The test uses a 10ms read timeout to exercise code paths that handle timed-out reads without throwing C++ exceptions. As part of setup, it inserts rows and flushes them to two SSTables, then runs a warm-up SELECT to populate internal caches (e.g. the auth cache) before the real test begins. The reason for this warm-up read was the possibility that the first read does additional operations (such as reading and caching authentication) that might throw exceptions internally. I couldn't verify that such exceptions actually happen in today's code, but they might (re)appear in the future, so we should keep the warm-up SELECT. On slow CI machines (aarch64, debug build), that warm-up SELECT can take longer than 10ms to read from the two SSTables. When it does, the read times out: the coordinator receives 0 responses from the local replica within the deadline and propagates a read_timeout_exception. Since the exception is not caught, it escapes the test lambda, is logged as "cql env callback failed", and causes Boost.Test to report a C++ failure at the do_with_cql_env_thread call site. This matches the CI failure seen in SCYLLADB-1774: ERROR ... replica_read_timeout_no_exception: cql env callback failed, error: exceptions::read_timeout_exception (Operation timed out for replica_read_timeout_no_exception.tbl - received only 0 responses from 1 CL=ONE.) The CI log also shows that only 12 reads were admitted (the warm-up read plus the 11 reads from the two prepare() calls and CREATE/INSERT statements made earlier), and the current permit was stuck in need_cpu state -- the reactor hadn't had a chance to schedule the read before the 10ms window elapsed. The fix catches read_timeout_exception from the warm-up SELECT and retries until the read succeeds. The warm-up is required for correctness: some lazy-init code paths (e.g. auth cache population) use C++ exceptions for control flow internally. Those exceptions must be absorbed before the cxx_exceptions baseline is sampled inside execute_test(); otherwise they would appear in the delta and cause a false test failure. Simply ignoring a timed-out warm-up is not safe, because the lazy-init exceptions would then fire during the 1000 test reads, inflating cxx_exceptions_after relative to cxx_exceptions_before. No other calls in setup are susceptible to the 10ms read timeout: - CREATE KEYSPACE, CREATE TABLE, INSERT, and flush use the write timeout (10s) and are not reads. - e.prepare() goes through the query processor without reading table data, so it is not subject to the read timeout. - The semaphore manipulation in Test 2 is internal and has no timeout. - All 1000 reads in execute_test() are expected to fail, so a timeout there is the happy path, not a failure. The 10ms timeout itself is fine for the test's purpose: it is deliberately aggressive so that reads reliably time out on the hot path being tested. The problem was only that the pre-test warm-up was not guarded against the same timeout. Fixes: SCYLLADB-1774 Signed-off-by: Nadav Har'El <nyh@scylladb.com> Closes scylladb/scylladb#29731
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.