10.4-MDEV-29684 Fixes for cluster wide write conflict resolving
If two high priority threads have lock conflict, we look at the
order of these transactions and honor the earlier transaction.
for_locking parameter in lock_rec_has_to_wait() has become
obsolete and it is now removed from the code .
MDEV-30080 Wrong result with LEFT JOINs involving constant tables
The reason things fails in 10.5 and above is that test_quick_select()
returns -1 (impossible range) for empty tables if there are any
conditions attached.
This didn't happen in 10.4 as the cost for a range was more than for
a table scan with 0 rows and get_key_scan_params() did not create any
range plans and thus did not mark the range as impossible.
The code that checked the 'impossible range' conditions did not take
into account all cases of LEFT JOIN usage.
Adding an extra check if the table is used with an ON condition in case
of 'impossible range' fixes the issue.
10.4-MDEV-29684 Fixes for cluster wide write conflict resolving
The rather recent thd_need_ordering_with() function does not take
high priority transactions' order in consideration. Chaged this
funtion to compare also transaction seqnos and favor earlier transaction.
MDEV-29512 deadlock between commit monitor and THD::LOCK_thd_data mutex
This commit contains only a mtr test for reproducing the issue in MDEV-29512
The actual fix will be pushed in wsrep-lib repository
The hanging in MDEV-29512 happens when binlog purging is attempted, and there is
one local BF aborted transaction waiting for commit monitor.
The test will launch two node cluster and enable binlogging with expire log days,
to force binlog purging to happen.
A local transaction is executed so that will become BF abort victim, and has advanced
to replication stage waiting for commit monitor for final cleanup (to mark position in innodb)
after that, applier is released to complete the BF abort and due to binlog configuration,
starting the binlog purging. This is where the hanging would occur, if code is buggy
MDEV-29684 Fixes for cluster wide write conflict resolving
Cluster conflict victim's THD is marked with wsrep_aborter.
THD::wsrep_aorter holds the thread ID of the hight priority tread,
which is currently carrying out BF aborting for this victim.
However, the BF abort operation is not always successful,
and in such case the wsrep_aborter mark should be removed.
In the old code, this wsrep_aborter resetting did not happen,
and this could lead to a situation where the sticky wsrep_aborter
mark prevents any further attempt to BF abort this transaction.
This commit fixes this issue, and resets wsrep_aborter after
unsuccesful BF abort attempt.
