We change the type of the `recovery_leader` config parameter and
`gossip_config::recovery_leader` from sstring to UUID. `recovery_leader`
is supposed to store host ID, so UUID is a natural choice.
After changing the type to UUID, if the user provides an incorrect UUID,
parsing `recovery_leader` will fail early, but the start-up will
continue. Outside the recovery procedure, `recovery_leader` will then be
ignored. In the recovery procedure, the start-up will fail on:
```
throw std::runtime_error(
"Cannot start - Raft-based topology has been enabled but persistent group 0 ID is not present. "
"If you are trying to run the Raft-based recovery procedure, you must set recovery_leader.");
```
(cherry picked from commit 445a15ff45)
The PyKMIP server uses an SQLite database to store artifacts such as
encryption keys. By default, SQLite performs a full journal and data
flush to disk on every CREATE TABLE operation. Each operation triggers
three fdatasync(2) calls. If we multiply this by 16, that is the number
of tables created by the server, we get a significant number of file
syncs, which can last for several seconds on slow machines.
This behavior has led to CI stability issues from KMIP unit tests where
the server failed to complete its schema creation within the 20-second
timeout (observed on spider9 and spider11).
Fix this by configuring the server to use an in-memory SQLite.
Fixes#24842.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Closesscylladb/scylladb#24995
(cherry picked from commit 2656fca504)
Closesscylladb/scylladb#25300
Right now, service levels are migrated in one group0 command and auth is migrated in the next one. This has a bad effect on the group0 state reload logic - modifying service levels in group0 causes the effective service levels cache to be recalculated, and to do so we need to fetch information about all roles. If the reload happens after SL upgrade and before auth upgrade, the query for roles will be directed to the legacy auth tables in system_auth - and the query, being a potentially remote query, has a timeout. If the query times out, it will throw an exception which will break the group0 apply fiber and the node will need to be restarted to bring it back to work.
In order to solve this issue, make sure that the service level module does not start populating and using the service level cache until both service levels and auth are migrated to raft. This is achieved by adding the check both to the cache population logic and the effective service level getter - they now look at service level's accessor new method, `can_use_effective_service_level_cache` which takes a look at the auth version.
Fixes: scylladb/scylladb#24963
Should be backported to all versions which support upgrade to topology over raft - the issue described here may put the cluster into a state which is difficult to get out of (group0 apply fiber can break on multiple nodes, which necessitates their restart).
- (cherry picked from commit 2bb800c004)
- (cherry picked from commit 3a082d314c)
Parent PR: #25188Closesscylladb/scylladb#25285
* github.com:scylladb/scylladb:
test: sl: verify that legacy auth is not queried in sl to raft upgrade
qos: don't populate effective service level cache until auth is migrated to raft
Adjust `test_service_levels_upgrade`: right before upgrade to topology
on raft, enable an error injection which triggers when the standard role
manager is about to query the legacy auth tables in the
system_auth keyspace. The preceding commit which fixes
scylladb/scylladb#24963 makes sure that the legacy tables are not
queried during upgrade to topology on raft, so the error injection does
not trigger and does not cause a problem; without that commit, the test
fails.
(cherry picked from commit 3a082d314c)
Right now, service levels are migrated in one group0 command and auth
is migrated in the next one. This has a bad effect on the group0 state
reload logic - modifying service levels in group0 causes the effective
service levels cache to be recalculated, and to do so we need to fetch
information about all roles. If the reload happens after SL upgrade and
before auth upgrade, the query for roles will be directed to the legacy
auth tables in system_auth - and the query, being a potentially remote
query, has a timeout. If the query times out, it will throw
an exception which will break the group0 apply fiber and the node will
need to be restarted to bring it back to work.
In order to solve this issue, make sure that the service level module
does not start populating and using the service level cache until both
service levels and auth are migrated to raft. This is achieved by adding
the check both to the cache population logic and the effective service
level getter - they now look at service level's accessor new method,
`can_use_effective_service_level_cache` which takes a look at the auth
version.
Fixes: scylladb/scylladb#24963
(cherry picked from commit 2bb800c004)
This PR adds the upgrade guide from version 2025.2 to 2025.3.
Also, it removes the upgrade guide existing for the previous version
that is irrelevant in 2025.2 (upgrade from 2025.1 to 2025.2).
Note that the new guide does not include the "Enable Consistent Topology Updates" page and note,
as users upgrading to 2025.3 have consistent topology updates already enabled.
Fixes https://github.com/scylladb/scylladb/issues/24696Closesscylladb/scylladb#25219
(cherry picked from commit 8365219d40)
Closesscylladb/scylladb#25248
This commit:
- Extends the Drivers support table with information on which driver supports tablets
and since which version.
- Adds the driver support policy to the Drivers page.
- Reorganizes the Drivers page to accommodate the updates.
In addition:
- The CPP-over-Rust driver is added to the table.
- The information about Serverless (which we don't support) is removed
and replaced with tablets to correctly describe the contents of the table.
Fixes https://github.com/scylladb/scylladb/issues/19471
Refs https://github.com/scylladb/scylladb-docs-homepage/issues/69Closesscylladb/scylladb#24635
(cherry picked from commit 18b4d4a77c)
Closesscylladb/scylladb#25251
This PR reverts the changes of #24418 since they can cause use-after-free.
The `raft_group0::abort()` was called in `storage_service::do_drain` (introduced in #24418) to stop the group0 Raft server before destroying local storage. This was necessary because `raft::server` depends on storage (via `raft_sys_table_storage` and `group0_state_machine`).
However, this caused issues: services like `sstable_dict_autotrainer` and `auth::service`, which use `group0_client` but are not stopped by `storage_service`, could trigger use-after-free if `raft_group0` was destroyed too early. This can happen both during normal shutdown and when 'nodetool drain' is used.
This PR reverts two of the three commits from #24418. The commit [e456d2d](e456d2d507) is not reverted because it only affects logging and does not impact correctness.
Fixesscylladb/scylladb#25221
Backport: this PR is a backport
Closesscylladb/scylladb#25206
* https://github.com/scylladb/scylladb:
Revert "main.cc: fix group0 shutdown order"
Revert "storage_service: test_group0_apply_while_node_is_being_shutdown"
Enhance and fix error handling in the `chunked_download_source` to prevent errors seeping from the request callback. Also stop retrying on seastar's side since it is going to break the integrity of data which maybe downloaded more than once for the same range.
Fixes: https://github.com/scylladb/scylladb/issues/25043
Should be backported to 2025.3 since we have an intention to release native backup/restore feature
- (cherry picked from commit d53095d72f)
- (cherry picked from commit b7ae6507cd)
- (cherry picked from commit ba910b29ce)
- (cherry picked from commit fc2c9dd290)
Parent PR: #24883Closesscylladb/scylladb#25137
* github.com:scylladb/scylladb:
s3_client: Disable Seastar-level retries in HTTP client creation
s3_test: Validate handling of non-`aws_error` exceptions
s3_client: Improve error handling in chunked_download_source
aws_error: Add factory method for `aws_error` from exception
When a node shuts down, in storage service, after storage_proxy RPCs are stopped, some write handlers within storage_proxy may still be waiting for background writes to complete. These handlers hold appropriate ERMs to block schema changes before the write finishes. After the RPCs are stopped, these writes cannot receive the replies anymore.
If, at the same time, there are RPC commands executing `barrier_and_drain`, they may get stuck waiting for these ERM holders to finish, potentially blocking node shutdown until the writes time out.
This change introduces cancellation of all outstanding write handlers from storage_service after the storage proxy RPCs were stopped.
Fixes scylladb/scylladb#23665
Backport: since this fixes an issue that frequently causes issues in CI, backport to 2025.1, 2025.2, and 2025.3.
- (cherry picked from commit bc934827bc)
- (cherry picked from commit e0dc73f52a)
Parent PR: #24714Closesscylladb/scylladb#25170
* github.com:scylladb/scylladb:
storage_service: Cancel all write requests on storage_proxy shutdown
test: Add test for unfinished writes during shutdown and topology change
Currently, progress of a parent task depends on expected_total_workload,
expected_children_number, and children progresses. Basically, if total
workload is known or all children have already been created, progresses
of children are summed up. Otherwise binary progress is returned.
As a result, two tasks of the same type may return progress in different
units. If they are children of the same task and this parent gathers the
progress - it becomes meaningless.
Drop expected_children_number as we can't assume that children are able
to show their progresses.
Modify get_progress method - progress is calculated based on children
progresses. If expected_total_workload isn't specified, the total
progress of a task may grow. If expected_total_workload isn't specified
and no children are created, empty progress (0/0) is returned.
Fixes: https://github.com/scylladb/scylladb/issues/24650.
Closesscylladb/scylladb#25113
(cherry picked from commit a7ee2bbbd8)
Closesscylladb/scylladb#25200
This series fixes one cause of oversized allocations - and therefore potentially stalls and increased tail latencies - in Alternator.
The first patch in the series is the main fix - the later patches are cleanups requested by reviewers but also involved other pre-existing code, so I did those cleanups as separate patches.
Alternator's Scan or Query operation return a page of results. When the number of items is not limited by a "Limit" parameter, the default is to return a 1 MB page. If items are short, a large number of them can fit in that 1MB. The test test_query.py::test_query_large_page_small_rows has 30,000 items returned in a single page.
In the response JSON, all these items are returned in a single array "Items". Before this patch, we build the full response as a RapidJSON object before sending it. The problem is that unfortunately, RapidJSON stores arrays as contiguous allocations. This results in large contiguous allocations in workloads that scan many small items, and large contiguous allocations can also cause stalls and high tail latencies. For example, before this patch, running
test/alternator/run --runveryslow \
test_query.py::test_query_large_page_small_rows
reports in the log:
oversized allocation: 573440 bytes.
After this patch, this warning no longer appears.
The patch solves the problem by collecting the scanned items not in a RapidJSON array, but rather in a chunked_vector<rjson::value>, i.e, a chunked (non-contiguous) array of items (each a JSON value). After collecting this array separately from the response object, we need to print its content without actually inserting it into the object - we add a new function print_with_extra_array() to do that.
The new separate-chunked-vector technique is used when a large number (currently, >256) of items were scanned. When there is a smaller number of items in a page (this is typical when each item is longer), we just insert those items in the object and print it as before.
Beyond the original slow test that demonstrated the oversized allocation (which is now gone), this patch also includes a new test which exercises the new code with a scan of 700 (>256) items in a page - but this new test is fast enough to be permanently in our test suite and not a manual "veryslow" test as the other test.
Fixes#23535
The stalls caused by large allocations was seen by actual users, so it makes sense to backport this patch. On the other hand, the patch while not big is fairly intrusive (modifies the nomal Scan and Query path and also the later patches do some cleanup of additional code) so there is some small risk involved in the backport.
- (cherry picked from commit 2385fba4b6)
- (cherry picked from commit d8fab2a01a)
- (cherry picked from commit 13ec94107a)
- (cherry picked from commit a248336e66)
Parent PR: #24480Closesscylladb/scylladb#25194
* github.com:scylladb/scylladb:
alternator: clean up by co-routinizing
alternator: avoid spamming the log when failing to write response
alternator: clean up and simplify request_return_type
alternator: avoid oversized allocation in Query/Scan
Reviewers of the previous patch complained on some ugly pre-existing
code in alternator/executor.cc, where returning from an asynchronous
(future) function require lengthy verbose casts. So this patch cleans
up a few instances of these ugly casts by using co_return instead of
return.
For example, the long and verbose
return make_ready_future<executor::request_return_type>(
rjson::print(std::move(response)));
can be changed to the shorter and more readable
co_return rjson::print(std::move(response));
This patch should not have any functional implications, and also not any
performance implications: I only coroutinized slow-path functions and
one function that was already "partially" coroutinized (and this was
expecially ugly and deserved being fixed).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
(cherry picked from commit a248336e66)
Both make_streamed() and new make_streamed_with_extra_array() functions,
used when returning a long response in Alternator, would write an error-
level log message if it failed to write the response. This log message
is probably not helpful, and may spam the log if the application causes
repeated errors intentionally or accidentally.
So drop these log messages. The exception is still thrown as usual.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
(cherry picked from commit 13ec94107a)
The previous patch introduced a function make_streamed_with_extra_array
which was a duplicate of the existing make_streamed. Reviewers
complained how baroque the new function is (just like the old function),
having to jump through hoops to return a copyable function working
on non-copyable objects, making strange-named copies and shared pointers
of everything.
We needed to return a copyable function (std::function) just because
Alternator used Seastar's json::json_return_type in the return type
from executor function (request_return_type). This json_return_type
contained either a sstring or an std::function, but neither was ever
really appropriate:
1. We want to return noncopyable_function, not an std::function!
2. We want to return an std::string (which rjson::print()) returns,
not an sstring!
So in this patch we stop using seastar::json::json_return_type
entirely in Alternator.
Alternator's request_return_type is now an std::variant of *three* types:
1. std::string for short responses,
2. noncopyable_function for long streamed response
3. api_error for errors.
The ugliest parts of make_streamed() where we made copies and shared
pointers to allow for a copyable function are all gone. Even nicer, a
lot of other ugly relics of using seastar::json_return_type are gone:
1. We no longer need obscure classes and functions like make_jsonable()
and json_string() to convert strings to response bodies - an operation
can simply return a string directly - usually returning
rjson::print(value) or a fixed string like "" and it just works.
2. There is no more usage of seastar::json in Alternator (except one
minor use of seastar::json::formatter::to_json in streams.cc that
can be removed later). Alternator uses RapidJSON for its JSON
needs, we don't need to use random pieces from a different JSON
library.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
(cherry picked from commit d8fab2a01a)
This patch fixes one cause of oversized allocations - and therefore
potentially stalls and increased tail latencies - in Alternator.
Alternator's Scan or Query operation return a page of results. When the
number of items is not limited by a "Limit" parameter, the default is
to return a 1 MB page. If items are short, a large number of them can
fit in that 1MB. The test test_query.py::test_query_large_page_small_rows
has 30,000 items returned in a single page.
In the response JSON, all these items are returned in a single array
"Items". Before this patch, we build the full response as a RapidJSON
object before sending it. The problem is that unfortunately, RapidJSON
stores arrays as contiguous allocations. This results in large
contiguous allocations in workloads that scan many small items, and
large contiguous allocations can also cause stalls and high tail
latencies. For example, before this patch, running
test/alternator/run --runveryslow \
test_query.py::test_query_large_page_small_rows
reports in the log:
oversized allocation: 573440 bytes.
After this patch, this warning no longer appears.
The patch solves the problem by collecting the scanned items not in a
RapidJSON array, but rather in a chunked_vector<rjson::value>, i.e,
a chunked (non-contiguous) array of items (each a JSON value).
After collecting this array separately from the response object, we
need to print its content without actually inserting it into the object -
we add a new function print_with_extra_array() to do that.
The new separate-chunked-vector technique is used when a large number
(currently, >256) of items were scanned. When there is a smaller number
of items in a page (this is typical when each item is longer), we just
insert those items in the object and print it as before.
Beyond the original slow test that demonstrated the oversized allocation
(which is now gone), this patch also includes a new test which
exercises the new code with a scan of 700 (>256) items in a page -
but this new test is fast enough to be permanently in our test suite
and not a manual "veryslow" test as the other test.
Fixes#23535
(cherry picked from commit 2385fba4b6)
Fixes#24574
* Ensure we close the embedded load_cache objects on encryption shutdown, otherwise we can, in unit testing, get destruction of these while a timer is still active -> assert
* Add extra exception handling to `network_error_test_helper`, so even if test framework might exception-escape, we properly stop the network proxy to avoid use after free.
- (cherry picked from commit ee98f5d361)
- (cherry picked from commit 8d37e5e24b)
Parent PR: #24633Closesscylladb/scylladb#24772
* github.com:scylladb/scylladb:
encryption_at_rest_test: Add exception handler to ensure proxy stop
encryption: Ensure stopping timers in provider cache objects
This issue happens with removenode, when RBNO is disabled, so range
streamer is used.
The deadlock happens in a scenario like this:
1. Start 3 nodes: {A, B, C}, RF=2
2. Node A is lost
3. removenode A
4. Both B and C gain ownership of ranges.
5. Streaming sessions are started with crossed directions: B->C, C->B
Readers created by sender side exhaust streaming semaphore on B and C.
Receiver side attempts to obtain a permit indirectly by calling
check_needs_view_update_path(), which reads local tables. That read is
blocked and times-out, causing streaming to fail. The streaming writer
is already using a tracking-only permit.
Even if we didn't deadlock, and the streaming semaphore was simply exhausted
by other receiving sessions (via tracking-only permit), the query may still time-out due to starvation.
To avoid that, run the query under a different scheduling group, which
translates to the system semaphore instead of the maintenance
semaphore, to break the dependency. The gossip group was chosen
because it shouldn't be contended and this change should not interfere
with it much.
Fixes#24807Fixes#24925
- (cherry picked from commit ee2fa58bd6)
- (cherry picked from commit dff2b01237)
Parent PR: #24929Closesscylladb/scylladb#25058
* github.com:scylladb/scylladb:
streaming: Avoid deadlock by running view checks in a separate scheduling group
service: migration_manager: Run group0 barrier in gossip scheduling group
During a graceful node shutdown, RPC listeners are stopped in `storage_service::drain_on_shutdown`
as one of the first steps. However, even after RPCs are shut down, some write handlers in
`storage_proxy` may still be waiting for background writes to complete. These handlers retain the ERM.
Since the RPC subsystem is no longer active, replies cannot be received, and if any RPC commands are
concurrently executing `barrier_and_drain`, they may get stuck waiting for those writes. This can block
the messaging server shutdown and delay the entire shutdown process until the write timeout occurs.
This change introduces the cancellation of all outstanding write handlers in `storage_proxy`
during shutdown to prevent unnecessary delays.
Fixesscylladb/scylladb#23665
(cherry picked from commit e0dc73f52a)
This test reproduces an issue where a topology change and an ongoing write query
during query coordinator shutdown can cause the node to get stuck.
When a node receives a write request, it creates a write handler that holds
a copy of the current table's ERM (Effective Replication Map). The ERM ensures
that no topology or schema changes occur while the request is being processed.
After the query coordinator receives the required number of replica write ACKs
to satisfy the consistency level (CL), it sends a reply to the client. However,
the write response handler remains alive until all replicas respond — the remaining
writes are handled in the background.
During shutdown, when all network connections are closed, these responses can no longer
be received. As a result, the write response handler is only destroyed once the write
timeout is reached.
This becomes problematic because the ERM held by the handler blocks topology or schema
change commands from executing. Since shutdown waits for these commands to complete,
this can lead to unnecessary delays in node shutdown and restarts, and occasional
test case failures.
Test for: scylladb/scylladb#23665
(cherry picked from commit bc934827bc)
Prevent Seastar from retrying HTTP requests to avoid buffer double-feed
issues when an entire request is retried. This could cause data
corruption in `chunked_download_source`. The change is global for every
instance of `s3_client`, but it is still safe because:
* Seastar's `http_client` resets connections regardless of retry behavior
* `s3_client` retry logic handles all error types—exceptions, HTTP errors,
and AWS-specific errors—via `http_retryable_client`
(cherry picked from commit fc2c9dd290)
Inject exceptions not wrapped in `aws_error` from request callback
lambda to verify they are properly caught and handled.
(cherry picked from commit ba910b29ce)
Create aws_error from raised exceptions when possible and respond
appropriately. Previously, non-aws_exception types leaked from the
request handler and were treated as non-retryable, causing potential
data corruption during download.
(cherry picked from commit b7ae6507cd)
Move `aws_error` creation logic out of `retryable_http_client` and
into the `aws_error` class to support reuse across components.
(cherry picked from commit d53095d72f)
Add `make_data_or_index_source` to the storages to utilize new S3 based data source which should improve restore performance
* Introduce the `encrypted_data_source` class that wraps an existing data source to read and decrypt data on the fly using block encryption. Also add unit tests to verify correct decryption behavior.
* Add `make_data_or_index_source` to the `storage` interface, implement it for `filesystem_storage` storage which just creates `data_source` from a file and for the `s3_storage` create a (maybe) decrypting source from s3 make_download_source. This change should solve performance improvement for reading large objects from S3 and should not affect anything for the `filesystem_storage`
Fixes: https://github.com/scylladb/scylladb/issues/22458
- (cherry picked from commit 211daeaa40)
- (cherry picked from commit 7e5e3c5569)
- (cherry picked from commit 0de61f56a2)
- (cherry picked from commit 8ac2978239)
- (cherry picked from commit dff9a229a7)
- (cherry picked from commit 8d49bb8af2)
Parent PR: #23695Closesscylladb/scylladb#25016
* github.com:scylladb/scylladb:
sstables: Start using `make_data_or_index_source` in `sstable`
sstables: refactor readers and sources to use coroutines
sstables: coroutinize futurized readers
sstables: add `make_data_or_index_source` to the `storage`
encryption: refactor key retrieval
encryption: add `encrypted_data_source` class
The set of columns of a CDC log table should be managed automatically
by Scylla, and the user should not have the ability to manipulate them
directly. That could lead to disastrous consequences such as a
segmentation fault.
In this commit, we're restricting those operations. We also provide two
validation tests.
One of the existing tests had to be adjusted as it modified the type
of a column in a CDC log table. Since the test simply verifies that
the user has sufficient permissions to perform `ALTER TABLE` on the log
table, the test is still valid.
Fixes scylladb/scylladb#24643
Backport: we should backport the change to all affected
branches to prevent the consequences that may affect the user.
- (cherry picked from commit 20d0050f4e)
- (cherry picked from commit 59800b1d66)
Parent PR: #25008Closesscylladb/scylladb#25108
* github.com:scylladb/scylladb:
cdc: Forbid altering columns of inactive CDC log table
cdc: Forbid altering columns of CDC log tables directly
When CDC becomes disabled on the base table, the CDC log table
still exsits (cf. scylladb/scylladb@adda43edc7).
If it continues to exist up to the point when CDC is re-enabled
on the base table, no new log table will be created -- instead,
the old olg table will be *re-attached*.
Since we want to avoid situations when the definition of the log
table has become misaligned with the definition of the base table
due to actions of the user, we forbid modifying the set of columns
or renaming them in CDC log tables, even when they're inactive.
Validation tests are provided.
(cherry picked from commit 59800b1d66)
The set of columns of a CDC log table should be managed automatically
by Scylla, and the user should not have the ability to manipulate them
directly. That could lead to disastrous consequences such as a
segmentation fault.
In this commit, we're restricting those operations. We also provide two
validation tests.
One of the existing tests had to be adjusted as it modified the type
of a column in a CDC log table. Since the test simply verifies that
the user has sufficient permissions to perform `ALTER TABLE` on the log
table, the test is still valid.
Fixesscylladb/scylladb#24643
(cherry picked from commit 20d0050f4e)
in the CDC log transformer, when creating a CDC mutation based on some
base table mutation, for each value of a base column we set the value in
the CDC column with the same name.
When looking up the column in the CDC schema by name, we may get a null
pointer if a column by that name is not found. This shouldn't happen
normally because the base schema and CDC schema should be compatible,
and for each base column there should be a CDC column with the same
name.
However, there are scenarios where the base schema and CDC schema are
incompatible for a short period of time when they are being altered.
When a base column is being added or dropped, we could get a base
mutation with this column set, and then the CDC transformer picks up the
latest CDC schema which doesn't have this column.
If such thing happens, we fix the code to throw an exception instead of
crashing on null pointer dereference. Currently we don't have a safer
approach to handle this, but this might be changed in the future. The
other alternative is dropping that data silently which we prefer not to
do.
Throwing an error is acceptable because this scenario most likely
indicates this behavior by the user:
* The user adds a new column, and start writing values to the column
before the ALTER is complete. or,
* The user drops a column, and continues writing values to the column
while it's being dropped.
Both cases might as well fail with an error because the column is not
found in the base table.
Fixes scylladb/scylladb#/24952
backport needed - simple fix for a node crash
- (cherry picked from commit b336f282ae)
- (cherry picked from commit 86dfa6324f)
Parent PR: #24986Closesscylladb/scylladb#25067
* github.com:scylladb/scylladb:
test: cdc: add test_cdc_with_alter
cdc: throw error if column doesn't exist
in the CDC log transformer, when creating a CDC mutation based on some
base table mutation, for each value of a base column we set the value in
the CDC column with the same name.
When looking up the column in the CDC schema by name, we may get a null
pointer if a column by that name is not found. This shouldn't happen
normally because the base schema and CDC schema should be compatible,
and for each base column there should be a CDC column with the same
name.
However, there are scenarios where the base schema and CDC schema are
incompatible for a short period of time when they are being altered.
When a base column is being added or dropped, we could get a base
mutation with this column set, and then the CDC transformer picks up the
latest CDC schema which doesn't have this column.
If such thing happens, we fix the code to throw an exception instead of
crashing on null pointer dereference. Currently we don't have a safer
approach to handle this, but this might be changed in the future. The
other alternative is dropping that data silently which we prefer not to
do.
Throwing an error is acceptable because this scenario most likely
indicates this behavior by the user:
* The user adds a new column, and start writing values to the column
before the ALTER is complete. or,
* The user drops a column, and continues writing values to the column
while it's being dropped.
Both cases might as well fail with an error because the column is not
found in the base table.
Fixesscylladb/scylladb#24952
(cherry picked from commit b336f282ae)
This issue happens with removenode, when RBNO is disabled, so range
streamer is used.
The deadlock happens in a scenario like this:
1. Start 3 nodes: {A, B, C}, RF=2
2. Node A is lost
3. removenode A
4. Both B and C gain ownership of ranges.
5. Streaming sessions are started with crossed directions: B->C, C->B
Readers created by sender side exhaust streaming semaphore on B and C.
Receiver side attempts to obtain a permit indirectly by calling
check_needs_view_update_path(), which reads local tables. That read is
blocked and times-out, causing streaming to fail. The streaming writer
is already using a tracking-only permit.
To avoid that, run the query under a different scheduling group, which
translates to the system semaphore instead of the maintenance
semaphore, to break the dependency. The gossip group was chosen
because it shouldn't be contended and this change should not interfere
with it much.
Fixes: #24807
(cherry picked from commit dff2b01237)
Fixes two issues.
One is potential priority inversion. The barrier will be executed
using scheduling group of the first fiber which triggers it, the rest
will block waiting on it. For example, CQL statements which need to
sync the schema on replica side can block on the barrier triggered by
streaming. That's undesirable. This is theoretical, not proved in the
field.
The second problem is blocking the error path. This barrier is called
from the streaming error handling path. If the streaming concurrency
semaphore is exhausted, and streaming fails due to timeout on
obtaining the permit in check_needs_view_update_path(), the error path
will block too because it will also attempt to obtain the permit as
part of the group0 barrier. Running it in the gossip scheduling group
prevents this.
Fixes#24925
(cherry picked from commit ee2fa58bd6)
The functions password_authenticator::start and
standard_role_manager::start have a similar structure: they spawn a
fiber which invokes a callback that performs some migration until that
migration succeeds. Both handlers set a shared promise called
_superuser_created_promise (those are actually two promises, one for the
password authenticator and the other for the role manager).
The handlers are similar in both cases. They check if auth is in legacy
mode, and behave differently depending on that. If in legacy mode, the
promise is set (if it was not set before), and some legacy migration
actions follow. In auth-on-raft mode, the superuser is attempted to be
created, and if it succeeds then the promise is _unconditionally_ set.
While it makes sense at a glance to set the promise unconditionally,
there is a non-obvious corner case during upgrade to topology on raft.
During the upgrade, auth switches from the legacy mode to auth on raft
mode. Thus, if the callback didn't succeed in legacy mode and then tries
to run in auth-on-raft mode and succeds, it will unconditionally set a
promise that was already set - this is a bug and triggers an assertion
in seastar.
Fix the issue by surrounding the `shared_promise::set_value` call with
an `if` - like it is already done for the legacy case.
Fixes: scylladb/scylladb#24975Closesscylladb/scylladb#24976
(cherry picked from commit a14b7f71fe)
Closesscylladb/scylladb#25019
