- 07 Mar, 2007 5 commits
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kostja@bodhi.local authored
into bodhi.local:/opt/local/work/mysql-5.1-runtime
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kostja@bodhi.local authored
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kostja@bodhi.local authored
into bodhi.local:/opt/local/work/mysql-5.1-runtime
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kostja@bodhi.local authored
into bodhi.local:/opt/local/work/mysql-5.0-26750
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kostja@bodhi.local authored
fixes). The legend: on a replication slave, in case a trigger creation was filtered out because of application of replicate-do-table/ replicate-ignore-table rule, the parsed definition of a trigger was not cleaned up properly. LEX::sphead member was left around and leaked memory. Until the actual implementation of support of replicate-ignore-table rules for triggers by the patch for Bug 24478 it was never the case that "case SQLCOM_CREATE_TRIGGER" was not executed once a trigger was parsed, so the deletion of lex->sphead there worked and the memory did not leak. The fix: The real cause of the bug is that there is no 1 or 2 places where we can clean up the main LEX after parse. And the reason we can not have just one or two places where we clean up the LEX is asymmetric behaviour of MYSQLparse in case of success or error. One of the root causes of this behaviour is the code in Item::Item() constructor. There, a newly created item adds itself to THD::free_list - a single-linked list of Items used in a statement. Yuck. This code is unaware that we may have more than one statement active at a time, and always assumes that the free_list of the current statement is located in THD::free_list. One day we need to be able to explicitly allocate an item in a given Query_arena. Thus, when parsing a definition of a stored procedure, like CREATE PROCEDURE p1() BEGIN SELECT a FROM t1; SELECT b FROM t1; END; we actually need to reset THD::mem_root, THD::free_list and THD::lex to parse the nested procedure statement (SELECT *). The actual reset and restore is implemented in semantic actions attached to sp_proc_stmt grammar rule. The problem is that in case of a parsing error inside a nested statement Bison generated parser would abort immediately, without executing the restore part of the semantic action. This would leave THD in an in-the-middle-of-parsing state. This is why we couldn't have had a single place where we clean up the LEX after MYSQLparse - in case of an error we needed to do a clean up immediately, in case of success a clean up could have been delayed. This left the door open for a memory leak. One of the following possibilities were considered when working on a fix: - patch the replication logic to do the clean up. Rejected as breaks module borders, replication code should not need to know the gory details of clean up procedure after CREATE TRIGGER. - wrap MYSQLparse with a function that would do a clean up. Rejected as ideally we should fix the problem when it happens, not adjust for it outside of the problematic code. - make sure MYSQLparse cleans up after itself by invoking the clean up functionality in the appropriate places before return. Implemented in this patch. - use %destructor rule for sp_proc_stmt to restore THD - cleaner than the prevoius approach, but rejected because needs a careful analysis of the side effects, and this patch is for 5.0, and long term we need to use the next alternative anyway - make sure that sp_proc_stmt doesn't juggle with THD - this is a large work that will affect many modules. Cleanup: move main_lex and main_mem_root from Statement to its only two descendants Prepared_statement and THD. This ensures that when a Statement instance was created for purposes of statement backup, we do not involve LEX constructor/destructor, which is fairly expensive. In order to track that the transformation produces equivalent functionality please check the respective constructors and destructors of Statement, Prepared_statement and THD - these members were used only there. This cleanup is unrelated to the patch.
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- 06 Mar, 2007 9 commits
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malff/marcsql@weblab.(none) authored
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.1-8407-merge
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malff/marcsql@weblab.(none) authored
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kostja@bodhi.local authored
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.0-8407_b
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.1-8407-merge
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kostja@bodhi.local authored
into bodhi.local:/opt/local/work/mysql-5.1-runtime-merge
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kostja@bodhi.local authored
into bodhi.local:/opt/local/work/mysql-5.1-runtime-merge
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malff/marcsql@weblab.(none) authored
Bug 18914 (Calling certain SPs from triggers fail) Bug 20713 (Functions will not not continue for SQLSTATE VALUE '42S02') Bug 21825 (Incorrect message error deleting records in a table with a trigger for inserting) Bug 22580 (DROP TABLE in nested stored procedure causes strange dependency error) Bug 25345 (Cursors from Functions) This fix resolves a long standing issue originally reported with bug 8407, which affect the behavior of Stored Procedures, Stored Functions and Trigger in many different ways, causing symptoms reported by all the bugs listed. In all cases, the root cause of the problem traces back to 8407 and how the server locks tables involved with sub statements. Prior to this fix, the implementation of stored routines would: - compute the transitive closure of all the tables referenced by a top level statement - open and lock all the tables involved - execute the top level statement "transitive closure of tables" means collecting: - all the tables, - all the stored functions, - all the views, - all the table triggers - all the stored procedures involved, and recursively inspect these objects definition to find more references to more objects, until the list of every object referenced does not grow any more. This mechanism is known as "pre-locking" tables before execution. The motivation for locking all the tables (possibly) used at once is to prevent dead locks. One problem with this approach is that, if the execution path the code really takes during runtime does not use a given table, and if the table is missing, the server would not execute the statement. This in particular has a major impact on triggers, since a missing table referenced by an update/delete trigger would prevent an insert trigger to run. Another problem is that stored routines might define SQL exception handlers to deal with missing tables, but the server implementation would never give user code a chance to execute this logic, since the routine is never executed when a missing table cause the pre-locking code to fail. With this fix, the internal implementation of the pre-locking code has been relaxed of some constraints, so that failure to open a table does not necessarily prevent execution of a stored routine. In particular, the pre-locking mechanism is now behaving as follows: 1) the first step, to compute the transitive closure of all the tables possibly referenced by a statement, is unchanged. 2) the next step, which is to open all the tables involved, only attempts to open the tables added by the pre-locking code, but silently fails without reporting any error or invoking any exception handler is the table is not present. This is achieved by trapping internal errors with Prelock_error_handler 3) the locking step only locks tables that were successfully opened. 4) when executing sub statements, the list of tables used by each statements is evaluated as before. The tables needed by the sub statement are expected to be already opened and locked. Statement referencing tables that were not opened in step 2) will fail to find the table in the open list, and only at this point will execution of the user code fail. 5) when a runtime exception is raised at 4), the instruction continuation destination (the next instruction to execute in case of SQL continue handlers) is evaluated. This is achieved with sp_instr::exec_open_and_lock_tables() 6) if a user exception handler is present in the stored routine, that handler is invoked as usual, so that ER_NO_SUCH_TABLE exceptions can be trapped by stored routines. If no handler exists, then the runtime execution will fail as expected. With all these changes, a side effect is that view security is impacted, in two different ways. First, a view defined as "select stored_function()", where the stored function references a table that may not exist, is considered valid. The rationale is that, because the stored function might trap exceptions during execution and still return a valid result, there is no way to decide when the view is created if a missing table really cause the view to be invalid. Secondly, testing for existence of tables is now done later during execution. View security, which consist of trapping errors and return a generic ER_VIEW_INVALID (to prevent disclosing information) was only implemented at very specific phases covering *opening* tables, but not covering the runtime execution. Because of this existing limitation, errors that were previously trapped and converted into ER_VIEW_INVALID are not trapped, causing table names to be reported to the user. This change is exposing an existing problem, which is independent and will be resolved separately.
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- 05 Mar, 2007 1 commit
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kostja@bodhi.local authored
into bodhi.local:/opt/local/work/mysql-5.0-runtime
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- 02 Mar, 2007 9 commits
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kostja@bodhi.local authored
conflicts without proper analysis and documentation of the nature of the conflict.
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kostja@bodhi.local authored
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rafal@quant.(none) authored
master info structure.
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Kristofer.Pettersson@naruto. authored
- winsock2.h must be included before windows.h
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.0-26093
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malff/marcsql@weblab.(none) authored
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.1-26093-merge
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malff/marcsql@weblab.(none) authored
results) Before this fix, the function BENCHMARK() would fail to evaluate expressions like "(select avg(a) from t1)" in debug builds (with an assert), or would report a time of zero in non debug builds. The root cause is that evaluation of DECIMAL_RESULT expressions was not supported in Item_func_benchmark::val_int(). This has been fixed by this change.
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malff/marcsql@weblab.(none) authored
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- 01 Mar, 2007 16 commits
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malff/marcsql@weblab.(none) authored
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malff/marcsql@weblab.(none) authored
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.0-rt-merge
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malff/marcsql@weblab.(none) authored
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rafal@quant.(none) authored
into quant.(none):/ext/mysql/bkroot/mysql-5.1-new-rpl
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lars/lthalmann@dl145k.mysql.com authored
into mysql.com:/nfsdisk1/lars/bk/mysql-5.1-new-rpl
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bar@mysql.com authored
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-4.1-runtime
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bar@mysql.com authored
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bar@mysql.com authored
into mysql.com:/home/bar/mysql-5.1-rpl
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bar@mysql.com authored
into mysql.com:/home/bar/mysql-5.1-rpl
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rafal@quant.(none) authored
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into mysql.com:/nfsdisk1/lars/MERGE/mysql-5.0-merge
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rafal@quant.(none) authored
into quant.(none):/ext/mysql/bkroot/mysql-5.0-rpl
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jamppa@bk-internal.mysql.com authored
into bk-internal.mysql.com:/data0/bk/mysql-5.0-marvel
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