use. However, because the reference counting was implemented via
mutexes, it was possible to double `RLock` the series file mutex. This
allows a `Lock` to arrive in-between the two `RLock`s, (such as when
deleting the database), causing deadlock.
This commit addresses this by ensuring that from within `IndexSet`
methods, when calling other `IndexSet` methods, that they're all
unexported, and that those unexported methods never take a lock on the
series file.
Keeping series file locking in exported `IndexSet` methods only, allows
one to see any future races more easily.
This commits adds a randomised deletion test, which aims to test the
correctness of deletions and drops in the index and series file.
The test works by maintaining its own index of points, series and
measurements, tracking the presence or absence or series.
There are four commands that can be randomly executed:
- insert a series at a random time
- drop an entire measurement
- drop an entire series
- delete series across a time range
After every invocation of one of these commands, `SHOW SERIES` is
executed on the server, and the results are compared to what the
test's series tracker believes should be present. If the results
differ then the test fails.
On failure, the last 100 queries executed, as well as the series
we expected, and the series returned by `SHOW SERIES`, are returned.
Edd Robinson