2d716f3ffe
Truncate doesn't really go well with concurrent writes. The fix (#23560) exposed a preexisting fragility which I missed. 1) truncate gets RP mark X, truncated_at = second T 2) new sstable written during snapshot or later, also at second T (difference of MS) 3) discard_sstables() get RP Y > saved RP X, since creation time of sstable with RP Y is equal to truncated_at = second T. So the problem is that truncate is using a clock of second granularity for filtering out sstables written later, and after we got low mark and truncate time, it can happen that a sstable is flushed later within the same second, but at a different millisecond. By switching to a millisecond clock (db_clock), we allow sstables written later within the same second from being filtered out. It's not perfect but extremely unlikely a new write lands and get flushed in the same millisecond we recorded truncated_at timepoint. In practice, truncate will not be used concurrently to writes, so this should be enough for our tests performing such concurrent actions. We're moving away from gc_clock which is our cheap lowres_clock, but time is only retrieved when creating sstable objects, which frequency of creation is low enough for not having significant consequences, and also db_clock should be cheap enough since it's usually syscall-less. Fixes #23771. Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com> Closes scylladb/scylladb#24426
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.