ScyllaMetrics is a useful generic component for retrieving metrics in a
pytest.
The commit moves the implementation from test_shedding.py to util.py to
make it reusable in other tests in cql-pytest.
There was a vague comment about CI using
larger limits for shedding. This turned out
to be false, and the real reason of different
limits is that Scylla handles the -m
command line option differently in
debug and release builds.
Debug builds use the default memory allocator
and the value of -m Scylla option
is given to each shard. In release builds
memory is evenly distributed between shards.
To accommodate for this we read the current
memory limit from Scylla metrics.
The helper class ScyllaMetrics was introduced to
handle metrics parsing logic. It can
potentially be reused for dealing with
metrics in other tests.
The test relies on exact request size, this doesn't
work if compression is applied. The driver enables
compression only if both the server and the client
agree on the codec to use. If compression package
(e.g. lz4) is not installed, the compression
is not used.
The trick with locally_supported_compressions is needed
since I couldn't find any standard means to disable
compression other than the compression flag
on the cluster object, which seemed too broad.
Fixes#12836
Calling _read_buf.close() doesn't imply eof(), some data
may have already been read into kernel or client buffers
and will be returned next time read() is called.
When the _server._max_request_size limit was exceeded
and the _read_buf was closed, the process_request method
finished and we started processing the next request in
connection::process. The unread data from _read_buf was
treated as the header of the next request frame, resulting
in "Invalid or unsupported protocol version" error.
The existing test_shed_too_large_request was adjusted.
It was originally written with the assumption that the data
of a large query would simply be dropped from the socket
and the connection could be used to handle the
next requests. This behaviour was changed in scylladb#8800,
now the connection is closed on the Scylla side and
can no longer be used. To check there are no errors
in this case, we use Scylla metrics, getting them
from the Scylla Prometheus API.
Some of the tests in test/cql-pytest share the same table but use
different keys to ensure they don't collide. Before this patch we used a
random key, which was usually fine, but we recently noticed that the
pytest-randomly plugin may cause different tests to run through the *same*
sequence of random numbers and ruin our intent that different tests use
different keys.
So instead of using a *random* key, let's use a *unique* key. We can
achieve this uniqueness trivially - using a counter variable - because
anyway the uniqueness is only needed inside a single temporary table -
which is different in every run.
Another benefit is that it will now be clearer that the tests are
deterministic and not random - the intent of a random_string() key
was never to randomly walk the entire key space (random_string()
anyway had a pretty narrow idea of what a random string looks like) -
it was just to get a unique key.
Refs #9988 (fixes it for cql-pytest, but not for test/alternator)
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
Fixtures in conftest.py (e.g., the test_keyspace fixture) can be shared by
all tests in all source files, so they are marked with the "session"
scope: All the tests in the testing session may share the same instance.
This is fine.
Some of test files have additional fixtures for creating special tables
needed only in those files. Those were also, unnecessarily, marked
"session" scope as well. This means that these temporary tables are
only deleted at the very end of test suite, event though they can be
deleted at the end of the test file which needed them - other test
source files don't have access to it anyway. This is exactly what the
"module" fixture scope is, so this patch changes all the fixtures that
are private to one test file to use the "module" scope.
After this patch, the teardown of the last test in the suite goes down
from 0.26 seconds to just 0.06 seconds.
Another benefit is that the peak disk usage of the test suite is
lower, because some of the temporary tables are deleted sooner.
This patch does not change any test functionality, and also does not
make any test faster - it just changes the order of the fixture
teardowns.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes#8932
This scylla-only test case tries to push a too-large request
to Scylla, and then retries with a smaller request, expecting
a success this time.
Refs #8193
