a3c379ea61
For join to work correctly versioning condition must be added to table on_expr. Without that JOIN_CACHE gets expression (1) trigcond(xtitle.row_end = TIMESTAMP'2038-01-19 06:14:07.999999') and trigcond(xtitle.elementId = x.`id` and xtitle.pkey = 'title') instead of (2) trigcond(xtitle.elementId = x.`id` and xtitle.pkey = 'title') for join_null_complements(). It is NULL-row of xtitle for complementing the join and the above comparisons of course FALSE, but trigcond (Item_func_trig_cond) makes them TRUE via its trig_var property which is bound to some boolean properties of JOIN_TAB. Expression (2) evaluated to TRUE because its trig_var is bound to first_inner_tab->not_null_compl. The expression (1) does not evaluate correctly because row_end comparison's trig_var is bound to first_inner->found earlier. As a result JOIN_CACHE::check_match() skipped the row for join_null_complements(). When we add versioning condition to table's on_expr the optimizer in make_join_select() distributes conditions differently. tmp_cond inherits on_expr value and in Good case it is full expression xgender.elementId = x.`id` and xgender.pkey = 'gender' and xgender.row_end = TIMESTAMP'2038-01-19 06:14:07.999999' while in Bad case it is only xgender.elementId = x.`id` and xgender.pkey = 'gender'. Later in Good row_end condition is optimized out and we get one trigcond in form of (2).
Code status:
travis-ci.org (10.3 branch)ci.appveyor.com
MariaDB: drop-in replacement for MySQL
MariaDB is designed as a drop-in replacement of MySQL(R) with more features, new storage engines, fewer bugs, and better performance.
MariaDB is brought to you by the MariaDB Foundation. Please read the CREDITS file for details about the MariaDB Foundation, and who is developing MariaDB.
MariaDB is developed by many of the original developers of MySQL who now work for the MariaDB Foundation and the MariaDB Corporation, and by many people in the community.
MySQL, which is the base of MariaDB, is a product and trademark of Oracle Corporation, Inc. For a list of developers and other contributors, see the Credits appendix. You can also run 'SHOW authors' to get a list of active contributors.
A description of the MariaDB project and a manual can be found at:
https://mariadb.com/kb/en/mariadb-vs-mysql-features/
https://mariadb.com/kb/en/mariadb-versus-mysql-features/
https://mariadb.com/kb/en/mariadb-versus-mysql-compatibility/
As MariaDB is a full replacement of MySQL, the MySQL manual at http://dev.mysql.com/doc is generally applicable.
Help:
More help is available from the Maria Discuss mailing list https://launchpad.net/~maria-discuss and the #maria IRC channel on Freenode.
Licensing:
NOTE:
MariaDB is specifically available only under version 2 of the GNU General Public License (GPLv2). (I.e. Without the "any later version" clause.) This is inherited from MySQL. Please see the README file in the MySQL distribution for more information.
License information can be found in the COPYING file. Third party license information can be found in the THIRDPARTY file.
Bug Reports:
Bug and/or error reports regarding MariaDB should be submitted at: https://jira.mariadb.org
For reporting security vulnerabilities see: https://mariadb.org/about/security-policy/
Bugs in the MySQL code can also be submitted at: https://bugs.mysql.com
The code for MariaDB, including all revision history, can be found at: https://github.com/MariaDB/server