When mysqldump is run to dump the `mysql` system database, it generates
INSERT statements into the table `mysql.gtid_slave_pos`.
After running the backup script
those inserts did not produce the expected gtid state on slave. In
particular the maximum of mysql.gtid_slave_pos.sub_id did not make
into
rpl_global_gtid_slave_state.last_sub_id
an in-memory object that is supposed to match the current state of the
table. And that was regardless of whether --gtid option was specified
or not. Later when the backup recipient server starts as slave
in *non-gtid* mode this desychronization may lead to a duplicate key
error.
This effect is corrected for --gtid mode mysqldump/mariadb-dump only
as the following. The fixes ensure the insert block of the dump
script is followed with a "summing-up" SET @global.gtid_slave_pos
assignment.
For the implemenation part, note a deferred print-out of
SET-gtid_slave_pos and associated comments is prefered over relocating
of the entire blocks if (opt_master,slave_data &&
do_show_master,slave_status) ... because of compatiblity
concern. Namely an error inside do_show_*() is handled in the new code
the same way, as early as, as before.
A regression test can be run in how-to-reproduce mode as well.
One affected mtr test observed.
rpl_mysqldump_slave.result "mismatch" shows now the new deferring print
of SET-gtid_slave_pos policy in action.
safety first - tell mariadb client not to execute dangerous
cli commands, they cannot be present in the dump anyway.
wrapping the command in /*!999999 ..... */ guarantees that
if a non-mariadb-cli client loads the dump and sends it to the
server - the server will ignore the command it doesn't understand
The patch for MDEV-15530 incorrectly added a column in the middle of SHOW
SLAVE STATUS output. This is wrong, as it breaks backwards compatibility
with existing applications and scripts. In this case, it even broke
mariadb-dump, which is included in the server source tree!
Revert the incorrect change, putting the new Replicate_Rewrite_DB at the end
of SHOW SLAVE STATUS output.
Add a testcase for the mariadb-dump --dump-slave wrong output problem. Also
add a testcase rpl.rpl_show_slave_status to hopefully prevent any future
incorrect additions to SHOW SLAVE STATUS.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
Recording both is useful on a replication relay when the backup
can be used to replace the server, or ack as a new replica to the
server.
If an option=2, commented is selected, allow the alternate option
to exist.
This still disables --dump-slave=1 --master-data=1 as having the
a CHANGE MASTER TO and START SLAVE on different positions would be
confusing and dangerious to the try to execute the output. The
previous behaviour of silently disabling --master-data occurs in
this case.
The commented code related to --dump-slave/--master-data is greatly
expanded for human consumption.
A redundant opt_slave_data= 0 was removed from get_opts. If
--dump-slave=1 or 2, then the only possible value of --master-data
is a valid one.
Re-order to preference gtid based replication.
Based of code from Elena Stepanova.
Review by: Brandon Nesterenko and Anel Husakovic
Because --delete-master-logs immediately purges logs after flushing,
it is possible the binlog dump thread would still be using the old
log when the purge executes, disallowing the file from being
deleted.
This patch institutes a work-around in the test as follows:
1) temporarily stop the slave so there is no chance the old binlog
is still being referenced.
2) set master_use_gtid=Slave_pos so the slave can still appear
up-to-date on the master after the master flushes/purges its logs
(while the slave is offline). Otherwise (i.e. if using binlog
file/pos), the slave would point to a purged log file, and receive
an error immediately upon connecting to the master.
Reviewed By
============
Andrei Elkin <andrei.elkin@mariadb.com>
Extending the rpl_mysqldump_slave.test to incorporate the
delete-master-logs option, and this options is alias of
get binlogs: show master status -> flush logs -> purge binary logs to <new_binlog>
sequence and this test is derived using the same pattern.
also we measure the pre and post log state
on the master following the mysqldump process. Introducing
assertions to validate the correct state.
