08c8e0d282
In the past we had issue #7933 where very long strings of consecutive
tombstones caused Alternator's paging to take an unbounded amount of
time and/or memory for a single page. This issue was fixed (by commit
e9cbc9ee85) but the two tests we had
reproducing that issue were left with the "xfail" mark.
They were also marked "veryslow" - each taking about 100 seconds - so
they didn't run by default so nobody noticed they started to pass.
In this patch I make these tests much faster (taking less than a second
together), confirm that they pass - and remove the "xfail" mark and
improve their descriptions.
The trick to making these tests faster is to not create a million
tombstones like we used to: We now know that after string of just 10,000
tombstones ('query_tombstone_page_limit') the page should end, so
we can check specifically this number. The story is more complicated for
partition tombstones, but there too it should be a multiple of
query_tombstone_page_limit. To make the tests even faster, we change
run.py to lower the query_tombstone_page_limit from the default 10,000
to 1000. The tests work correctly even without this change, but they are
ten times faster with it.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes #12350
Single-node functional tests for Scylla's CQL features.
These tests use the Python CQL library and the pytest frameworks. By using an actual CQL library for the tests, they can be run against any implementation of CQL - both Scylla and Cassandra. Most tests - except in rare cases - should pass on both, to ensure that Scylla is compatible with Cassandra in most features.
To run all tests against an already-running local installation of Scylla
or Cassandra on localhost, just run pytest. The "--host" and "--port"
can be used to give a different location for the running Scylla or Cassanra.
The "--ssl" option can be used to use an encrypted (TLSv1.2) connection.
More conveniently, we have two scripts - "run" and "run-cassandra" - which do all the work necessary to start Scylla or Cassandra (respectively), and run the tests on them. The Scylla or Cassandra process is run in a temporary directory which is automatically deleted when the test ends.
"run" automatically picks the most recently compiled version of Scylla in
build/*/scylla - but this choice of Scylla executable can be overridden with
the SCYLLA environment variable. "run-cassandra" defaults to running the
command cassandra from the user's path, but this can be overriden by setting
the CASSANDRA environment variable to the path of the cassandra script,
e.g., export CASSANDRA=$HOME/apache-cassandra-3.11.10/bin/cassandra.
A few of the tests also require the nodetool when running on Cassandra -
this tool is again expected to be in the user's path, or be overridden with
the NODETOOL environment variable. Nodetool is not needed to test
Scylla.
Additional options can be passed to "pytest" or to "run" / "run-cassandra" to control which tests to run:
- To run all tests in a single file, do
pytest test_table.py. - To run a single specific test, do
pytest test_table.py::test_create_table_unsupported_names. - To run the same test or tests 100 times, add the
--count=100option. This is faster than runningrun100 times, because Scylla is only run once, and also counts for you how many of the runs failed. Forpytestto support the--countoption, you need to install a pytest extension:pip install pytest-repeat
Additional useful pytest options, especially useful for debugging tests:
- -v: show the names of each individual test running instead of just dots.
- -s: show the full output of running tests (by default, pytest captures the test's output and only displays it if a test fails)