4d9271df98
This is yet another part in the BTI index project. Overarching issue: https://github.com/scylladb/scylladb/issues/19191 Previous part: https://github.com/scylladb/scylladb/pull/25626 Next parts: make `ms` the default. Then, general tweaks and improvements. Later, potentially a full `da` format implementation. This patch series introduces a new, Scylla-only sstable format version `ms`, which is like `me`, but with the index components (Summary.db and Index.db) replaced with BTI index components (Partitions.db and Rows.db), as they are in Cassandra 5.0's `da` format version. (Eventually we want to just implement `da`, but there are several other changes (unrelated to the index files) between `me` and `da`. By adding this `ms` as an intermediate step we can adapt the new index formats without dragging all the other changes into the mix (and raising the risk of regressions, which is already high)). The high-level structure of the PR is: 1. Introduce new component types — `Partitions` and `Rows`. 2. Teach `class sstable` to open them when they exist. 3. Teach the sstable writer how to write index data to them. 4. Teach `class sstable` and unit tests how to deal with sstables that have no `Index` or `Summary` (but have `Partitions` and `Rows` instead). 5. Introduce the new sstable version `ms`, specify that it has `Partitions` and `Rows` instead of `Index` and `Summary`. 6. Prepare unit tests for the appearance of `ms`. 7. Enable `ms` in unit tests. 8. Make `ms` enablable via db::config (with a silent fall back to `me` until the new `MS_SSTABLE_FORMAT` cluster feature is enabled). 9. Prepare integration tests for the appearance of `ms`. 10. Enable both `ms` and `me` in tests where we want both versions to be tested. This series doesn't make `ms` the default yet, because that requires teaching Scylla Manager and a few dtests about the new format first. It can be enabled by setting `sstable_format: ms` in the config. Per a review request, here is an example from `perf_fast_forward`, demonstrating some motivation for a new format. (Although not the main one. The main motivations are getting rid of restrictions on the RAM:disk ratio, and index read throughput for datasets with tiny partitions). The dataset was populated with `build/release/scylla perf-fast-forward --smp=1 --sstable-format=$VERSION --data-directory=data.$VERSION --column-index-size-in-kb=1 --populate --random-seed=0`. This test involves a partition with 1000000 clustering rows (with 32-bit keys and 100-byte values) and ~500 index blocks, and queries a few particular rows from the partition. Since the branching factor for the BIG promoted index is 2 (it's a binary search), the lookup involves ~11.2 sequential page reads per row. The BTI format has a more reasonable branching factor, so it involves ~2.3 page reads per row. `build/release/scylla perf-fast-forward --smp=1 --data-directory=perf_fast_forward_data/me --run-tests=large-partition-select-few-rows`: ``` offset stride rows iterations avg aio aio (KiB) 500000 1 1 70 18.0 18 128 500001 1 1 647 19.0 19 132 0 1000000 1 748 15.0 15 116 0 500000 2 372 29.0 29 284 0 250000 4 227 56.0 56 504 0 125000 8 116 106.0 106 928 0 62500 16 67 195.0 195 1732 ``` `build/release/scylla perf-fast-forward --smp=1 --data-directory=perf_fast_forward_data/ms --run-tests=large-partition-select-few-rows`: ``` offset stride rows iterations avg aio aio (KiB) 500000 1 1 51 5.1 5 20 500001 1 1 64 5.3 5 20 0 1000000 1 679 4.0 4 16 0 500000 2 492 8.0 8 88 0 250000 4 804 16.0 16 232 0 125000 8 409 31.0 31 516 0 62500 16 97 54.0 54 1056 ``` Index file size comparison for the default `perf_fast_forward` tables with `--random-seed=0`: Large partition table (dominated by intra-partition index): 2.4 MB with `me`, 732 kB with `ms`. For the small partitions table (dominated by inter-partition index): 11 MB with `me`, 8.4 MB with `ms`. External tests: I ran SCT test `longevity-mv-si-4days-streaming-test` test on 6 nodes with 30 shards each for 8 hours. No anomalies were observed. New functionality, no backport needed. Closes scylladb/scylladb#26215 * github.com:scylladb/scylladb: test/boost/bloom_filter_test: add test_rebuild_from_temporary_hashes test/cluster: add test_bti_index.py test: prepare bypass_cache_test.py for `ms` sstables sstables/trie/bti_index_reader: add a failure injection in advance_lower_and_check_if_present test/cqlpy/test_sstable_validation.py: prepare the test for `ms` sstables tools/scylla-sstable: add `--sstable-version=?` to `scylla sstable write` db/config: expose "ms" format to the users via database config test: in Python tests, prepare some sstable filename regexes for `ms` sstables: add `ms` to `all_sstable_versions` test/boost/sstable_3_x_test: add `ms` sstables to multi-version tests test/lib/index_reader_assertions: skip some row index checks for BTI indexes test/boost/sstable_inexact_index_test: explicitly use a `me` sstable test/boost/sstable_datafile_test: skip test_broken_promoted_index_is_skipped for `ms` sstables test/resource: add `ms` sample sstable files for relevant tests test/boost/sstable_compaction_test: prepare for `ms` sstables. test/boost/index_reader_test: prepare for `ms` sstables test/boost/bloom_filter_tests: prepare for `ms` sstables test/boost/sstable_datafile_test: prepare for `ms` sstables test/boost/sstable_test: prepare for `ms` sstables. sstables: introduce `ms` sstable format version tools/scylla-sstable: default to "preferred" sstable version, not "highest" sstables/mx/reader: use the same hashed_key for the bloom filter and the index reader sstables/trie/bti_index_reader: allow the caller to passing a precalculated murmur hash sstables/trie/bti_partition_index_writer: in add(), get the key hash from the caller sstables/mx: make Index and Summary components optional sstables: open Partitions.db early when it's needed to populate key range for sharding metadata sstables: adapt sstable::set_first_and_last_keys to sstables without Summary sstables: implement an alternative way to rebuild bloom filters for sstables without Index utils/bloom_filter: add `add(const hashed_key&)` sstables: adapt estimated_keys_for_range to sstables without Summary sstables: make `sstable::estimated_keys_for_range` asynchronous sstables/sstable: compute get_estimated_key_count() from Statistics instead of Summary replica/database: add table::estimated_partitions_in_range() sstables/mx: implement sstable::has_partition_key using a regular read sstables: use BTI index for queries, when present and enabled sstables/mx/writer: populate BTI index files sstables: create and open BTI index files, when enabled sstables: introduce Partition and Rows component types sstables/mx/writer: make `_pi_write_m.partition_tombstone` a `sstables::deletion_time`
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:
-
Some simple tests that check stand-alone C++ functions or classes use Boost's
BOOST_AUTO_TEST_CASE. -
Some tests require Seastar features, and need to be declared with Seastar's extensions to Boost.Test, namely
SEASTAR_TEST_CASE. -
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()ordo_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.