6fb37ae77f
Scylla implements `LWT` in the` storage_proxy::cas` method. This method expects to be called on a specific shard, represented by the `cas_shard` parameter. Clients must create this object before calling `storage_proxy::cas`, check its `this_shard()` method, and jump to `cas_shard.shard()` if it returns false. The nuance is that by the time the request reaches the destination shard, the tablet may have already advanced in its migration state machine. For example, a client may acquire a `cas_shard` at the `streaming` tablet state, then submit a request to another shard via `smp::submit_to(cas_shard.shard())`. However, the new `cas_shard` created on that other shard might already be in the `write_both_read_new` state, and its `cas_shard.shard()` would not be equal to `this_shard_id()`. Such broken invariant results in an `on_internal_error` in `storage_proxy::cas`. Clients of `storage_proxy::cas` are expected to check` cas_shard.this_shard()` and recursively jump to another shard if it returns false. Most calls to `storage_proxy::cas` already implement this logic. The only exception is `executor::do_batch_write`, which currently checks `cas_shard.this_shard()` only once. This can break the invariant if the tablet state changes more than once during the operation. This PR fixes the issue by implementing recursive `cas_shard.this_shard()` checks in `executor::do_batch_write`. It also adds a test that reproduces the problem. Fixes: scylladb/scylladb#27353 backport: need to be backported to 2025.4 - (cherry picked from commite60bcd0011) - (cherry picked from commit74bf24a4a7) - (cherry picked from commit9bef142328) - (cherry picked from commitc6eec4eeef) - (cherry picked from commit3a865fe991) - (cherry picked from commit0bcc2977bb) - (cherry picked from commit608eee0357) Parent PR: #27396 Closes scylladb/scylladb#27529 * github.com:scylladb/scylladb: alternator/executor.cc: eliminate redundant dk copy alternator/executor.cc: release cas_shard on the original shard alternator/executor.cc: move shard check into cas_write alternator/executor.cc: make cas_write a private method alternator/executor.cc: make do_batch_write a private method alternator/executor.cc: fix indent test_alternator: add test_alternator_invalid_shard_for_lwt alternator/executor.cc: avoid cross-shard free
Scylla in-source tests.
For details on how to run the tests, see docs/dev/testing.md
Shared C++ utils, libraries are in lib/, for Python - pylib/
alternator - Python tests which connect to a single server and use the DynamoDB API unit, boost, raft - unit tests in C++ cqlpy - Python tests which connect to a single server and use CQL topology* - tests that set up clusters and add/remove nodes cql - approval tests that use CQL and pre-recorded output rest_api - tests for Scylla REST API Port 9000 scylla-gdb - tests for scylla-gdb.py helper script nodetool - tests for C++ implementation of nodetool
If you can use an existing folder, consider adding your test to it. New folders should be used for new large categories/subsystems, or when the test environment is significantly different from some existing suite, e.g. you plan to start scylladb with different configuration, and you intend to add many tests and would like them to reuse an existing Scylla cluster (clusters can be reused for tests within the same folder).
To add a new folder, create a new directory, and then
copy & edit its suite.ini.