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.
Fix various typos, in comments and DEBUG statements, and code changes
are non-functional.
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.
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
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
Flush stdout on finalizing of mysqldump/mysqlbinlog output
to avoid truncation.
The same patch has been applied to the mysqltest.cc code with
commit 34ff714b0d
Author: Magnus Svensson <msvensson@mysql.com>
Date: Fri Nov 14 11:06:56 2008 +0100
WL#4189 Make mysqltest flush log file at close if logfile is stdout
but not to mysqldump.c/mysqlbinlog.cc
The MariaDB code base uses strcat() and strcpy() in several
places. These are known to have memory safety issues and their usage is
discouraged. Common security scanners like Flawfinder flags them. In MariaDB we
should start using modern and safer variants on these functions.
This is similar to memory issues fixes in 19af1890b5
and 9de9f105b5 but now replace use of strcat()
and strcpy() with safer options strncat() and strncpy().
However, add '\0' forcefully to make sure the result string is correct since
for these two functions it is not guaranteed what new string will be null-terminated.
Example:
size_t dest_len = sizeof(g->Message);
strncpy(g->Message, "Null json tree", dest_len); strncat(g->Message, ":",
sizeof(g->Message) - strlen(g->Message)); size_t wrote_sz = strlen(g->Message);
size_t cur_len = wrote_sz >= dest_len ? dest_len - 1 : wrote_sz;
g->Message[cur_len] = '\0';
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the BSD-new
license. I am contributing on behalf of my employer Amazon Web Services
-- Reviewer and co-author Vicențiu Ciorbaru <vicentiu@mariadb.org>
-- Reviewer additions:
* The initial function implementation was flawed. Replaced with a simpler
and also correct version.
* Simplified code by making use of snprintf instead of chaining strcat.
* Simplified code by removing dynamic string construction in the first
place and using static strings if possible. See connect storage engine
changes.
This is particularly important for Azure where there is no
MyISAM support in their MariaDB cloud product.
Like mysqldumper does, a view can satisfy the requirement
like a table, without constraints. The views in frm files are
text form and don't have column limits.
Thanks Thomas Casteleyn for the suggestion.
With a global non-default max-statement-time of a time interval that exceed
the query time mysqldump queries when doing a backup.
To solve both, add a max-statement-time option, defaulting to 0 (unlimited time).
Also like mariabackup, set the session wait_timeout=DEFAULT (28800). The
time/processing between mysqldump times isn't expected to get that
close ever, but let's adopt the standard of mariabackup as no-one has
challenged it has having a detrimental effect.
Reviewer and test case author Daniel Black
or slow query log when the log_output=TABLE.
When this happens, we temporary disable by changing log_output until
we've created the general_log and slow_log tables again.
Move </database> in xml mode until after the transaction_registry.
General_log and slow_log tables where moved to be first to be dumped so
that the disabling of the general/slow queries is minimal.
Previously the correct SQL mode for a stored routine or
package was only set before doing the CREATE part, this
worked out for PROCEDUREs and FUNCTIONs, but with ORACLE
mode specific PACKAGEs the DROP also only works in ORACLE
mode.
Moving the setting of the sql_mode a few lines up to happen
right before the DROP statement is writen fixes this.
One should not change the program arguments!
This change also reduces warnings from the icc compiler.
Almost all changes are just syntax changes (adding const to
'get_one_option function' declarations).
Other changes:
- Added a few cast of 'argument' from 'const char*' to 'char *'. This
was mainly in calls to 'external' functions we don't have control of.
- Ensure that all reset of 'password command line argument' are similar.
(In almost all cases it was just adding a comment and a cast)
- In mysqlbinlog.cc and mysqld.cc there was a few cases that changed
the command line argument. These places where changed to instead allocate
the option in a MEM_ROOT to avoid changing the argument. Some of this
code was changed to ensure that different programs did parsing the
same way. Added a test case for the changes in mysqlbinlog.cc
- Changed a few variables that took their value from command line options
from 'char *' to 'const char *'.
statistics calculation
Analysis: When --replace or --insert-ignore is not given, dumping of
mysql.innodb_index_stats and mysql.innodb_table_stats will result into race
condition.
Fix: Check if these options are present with --system=stats (because dumping
under --system=stats is safe). Otherwise, dump only structure, ignoring data
because innodb will recalculate data anyway.
Dump sequences first.
This atch made to keep it small and
to keep number of queries to the server the same.
Order of tables in a dump can not be changed
(except sequences first) because mysql_list_tables
uses SHOW TABLES and I used SHOW FULL TABLES.
statistics calculation
mysqldump --system=stats and --system=timezones by default used
ordinary INSERT statements populate EITS, innodb stats, and timezone tables.
As these all have primary keys it could result in conflict.
The behavior desired with --system= is to replace the tables.
As such we assume --replace for the purposes of stats and timezone tables
there if --insert-ignore isn't specified.
Add --system={all, users, plugins, udfs, servers, stats, timezones}
This will dump system information from the server in
a logical form like:
* CREATE USER
* GRANT
* SET DEFAULT ROLE
* CREATE ROLE
* CREATE SERVER
* INSTALL PLUGIN
* CREATE FUNCTION
"stats" is the innodb statistics tables or EITS and
these are dumped as INSERT/REPLACE INTO statements
without recreating the table.
"timezones" is the collection of timezone tables
which are important to transfer to generate identical
results on restoration.
Two other options have an effect on the SQL generated by
--system=all. These are mutually exclusive of each other.
* --replace
* --insert-ignore
--replace will include "OR REPLACE" into the logical form
like:
* CREATE OR REPLACE USER ...
* DROP ROLE IF EXISTS (MySQL-8.0+)
* CREATE OR REPLACE ROLE ...
* UNINSTALL PLUGIN IF EXISTS (10.4+) ... (before INSTALL PLUGIN)
* DROP FUNCTION IF EXISTS (MySQL-5.7+)
* CREATE OR REPLACE [AGGREGATE] FUNCTION
* CREATE OR REPLACE SERVER
--insert-ignore uses the construct " IF NOT EXISTS" where
supported in the logical syntax.
'CREATE OR REPLACE USER' includes protection against
being run as the same user that is importing the mysqldump.
Includes experimental support for dumping mysql-5.7/8.0
system tables and exporting logical SQL compatible with MySQL.
Updates mysqldump man page, including this information and
(removing obsolute bug reference)
Reviewed-by: anel@mariadb.org
- Original patch was contributed by Jani Tolonen <jani.k.tolonen@gmail.com>
https://github.com/an3l/server/commits/bb-10.3-anel-MDEV-21786-dump-sequence
which distinguishes data structure (linked list) of sequences from
tables.
- Added standard sql output to prevent future changes
of sequences and disabled locks for sequences.
- Added test case for `MDEV-20070: mysqldump won't work correct on
sequences` where table column depends on sequence value.
- Restore sequence last value in the following way:
- Find `next_not_cached_value` and use it to `setval()`
- We just need for logical restore, so don't execute `setval()`
- `setval()` should be showed also in case of `--no-data` option.
Reviewed-by: daniel@mariadb.org
