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MariaDB server is a community developed fork of MySQL server. Started by core members of the original MySQL team, MariaDB actively works with outside developers to deliver the most featureful, stable, and sanely licensed open SQL server in the industry.
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crashes server (prepared statements)": the bug was that all boolean items always recovered its original arguments at statement cleanup stage. This collided with Item_subselect::select_transformer, which tries to permanently change the item tree to use a transformed subselect instead of original one. So we had this call sequence for prepare: mysql_stmt_prepare -> JOIN::prepare -> Item_subselect::fix_fields -> the item tree gets transformed -> Item_bool_rowready_func2::cleanup, item tree is recovered to original state, while it shouldn't have been; mysql_stmt_execute -> attempts to execute a broken tree -> crash. Now instead of bluntly recovering all arguments of bool functions in Item_bool_rowready_func2::cleanup, we recover only those which were changed, and do it in one place. There still would exist a possibility for a collision with subselect tranformation, if permanent and temporary changes were performed at the same stage. But fortunately subselect transformation is always done first, so it doesn't conflict with the optimization done by propogate_cond_constants. Now we have: mysql_stmt_prepare -> JOIN::prepare -> subselect transformation permanently changes the tree -> cleanup doesn't recover anything, because nothing was registered for recovery. mysql_stmt_execute -> JOIN::prepare (the tree is already transformed, so it doesn't change), JOIN::optimize -> propogate_cond_constants -> temporary changes the item tree with constants -> JOIN::execute -> cleanup -> the changes done by propogate_cond_constants are recovered, as they were registered for recovery. mysql-test/r/ps.result: Bug#5987: test results fixed. mysql-test/t/ps.test: A test for bug#5987 "subselect in bool function crashes server (prepared statements)" sql/item.cc: resolve_const_item is now responsible to register all changes of the item tree for recovery sql/item.h: resolve_const_item signagture changed sql/item_cmpfunc.h: Arguments of boolean functions are now recovered using the centralized registry of THD. sql/sql_class.cc: It's crucial to add new items to the beginning of the recovery list, so that the recovery is performed in LIFO mode: otherwise if we change one node of a tree twice, it will be recovered to some intermediate state. sql/sql_select.cc: change_cond_ref_to_const and propogate_cond_constants are now responsible to register all changes of the item tree for recovery. The recovery is done using the centralized THD registry of changed tree items. |
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| dbug | ||
| Docs | ||
| extra | ||
| heap | ||
| include | ||
| innobase | ||
| isam | ||
| libmysql | ||
| libmysql_r | ||
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| man | ||
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| strings | ||
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| README | ||
This is a release of MySQL, a GPL (free) SQL database server (more licence information in the PUBLIC file and in the reference manual). Please read the "Upgrading from..." section in the manual first, if you are migrating from older versions of MySQL! The latest information about MySQL can be found at: http://www.mysql.com To see what it can do take a look at the features section in the manual. For installation instructions see the Installation chapter in the manual. For future plans see the TODO appendix in the manual. New features/bug fixes history is in the news appendix in the manual. For the currently known bugs/misfeatures (known errors) see the bugs appendix in the manual. For examples of SQL and benchmarking information see the bench directory. The manual mentioned above can be found in the Docs directory. The manual is available in the following formats: as plain ASCII text in Docs/manual.txt, in HTML format in Docs/manual_toc.html, as GNU Info in Docs/mysql.info and as PostScript in Docs/manual.ps. MySQL is brought to you by the MySQL team at MySQL AB For a list of developers and other contributors, see the Credits appendix in the manual. ************************************************************ IMPORTANT: Send bug (error) reports, questions and comments to the mailing list at mysql@lists.mysql.com Please use the 'mysqlbug' script when posting bug reports or questions about MySQL. mysqlbug will gather some information about your system and start your editor with a form in which you can describe your problem. Bug reports might be silently ignored by the MySQL maintainers if there is not a good reason included in the report as to why mysqlbug has not been used. A report that says 'MySQL does not work for me. Why?' is not considered a valid bug report. The mysqlbug script can be found in the 'scripts' directory of the distribution, that is '<where-you-installed-mysql>/scripts'.