- 15 Mar, 2007 1 commit
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guilhem@gbichot3.local authored
into gbichot3.local:/home/mysql_src/mysql-5.1-runtime-735-realfix
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- 14 Mar, 2007 4 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-5.1-26503-merge
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.0-26503
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malff/marcsql@weblab.(none) authored
Before this fix, the parser would accept illegal code in SQL exceptions handlers, that later causes the runtime to crash when executing the code, due to memory violations in the exception handler stack. The root cause of the problem is instructions within an exception handler that jumps to code located outside of the handler. This is illegal according to the SQL 2003 standard, since labels located outside the handler are not supposed to be visible (they are "out of scope"), so any instruction that jumps to these labels, like ITERATE or LEAVE, should not parse. The section of the standard that is relevant for this is : SQL:2003 SQL/PSM (ISO/IEC 9075-4:2003) section 13.1 <compound statement>, syntax rule 4 <quote> The scope of the <beginning label> is CS excluding every <SQL schema statement> contained in CS and excluding every <local handler declaration list> contained in CS. <beginning label> shall not be equivalent to any other <beginning label>s within that scope. </quote> With this fix, the C++ class sp_pcontext, which represent the "parsing context" tree (a.k.a symbol table) of a stored procedure, has been changed as follows: - constructors have been cleaned up, so that only building a root node for the tree is public; building nodes inside a tree is not public. - a new member, m_label_scope, indicates if a given syntactic context belongs to a DECLARE HANDLER block, - label resolution, in the method find_label(), has been changed to implement the restriction of scope regarding labels used in a compound statement. The actions in the parser, when parsing the body of a SQL exception handler, have been changed as follows: - the implementation of an exception handler (DECLARE HANDLER) now creates explicitly a new sp_pcontext, to isolate the code inside the handler from the containing compound statement context. - registering exception handlers as a result occurs in the parent context, see the rule sp_hcond_element - the code in sp_hcond_list has been cleaned up, to avoid code duplication In addition, the flags IN_SIMPLE_CASE and IN_HANDLER, declared in sp_head.h have been removed, since they are unused and broken by design (as seen with Bug 19194 (Right recursion in parser for CASE causes excessive stack usage, limitation), representing a stack in a single flag is not possible. Tests in sp-error have been added to show that illegal constructs are now rejected. Tests in sp have been added for code coverage, to show that ITERATE or LEAVE statements are legal when jumping to a label in scope, inside the body of an exception handler.
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- 13 Mar, 2007 1 commit
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kroki/tomash@moonlight.home authored
lock table for writing during prepare of statement. When single call open_normal_and_derived_tables() was used, we never set table_count to the right value. This patch reverts the part of the old code that does open_tables() (and sets table_count), then checks if table_list->multitable_view is set (and returns if so, using table_count value), and only then it does mysql_handle_derived().
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- 09 Mar, 2007 8 commits
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kroki/tomash@moonlight.home authored
into moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug16425
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guilhem@gbichot3.local authored
Cache". WL#1569 "Prepared Statements: implement support of Query Cache". Prepared SELECTs did not look up in the query cache, and their results were not stored in the query cache. This made them slower than non-prepared SELECTs in some cases. The fix is to re-use the expanded query (the prepared query where "?" placeholders are replaced by their values, at execution time) for searching/storing in the query cache. It works fine for statements prepared via mysql_stmt_prepare(), which are the most commonly used and were the scope of this bugfix and WL. It works less fine for statements prepared via the SQL command PREPARE...FROM, which are still not using the query cache if they have at least one parameter (because then the expanded query contains names of user variables, and user variables don't work with the query cache, even in non-prepared queries). Note that results from prepared SELECTs, which are in the binary protocol, and results from normal SELECTs, which are in the text protocol, ignore each other in the query cache, because a result in the binary protocol should never be served to a SELECT expecting the text protocol and vice-versa. Note, after this patch, bug 25843 starts applying to query cache ("changing default database between PREPARE and EXECUTE of statement breaks binlog"), we need to fix it.
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guilhem@gbichot3.local authored
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kroki/tomash@moonlight.home authored
for bug#16425: Events: no DEFINER clause. The problem was that there were two rules ALTER view_algorithm_opt definer ... VIEW ... ALTER definer EVENT ... so when there was 'ALTER definer' in the input it was unclear if empty view_algorithm_opt should be executed or not. We solve this by introducing three distinct rules ALTER view_algorithm definer ... VIEW ... ALTER definer ... VIEW ... ALTER definer EVENT ... that remove the ambiguity.
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kroki/tomash@moonlight.home authored
into moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug9953
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kroki/tomash@moonlight.home authored
The problem was that some facilities (like CONVERT_TZ() function or server HELP statement) may require implicit access to some tables in 'mysql' database. This access was done by ordinary means of adding such tables to the list of tables the query is going to open. However, if we issued LOCK TABLES before that, we would get "table was not locked" error trying to open such implicit tables. The solution is to treat certain tables as MySQL system tables, like we already do for mysql.proc. Such tables may be opened for reading at any moment regardless of any locks in effect. The cost of this is that system table may be locked for writing only together with other system tables, it is disallowed to lock system tables for writing and have any other lock on any other table. After this patch the following tables are treated as MySQL system tables: mysql.help_category mysql.help_keyword mysql.help_relation mysql.help_topic mysql.proc (it already was) mysql.time_zone mysql.time_zone_leap_second mysql.time_zone_name mysql.time_zone_transition mysql.time_zone_transition_type These tables are now opened with open_system_tables_for_read() and closed with close_system_tables(), or one table may be opened with open_system_table_for_update() and closed with close_thread_tables() (the latter is used for mysql.proc table, which is updated as part of normal MySQL server operation). These functions may be used when some tables were opened and locked already. NOTE: online update of time zone tables is not possible during replication, because there's no time zone cache flush neither on LOCK TABLES, nor on FLUSH TABLES, so the master may serve stale time zone data from cache, while on slave updated data will be loaded from the time zone tables.
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anozdrin/alik@booka.opbmk authored
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anozdrin/alik@booka.opbmk authored
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- 08 Mar, 2007 3 commits
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kroki/tomash@moonlight.home authored
into moonlight.home:/home/tomash/src/mysql_ab/mysql-5.0-bug20492
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kroki/tomash@moonlight.home authored
into moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug20492
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kostja@bodhi.local authored
to a pointer to object, that is, int foo(); void *bar= (void*) foo is not allowed.
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- 07 Mar, 2007 11 commits
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malff/marcsql@weblab.(none) authored
into weblab.(none):/home/marcsql/TREE/mysql-5.1-8407-cleanup
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kroki/tomash@moonlight.home authored
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malff/marcsql@weblab.(none) authored
Bug 8407, post review cleanup: use instr::get_cont_dest() to get the instruction continuation instruction, for CONTINUE exception handlers.
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kroki/tomash@moonlight.home authored
into moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug18326
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kroki/tomash@moonlight.home authored
During statement prepare phase the tables were locked as if the statement is being executed, however this is not necessary. The solution is to not lock tables on statement prepare phase. Opening tables is enough to prevent DDL on them, and during statement prepare we do not access nor modify any data.
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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
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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 2 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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