The problem was a race condition on shutdown -- when IM got shutdown
request while a guarded mysqld is starting. In this case the Guardian
thread tried to stop the mysqld, but might fail if the mysqld hadn't
created pid-file so far. When this happened, the mysqld-monitor thread
didn't stop, so the assert in Thread_registry happened.
The fix is to make several attempts to stop mysqld if it is active.
- BUG#22306: STOP INSTANCE can not be applied for instances in Crashed,
Failed and Abandoned;
- BUG#23476: DROP INSTANCE does not work
- BUG#23215: STOP INSTANCE takes too much time
BUG#22306:
The problem was that STOP INSTANCE checked that mysqld is up and running.
If it was not so, STOP INSTANCE reported an error. Now, STOP INSTANCE
reports an error if the instance has been started (mysqld can be down).
BUG#23476:
The problem was that DROP INSTANCE tried to stop inactive instance. The fix is
trivial.
BUG#23215:
The problem was that locks were not acquired properly, so the
instance-monitoring thread could not acquire the mutex, holded by the
query-processing thread.
The fix is to simplify locking scheme by moving instance-related information to
Instance-class out of Guardian-class. This allows to get rid of storing a
separate list of Instance-information in Guardian and keeping it synchronized
with the original list in Instance_map.
Alik's patch for BUG#22306: STOP INSTANCE can not be applied for
instances in Crashed, Failed and Abandoned" to ease review process.
Evaluate global variable linuxthreads before starting threads to avoid
a race.
The problem was that IM stoped guarded instances on shutdown,
but didn't wait for them to stop.
The fix is to wait for guarded instances to stop before exitting
from the main thread.
The idea is that Instance-monitoring thread should add itself
to Thread_registry so that it will be taken into account on shutdown.
However, Thread_registry should not signal it on shutdown in order to
not interrupt wait()/waitpid().
- WL#3158: IM: Instance configuration extensions;
- WL#3159: IM: --bootstrap and --start-default-instance modes
The following new statements have been added:
- CREATE INSTANCE;
- DROP INSTANCE;
The behaviour of the following statements have been changed:
- SET;
- UNSET;
- FLUSH INSTANCES;
- SHOW INSTANCES;
- SHOW INSTANCE OPTIONS;
