Issue:
Mariadb acquires additional MDL locks on UPDATE/INSERT/DELETE statements
on table with foreign keys. For example, table t1 references t2, an
UPDATE to t1 will MDL lock t2 in addition to t1.
A replica may deliver an ALTER t1 and UPDATE t2 concurrently for
applying. Then the UPDATE may acquire MDL lock for t1, followed by a
conflict when the ALTER attempts to MDL lock on t1. Causing a BF-BF
conflict.
Solution:
Additional keys for the referenced/foreign table needs to be added
to avoid potential MDL conflicts with concurrent update and DDLs.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
Appliers need to verify foreign key constraints during normal
operation, in multi-active topologies, and for this reason appliers
are configured to enable FK checking.
However, during node joining, in IST and latter catch up period,
the node is still idle (from local connections), and only source
for incoming transactions is the cluster sending certified write
sets for applying. IST happens with parallel applying, and there
is a possibility that foreign key check cause lock conflicts between
appliers accessing FK child and parent tables. Also, the excessive
FK checking will slow down IST process somewhat.
For this reasons, we could relax FK checks for appliers during IST
and catch up periods. The relaxed FK check mode should, however, be
configurable e.g. by wsrep_mode flag: SKIP_APPLIER_FK_CHECKS_IN_IST.
When this operation mode is set, and the node is processing IST or
catch up, appliers should skip FK checking.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
Problem was incorrect handling of partitioned tables,
because db_type == DB_TYPE_PARTITION_DB
wsrep_should_replicate_ddl incorrectly marked
DDL as not replicatable. However, in partitioned
tables we should check implementing storage engine
from table->file->partition_ht() if available because
if partition handler is InnoDB all DDL should be allowed
even with wsrep_strict_ddl. For other storage engines
DDL should not be allowed and error should be issued.
This is 10.6 version of the fix.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
Problem was incorrect handling of partitioned tables,
because db_type == DB_TYPE_PARTITION_DB
wsrep_should_replicate_ddl incorrectly marked
DDL as not replicatable. However, in partitioned
tables we should check implementing storage engine
from table->file->partition_ht() if available because
if partition handler is InnoDB all DDL should be allowed
even with wsrep_strict_ddl. For other storage engines
DDL should not be allowed and error should be issued.
This is 10.5 version of the fix.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
DROP TABLE on child and UPDATE of parent table can cause an MDL BF-BF
conflict when applied concurrently.
DROP TABLE takes MDL locks on both child and its parent table, however
it only it did not add certification keys for the parent table.
This patch adds the following:
* Append certification keys corresponding to all parent tables
before DROP TABLE replication.
* Fix wsrep_append_fk_parent_table() so that it works when it is
given a table list containing temporary tables.
* Make sure function wsrep_append_fk_parent_table() is only called
for local transaction. That was not the case for ALTER TABLE.
* Add a test case that verifies that UPDATE parent depends on
preceeding DROP TABLE child.
* Adapt galera_ddl_fk_conflict test to work with DROP TABLE as well.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
It's read for every command execution, and during slave replication
for every applied event.
It's also planned to be used during write set applying, so it means
mostly every server thread is going to compete for the mutex covering
this variable, especially considering how rarely it changes.
Converting wsrep_ready to atomic relaxes the things.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
wsrep_plugin_init(), wsrep_plugin_deinit(): Remove these dummy functions
in order to fix an error that would be flagged by cmake -DWITH_UBSAN=ON
when using clang.
wsrep_show_ready(), wsrep_show_bf_aborts(): Correct the signature.
- Add selected tables as shared keys for CTAS certification
- Set proper security context on the replayer thread
- Disallow CTAS command retry
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
There was two related problems:
(1) Galera node that is defined as a slave to async MariaDB
master at restart might do SST (state stransfer) and
part of that it will copy mysql.gtid_slave_pos table.
Problem is that updates on that table are not replicated
on a cluster. Therefore, table from donor that is not
slave is copied and joiner looses gtid position it was
and start executing events from wrong position of the binlog.
This incorrect position could break replication and
causes node to be dropped and requiring user action.
(2) Slave sql thread might start executing events before
galera is ready (wsrep_ready=ON) and that could also
cause node to be dropped from the cluster.
In this fix we enable replication of mysql.gtid_slave_pos
table on a cluster. In this way all nodes in a cluster
will know gtid slave position and even after SST joiner
knows correct gtid position to start.
Furthermore, we wait galera to be ready before slave
sql thread executes any events to prevent too early
execution.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
This commit changes backup execution (namely the block ddl phase),
so that node is not paused from cluster. Instead, the following
backup execution is declared as vulnerable for possible cluster
level conflicts, especially with DDL statement applying.
With this, the mariabackup execution may be aborted, if DDL
statements happen during backup execution. This abortable
backup execution is optional feature and may be
enabled/disabled by wsrep_mode: BF_ABORT_MARIABACKUP.
Note that old style node desync and pause, despite of
WSREP_MODE_BF_MARIABACKUP is needed if node is operating as
SST donor.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
Making changes to wsrep_mysqld.h causes large parts of server code to
be recompiled. The reason is that wsrep_mysqld.h is included by
sql_class.h, even tough very little of wsrep_mysqld.h is needed in
sql_class.h. This commit introduces a new header file, wsrep_on.h,
which is meant to be included from sql_class.h, and contains only
macros and variable declarations used to determine whether wsrep is
enabled.
Also, header wsrep.h should only contain definitions that are also
used outside of sql/. Therefore, move WSREP_TO_ISOLATION* and
WSREP_SYNC_WAIT macros to wsrep_mysqld.h.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
Integration with status reporter in wsrep-lib.
Status reporter reports changes in wsrep state and logged errors/
warnings to a json file which then can be read and interpreted by
an external monitoring tool.
Rationale: until the server is fully initialized it is unaccessible
by client and the only source of information is an error log which
is not machine-friendly. Since wsrep node can spend a very long time
in initialization phase (state transfer), it may be a very long time
that automatic tools can't easily monitor its liveness and progression.
New variable: wsrep_status_file specifies the output file name.
If not set, no file is created and no reporting is done.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
* Fix test galera.MW-44 to make it work with --ps-protocol
* Skip test galera.MW-328C under --ps-protocol This test
relies on wsrep_retry_autocommit, which has no effect
under ps-protocol.
* Return WSREP related errors on COM_STMT_PREPARE commands
Change wsrep_command_no_result() to allow sending back errors
when a statement is prepared. For example, to handle deadlock
error due to BF aborted transaction during prepare.
* Add sync waiting before statement prepare
When a statement is prepared, tables used in the statement may be
opened and checked for existence. Because of that, some tests (for
example galera_create_table_as_select) that CREATE a table in one node
and then SELECT from the same table in another node may result in errors
due to non existing table.
To make tests behave similarly under normal and PS protocol, we add a
call to sync wait before preparing statements that would sync wait
during normal execution.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
