spawned threads with a reusable class Thread.
This is the second idea implemented in the Alik's patch for
BUG#22306: STOP INSTANCE can not be applied for instances in Crashed,
Failed and Abandoned.
Commiting separately to ease review process.
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().
Remove race situations that occur when removing pidfiles. Primarily each process should remove its own
pidfile, secondly it should be removed by the process that created it and _only_ if it's
certain the process is dead. Third, mysql-test-run.pl will remove the pidfile when process has been killed.
- Set state of an instance to STARTING _before_ calling instance->start()
- Check that pidfile of instance has been created before changing STARTING => STARTED
- Only remove the pidfile if IM kills an instance with SIGKILL, otherwise the instance will remove it itself
- 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;
duration of the whole 'flush instances'. As a consequence,
it was possible to query instance map, while it is in the
inconsistent state. The patch was reworked after review.
