If allow_write_both_read_old tablet transition stage fails, move
to cleanup_target stage before reverting migration.
It's a preparation for further patches which deallocate storage
group of a tablet during cleanup.
Someone thought that they actually represent real keys (the 'EXAMPLE' in their name was not enough).
Converted them to be as clear as can be, example data.
Signed-off-by: Yaniv Kaul <yaniv.kaul@scylladb.com>
Closesscylladb/scylladb#18565
This is the second half of the fix for issue #13968. The first half is already merged with PR #18346
Scylla issues warnings for partitions containing more rows than a configured threshold. The warning is issued by inserting a row into the `system.large_partitions` table. This row contains the information about the partition for which the warning is issued: keyspace, table, sstable, partition key and size, compaction time and the number of rows in the partition. A previous PR #18346 also added range tombstone count to this row.
This change adds a new counter for dead rows to the large_partitions table.
This change also adds cluster feature protection for writing into these new counters. This is needed in case a cluster is in the process of being upgraded to this new version, after which an upgraded node writes data with the new schema into `system.large_partitions`, and finally a node is then rolled back to an old version. This node will then revert the schema to the old version, but the written sstables will still contain data with the new counters, causing any readers of this table to throw errors when they encounter these cells.
This is an enhancement, and backporting is not needed.
Fixes#13968Closesscylladb/scylladb#18458
* github.com:scylladb/scylladb:
sstable: added test for counting dead rows
sstable: added docs for system.large_partitions.dead_rows
sstable: added cluster feature for dead rows and range tombstones
sstable: write dead_rows count to system.large_partitions
sstable: added counter for dead rows
This pull request introduces host ID in the Hinted Handoff module. Nodes are now identified by their host IDs instead of their IPs. The conversion occurs on the boundary between the module and `storage_proxy.hh`, but aside from that, IPs have been erased.
The changes take into considerations that there might still be old hints, still identified by IPs, on disk – at start-up, we map them to host IDs if it's possible so that they're not lost.
Refs scylladb/scylladb#6403Fixesscylladb/scylladb#12278Closesscylladb/scylladb#15567
* github.com:scylladb/scylladb:
docs: Update Hinted Handoff documentation
db/hints: Add endpoint_downtime_not_bigger_than()
db/hints: Migrate hinted handoff when cluster feature is enabled
db/hints: Handle arbitrary directories in resource manager
db/hints: Start using hint_directory_manager
db/hints: Enforce providing IP in get_ep_manager()
db/hints: Introduce hint_directory_manager
db/hints/resource_manager: Update function description
db/hints: Coroutinize space_watchdog::scan_one_ep_dir()
db/hints: Expose update lock of space watchdog
db/hints: Add function for migrating hint directories to host ID
db/hints: Take both IP and host ID when storing hints
db/hints: Prepare initializing endpoint managers for migrating from IP to host ID
db/hints: Migrate to locator::host_id
db/hints: Remove noexcept in do_send_one_mutation()
service: Add locator::host_id to on_leave_cluster
service: Fix indentation
db/hints: Fix indentation
Finalization of tablet split was only synchronizing with migrations, but
that's not enough as we want to make sure that all processes like repair
completes first as they might hold erm and therefore will be working
with a "stale" version of token metadata.
For synchronization to work properly, handling of tablet split finalize
will now take over the state machine, when possible, and execute a
global token metadata barrier to guarantee that update in topology by
split won't cause problems. Repair for example could be writing a
sstable with stale metadata, and therefore, could generate a sstable
that spans multiple tablets. We don't want that to happen, therefore
we need the barrier.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closesscylladb/scylladb#18380
Repair may miss some tablets that migrated across nodes.
So if tombstones expire after some timeout, then we can
have data resurrection.
Set default tombstone_gc mode to "repair" for tables which
use tablets (if repair is required).
Fixes: #16627.
Closesscylladb/scylladb#18013
* github.com:scylladb/scylladb:
test: check default value of tombstone_gc
test: topology: move some functions to util.py
cql3: statements: change default tombstone_gc mode for tablets
Currently, if tombstone_gc mode isn't specified for a table,
then "timeout" is used by default. With tablets, running
"nodetool repair -pr" may miss a tablet if it migrated across
the nodes. Then, if we expire tombstones for ranges that
weren't repaired, we may get data resurrection.
Set default tombstone_gc mode value for DDLs that don't
specify it. It's set to "repair" for tables which use tablets
unless they use local replication strategy or rf = 1.
Otherwise it's set to "timeout".
This commit includes updates related to replacing system_auth with system_auth_v2.
- The keyspace name system_auth is renamed to system_auth_v2.
- The procedures are updated to account for system_auth_v2.
- No longer required system_auth RF changes are removed from procedures.
- The information is added that if the consistent topology updates feature
was not enabled upon upgrade from 5.4, there are limitations or additional
steps to do (depending on the procedure).
The files with that kind of information are to be found in _common folders
and included as needed.
- The upgrade guide has been updated to reflect system_auth_v2 and related impacts.
Closesscylladb/scylladb#18077
Maintainers are also allowed to commit their own backport PR. They are
allowed to backport their own code, opening a PR to get a CI run for a
backport doesn't change this.
Closesscylladb/scylladb#17727
in order to help the developers to understand the transitions
of `node_state` and the `transition_state` on each of the `node_state`,
in this change, the nested state machine diagram is added to the
node state diagram.
please note, instead of trying to merge similar states like
bootstrapping and replacing into a single state, we keep them as
separate ones, and replicate the nested state machine diagram in them
as well, to be more clear.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18025
This PR fixes a problem with replacing a node with tablets when
RF=N. Currently, this will fail because tablet replica allocation for
rebuild will not be able to find a viable destination, as the replacing node
is not considered to be a candidate. It cannot be a candidate because
replace rolls back on failure and we cannot roll back after tablets
were migrated.
The solution taken here is to not drain tablet replicas from replaced
node during topology request but leave it to happen later after the
replaced node is in left state and replacing node is in normal state.
The replacing node waits for this draining to be complete on boot
before the node is considered booted.
Fixes https://github.com/scylladb/scylladb/issues/17025
Nodes in the left state will be kept in tablet replica sets for a while after node
replace is done, until the new replica is rebuilt. So we need to know
about those node's location (dc, rack) for two reasons:
1) algorithms which work with replica sets filter nodes based on their location. For example materialized views code which pairs base replicas with view replicas filters by datacenter first.
2) tablet scheduler needs to identify each node's location in order to make decisions about new replica placement.
It's ok to not know the IP, and we don't keep it. Those nodes will not
be present in the IP-based replica sets, e.g. those returned by
get_natural_endpoints(), only in host_id-based replica
sets. storage_proxy request coordination is not affected.
Nodes in the left state are still not present in token ring, and not
considered to be members of the ring (datacanter endpoints excludes them).
In the future we could make the change even more transparent by only
loading locator::node* for those nodes and keeping node* in tablet replica sets.
Currently left nodes are never removed from topology, so will
accumulate in memory. We could garbage-collect them from topology
coordinator if a left node is absent in any replica set. That means we
need a new state - left_for_real.
Closesscylladb/scylladb#17388
* github.com:scylladb/scylladb:
test: py: Add test for view replica pairing after replace
raft, api: Add RESTful API to query current leader of a raft group
test: test_tablets_removenode: Verify replacing when there is no spare node
doc: topology-on-raft: Document replace behavior with tablets
tablets, raft topology: Rebuild tablets after replacing node is normal
tablets: load_balancer: Access node attributes via node struct
tablets: load_balancer: Extract ensure_node()
mv: Switch to using host_id-based replica set
effective_replication_map: Introduce host_id-based get_replicas()
raft topology: Keep nodes in the left state to topology
tablets: Introduce read_required_hosts()
The test.py usage is documented, the ability to run a specific test by
its name is described in doc. Extend it with the new ability to run
specific test case as well.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
this "misspelling" was identified by codespell. actually, it's not
quite a misspelling, as "UPDATE" and "INSERT" are keywords in CQL.
so we intended to emaphasis them, so to make codespell more useful,
and to preserve the intention, let's quote the keywords with backticks.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17391
When we create a CDC generation and ring-delay is non-zero, the
timestamp of the new generation is in the future. Hence, we can
have multiple generations that can be written to. However, if we
add a new node to the cluster with the Raft-based topology, it
receives only the last committed generation. So, this node will
be rejecting writes considered correct by the other nodes until
the last committed generation starts operating.
In scylladb/scylladb#17134, we have allowed sending writes to the
previous CDC generations. So, the situation became even more
complicated. We need to adjust the Raft-based topology to ensure
all required generations are loaded into memory and their data
isn't cleared too early.
This patch is the first step of the adjustment. We replace
`current_cdc_generation_{uuid, timestamp}` with the set containing
IDs of all committed generations - `committed_cdc_generations`.
This set is sorted by timestamps, just like
`unpublished_cdc_generations`.
This patch is mostly refactoring. The last generation in
`committed_cdc_generations` is the equivalent of the previous
`current_cdc_generation_{uuid, timestamp}`. The other generations
are irrelevant for now. They will be used in the following patches.
After introducing `committed_cdc_generations`, a newly committed
generation is also unpublished (it was current and unpublished
before the patch). We introduce `add_new_committed_cdc_generation`,
which updates both sets of generations so that we don't have to
call `add_committed_cdc_generation` and
`add_unpublished_cdc_generation` together. It's easy to forget
that both of them are necessary. Before this patch, there was
no call to `add_unpublished_cdc_generation` in
`topology_coordinator::build_coordinator_state`. It was a bug
reported in scylladb/scylladb#17288. This patch fixes it.
This patch also removes "the current generation" notion from the
Raft-based topology. For the Raft-based topology, the current
generation was the last committed generation. However, for the
`cdc::metadata`, it was the generation operating now. These two
generations could be different, which was confusing. For the
`cdc::metadata`, the current generation is relevant as it is
handled differently, but for the Raft-based topology, it isn't.
Therefore, we change only the Raft-based topology. The generation
called "current" is called "the last committed" from now.
Before this PR, writes to the previous CDC generations would
always be rejected. After this PR, they will be accepted if the
write's timestamp is greater than `now - generation_leeway`.
This change was proposed around 3 years ago. The motivation was
to improve user experience. If a client generates timestamps by
itself and its clock is desynchronized with the clock of the node
the client is connected to, there could be a period during
generation switching when writes fail. We didn't consider this
problem critical because the client could simply retry a failed
write with a higher timestamp. Eventually, it would succeed. This
approach is safe because these failed writes cannot have any side
effects. However, it can be inconvenient. Writing to previous
generations was proposed to improve it.
The idea was rejected 3 years ago. Recently, it turned out that
there is a case when the client cannot retry a write with the
increased timestamp. It happens when a table uses CDC and LWT,
which makes timestamps permanent. Once Paxos commits an entry
with a given timestamp, Scylla will keep trying to apply that entry
until it succeeds, with the same timestamp. Applying the entry
involves writing to the CDC log table. If it fails, we get stuck.
It's a major bug with an unknown perfect solution.
Allowing writes to previous generations for `generation_leeway` is
a probabilistic fix that should solve the problem in practice.
Apart from this change, this PR adds tests for it and updates
the documentation.
This PR is sufficient to enable writes to the previous generations
only in the gossiper-based topology. The Raft-based topology
needs some adjustments in loading and cleaning CDC generations.
These changes won't interfere with the changes introduced in this
PR, so they are left for a follow-up.
Fixesscylladb/scylladb#7251Fixesscylladb/scylladb#15260Closesscylladb/scylladb#17134
* github.com:scylladb/scylladb:
docs: using-scylla: cdc: remove info about failing writes to old generations
docs: dev: cdc: document writing to previous CDC generations
test: add test_writes_to_previous_cdc_generations
cdc: generation: allow increasing generation_leeway through error injection
cdc: metadata: allow sending writes to the previous generations
This PR implements a procedure that upgrades existing clusters to use
raft-based topology operations. The procedure does not start
automatically, it must be triggered manually by the administrator after
making sure that no topology operations are currently running.
Upgrade is triggered by sending `POST
/storage_service/raft_topology/upgrade` request. This causes the
topology coordinator to start who drives the rest of the process: it
builds the `system.topology` state based on information observed in
gossip and tells all nodes to switch to raft mode. Then, topology
coordinator runs normally.
Upgrade progress is tracked in a new static column `upgrade_state` in
`system.topology`.
The procedure also serves as an extension to the current recovery
procedure on raft. The current recovery procedure requires restarting
nodes in a special mode which disables raft, perform `nodetool
removenode` on the dead nodes, clean up some state on the nodes and
restart them so that they automatically rebuild the group 0. Raft
topology fits into existing procedure by falling back to legacy topology
operations after disabling raft. After rebuilding the group 0, upgrade
needs to be triggered again.
Because upgrade is manual and it might not be convenient for
administrators to run it right after upgrading the cluster, we allow the
cluster to operate in legacy topology operations mode until upgrade,
which includes allowing new nodes to join. In order to allow it, nodes
now ask the cluster about the mode they should use to join before
proceeding by using a new `JOIN_NODE_QUERY` RPC.
The procedure is explained in more detail in `topology-over-raft.md`.
Fixes: https://github.com/scylladb/scylladb/issues/15008Closesscylladb/scylladb#17077
* github.com:scylladb/scylladb:
test/topology_custom: upgrade/recovery tests for topology on raft
cdc/generation_service: in legacy mode, fall back to raft tables
system_keyspace: add read_cdc_generation_opt
cdc/generation_service: turn off gossip notifications in raft topo mode
cql_test_env: move raft_topology_change_enabled var earlier
group0_state_machine: pull snapshot after raft topology feature enabled
storage_service: disable persistent feature enabler on upgrade
storage_service: replicate raft features to system.peers
storage_service: gossip tokens and cdc generation in raft topology mode
API: add api for triggering and monitoring topology-on-raft upgrade
storage_service: infer which topology operations to use on startup
storage_service: set the topology kind value based on group 0 state
raft_group0: expose link to the upgrade doc in the header
feature_service: fall back to checking legacy features on startup
storage_service: add fiber for tracking the topology upgrade progress
gms: feature_service: add SUPPORTS_CONSISTENT_TOPOLOGY_CHANGES
topology_coordinator: implement core upgrade logic
topology_coordinator: extract top-level error handling logic
storage_service: initialize discovery leader's state earlier
topology_coordinator: allow for custom sharding info in prepare_and_broadcast_cdc_generation_data
topology_coordinator: allow for custom sharding info in prepare_new_cdc_generation_data
topology_coordinator: remove outdated fixme in prepare_new_cdc_generation_data
topology_state_machine: introduce upgrade_state
storage_service: disallow topology ops when upgrade is in progress
raft_group0_client: add in_recovery method
storage_service: introduce join_node_query verb
raft_group0: make discover_group0 public
raft_group0: filter current node's IP in discover_group0
raft_group0: remove my_id arg from discover_group0
storage_service: make _raft_topology_change_enabled more advanced
docs: document raft topology upgrade and recovery
In one of the previous patches, we changed the `rollback_to_normal`
state from a node state to a transition state. We document it
in this patch. The node state wasn't documented, so there is
nothing to remove.
The motivation for tablet resizing is that we want to keep the average tablet size reasonable, such that load rebalancing can remain efficient. Too large tablet makes migration inefficient, therefore slowing down the balancer.
If the avg size grows beyond the upper bound (split threshold), then balancer decides to split. Split spans all tablets of a table, due to power-of-two constraint.
Likewise, if the avg size decreases below the lower bound (merge threshold), then merge takes place in order to grow the avg size. Merge is not implemented yet, although this series lays foundation for it to be impĺemented later on.
A resize decision can be revoked if the avg size changes and the decision is no longer needed. For example, let's say table is being split and avg size drops below the target size (which is 50% of split threshold and 100% of merge one). That means after split, the avg size would drop below the merge threshold, causing a merge after split, which is wasteful, so it's better to just cancel the split.
Tablet metadata gains 2 new fields for managing this:
resize_type: resize decision type, can be either of "merge", "split", or "none".
resize_seq_number: a sequence number that works as the global identifier of the decision (monotonically increasing, increased by 1 on every new decision emitted by the coordinator).
A new RPC was implemented to pull stats from each table replica, such that load balancer can calculate the avg tablet size and know the "split status", for a given table. Avg size is aggregated carefully while taking RF of each DC into account (which might differ).
When a table is done splitting its storage, it loads (mirror) the resize_seq_number from tablet metadata into its local state (in another words, my split status is ready). If a table is split ready, coordinator will see that table's seq number is the same as the one in tablet metadata. Helps to distinguish stale decisions from the latest one (in case decisions are revoked and re-emited later on). Also, it's aggregated carefully, by taking the minimum among all replicas, so coordinator will only update topology when all replicas are ready.
When load balancer emits split decision, replicas will listen to need to split with a "split monitor" that is awakened once a table has replication metadata updated and detects the need for split (i.e. resize_type field is "split").
The split monitor will start splitting of compaction groups (using mechanism introduced here: 081f30d149) for the table. And once splitting work is completed, the table updates its local state as having completed split.
When coordinator pulls the split status of all replicas for a table via RPC, the balancer can see whether that table is ready for "finalizing" the decision, which is about updating tablet metadata to split each tablet into two. Once table replicas have their replication metadata updated with the new tablet count, they can update appropriately their set of compaction groups (that were previously split in the preparation step).
Fixes#16536.
Closesscylladb/scylladb#16580
* github.com:scylladb/scylladb:
test/topology_experimental_raft: Add tablet split test
replica: Bypass reshape on boot with tablets temporarily
replica: Fix table::compaction_group_for_sstable() for tablet streaming
test/topology_experimental_raft: Disable load balancer in test fencing
replica: Remap compaction groups when tablet split is finalized
service: Split tablet map when split request is finalized
replica: Update table split status if completed split compaction work
storage_service: Implement split monitor
topology_cordinator: Generate updates for resize decisions made by balancer
load_balancer: Introduce metrics for resize decisions
db: Make target tablet size a live-updateable config option
load_balancer: Implement resize decisions
service: Wire table_resize_plan into migration_plan
service: Introduce table_resize_plan
tablet_mutation_builder: Add set_resize_decision()
topology_coordinator: Wire load stats into load balancer
storage_service: Allow tablet split and migration to happen concurrently
topology_coordinator: Periodically retrieve table_load_stats
locator: Introduce topology::get_datacenter_nodes()
storage_service: Implement table_load_stats RPC
replica: Expose table_load_stats in table
replica: Introduce storage_group::live_disk_space_used()
locator: Introduce table_load_stats
tablets: Add resize decision metadata to tablet metadata
locator: Introduce resize_decision
In one of the previous patches, we changed the `left_token_ring`
state from a node state to a transition state. We document it
in this patch. The node state wasn't documented, so there is
nothing to remove.
This implements the ability in load balancer to emit split or merge
requests, cancel ongoing ones if they're no longer needed, and
also finalize those that are ready for the topology changes.
That's all based on average tablet size, collected by coordinator
from all nodes, and split and merge thresholds.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
The new metadata describes the ongoing resize operation (can be either
of merge, split or none) that spans tablets of a given table.
That's managed by group0, so down nodes will be able to see the
decision when they come back up and see the changes to the
metadata.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
New tablet replicas are allocated and rebuilt synchronously with node
operations. They are safely rebuilt from all existing replicas.
The list of ignored nodes passed to node operations is respected.
Tablet scheduler is responsible for scheduling tablet rebuilding transition which
changes the replicas set. The infrastructure for handling decommission
in tablet scheduler is reused for this.
Scheduling is done incrementally, respecting per-shard load
limits. Rebuilding transitions are recognized by load calculation to
affect all tablet replicas.
New kind of tablet transition is introduced called "rebuild" which
adds new tablet replica and rebuilds it from existing replicas. Other
than that, the transition goes through the same stages as regular
migration to ensure safe synchronization with request coordinators.
In this PR we simply stream from all tablet replicas. Later we should
switch to calling repair to avoid sending excessive amounts of data.
Fixes https://github.com/scylladb/scylladb/issues/16690.
Closesscylladb/scylladb#16894
* github.com:scylladb/scylladb:
tests: tablets: Add tests for removenode and replace
tablets: Add support for removenode and replace handling
topology_coordinator: tablets: Do not fail in a tight loop
topology_coordinator: tablets: Avoid warnings about ignored failured future
storage_service, topology: Track excluded state in locator::topology
raft topology: Introduce param-less topology::get_excluded_nodes()
raft topology: Move get_excluded_nodes() to topology
tablets: load_balancer: Generalize load tracking
tablets: Introduce get_migration_streaming_info() which works on migration request
tablets: Move migration_to_transition_info() to tablets.hh
tablets: Extract get_new_replicas() which works on migraiton request
tablets: Move tablet_migration_info to tablets.hh
tablets: Store transition kind per tablet
Add `docs/dev/code-coverage.md` with explanations about how to work with
the different tools added for coverage reporting and cli options added
to `configure.py` and `test.py`
Signed-off-by: Eliran Sinvani <eliransin@scylladb.com>
Tablets metadata is quite expensive to generate (each data_value is
an allocation), so an old driver (without support for tablets) will
generate huge amounts of such notifications. This commit adds a way
to negotiate generation of the notification: a new driver will ask
for them, and an old driver won't get them. It uses the
OPTIONS/SUPPORTED/STARTUP protocol described in native_protocol_v4.spec.
Closesscylladb/scylladb#16611
Previously, the tablet information was sent to the drivers
in two pieces within the custom_payload. We had information
about the replicas under the `tablet_replicas` key and token range
information under `token_range`. These names were quite generic
and might have caused problems for other custom_payload users.
Additionally, dividing the information into two pieces raised
the question of what to do if one key is present while the other
is missing.
This commit changes the serialization mechanism to pack all information
under one specific name, `tablets-routing-v1`.
From: Sylwia Szunejko <sylwia.szunejko@scylladb.com>
Closesscylladb/scylladb#16148
When performing a schema change through group 0, extend the schema mutations with a version that's persisted and then used by the nodes in the cluster in place of the old schema digest, which becomes horribly slow as we perform more and more schema changes (#7620).
If the change is a table create or alter, also extend the mutations with a version for this table to be used for `schema::version()`s instead of having each node calculate a hash which is susceptible to bugs (#13957).
When performing a schema change in Raft RECOVERY mode we also extend schema mutations which forces nodes to revert to the old way of calculating schema versions when necessary.
We can only introduce these extensions if all of the cluster understands them, so protect this code by a new cluster/schema feature, `GROUP0_SCHEMA_VERSIONING`.
Fixes: #7620Fixes: #13957
---
This is a reincarnation of PR scylladb/scylladb#15331. The previous PR was reverted due to a bug it unmasked; the bug has now been fixed (scylladb/scylladb#16139). Some refactors from the previous PR were already merged separately, so this one is a bit smaller.
I have checked with @Lorak-mmk's reproducer (https://github.com/Lorak-mmk/udt_schema_change_reproducer -- many thanks for it!) that the originally exposed bug is no longer reproducing on this PR, and that it can still be reproduced if I revert the aforementioned fix on top of this PR.
Closesscylladb/scylladb#16242
* github.com:scylladb/scylladb:
docs: describe group 0 schema versioning in raft docs
test: add test for group 0 schema versioning
feature_service: enable `GROUP0_SCHEMA_VERSIONING` in Raft mode
schema_tables: don't delete `version` cell from `scylla_tables` mutations from group 0
migration_manager: add `committed_by_group0` flag to `system.scylla_tables` mutations
schema_tables: use schema version from group 0 if present
migration_manager: store `group0_schema_version` in `scylla_local` during schema changes
system_keyspace: make `get/set_scylla_local_param` public
feature_service: add `GROUP0_SCHEMA_VERSIONING` feature
Tablet streaming involves asynchronous RPCs to other replicas which transfer writes. We want side-effects from streaming only within the migration stage in which the streaming was started. This is currently not guaranteed on failure. When streaming master fails (e.g. due to RPC failing), it can be that some streaming work is still alive somewhere (e.g. RPC on wire) and will have side-effects at some point later.
This PR implements tracking of all operations involved in streaming which may have side-effects, which allows the topology change coordinator to fence them and wait for them to complete if they were already admitted.
The tracking and fencing is implemented by using global "sessions", created for streaming of a single tablet. Session is globally identified by UUID. The identifier is assigned by the topology change coordinator, and stored in system.tablets. Sessions are created and closed based on group0 state (tablet metadata) by the barrier command sent to each replica, which we already do on transitions between stages. Also, each barrier waits for sessions which have been closed to be drained.
The barrier is blocked only if there is some session with work which was left behind by unsuccessful streaming. In which case it should not be blocked for long, because streaming process checks often if the guard was left behind and stops if it was.
This mechanism of tracking is fault-tolerant: session id is stored in group0, so coordinator can make progress on failover. The barriers guarantee that session exists on all replicas, and that it will be closed on all replicas.
Closesscylladb/scylladb#15847
* github.com:scylladb/scylladb:
test: tablets: Add test for failed streaming being fenced away
error_injection: Introduce poll_for_message()
error_injection: Make is_enabled() public
api: Add API to kill connection to a particular host
range_streamer: Do not block topology change barriers around streaming
range_streamer, tablets: Do not keep token metadata around streaming
tablets: Fail gracefully when migrating tablet has no pending replica
storage_service, api: Add API to disable tablet balancing
storage_service, api: Add API to migrate a tablet
storage_service, raft topology: Run streaming under session topology guard
storage_service, tablets: Use session to guard tablet streaming
tablets: Add per-tablet session id field to tablet metadata
service: range_streamer: Propagate topology_guard to receivers
streaming: Always close the rpc::sink
storage_service: Introduce concept of a topology_guard
storage_service: Introduce session concept
tablets: Fix topology_metadata_guard holding on to the old erm
docs: Document the topology_guard mechanism
Prototype implementation of format suggested/requested by @avikivity:
Divides segments into disk-write-alignment sized pages, each tagged with segment ID + CRC of data content.
When read, we both verify sector integrity (CRC) to detect corruption, as well as matching ID read with expected one.
If the latter mismatches we have a prematurely terminated segment (read truncation), which, depending on whether the CL is
written in batch or periodic mode, as well as explicit sync, can mean data loss.
Note: all-zero pages are treated as kosher, both to align with newly allocated segments, as well as fully terminated (zero-page) ones.
Note: This is a preview/RFC - the rest of the file format is not modified. At least parts of entry CRC could probably be removed, but I have not done so yet (needs some thinking).
Note: Some slight abstraction breaks in impl. and probably less than maximal efficiency.
v2:
* Removed entry CRC:s in file format.
* Added docs on format v3
* Added one more test for recycling-truncation
v3:
* Fixed typos in size calc and docs
* Changed sect metadata order
* Explicit iter type
Closesscylladb/scylladb#15494
* github.com:scylladb/scylladb:
commitlog_test: Add test for replaying large-ish mutation
commitlog_test: Add additional test for segmnent truncation
docs: Add docs on commitlog format 3
commitlog: Remove entry CRC from file format
commitlog: Implement new format using CRC:ed sectors
commitlog: Add iterator adaptor for doing buffer splitting into sub-page ranges
fragmented_temporary_buffer: Add const iterator access to underlying buffers
commitlog_replayer: differentiate between truncated file and corrupt entries
This patch series adds error handling for streaming failure during
topology operations instead of an infinite retry. If streaming fails the
operation is rolled back: bootstrap/replace nodes move to left and
decommissioned/remove nodes move back to normal state.
* 'gleb/streaming-failure-rollback-v4' of github.com:scylladb/scylla-dev:
raft: make sure that all operation forwarded to a leader are completed before destroying raft server
storage_service: raft topology: remove code duplication from global_tablet_token_metadata_barrier
tests: add tests for streaming failure in bootstrap/replace/remove/decomission
test/pylib: do not stop node if decommission failed with an expected error
storage_service: raft topology: fix typo in "decommission" everywhere
storage_service: raft topology: add streaming error injection
storage_service: raft topology: do not increase topology version during CDC repair
storage_service: raft topology: rollback topology operation on streaming failure.
storage_service: raft topology: load request parameters in left_token_ring state as well
storage_service: raft topology: do not report term_changed_error during global_token_metadata_barrier as an error
storage_service: raft topology: change global_token_metadata_barrier error handling to try/catch
storage_service: raft topology: make global_token_metadata_barrier node independent
storage_service: raft topology: split get_excluded_nodes from exec_global_command
storage_service: raft topology: drop unused include_local and do_retake parameters from exec_global_command which are always true
storage_service: raft topology: simplify streaming RPC failure handling
