This patch fixes two problems that may arise when changing the
value of wsrep_slave_threads:
1) Threads may be leaked if wsrep_slave_threads is changed
repeatedly. Specifically, when changing the number of slave
threads, we keep track of wsrep_slave_count_change, the
number of slaves to start / stop. The problem arises when
wsrep_slave_count_change is updated before slaves had a
chance to exit (threads may take some time to exit, as they
exit only after commiting one more replication event).
The fix is to update wsrep_slave_count_change such that it
reflects the number of threads that already exited or are
scheduled to exit.
2) Attempting to set out of range value for wsrep_slave_threads
(below 1 / above 512) results in wsrep_slave_count_change to
be computed based on the out of range value, even though a
warning is generated and wsrep_slave_threads is set to a
truncated value. wsrep_slave_count_change is computed in
wsrep_slave_threads_check(), which is called before mysql
checks for valid range. Fix is to update wsrep_count_change
whenever wsrep_slave_threads is updated with a valid value.
Applier does not reset thd->wsrep_apply_toi if applier thread decides
to exit by setting 'exit= true'. The problem is that galera side may
decide not to kill the applier thread: for instance if we try to
SET wsrep_slave_threads = 0; then galera refuses to kill the last
applier thread. If this happens we are left with a thd which has not
been reset to the initial state.
This patch ensures that the thd is reset regardless of the applier
thread exiting or not.
Comment from Codership:-
To fix the problem, we changed the certification logic in galera to treat insert
on child table row as exclusive to prevent any operation on referenced
parent table row. At the same time, update and delete on
child table row were demoted to "shared", which makes it possible to
update/delete referenced parent table row, but only in a later transaction.
This change allows somewhat more concurrency for foreign key constrained
transactions, but is still safe for correct certification end result.
It is assumed that both insert..select statements take so
long that drop database from node2 gets to abort them both
but on fast machines it was too small. Increased the size
of insert.
* remove part of galera_var_cluster_address.test that can not be tested reliably
* reduce running time for galera_gcache_recover_manytrx.test
* Additional wait_conditions for GAL-401.test
Signed-off-by: Sachin Setiya <sachin.setiya@mariadb.com>
* a dedicated test for wsrep_retry_autocommit
* some galera_toi_* tests were only passing because wsrep_retry_autocommit
was in effect. The tests were changed to do not use autocommit
* higher timeout values in galera_2nodes.cnf , galera_3nodes.cnf
Signed-off-by: Sachin Setiya <sachin.setiya@mariadb.com>
It is assumed that both insert..select statements take so
long that drop database from node2 gets to abort them both
but on fast machines it was too small. Increased the size
of insert.
* remove part of galera_var_cluster_address.test that can not be tested reliably
* reduce running time for galera_gcache_recover_manytrx.test
* Additional wait_conditions for GAL-401.test
Signed-off-by: Sachin Setiya <sachinsetia1001@gmail.com>
* a dedicated test for wsrep_retry_autocommit
* some galera_toi_* tests were only passing because wsrep_retry_autocommit
was in effect. The tests were changed to do not use autocommit
* higher timeout values in galera_2nodes.cnf , galera_3nodes.cnf
# Conflicts:
# mysql-test/suite/galera/galera_2nodes.cnf
# mysql-test/suite/galera/r/galera_defaults.result
# mysql-test/suite/galera_3nodes/galera_3nodes.cnf
Note: At least one test is unstable, failing with the following:
./mtr --mysqld=--innodb-purge-threads=9 --big-test --no-reorder \
galera.galera_parallel_autoinc_largetrx galera.galera_var_slave_threads
The result difference is dependent on innodb_purge_threads.
.. wsrep_max_ws_rows causes cluster to break when running
Galera cluster in TOI mode
Problem:
While copying records to temporary table during ALTER TABLE,
if there are more than wsrep_max_wsrep_rows records, the
command fails.
Fix:
Since, the temporary table records are not placed into the
binary log, wsrep_affected_rows must not be incremented.
Added a test.
that must not send a response
Problem:- When using wsrep (w/ galera) and issuing commands that can
cause deadlocks, deadlock exception errors are sent in responses to
commands such as close prepared statement and close connection which,
by spec, must not send a response.
Solution:- In dispatch_command, we will handle COM_QUIT and COM_STMT_CLOSE
commands even in case of error.
Patch Credit:- Jaka Močnik
Problem:-
The condition that checks for node readiness is too strict as it does
not allow SELECTs even if these selects do not access any tables.
For example,if we run
SELECT 1;
OR
SELECT @@max_allowed_packet;
Solution:-
We need not to report this error when all_tables(lex->query_tables)
is NULL:
Tasks:-
Changes in wsrep_dirty_reads variable
1.) Global + Session scope (Current: session-only)
2.) Can be set using command line.
3.) Allow all commands that do not change data (besides SELECT)
4.) Allow prepared Statements that do not change data
5.) Works with wsrep_sync_wait enabled
Tasks:-
Changes in wsrep_dirty_reads variable
1.) Global + Session scope (Current: session-only)
2.) Can be set using command line.
3.) Allow all commands that do not change data (besides SELECT)
4.) Allow prepared Statements that do not change data
5.) Works with wsrep_sync_wait enabled
Problem:-
The condition that checks for node readiness is too strict as it does
not allow SELECTs even if these selects do not access any tables.
For example,if we run
SELECT 1;
OR
SELECT @@max_allowed_packet;
Solution:-
We need not to report this error when all_tables(lex->query_tables)
is NULL:
During total-order replication, Query_log_event's checksum_alg
should be explicitly set to the current binlog_checksum as it
is not set for DML queries.
Note: wsrep_replicate_myisam enables replication of DMLs on
MyISAM tables using TOI.
Problem:-
The condition that checks for node readiness is too strict as it does
not allow SELECTs even if these selects do not access any tables.
For example,if we run
SELECT 1;
OR
SELECT @@max_allowed_packet;
Solution:-
We need not to report this error when all_tables(lex->query_tables)
is NULL:
In galera cluster, the definer (and thus binlog invoker) must be set
for CREATE ROLE before Query_log_event is created during TOI on the
originating node.
