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- 11 Nov, 2010 1 commit
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Dmitry Lenev authored
bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations.
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- 24 Sep, 2010 1 commit
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Jon Olav Hauglid authored
but broken. Before this patch, it was allowed to use stored functions in HANDLER ... READ statements. The problem was that this functionality was not really supported by the code. Proper locking would for example not be performed, and it was also possible to break replication by having stored functions that performed updates. This patch disallows the use of stored functions in HANDLER ... READ. Any such statement will now give an ER_NOT_SUPPORTED_YET error. This is an incompatible change and should be reflected in the documentation. Test case added to handler_myisam/handler_innodb.test.
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- 05 Jul, 2010 1 commit
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Jon Olav Hauglid authored
This assert checks that the server does not try to send EOF to the client if there has been some error during processing. This to make sure that the error is in fact sent to the client. The problem was that any errors during processing of WHERE conditions in HANDLER ... READ statements where not detected by the handler code. The handler code therefore still tried to send EOF to the client, triggering the assert. The bug was only noticeable in debug builds. This patch fixes the problem by making sure that the handler code checks for errors during condition processing and acts accordingly.
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- 09 Jun, 2010 1 commit
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Ramil Kalimullin authored
Problem: the server missed the fact that one can read from 2 indexes alternately using HANDLER interface. Fix: check if the same (initialized) index is involved reading next/prev values from the index.
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- 25 Mar, 2010 1 commit
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Sergey Vojtovich authored
Invalid memory read if HANDLER ... READ NEXT is executed after failed (e.g. empty table) HANDLER ... READ FIRST. The problem was that we attempted to perform READ NEXT, whereas there is no pivot available from failed READ FIRST. With this fix READ NEXT after failed READ FIRST equals to READ FIRST. This bug affects MyISAM tables only.
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- 25 Feb, 2010 1 commit
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Jon Olav Hauglid authored
bool MDL_context::try_acquire_lock(MDL_request*) This assert was triggered in the following way: 1) HANDLER OPEN t1 from connection 1 2) DROP TABLE t1 from connection 2. This will block due to the metadata lock held by the open handler in connection 1. 3) DML statement (e.g. INSERT) from connection 1. This will close the table opened by the HANDLER in 1) and release its metadata lock. This is done due to the pending exclusive metadata lock from 2). 4) DROP TABLE t1 from connection 2 now completes and removes table t1. 5) HANDLER READ from connection 1. Since the handler table was closed in 3), the handler code will try to reopen the table. First a new metadata lock on t1 will be granted before the command fails since the table was removed in 4). 6) HANDLER READ from connection 1. This caused the assert. The reason for the assert was that the MDL_request's pointer to the lock ticket was not reset when the statement failed. HANDLER READ then tried to acquire a lock using the same MDL_request object, triggering the assert. This bug was only noticeable on debug builds and did not cause any problems on release builds. This patch fixes the problem by assuring that the pointer to the metadata lock ticket is reset when reopening of handler tables fails. Test case added to handler.inc
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- 15 Feb, 2010 1 commit
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Dmitry Lenev authored
TEMPORARY + HANDLER + LOCK + SP". Server crashed when one: 1) Opened HANDLER or acquired global read lock 2) Then locked one or several temporary tables with LOCK TABLES statement (but no base tables). 3) Then issued any statement causing commit (explicit or implicit). 4) Issued statement which should have closed HANDLER or released global read lock. The problem was that when entering LOCK TABLES mode in the scenario described above we incorrectly set transactional MDL sentinel to zero. As result during commit all metadata locks were released (including lock for open HANDLER or global metadata shared lock). Indeed, attempt to release metadata lock for the second time which happened during HANLDER CLOSE or during release of GLR caused crash. This patch fixes problem by changing MDL_context's set_trans_sentinel() method to set sentinel to correct value (it should point to the most recent ticket).
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- 12 Feb, 2010 1 commit
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Dmitry Lenev authored
failed in enter_locked_tables_mode". Server was aborted due to assertion failure when one tried to execute statement requiring prelocking (i.e. firing triggers or using stored functions) while having open HANDLERs. The problem was that THD::enter_locked_tables_mode() method which was called at the beginning of execution of prelocked statement assumed there are no open HANDLERs. It had to do so because corresponding THD::leave_locked_tables_mode() method was unable to properly restore MDL sentinel when leaving LOCK TABLES/prelocked mode in the presence of open HANDLERs. This patch solves this problem by changing the latter method to properly restore MDL sentinel and thus removing need for this assumption. As a side-effect, it lifts unjustified limitation by allowing to keep HANDLERs open when entering LOCK TABLES mode.
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- 06 Feb, 2010 1 commit
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Jon Olav Hauglid authored
failed on HANDLER + I_S This assert was triggered when an I_S query tried to acquire a metadata lock on a table which was already locked by a HANDLER statement in the same connection. First the HANDLER took a MDL_SHARED lock. Afterwards, the I_S query requested a MDL_SHARED_HIGH_PRIO lock. The existing MDL_SHARED ticket is found in find_ticket() since it satisfies ticket->has_stronger_or_equal_type(mdl_request->type) as MDL_SHARED and MDL_SHARED_HIGH_PRIO have equal strengths, just different priority. However, two asserts later check lock type strengths using relational operators (>= and <=) rather than MDL_ticket::has_stronger_or_equal_type(). These asserts are triggered since MDL_SHARED >= MDL_SHARED_HIGH_PRIORITY is false (mapped to 1 and 2 respectively). This patch updates the asserts to use MDL_ticket::has_stronger_or_equal_type() rather than relational operators to check lock type strength. Test case added to include/handler.inc.
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- 05 Feb, 2010 1 commit
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Jon Olav Hauglid authored
HANDLER OPEN The problem was a too restrictive assert in the code for HANDLER ... OPEN and HANDLER ... READ that checked table->next to verify that we didn't open views or merge tables. This pointer is also used to link temporary tables together (see thd->temporary_tables). In this case TABLE::next can be set even if we're trying to open a single table. This patch adjust the two asserts to also check for the presence of temporary tables. Test case added to handler_myisam.test.
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- 01 Feb, 2010 1 commit
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Dmitry Lenev authored
Add a wait-for graph based deadlock detector to the MDL subsystem. Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and bug #37346 "innodb does not detect deadlock between update and alter table". The first bug manifested itself as an unwarranted abort of a transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER statement, when this transaction tried to repeat use of a table, which it has already used in a similar fashion before ALTER started. The second bug showed up as a deadlock between table-level locks and InnoDB row locks, which was "detected" only after innodb_lock_wait_timeout timeout. A transaction would start using the table and modify a few rows. Then ALTER TABLE would come in, and start copying rows into a temporary table. Eventually it would stumble on the modified records and get blocked on a row lock. The first transaction would try to do more updates, and get blocked on thr_lock.c lock. This situation of circular wait would only get resolved by a timeout. Both these bugs stemmed from inadequate solutions to the problem of deadlocks occurring between different locking subsystems. In the first case we tried to avoid deadlocks between metadata locking and table-level locking subsystems, when upgrading shared metadata lock to exclusive one. Transactions holding the shared lock on the table and waiting for some table-level lock used to be aborted too aggressively. We also allowed ALTER TABLE to start in presence of transactions that modify the subject table. ALTER TABLE acquires TL_WRITE_ALLOW_READ lock at start, and that block all writes against the table (naturally, we don't want any writes to be lost when switching the old and the new table). TL_WRITE_ALLOW_READ lock, in turn, would block the started transaction on thr_lock.c lock, should they do more updates. This, again, lead to the need to abort such transactions. The second bug occurred simply because we didn't have any mechanism to detect deadlocks between the table-level locks in thr_lock.c and row-level locks in InnoDB, other than innodb_lock_wait_timeout. This patch solves both these problems by moving lock conflicts which are causing these deadlocks into the metadata locking subsystem, thus making it possible to avoid or detect such deadlocks inside MDL. To do this we introduce new type-of-operation-aware metadata locks, which allow MDL subsystem to know not only the fact that transaction has used or is going to use some object but also what kind of operation it has carried out or going to carry out on the object. This, along with the addition of a special kind of upgradable metadata lock, allows ALTER TABLE to wait until all transactions which has updated the table to go away. This solves the second issue. Another special type of upgradable metadata lock is acquired by LOCK TABLE WRITE. This second lock type allows to solve the first issue, since abortion of table-level locks in event of DDL under LOCK TABLES becomes also unnecessary. Below follows the list of incompatible changes introduced by this patch: - From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those statements that acquire TL_WRITE_ALLOW_READ lock) wait for all transactions which has *updated* the table to complete. - From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE (i.e. all statements which acquire TL_WRITE table-level lock) wait for all transaction which *updated or read* from the table to complete. As a consequence, innodb_table_locks=0 option no longer applies to LOCK TABLES ... WRITE. - DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort statements or transactions which use tables being dropped or renamed, and instead wait for these transactions to complete. - Since LOCK TABLES WRITE now takes a special metadata lock, not compatible with with reads or writes against the subject table and transaction-wide, thr_lock.c deadlock avoidance algorithm that used to ensure absence of deadlocks between LOCK TABLES WRITE and other statements is no longer sufficient, even for MyISAM. The wait-for graph based deadlock detector of MDL subsystem may sometimes be necessary and is involved. This may lead to ER_LOCK_DEADLOCK error produced for multi-statement transactions even if these only use MyISAM: session 1: session 2: begin; update t1 ... lock table t2 write, t1 write; -- gets a lock on t2, blocks on t1 update t2 ... (ER_LOCK_DEADLOCK) - Finally, support of LOW_PRIORITY option for LOCK TABLES ... WRITE was abandoned. LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same priority as the usual LOCK TABLE ... WRITE. SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE in the wait queue. - We do not take upgradable metadata locks on implicitly locked tables. So if one has, say, a view v1 that uses table t1, and issues: LOCK TABLE v1 WRITE; FLUSH TABLE t1; -- (or just 'FLUSH TABLES'), an error is produced. In order to be able to perform DDL on a table under LOCK TABLES, the table must be locked explicitly in the LOCK TABLES list.
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- 21 Jan, 2010 1 commit
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Dmitry Lenev authored
condition variable per context instead of one mutex and one conditional variable for the whole subsystem. This should increase concurrency in this subsystem. It also opens the way for further changes which are necessary to solve such bugs as bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and bug #37346 "innodb does not detect deadlock between update and alter table". Two other notable changes done by this patch: - MDL subsystem no longer implicitly acquires global intention exclusive metadata lock when per-object metadata lock is acquired. Now this has to be done by explicit calls outside of MDL subsystem. - Instead of using separate MDL_context for opening system tables/tables for purposes of I_S we now create MDL savepoint in the main context before opening tables and rollback to this savepoint after closing them. This means that it is now possible to get ER_LOCK_DEADLOCK error even not inside a transaction. This might happen in unlikely case when one runs DDL on one of system tables while also running DDL on some other tables. Cases when this ER_LOCK_DEADLOCK error is not justified will be addressed by advanced deadlock detector for MDL subsystem which we plan to implement.
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- 30 Dec, 2009 1 commit
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Dmitry Lenev authored
This change is supposed to reduce number of ER_LOCK_DEADLOCK errors which occur when multi-statement transaction encounters conflicting metadata lock in cases when waiting is possible. The idea is not to fail ER_LOCK_DEADLOCK error immediately when we encounter conflicting metadata lock. Instead we release all metadata locks acquired by current statement and start to wait until conflicting lock go away. To avoid deadlocks we use simple empiric which aborts waiting with ER_LOCK_DEADLOCK error if it turns out that somebody is waiting for metadata locks owned by this transaction. This patch also fixes bug #46273 "MySQL 5.4.4 new MDL: Bug#989 is not fully fixed in case of ALTER". The bug was that concurrent execution of UPDATE or MULTI-UPDATE statement as a part of multi-statement transaction that already has used table being updated and ALTER TABLE statement might have resulted of loss of isolation between this transaction and ALTER TABLE statement, which manifested itself as changes performed by ALTER TABLE becoming visible in transaction and wrong binary log order as a consequence. This problem occurred when UPDATE or MULTI-UPDATE's wait in mysql_lock_tables() call was aborted due to metadata lock upgrade performed by concurrent ALTER TABLE. After such abort all metadata locks held by transaction were released but transaction silently continued to be executed as if nothing has happened. We solve this problem by changing our code not to release all locks in such case. Instead we release only locks which were acquired by current statement and then try to reacquire them by restarting open/lock tables process. We piggyback on simple deadlock detector implementation since this change has to be done anyway for it.
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- 22 Dec, 2009 1 commit
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Konstantin Osipov authored
"HANDLER statements within a transaction might lead to deadlocks". Introduce a notion of a sentinel to MDL_context. A sentinel is a ticket that separates all tickets in the context into two groups: before and after it. Currently we can have (and need) only one designated sentinel -- it separates all locks taken by LOCK TABLE or HANDLER statement, which must survive COMMIT and ROLLBACK and all other locks, which must be released at COMMIT or ROLLBACK. The tricky part is maintaining the sentinel up to date when someone release its corresponding ticket. This can happen, e.g. if someone issues DROP TABLE under LOCK TABLES (generally, see all calls to release_all_locks_for_name()). MDL_context::release_ticket() is modified to take care of it. ****** A fix and a test case for Bug#46224 "HANDLER statements within a transaction might lead to deadlocks". An attempt to mix HANDLER SQL statements, which are transaction- agnostic, an open multi-statement transaction, and DDL against the involved tables (in a concurrent connection) could lead to a deadlock. The deadlock would occur when HANDLER OPEN or HANDLER READ would have to wait on a conflicting metadata lock. If the connection that issued HANDLER statement also had other metadata locks (say, acquired in scope of a transaction), a classical deadlock situation of mutual wait could occur. Incompatible change: entering LOCK TABLES mode automatically closes all open HANDLERs in the current connection. Incompatible change: previously an attempt to wait on a lock in a connection that has an open HANDLER statement could wait indefinitely/deadlock. After this patch, an error ER_LOCK_DEADLOCK is produced. The idea of the fix is to merge thd->handler_mdl_context with the main mdl_context of the connection, used for transactional locks. This makes deadlock detection possible, since all waits with locks are "visible" and available to analysis in a single MDL context of the connection. Since HANDLER locks and transactional locks have a different life cycle -- HANDLERs are explicitly open and closed, and so are HANDLER locks, explicitly acquired and released, whereas transactional locks "accumulate" till the end of a transaction and are released only with COMMIT, ROLLBACK and ROLLBACK TO SAVEPOINT, a concept of "sentinel" was introduced to MDL_context. All locks, HANDLER and others, reside in the same linked list. However, a selected element of the list separates locks with different life cycle. HANDLER locks always reside at the end of the list, after the sentinel. Transactional locks are prepended to the beginning of the list, before the sentinel. Thus, ROLLBACK, COMMIT or ROLLBACK TO SAVEPOINT, only release those locks that reside before the sentinel. HANDLER locks must be released explicitly as part of HANDLER CLOSE statement, or an implicit close. The same approach with sentinel is also employed for LOCK TABLES locks. Since HANDLER and LOCK TABLES statement has never worked together, the implementation is made simple and only maintains one sentinel, which is used either for HANDLER locks, or for LOCK TABLES locks.
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- 30 Nov, 2009 1 commit
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Konstantin Osipov authored
Backport of: ------------------------------------------------------------ revno: 2630.4.1 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Fri 2008-05-23 17:54:03 +0400 message: WL#3726 "DDL locking for all metadata objects". After review fixes in progress. ------------------------------------------------------------ This is the first patch in series. It transforms the metadata locking subsystem to use a dedicated module (mdl.h,cc). No significant changes in the locking protocol. The import passes the test suite with the exception of deprecated/removed 6.0 features, and MERGE tables. The latter are subject to a fix by WL#4144. Unfortunately, the original changeset comments got lost in a merge, thus this import has its own (largely insufficient) comments. This patch fixes Bug#25144 "replication / binlog with view breaks". Warning: this patch introduces an incompatible change: Under LOCK TABLES, it's no longer possible to FLUSH a table that was not locked for WRITE. Under LOCK TABLES, it's no longer possible to DROP a table or VIEW that was not locked for WRITE. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.2 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 14:03:45 +0400 message: WL#3726 "DDL locking for all metadata objects". After review fixes in progress. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.3 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 14:08:51 +0400 message: WL#3726 "DDL locking for all metadata objects" Fixed failing Windows builds by adding mdl.cc to the lists of files needed to build server/libmysqld on Windows. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.4 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 21:57:58 +0400 message: WL#3726 "DDL locking for all metadata objects". Fix for assert failures in kill.test which occured when one tried to kill ALTER TABLE statement on merge table while it was waiting in wait_while_table_is_used() for other connections to close this table. These assert failures stemmed from the fact that cleanup code in this case assumed that temporary table representing new version of table was open with adding to THD::temporary_tables list while code which were opening this temporary table wasn't always fulfilling this. This patch changes code that opens new version of table to always do this linking in. It also streamlines cleanup process for cases when error occurs while we have new version of table open. ****** WL#3726 "DDL locking for all metadata objects" Add libmysqld/mdl.cc to .bzrignore. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.6 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sun 2008-05-25 00:33:22 +0400 message: WL#3726 "DDL locking for all metadata objects". Addition to the fix of assert failures in kill.test caused by changes for this worklog. Make sure we close the new table only once.
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- 22 Sep, 2009 1 commit
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MySQL Build Team authored
> ------------------------------------------------------------ > revno: 3075 > revision-id: ramil@mysql.com-20090821055535-a5aeas33epokjjnp > parent: joro@sun.com-20090820141122-gq6eyozybvar4o4s > committer: Ramil Kalimullin <ramil@mysql.com> > branch nick: mysql-5.1-bugteam > timestamp: Fri 2009-08-21 10:55:35 +0500 > message: > Fix for bug #46456 [Ver->Prg]: HANDLER OPEN + TRUNCATE + DROP > (temporary) TABLE, crash > > Problem: if one has an open "HANDLER t1", further "TRUNCATE t1" > doesn't close the handler and leaves handler table hash in an > inconsistent state, that may lead to a server crash. > > Fix: TRUNCATE should implicitly close all open handlers. > > Doc. request: the fact should be described in the manual accordingly.
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- 21 Aug, 2009 1 commit
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Ramil Kalimullin authored
(temporary) TABLE, crash Problem: if one has an open "HANDLER t1", further "TRUNCATE t1" doesn't close the handler and leaves handler table hash in an inconsistent state, that may lead to a server crash. Fix: TRUNCATE should implicitly close all open handlers. Doc. request: the fact should be described in the manual accordingly.
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- 24 Jun, 2009 1 commit
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MySQL Build Team authored
> ------------------------------------------------------------ > revno: 2857.1.8 > revision-id: sergey.glukhov@sun.com-20090417084627-yvt63k51vvvjbx9j > parent: anurag.shekhar@sun.com-20090417055354-7vw80v1rwn0z1tt4 > parent: sergey.glukhov@sun.com-20090417074115-dv9h5ijalj2hgq3r > committer: Sergey Glukhov <Sergey.Glukhov@sun.com> > branch nick: mysql-5.1-bugteam > timestamp: Fri 2009-04-17 13:46:27 +0500 > message: > 5.0-bugteam->5.1-bugteam merge > ------------------------------------------------------------ > revno: 1810.3882.12 > revision-id: sergey.glukhov@sun.com-20090417074115-dv9h5ijalj2hgq3r > parent: patrick.crews@sun.com-20090416174744-u9fxu6ophud91a1h > committer: Sergey Glukhov <Sergey.Glukhov@sun.com> > branch nick: mysql-5.0-bugteam > timestamp: Fri 2009-04-17 12:41:15 +0500 > message: > Bug#44151 using handler commands on information_schema tables crashes server > information schema tables are based on internal tmp tables which are removed > after each statement execution. So HANDLER comands can not be used with > information schema.
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- 20 Nov, 2007 1 commit
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davi@endora.local authored
The problem is that DROP TABLE and other DDL statements failed to automatically close handlers associated with tables that were marked for reopen (FLUSH TABLES). The current implementation fails to properly discard handlers of dropped tables (that were marked for reopen) because it searches on the open handler tables list and using the current alias of the table being dropped. The problem is that it must not use the open handler tables list to search because the table might have been closed (marked for reopen) by a flush tables command and also it must not use the current table alias at all since multiple different aliases may be associated with a single table. This is specially visible when a user has two open handlers (using alias) of a same table and a flush tables command is issued before the table is dropped (see test case). Scanning the handler table list is also useless for dropping handlers associated with temporary tables, because temporary tables are not kept in the THD::handler_tables list. The solution is to simple scan the handlers hash table searching for, and deleting all handlers with matching table names if the reopen flag is not passed to the flush function, indicating that the handlers should be deleted. All matching handlers are deleted even if the associated the table is not open.
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- 01 Nov, 2007 1 commit
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davi@endora.local authored
If a stored function that contains a drop temporary table statement is invoked by a create temporary table of the same name may cause a server crash. The problem is that when dropping a table no check is done to ensure that table is not being used by some outer query (or outer statement), potentially leaving the outer query with a reference to a stale (freed) table. The solution is when dropping a temporary table, always check if the table is being used by some outer statement as a temporary table can be dropped inside stored procedures. The check is performed by looking at the TABLE::query_id value for temporary tables. To simplify this check and to solve a bug related to handling of temporary tables in prelocked mode, this patch changes the way in which this member is used to track the fact that table is used/unused. Now we ensure that TABLE::query_id is zero for unused temporary tables (which means that all temporary tables which were used by a statement should be marked as free for reuse after it's execution has been completed).
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- 11 Oct, 2007 1 commit
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davi@moksha.com.br authored
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- 10 Oct, 2007 1 commit
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davi@moksha.com.br authored
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- 29 Aug, 2007 1 commit
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davi@moksha.local authored
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- 16 Aug, 2006 2 commits
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mleich@three.local.lan authored
WL#3397 Refactoring storage engine test cases (for falcon) It contains fixes according to second code review. - Remove any occurence of hardcoded assignments of storage engines - Use variable names exact telling what it is used for - Updated comments - remove trailing spaces
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mleich@three.local.lan authored
WL#3397 Refactoring storage engine test cases (for falcon) It contains also fixes according to code review. Contents: Testcases which were in history dedicated to InnoDB or MyISAM only. Modifications: 1. Shift the main testing code into include/<testing field>.inc Introduce $variables which can be used to omit tests for features which are not supported by certain storage engines. 2. The storage engine to be tested is assigned within the toplevel script (t/<whatever>_<engine>.test) via variable $engine_type and the the main testing code is sourced from include/<testing field>.inc 3. Some toplevel testscripts have to be renamed to - avoid immediate or future namespace clashes - show via filename which storage engine is tested 4. Minor code cleanup like remove trailing spaces, some additional comments ....
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- 05 Jan, 2006 1 commit
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monty@mysql.com authored
- Fixed tests - Optimized new code - Fixed some unlikely core dumps - Better bug fixes for: - #14397 - OPTIMIZE TABLE with an open HANDLER causes a crash - #14850 (ERROR 1062 when a quering a view using a Group By on a column that can be null
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- 15 Nov, 2005 1 commit
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ingo@mysql.com authored
Version for 5.0. It fixes three problems: 1. The cause of the bug was that we did not check the table version for the HANDLER ... READ commands. We did not notice when a table was replaced by a new one. This can happen during ALTER TABLE, REPAIR TABLE, and OPTIMIZE TABLE (there might be more cases). I call the fix for this problem "the primary bug fix". 2. mysql_ha_flush() was not always called with a locked LOCK_open. Though the function comment clearly said it must. I changed the code so that the locking is done when required. I call the fix for this problem "the secondary fix". 3. In 5.0 (not in 4.1 or 4.0) DROP TABLE had a possible deadlock flaw in concur with FLUSH TABLES WITH READ LOCK. I call the fix for this problem "the 5.0 addendum fix".
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- 03 Nov, 2005 1 commit
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ingo@mysql.com authored
Version for 4.0. It fixes two problems: 1. The cause of the bug was that we did not check the table version for the HANDLER ... READ commands. We did not notice when a table was replaced by a new one. This can happen during ALTER TABLE, REPAIR TABLE, and OPTIMIZE TABLE (there might be more cases). I call the fix for this problem "the primary bug fix". 2. mysql_ha_flush() was not always called with a locked LOCK_open. Though the function comment clearly said it must. I changed the code so that the locking is done when required. I call the fix for this problem "the secondary fix".
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- 07 Oct, 2004 1 commit
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monty@mysql.com authored
Some bigger code changes was necessary becasue of the multi-table-update and the new HANDLER code
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- 24 Sep, 2004 1 commit
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ingo@mysql.com authored
BUG#4335 - one name can be handler open'ed many times. Reworked the HANDLER functions and interface. Using a HASH to store information on open tables that survives FLUSH TABLE. HANDLER tables alias names must now be unique, though it is allowed in 4.0 to qualify them with the database name of the base table.
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- 16 Jun, 2004 1 commit
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paul@ice.snake.net authored
and affected test results.
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- 15 Jun, 2004 1 commit
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paul@kite-hub.kitebird.com authored
and affected test results.
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- 18 May, 2004 1 commit
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sergefp@mysql.com authored
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- 13 Jan, 2004 1 commit
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serg@serg.mylan authored
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- 16 Dec, 2003 1 commit
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monty@mysql.com authored
Make ENGINE= an alias for TYPE= (Compabiltiy with 4.1) Fix when using symlinked data files and realpath() is not working
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- 10 Dec, 2003 1 commit
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Deprecate the use of TYPE=... Preferred syntax is ENGINE=
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- 18 Aug, 2003 1 commit
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monty@mashka.mysql.fi authored
Use server character set if --default-character-set is not used Added convert_string() for more efficient alloc+character-set convert of strings
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- 04 Jul, 2003 3 commits
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ram@mysql.r18.ru authored
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serg@serg.mylan authored
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ram@mysql.r18.ru authored
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