is no longer used
group0: drop raft address map dependency from raft_rpc
group0: move raft_ticker_type definition from raft_address_map.hh
storage_service: do not update raft address map on gossiper events
group0: drop raft address map dependency from raft_server_with_timeouts
group0: move group0 upgrade code to host ids
repair: drop raft address map dependency
group0: remove unused raft address map getter from raft_group0
group0: drop raft address map from group0_state_machine dependency since it is not used there any more
group0: remove dependency on raft address map from group0_state_id_handler
gossiper: add get_application_state_ptr that searches by host_id
gossiper: change get_live_token_owners to return host ids
view: move view building to host id
hints: use host id to send hints
storage_proxy: remove id_vector_to_addr since it is no longer used
db: consistency_level: change is_sufficient_live_nodes to work on host ids
...
now that we are allowed to use C++23. we now have the luxury of using
`std::views::transform`.
in this change, we:
- replace `boost::adaptors::transformed` with `std::views::transform`
- use `fmt::join()` when appropriate where `boost::algorithm::join()`
is not applicable to a range view returned by `std::view::transform`.
- use `std::ranges::fold_left()` to accumulate the range returned by
`std::view::transform`
- use `std::ranges::fold_left()` to get the maximum element in the
range returned by `std::view::transform`
- use `std::ranges::min()` to get the minimal element in the range
returned by `std::view::transform`
- use `std::ranges::equal()` to compare the range views returned
by `std::view::transform`
- remove unused `#include <boost/range/adaptor/transformed.hpp>`
- use `std::ranges::subrange()` instead of `boost::make_iterator_range()`,
to feed `std::views::transform()` a view range.
to reduce the dependency to boost for better maintainability, and
leverage standard library features for better long-term support.
this change is part of our ongoing effort to modernize our codebase
and reduce external dependencies where possible.
limitations:
there are still a couple places where we are still using
`boost::adaptors::transformed` due to the lack of a C++23 alternative
for `boost::join()` and `boost::adaptors::uniqued`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21700
Currently the locator::topology object, when created, does not contain
local node, but it is started to be used to access local database. It
sort of work now because there are explicit checks in the code to handle
this special case like in topology::get_location for instance. We do not
want to hack around it and instead rely on an invariant that the local
node is always there. To do that we add local node during
locator::topology creation. There is a catch though. Unlike with IP host
ID is not known during startup. We actually need to read from the
database to know it, so the topology starts with host ID zero and then
it changes once to the real one. This is not a problem though. As long as
the (one node) topology is consistent (_cfg.this_host_id is equal to the
node's id) local access will work.
Test both configuration values for `enable_tablets`
and the possibility to explicitly enable or disable
tablets, respectively, when creating a keyspace using the
`tablets = {'enabled': true|false}` CREATE KEYSPACE option.
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).
Test both configuration values for `enable_tablets`
and the possibility to explicitly enable or disable
tablets, respectively, when creating a keyspace using the
`tablets = {'enabled': true|false}` CREATE KEYSPACE option.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
This includes way too much, including <boost/regex.hpp>, which is huge.
Drop includes of adaptors.hpp and replace by what is needed.
Closesscylladb/scylladb#21187
When we made the raft-based topology mandatory, all boost test
tests started using it. Then, `test_read_required_hosts` started
failing. We left investigating it for later and started running it
with `force-gossip-topology-changes` to make it pass.
Currently, the test doesn't fail with the raft-based topology
anymore. Hence, we remove the FIXME and run the test with a normal
config.
We don't know when and why the test stopped failing. Investigating
it wouldn't be easy, since we don't even know why it failed in the
first place. We suspect that there was some bug that is now fixed.
This patch only fixes a test, there is no need to backport it.
Fixesscylladb/scylladb#18463Closesscylladb/scylladb#20960
In one of the following patches, we introduce support for zero-token
nodes. From that point, getting all nodes and getting all token
owners isn't equivalent. In this patch, we ensure that we consider
only token owners when we want to consider only token owners (for
example, in the replication logic), and we consider all nodes when
we want to consider all nodes (for example, in the topology logic).
The main purpose of this patch is to make the PR introducing
zero-token nodes easier to review. The patch that introduces
zero-token nodes is already complicated. We don't want trivial
changes from this patch to make noise there.
This patch introduces changes needed for zero-token nodes only in the
Raft-based topology and in the recovery mode. Zero-token nodes are
unsupported in the gossip-based topology outside recovery.
Some functions added to `token_metadata` and `topology` are
inefficient because they compute a new data structure in every call.
They are never called in the hot path, so it's not a serious problem.
Nevertheless, we should improve it somehow. Note that it's not
obvious how to do it because we don't want to make `token_metadata`
store topology-related data. Similarly, we don't want to make
`topology` store token-related data. We can think of an improvement
in a follow-up.
We don't remove unused `topology::get_datacenter_rack_nodes` and
`topology::get_datacenter_nodes`. These function can be useful in the
future. Also, `topology::_dc_nodes` is used internally in `topology`.
In one of the following patches, we change the gossiper to work the
same for zero-token nodes and token-owning nodes. We replace
occurrences of `is_normal_token_owner` with topology-based
conditions. We want to rely on the invariant that token-owning nodes
own tokens if and only if they are in the normal or leaving state.
However, this invariant can be broken in the gossip-based topology
when a new node joins the cluster. When a boostrapping node starts
gossiping, other nodes add it to their topology in
`storage_service::on_alive`. Surprisingly, the state of the new node
is set to `normal`, as it's the default value used by
`add_or_update_endpoint`. Later, the state will be set to
`bootstrapping` or `replacing`, and finally it will be set again to
`normal` when the join operation finishes. We fix this strange
behavior by setting the node state to `none` in
`storage_service::on_alive` for nodes not present in the topology.
Note that we must add such nodes to the topology. Other code needs
their Host ID, IP, and location.
We change the default node state from `normal` to `none` in
`add_or_update_endpoint` to prevent bugs like the one in
`storage_service::on_alive`. Also, we ensure that nodes in the `none`
state are ignored in the getters of `locator::topology`.
In one of the following patches, we make NetworkTopologyStrategy
and the tablet load balancer consider only normal token owners to
ensure they ignore zero-token nodes. Some unit tests would start
failing after this change because they do not ensure that all
nodes are normal token owners. This patch prevents it.
Judging by the logic in the test cases in
`network_topology_strategy_test`, `point++` was probably intended
anyway.
Now, when each shard storage_group_manager keeps
only the storage_groups for the tablet replica it owns,
we can simple return the storage_group map size
instead of counting the number of tablet replicas
mapped to this shard.
Add a unit test that sums the tablet count
on all shards and tests that the sum is equal
to the configured default `initial_tablets.
Fixes#18909
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#20223
Keep lw_shared_ptr<tablet_map> in the tablet map and use COW semantics.
To prevent accidental changes to shared tablet_map instances, all
modifications to a tablet_map have to go through a new
`mutate_tablet_map()` method, which implements the copy-modify-swap
idiom.
If tablet-based table is created concurrently with node being
decommissioned after tablets are already drained, the new table may be
permanently left with replicas on the node which is no longer in the
topology. That creates an immidiate availability risk because we are
running with one replica down.
This also violates invariants about replica placement and this state
cannot be fixed by topology operations.
One effect is that this will lead to load balancer failure which will
inhibit progress of any topology operations:
load_balancer - Replica 154b0380-1dd2-11b2-9fdd-7156aa720e1a:0 of tablet 7e03dd40-537b-11ef-9fdd-7156aa720e1a:1 not found in topology, at: ...
Fixes#20032Closesscylladb/scylladb#20053
Users outside of the token module don't
need to mess with the token::kind.
They can only create key tokens.
Never, minimum or maximum tokens, with a particular
datya value.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
sizeof(dht::token) is only 16 bytes and therefore
it can be passed with 2 registers.
There is no sense in defining minimum_token
and maximum_token out of line, returning a token&
to statically allocated values that require memory
access/copy, while the only call sites that needs
to point to the static min/max tokens are in
dht::ring_position_view.
Instead, they can be defined inline as constexpr
functions and return their const values.
Respectively, define token ctors and methods
as constexpr where applicable (and noexcept while at it
where applicable)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
... and replace it with boolean enable_tablets option. All the places
in the code are patched to check the latter option instead of the former
feature.
The option is OFF by default, but the default scylla.yaml file sets this
to true, so that newly installed clusters turn tablets ON.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#18898
Note we're suppressing a UBSanitizer overflow error in UTs. That's
because our linter complains about a possible overflow, which never
happens, but tests are still failing because of it.
in this change, we trade the `boost_test_print_type()` overloads
for the generic template of `boost_test_print_type()`, except for
those in the very small tests, which presumably want to keep
themselves relative self-contained.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18727
