mirror of
https://github.com/MariaDB/server.git
synced 2025-11-30 05:23:50 +03:00
4bad6aa9ae
Analysis: ======== When a given client session ends on a master, the server logs a DROP TEMPORARY TABLE IF EXISTS statement for each temporary table that still exists in the current session. It ensures a proper temporary table cleanup on the slave. In order to write the DROP TEMPORARY TABLE query in binary log a 'Query_log_event' object is created. Within the 'Query_log_event' constructor 'thd->lex->sql_command' is read to identify what type of cache needs to be used to write the query. When the code reaches here as part of THD::cleanup the 'thd->lex->sql_command' will be in an invalid state. The 'thd->lex' could have been cleared or it could be pointing to a statement which was in the middle of execution when the session ended. In such cases ASAN reports use-after-poison error. Fix: === The 'THD::Cleanup' code invokes 'THD::log_events_and_free_tmp_shares' to look for temporary tables and write appropriate DROP TABLE stmts for them. This cleanup code provides a special flag named 'direct=TRUE' to the Query_log_event constructor. Having 'direct=TRUE' means that this query doesn't require any caching. Hence in this scenario the 'Query_log_event' constructor should respect the 'direct' flag and simply skip the logic of deciding the type of cache to be used for the statement. Hence the code will not access the stale lex object.
How to run. =========== ./mysql-test-run.pl --suite=rpl --mysqld=--binlog-format=mixed