Ceph

RocksDBOption test occasionally fails with output like this:

did not load config file, using default settings.
[==========] Running 2 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 2 tests from RocksDBOption
[ RUN      ] RocksDBOption.simple
[       OK ] RocksDBOption.simple (9 ms)
[ RUN      ] RocksDBOption.interpret
2024-06-20T00:17:00.483+0000 7efd14527380 -1 Errors while parsing config file!
2024-06-20T00:17:00.483+0000 7efd14527380 -1 can't open ceph.conf: (2) No such file or directory
2024-06-20T00:17:00.483+0000 7efd14527380 -1 Errors while parsing config file!
2024-06-20T00:17:00.483+0000 7efd14527380 -1 can't open ceph.conf: (2) No such file or directory
/home/jenkins-build/build/workspace/ceph-pull-requests/src/test/objectstore/TestRocksdbOptionParse.cc:73: Failure
Expected equality of these values:
  15u
    Which is: 15
  thread_list.size()
    Which is: 14
[  FAILED  ] RocksDBOption.interpret (107 ms)
[----------] 2 tests from RocksDBOption (116 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test suite ran. (116 ms total)
[  PASSED  ] 1 test.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] RocksDBOption.interpret

 1 FAILED TEST

Test is checking that RocksDB has parsed the options and created the correct number of threads.

The problem is that RocksDB does not register its threads until they start running, but returns from initialization as soon as they have been created. There is race hazard where the scheduler might not have bothered to run the threads before the test queries how many threads are registered.

The test case has a 100ms sleep but clearly this isn't always sufficient