- MariaDB\ 71.8%
- C++ 16.4%
- C 10.4%
- Shell 0.5%
- Perl 0.4%
- Other 0.3%
The asserion failure was caused by this query
select /*id=1*/ from t1
where
col= ( select /*id=2*/ from ... where corr_cond1
union
select /*id=4*/ from ... where corr_cond2)
Here,
- select with id=2 was correlated due to corr_cond1.
- select with id=4 was initially correlated due to corr_cond2, but then
the optimizer optimized away the correlation, making the select with id=4
uncorrelated.
However, since select with id=2 remained correlated, the execution had to
re-compute the whole UNION. When it tried to execute select with id=4, it
hit an assertion (join buffer already free'd).
This is because select with id=4 has freed its execution structures after
it has been executed once. The select is uncorrelated, so it did not expect
it would need to be executed for the second time.
Fixed this by adding this logic in
st_select_lex::optimize_unflattened_subqueries():
If a member of a UNION is correlated, mark all its members as
correlated, so that they are prepared to be executed multiple times.
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| BUILD | ||
| client | ||
| cmake | ||
| dbug | ||
| debian | ||
| Docs | ||
| extra | ||
| include | ||
| libmariadb@f6c3d9fd2a | ||
| libmysqld | ||
| libservices | ||
| man | ||
| mysql-test | ||
| mysys | ||
| mysys_ssl | ||
| pcre | ||
| plugin | ||
| randgen/conf | ||
| scripts | ||
| sql | ||
| sql-bench | ||
| sql-common | ||
| storage | ||
| strings | ||
| support-files | ||
| tests | ||
| unittest | ||
| vio | ||
| win | ||
| wsrep | ||
| zlib | ||
| .clang-format | ||
| .gitattributes | ||
| .gitignore | ||
| .gitmodules | ||
| .travis.compiler.sh | ||
| .travis.yml | ||
| appveyor.yml | ||
| BUILD-CMAKE | ||
| CMakeLists.txt | ||
| config.h.cmake | ||
| configure.cmake | ||
| COPYING | ||
| CREDITS | ||
| INSTALL-SOURCE | ||
| INSTALL-WIN-SOURCE | ||
| KNOWN_BUGS.txt | ||
| README.md | ||
| THIRDPARTY | ||
| VERSION | ||
Code status:
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