MDEV-22021: Galera database could get inconsistent with rollback to savepoint
When binlog is disabled, WSREP will not behave correctly when
SAVEPOINT ROLLBACK is executed since we don't register handlers for such case.
Fixed by registering WSREP handlerton for SAVEPOINT related commands.
MDEV-21473 conflicts with async slave BF aborting (#1475)
If async slave thread (slave SQL handler), becomes a BF victim, it may occasionally happen that rollbacker thread is used to carry out the rollback instead of the async slave thread.
This can happen, if async slave thread has flagged "idle" state when BF thread tries to figure out how to kill the victim.
The issue was possible to test by using a galera cluster as slave for external master, and issuing high load of conflicting writes through async replication and directly against galera cluster nodes.
However, a deterministic mtr test for the "conflict window" has not yet been worked on.
The fix, in this patch makes sure that async slave thread state is never set to IDLE. This prevents the rollbacker thread to intervene.
The wsrep_query_state change was refactored to happen by dedicated function to make controlling the idle state change in one place.
MDEV-21572 buf_page_get_gen() should apply buffered page initialized
redo log during recovery
- InnoDB unnecessarily reads the page even though it has fully initialized
buffered redo log records. Allow the page initialization redo log to
apply for the page in buf_page_get_gen() during recovery.
- Renamed buf_page_get_gen() to buf_page_get_low()
- Newly added buf_page_get_gen() will check for buffered redo log for
the particular page id during recovery
- Added new function buf_page_mtr_lock() which basically latches the page
for the given latch type.
- recv_recovery_create_page() is inline function which creates a page
if it has page initialization redo log records.
