Files
scylladb/test/boost
Avi Kivity ca80ee8586 Merge 'Introduce maintenance scheduling supergroup and do initial population' from Pavel Emelyanov
The supergroup replaces streaming (a.k.a. maintenance as well) group, inherits 200 shares from it and consists of four sub-groups (all have equal shares of 200 withing the new supergroup)

* maintenance_compaction. This group configures `compaction_manager::maintenance_sg()` group. User-triggered compaction runs in it
* backup. This group configures `snapshot_ctl::config::backup_sched_group`. Native backup activity runs there
* maintenance. It's a new "visible" name, everything that was called "maintenance" in the code ran in "streaming" group. Now it will run in "maintenance". The activities include those that don't communicate over RPC (see below why)
  * `tablet_allocator::balance_tablets()`
  * `sstables_manager::components_reclaim_reload_fiber()`
  * `tablet_storage_group_manager::merge_completion_fiber()`
  * metrics exporting http server altogether
* streaming. This is purely existing streaming group that just moves under the new supergroup. Everything else that was run there, continues doing so, including
  * hints sender
  * all view building related components (update generator, builder, workers)
  * repair
  * stream_manager
  * messaging service (except for verb handlers that switch groups)
  * join_cluster() activity
  * REST API
  * ... something else I forgot

The `--maintenance_io_throughput_mb_per_sec` option is introduced. It controls the IO throughput limit applied to the maintenance supergroup. If not set, the `--stream_io_throughput_mb_per_sec` option is used to preserve backward compatibility.

All new sched groups inherit `request_class::maintenance` (however, "backup" seem not to make any requests yet).

Moving more activities from "streaming" into "maintenance" (or its own group) is possible, but one will need to take care of RPC group switching. The thing is that when a client makes an RPC call, the server may switch to one of pre-negotiated scheduling groups. Verbs for existing activities that run in "streaming" group are routed through RPC index that negotiates "streaming" group on the server side. If any of that client code moves to some other group, server will still run the handlers in "streaming" which is not quite expected. That's one of the main reasons why only the selected fibers were moved to their own "maintenance" group. Similar for backup -- this code doesn't use RPC, so it can be moved. Restoring code uses load-and-stream and corresponding RPCs, so it cannot be just moved into its own new group.

Fixes SCYLLADB-351

New feature, not backporting

Closes scylladb/scylladb#28542

* github.com:scylladb/scylladb:
  code: Add maintenance/maintenance group
  backup: Add maintenance/backup group
  compaction: Add maintenance/maintenance_compaction group
  main: Introduce maintenance supergroup
  main: Move all maintenance sched group into streaming one
  database: Use local variable for current_scheduling_group
  code: Live-update IO throughputs from main
2026-04-12 00:34:48 +03:00
..
2026-04-05 18:28:23 +03:00

Scylla unit tests using C++ and the Boost test framework

The source files in this directory are Scylla unit tests written in C++ using the Boost.Test framework. These unit tests come in three flavors:

  1. Some simple tests that check stand-alone C++ functions or classes use Boost's BOOST_AUTO_TEST_CASE.

  2. Some tests require Seastar features, and need to be declared with Seastar's extensions to Boost.Test, namely SEASTAR_TEST_CASE.

  3. Even more elaborate tests require not just a functioning Seastar environment but also a complete (or partial) Scylla environment. Those tests use the do_with_cql_env() or do_with_cql_env_thread() function to set up a mostly-functioning environment behaving like a single-node Scylla, in which the test can run.

While we have many tests of the third flavor, writing new tests of this type should be reserved to white box tests - tests where it is necessary to inspect or control Scylla internals that do not have user-facing APIs such as CQL. In contrast, black-box tests - tests that can be written only using user-facing APIs, should be written in one of newer test frameworks that we offer - such as test/cqlpy or test/alternator (in Python, using the CQL or DynamoDB APIs respectively) or test/cql (using textual CQL commands), or - if more than one Scylla node is needed for a test - using the test/topology* framework.

Running tests

Because these are C++ tests, they need to be compiled before running. To compile a single test executable row_cache_test, use a command like

ninja build/dev/test/boost/row_cache_test

You can also use ninja dev-test to build all C++ tests, or use ninja deb-build to build the C++ tests and also the full Scylla executable (however, note that full Scylla executable isn't needed to run Boost tests).

Replace "dev" by "debug" or "release" in the examples above and below to use the "debug" build mode (which, importantly, compiles the test with ASAN and UBSAN enabling on and helps catch difficult-to-catch use-after-free bugs) or the "release" build mode (optimized for run speed).

To run an entire test file row_cache_test, including all its test functions, use a command like:

build/dev/test/boost/row_cache_test -- -c1 -m1G 

to run a single test function test_reproduce_18045() from the longer test file, use a command like:

build/dev/test/boost/row_cache_test -t test_reproduce_18045 -- -c1 -m1G 

In these command lines, the parameters before the -- are passed to Boost.Test, while the parameters after the -- are passed to the test code, and in particular to Seastar. In this example Seastar is asked to run on one CPU (-c1) and use 1G of memory (-m1G) instead of hogging the entire machine. The Boost.Test option -t test_reproduce_18045 asks it to run just this one test function instead of all the test functions in the executable.

Unfortunately, interrupting a running test with control-C while doesn't work. This is a known bug (#5696). Kill a test with SIGKILL (-9) if you need to kill it while it's running.

Boost tests can also be run using test.py - which is a script that provides a uniform way to run all tests in scylladb.git - C++ tests, Python tests, etc.

Execution with pytest

To run all tests with pytest execute

pytest test/boost

To execute all tests in one file, provide the path to the source filename as a parameter

pytest test/boost/aggregate_fcts_test.cc

Since it's a normal path, autocompletion works in the terminal out of the box.

To execute only one test function, provide the path to the source file and function name

pytest --mode dev test/boost/aggregate_fcts_test.cc::test_aggregate_avg

To provide a specific mode, use the next parameter --mode dev, if parameter isn't provided pytest tries to use ninja mode_list to find out the compiled modes.

Parallel execution is controlled by pytest-xdist and the parameter -n auto. This command starts tests with the number of workers equal to CPU cores. The useful command to discover the tests in the file or directory is

pytest --collect-only -q --mode dev test/boost/aggregate_fcts_test.cc

That will return all test functions in the file. To execute only one function from the test, you can invoke the output from the previous command. However, suffix for mode should be skipped. For example, output shows in the terminal something like this test/boost/aggregate_fcts_test.cc::test_aggregate_avg.dev. So to execute this specific test function, please use the next command

pytest --mode dev test/boost/aggregate_fcts_test.cc::test_aggregate_avg

Writing tests

Because of the large build time and build size of each separate test executable, it is recommended to put test functions into relatively large source files. But not too large - to keep compilation time of a single source file (during development) at reasonable levels.

When adding new source files in test/boost, don't forget to list the new source file in configure.py and also in CMakeLists.txt. The former is needed by our CI, but the latter is preferred by some developers.