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Alexander Nozdrin authored
Conflicts: - mysql-test/r/mysqld--help-win.result - sql/sys_vars.cc Original revsion (in next-mr-bugfixing): ------------------------------------------------------------ revno: 2971 [merge] revision-id: alfranio.correia@sun.com-20100121210527-rbuheu5rnsmcakh1 committer: Alfranio Correia <alfranio.correia@sun.com> branch nick: mysql-next-mr-bugfixing timestamp: Thu 2010-01-21 21:05:27 +0000 message: BUG#46364 MyISAM transbuffer problems (NTM problem) It is well-known that due to concurrency issues, a slave can become inconsistent when a transaction contains updates to both transaction and non-transactional tables. In a nutshell, the current code-base tries to preserve causality among the statements by writing non-transactional statements to the txn-cache which is flushed upon commit. However, modifications done to non-transactional tables on behalf of a transaction become immediately visible to other connections but may not immediately get into the binary log and therefore consistency may be broken. In general, it is impossible to automatically detect causality/dependency among statements by just analyzing the statements sent to the server. This happen because dependency may be hidden in the application code and it is necessary to know a priori all the statements processed in the context of a transaction such as in a procedure. Moreover, even for the few cases that we could automatically address in the server, the computation effort required could make the approach infeasible. So, in this patch we introduce the option - "--binlog-direct-non-transactional-updates" that can be used to bypass the current behavior in order to write directly to binary log statements that change non-transactional tables. Besides, it is used to enable the WL#2687 which is disabled by default. ------------------------------------------------------------ revno: 2970.1.1 revision-id: alfranio.correia@sun.com-20100121131034-183r4qdyld7an5a0 parent: alik@sun.com-20100121083914-r9rz2myto3tkdya0 committer: Alfranio Correia <alfranio.correia@sun.com> branch nick: mysql-next-mr-bugfixing timestamp: Thu 2010-01-21 13:10:34 +0000 message: BUG#46364 MyISAM transbuffer problems (NTM problem) It is well-known that due to concurrency issues, a slave can become inconsistent when a transaction contains updates to both transaction and non-transactional tables. In a nutshell, the current code-base tries to preserve causality among the statements by writing non-transactional statements to the txn-cache which is flushed upon commit. However, modifications done to non-transactional tables on behalf of a transaction become immediately visible to other connections but may not immediately get into the binary log and therefore consistency may be broken. In general, it is impossible to automatically detect causality/dependency among statements by just analyzing the statements sent to the server. This happen because dependency may be hidden in the application code and it is necessary to know a priori all the statements processed in the context of a transaction such as in a procedure. Moreover, even for the few cases that we could automatically address in the server, the computation effort required could make the approach infeasible. So, in this patch we introduce the option - "--binlog-direct-non-transactional-updates" that can be used to bypass the current behavior in order to write directly to binary log statements that change non-transactional tables. Besides, it is used to enable the WL#2687 which is disabled by default.
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