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.
If the initialization of the wsrep provider failed, in some
cases the internal variable wrep_inited indicating that the
initialization has already been completed is still set to
"1", which then leads to confusion in the initialization
status. To solve the problem, we should set this variable
to "1" only if the wsrep provider initialization really
completed successfully.
An earlier issue has already been fixed for branch 10.4,
and this patch contains a fix for earlier versions (where
Galera 3.x is used).
Found two bugs
(1) have_committing_connections was missing mutex unlock on one
exit case. As this function is called on a loop it caused mutex
lock when we already owned the mutex. This could cause hang.
(2) wsrep_RSU_begin did set up error code when partition to
be dropped could not be MDL-locked because of concurrent
operations but wrong error code was propagated to upper layer
causing error to be ignored. This could have also caused
the hang.
This PR contains a mtr test for reproducing a failure with replicating create table as select statement (CTAS) through asynchronous mariadb replication to mariadb galera cluster.
The problem happens when CTAS replication contains both create table statement followed by row events for populating the table. In such situation, the galera node operating as mariadb replication slave, will first replicate only the create table part into the cluster, and then perform another replication containing both the create table and row events. This will lead all other nodes to fail for duplicate table create attempt, and crash due to this failure.
PR contains also a fix, which identifies the situation when CTAS has been replicated, and makes further scan in async replication stream to see if there are following row events. The slave node will replicate either single TOI in case the CTAS table is empty, or if CTAS table contains rows, then single bundled write set with create table and row events is replicated to galera cluster.
This fix should keep master server's GTID's for CTAS replication in sync with GTID's in galera cluster.
Lock wait can happen on secondary index when doing FK checks for wsrep.
We should just return error to upper layer and applier will retry
operation when needed.
Re-enable some Galera tests that should have been enabled.
Add client_ed25519.so to debian/libmariadb3.install;
merge e47a143fc0 correctly.
Remove a duplicated #include from wsrep_mysqld.cc.
Galera threads were not registered to performance schema and
used pthread_create when mysql_thread_create should have been
used.
Added test case to verify current galera performance schema
instrumentation does work.
Problem was that tests select INFORMATION_SCHEMA.PROCESSLIST processes
from user system user and empty state. Thus, there is not clear
state for slave threads.
Changes:
- Added new status variables that store current amount of applier threads
(wsrep_applier_thread_count) and rollbacker threads
(wsrep_rollbacker_thread_count). This will make clear how many slave threads
of certain type there is.
- Added THD state "wsrep applier idle" when applier slave thread is
waiting for work. This makes finding slave/applier threads easier.
- Added force-restart option for mtr to always restart servers between tests
to avoid race on start of the test
- Added wait_condition_with_debug to wait until the passed statement returns
true, or the operation times out. If operation times out, the additional error
statement will be executed
Changes to be committed:
new file: mysql-test/include/force_restart.inc
new file: mysql-test/include/wait_condition_with_debug.inc
modified: mysql-test/mysql-test-run.pl
modified: mysql-test/suite/galera/disabled.def
modified: mysql-test/suite/galera/r/MW-336.result
modified: mysql-test/suite/galera/r/galera_kill_applier.result
modified: mysql-test/suite/galera/r/galera_var_slave_threads.result
new file: mysql-test/suite/galera/t/MW-336.cnf
modified: mysql-test/suite/galera/t/MW-336.test
modified: mysql-test/suite/galera/t/galera_kill_applier.test
modified: mysql-test/suite/galera/t/galera_parallel_autoinc_largetrx.test
modified: mysql-test/suite/galera/t/galera_parallel_autoinc_manytrx.test
modified: mysql-test/suite/galera/t/galera_var_slave_threads.test
modified: mysql-test/suite/wsrep/disabled.def
modified: mysql-test/suite/wsrep/r/variables.result
modified: mysql-test/suite/wsrep/t/variables.test
modified: sql/mysqld.cc
modified: sql/wsrep_mysqld.cc
modified: sql/wsrep_mysqld.h
modified: sql/wsrep_thd.cc
modified: sql/wsrep_var.cc
This reverts commit 21b2fada7a
and commit 81d71ee6b2.
The MDEV-18464 change introduces a few data race issues. Contrary to
the documentation, the field trx_t::victim is not always being protected
by lock_sys_t::mutex and trx_t::mutex. Most importantly, it seems
that KILL QUERY could wrongly avoid acquiring both mutexes when
invoking lock_trx_handle_wait_low(), in case another thread had
already set trx->victim=true.
We also revert MDEV-12009, because it should depend on the MDEV-18464
fix being present.
As noted on kill_one_thread SUPER should be able to kill even
system threads i.e. threads/query flagged as high priority or
wsrep applier thread. Normal user, should not able to kill
threads/query flagged as high priority (BF) or wsrep applier
thread.
The second line of changes related to replacing xtrabackup with
mariabackup:
1) All unnecessary references to xtrabackup are removed from
the documentation, from some comments, from the control files
that are used to prepare the packages.
2) Made corrections of the tests from the galera_3nodes suite
that mentioned xtrabackup or the old (associated with xtrabackup)
version of innobackupex.
3) Fixed flaws in the galera_3nodes mtr suite control scripts,
because of which they could not work with mariabackup.
4) Fixed numerous bugs in the SST scripts and in the mtr test
files (galera_3nodes mtr suite) that prevented the use of Galera
with IPv6 addresses.
5) Fixed flaws in tests for rsync and mysqldump (for galera_3nodes
mtr tests suite). These tests were not performed successfully without
these fixes.
https://jira.mariadb.org/browse/MDEV-17835
Problem was that controlling connection i.e. connection that
executed the query SET GLOBAL wsrep_reject_queries = ALL_KILL;
was also killed but server would try to send result from that
query to controlling connection resulting a assertion
mysqld: /home/jan/mysql/10.2-sst/include/mysql/psi/mysql_socket.h:738: inline_mysql_socket_send: Assertion `mysql_socket.fd != -1' failed.
as socket was closed when controlling connection was closed.
wsrep_close_client_connections()
Do not close controlling connection and instead of
wsrep_close_thread() we do now soft kill by THD::awake
wsrep_reject_queries_update()
Call wsrep_close_client_connections using current thd.
Problem was that controlling connection i.e. connection that
executed the query SET GLOBAL wsrep_reject_queries = ALL_KILL;
was also killed but server would try to send result from that
query to controlling connection resulting a assertion
mysqld: /home/jan/mysql/10.2-sst/include/mysql/psi/mysql_socket.h:738: inline_mysql_socket_send: Assertion `mysql_socket.fd != -1' failed.
as socket was closed when controlling connection was closed.
wsrep_close_client_connections()
Do not close controlling connection and instead of
wsrep_close_thread() we do now soft kill by THD::awake
wsrep_reject_queries_update()
Call wsrep_close_client_connections using current thd.
main.derived_cond_pushdown: Move all 10.3 tests to the end,
trim trailing white space, and add an "End of 10.3 tests" marker.
Add --sorted_result to tests where the ordering is not deterministic.
main.win_percentile: Add --sorted_result to tests where the
ordering is no longer deterministic.
This is used for controlling whether to use a new/optimized
certification rules or the old/classic ones that could cause more
certification failures - when foreign keys are used and two INSERTs are
done concurrently to the child table from different nodes.
(cherry picked from commit 815d73e6af8daace6262ab63ca6c043ffc4204b3)
Adding a FK constraint to an existing table (ALTER TABLE ADD FOREIGN
KEY) causes the applier to fail, if a concurrent DML statement that
violate the new constraint (i.e. a DELETE or UPDATE of record in the
parent table).
For exmaple, the following scenario causes a crash in the applier:
1. ALTER successfully adds FK constraint in node_1
2. On node_2 is UPDATE is in pre_commit() and has certified successfully
3. ALTER is delivered in node_2 and BF aborts DML
4. Applying UPDATE event causes FK violation in node_1
To avoid this situation it is necessary for UPDATE to fail during
certification. And for the UPDATE to fail certfication it is necessary
that ALTER appends certification keys for both the child and the parent
table. Before this patch, ALTER TABLE ADD FK only appended keys for
child table which is ALTERed.
Restricted output for CREATE USER, GRANT, REVOKE and SET PASSWORD
so that it shows only above keywords but not rest of query i.e.
not user or password.
Restricted output for CREATE USER, GRANT, REVOKE and SET PASSWORD
so that it shows only above keywords but not rest of query i.e.
not user or password.
