9a5a86f293
Problem: ======== The mysqlbinlog tool is leaking memory, causing failures in various tests when compiling and testing with AddressSanitizer or LeakSanitizer like this: cmake -DCMAKE_BUILD_TYPE=Debug -DWITH_ASAN:BOOL=ON /path/to/source make -j$(nproc) cd mysql-test ASAN_OPTIONS=abort_on_error=1 ./mtr --parallel=auto Analysis: ========= Two types of leaks were observed during above execution. 1) Leak in Log_event::read_log_event(char const*, unsigned int, char const**, Format_description_log_event const*, char) File: sql/log_event.cc:2150 For all row based replication events the memory which is allocated during read_log_event is not freed after the event is processed. The event specific memory has to be retained only when flashback option is enabled with mysqlbinlog tool. In this case all the events are retained till the end statement is received and they are processed in reverse order and they are destroyed. But in the existing code all events are retained irrespective of flashback mode. Hence the memory leaks are observed. 2) read_remote_annotate_event(unsigned char*, unsigned long, char const**) File: client/mysqlbinlog.cc:194 In general the Annotate event is not printed immediately because all subsequent rbr-events can be filtered away. Instead it will be printed together with the first not filtered away Table map or the last rbr will be processed. While reading remote annotate events memory is allocated for event buffer and event's temp_buf is made to point to the allocated buffer as shown below. The TRUE flag is used for doing proper cleanup using free_temp_buf(). i.e at the time of deletion of annotate event its destructor takes care of clearing the temp_buf. /* Ensure the event->temp_buf is pointing to the allocated buffer. (TRUE = free temp_buf on the event deletion) */ event->register_temp_buf((char*)event_buf, TRUE); But existing code does the following when it receives a remote annotate_event. if (remote_opt) ev->temp_buf= 0; That is code immediately sets temp_buf=0, because of which free_temp_buf() call will return empty handed as it has lost the reference to the allocated temporary buffer. This results in memory leak Fix: ==== 1) If not in flashback mode, destroy the memory for events once they are processed. 2) Remove the ev->temp_buf=0 code for remote option. Let the proper cleanup to be done as part of free_temp_buf().
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.
License:
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, COPYING.LESSER, and COPYING.thirdparty files.
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
Code status:
travis-ci.org (10.2 branch)