1. 11 Nov, 2010 1 commit
    • Dmitry Lenev's avatar
      Patch that refactors global read lock implementation and fixes · 6bf6272f
      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.
      
      mysql-test/include/check_ftwrl_compatible.inc:
        Added helper script which allows to check that a statement is
        compatible with FLUSH TABLES WITH READ LOCK.
      mysql-test/include/check_ftwrl_incompatible.inc:
        Added helper script which allows to check that a statement is
        incompatible with FLUSH TABLES WITH READ LOCK.
      mysql-test/include/handler.inc:
        Adjusted test case to the fact that now DROP TABLE closes
        open HANDLERs for the table to be dropped before checking
        if there active FTWRL in this connection.
      mysql-test/include/wait_show_condition.inc:
        Fixed small error in the timeout message. The correct name
        of variable used as parameter for this script is "$condition"
        and not "$wait_condition".
      mysql-test/r/delayed.result:
        Added test coverage for scenario which triggered assert in
        metadata locking subsystem.
      mysql-test/r/events_2.result:
        Updated test results after prohibiting event DDL operations
        under LOCK TABLES.
      mysql-test/r/flush.result:
        Added test coverage for bug #57006 "Deadlock between HANDLER
        and FLUSH TABLES WITH READ LOCK".
      mysql-test/r/flush_read_lock.result:
        Added test coverage for various aspects of FLUSH TABLES WITH
        READ LOCK functionality.
      mysql-test/r/flush_read_lock_kill.result:
        Adjusted test case after replacing custom global read lock
        implementation with one based on metadata locks. Use new
        debug_sync point. Do not disable concurrent inserts as now
        InnoDB we always use InnoDB table.
      mysql-test/r/handler_innodb.result:
        Adjusted test case to the fact that now DROP TABLE closes
        open HANDLERs for the table to be dropped before checking
        if there active FTWRL in this connection.
      mysql-test/r/handler_myisam.result:
        Adjusted test case to the fact that now DROP TABLE closes
        open HANDLERs for the table to be dropped before checking
        if there active FTWRL in this connection.
      mysql-test/r/mdl_sync.result:
        Adjusted test case after replacing custom global read lock
        implementation with one based on metadata locks. Replaced
        usage of GRL-specific debug_sync's with appropriate sync
        points in MDL subsystem.
      mysql-test/suite/perfschema/r/dml_setup_instruments.result:
        Updated test results after removing global
        COND_global_read_lock condition variable.
      mysql-test/suite/perfschema/r/func_file_io.result:
        Ensure that this test doesn't affect subsequent tests.
        At the end of its execution enable back P_S instrumentation
        which this test disables at some point.
      mysql-test/suite/perfschema/r/func_mutex.result:
        Ensure that this test doesn't affect subsequent tests.
        At the end of its execution enable back P_S instrumentation
        which this test disables at some point.
      mysql-test/suite/perfschema/r/global_read_lock.result:
        Adjusted test case to take into account that new GRL
        implementation is based on MDL.
      mysql-test/suite/perfschema/r/server_init.result:
        Adjusted test case after replacing custom global read
        lock implementation with one based on MDL and replacing
        LOCK_event_metadata mutex with metadata lock.
      mysql-test/suite/perfschema/t/func_file_io.test:
        Ensure that this test doesn't affect subsequent tests.
        At the end of its execution enable back P_S instrumentation
        which this test disables at some point.
      mysql-test/suite/perfschema/t/func_mutex.test:
        Ensure that this test doesn't affect subsequent tests.
        At the end of its execution enable back P_S instrumentation
        which this test disables at some point.
      mysql-test/suite/perfschema/t/global_read_lock.test:
        Adjusted test case to take into account that new GRL
        implementation is based on MDL.
      mysql-test/suite/perfschema/t/server_init.test:
        Adjusted test case after replacing custom global read
        lock implementation with one based on MDL and replacing
        LOCK_event_metadata mutex with metadata lock.
      mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result:
        Updated test results after prohibiting event DDL under
        LOCK TABLES.
      mysql-test/t/delayed.test:
        Added test coverage for scenario which triggered assert in
        metadata locking subsystem.
      mysql-test/t/events_2.test:
        Updated test case after prohibiting event DDL operations
        under LOCK TABLES.
      mysql-test/t/flush.test:
        Added test coverage for bug #57006 "Deadlock between HANDLER
        and FLUSH TABLES WITH READ LOCK".
      mysql-test/t/flush_block_commit.test:
        Adjusted test case after changing thread state name which
        is used when COMMIT waits for FLUSH TABLES WITH READ LOCK
        from "Waiting for release of readlock" to "Waiting for commit
        lock".
      mysql-test/t/flush_block_commit_notembedded.test:
        Adjusted test case after changing thread state name which is
        used when DML waits for FLUSH TABLES WITH READ LOCK. Now we
        use "Waiting for global read lock" in this case.
      mysql-test/t/flush_read_lock.test:
        Added test coverage for various aspects of FLUSH TABLES WITH
        READ LOCK functionality.
      mysql-test/t/flush_read_lock_kill-master.opt:
        We no longer need to use make_global_read_lock_block_commit_loop
        debug tag in this test. Instead we rely on an appropriate
        debug_sync point in MDL code.
      mysql-test/t/flush_read_lock_kill.test:
        Adjusted test case after replacing custom global read lock
        implementation with one based on metadata locks. Use new
        debug_sync point. Do not disable concurrent inserts as now
        InnoDB we always use InnoDB table.
      mysql-test/t/lock_multi.test:
        Adjusted test case after changing thread state names which
        are used when DML or DDL waits for FLUSH TABLES WITH READ
        LOCK to "Waiting for global read lock".
      mysql-test/t/mdl_sync.test:
        Adjusted test case after replacing custom global read lock
        implementation with one based on metadata locks. Replaced
        usage of GRL-specific debug_sync's with appropriate sync
        points in MDL subsystem. Updated thread state names which
        are used when DDL waits for FTWRL.
      mysql-test/t/trigger_notembedded.test:
        Adjusted test case after changing thread state names which
        are used when DML or DDL waits for FLUSH TABLES WITH READ
        LOCK to "Waiting for global read lock".
      sql/event_data_objects.cc:
        Removed Event_queue_element::status/last_executed_changed
        members and Event_queue_element::update_timing_fields()
        method. We no longer use this class for updating mysql.events
        once event is chosen for execution. Accesses to instances of
        this class in scheduler thread require protection by
        Event_queue::LOCK_event_queue mutex and we try to avoid
        updating table while holding this lock.
      sql/event_data_objects.h:
        Removed Event_queue_element::status/last_executed_changed
        members and Event_queue_element::update_timing_fields()
        method. We no longer use this class for updating mysql.events
        once event is chosen for execution. Accesses to instances of
        this class in scheduler thread require protection by
        Event_queue::LOCK_event_queue mutex and we try to avoid
        updating table while holding this lock.
      sql/event_db_repository.cc:
        - Changed Event_db_repository methods to not release all
          metadata locks once they are done updating mysql.events
          table. This allows to keep metadata lock protecting
          against GRL and lock protecting particular event around
          until corresponding DDL statement is written to the binary
          log.
        - Removed logic for conditional update of "status" and
          "last_executed" fields from update_timing_fields_for_event()
          method. In the only case when this method is called now
          "last_executed" is always modified and tracking change
          of "status" is too much hassle.
      sql/event_db_repository.h:
        Removed logic for conditional update of "status" and
        "last_executed" fields from Event_db_repository::
        update_timing_fields_for_event() method.
        In the only case when this method is called now "last_executed"
        is always modified and tracking change of "status" field is
        too much hassle.
      sql/event_queue.cc:
        Changed event scheduler code not to update mysql.events
        table while holding Event_queue::LOCK_event_queue mutex.
        Doing so led to a deadlock with a new GRL implementation.
        This deadlock didn't occur with old implementation due to
        fact that code acquiring protection against GRL ignored
        pending GRL requests (which lead to GRL starvation).
        One of goals of new implementation is to disallow GRL
        starvation and so we have to solve problem with this
        deadlock in a different way.
      sql/events.cc:
        Changed methods of Events class to acquire protection
        against GRL while perfoming DDL statement and keep it
        until statement is written to the binary log.
        Unfortunately this step together with new GRL implementation
        exposed deadlock involving Events::LOCK_event_metadata
        and GRL. To solve it Events::LOCK_event_metadata mutex was
        replaced with a metadata lock on event. As a side-effect
        events DDL has to be prohibited under LOCK TABLES even in
        cases when mysql.events table was explicitly locked for
        write.
      sql/events.h:
        Replaced Events::LOCK_event_metadata mutex with a metadata
        lock on event.
      sql/ha_ndbcluster.cc:
        Updated code after replacing custom global read lock
        implementation with one based on MDL. Since MDL subsystem
        should now be able to detect deadlocks involving metadata
        locks and GRL there is no need for special handling of
        active GRL.
      sql/handler.cc:
        Replaced custom implementation of global read lock with
        one based on metadata locks. Consequently when doing
        commit instead of calling method of Global_read_lock
        class to acquire protection against GRL we simply acquire
        IX in COMMIT namespace.
      sql/lock.cc:
        Replaced custom implementation of global read lock with
        one based on metadata locks. This step allows to expose
        wait for GRL to deadlock detector of MDL subsystem and
        thus succesfully resolve deadlocks similar to one behind
        bug #57006 "Deadlock between HANDLER and FLUSH TABLES
        WITH READ LOCK". It also solves problem with GRL starvation
        described in bug #54673 "It takes too long to get readlock
        for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used
        by GRL give preference to FTWRL statement instead of DML
        statements (if needed in future this can be changed to
        fair scheduling).
        
        Similar to old implementation of acquisition of GRL 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.
        
        To support this change:
        - Global_read_lock::lock/unlock_global_read_lock and
          make_global_read_lock_block_commit methods were changed
          accordingly.
        - Global_read_lock::wait_if_global_read_lock() and
          start_waiting_global_read_lock() methods were dropped.
          It is now responsibility of code acquiring metadata locks
          opening tables to acquire protection against GRL by
          explicitly taking global IX lock with statement duration.
        - Global variables, mutex and condition variable used by
          old implementation was removed.
        - lock_routine_name() was changed to use statement duration for
          its global IX lock. It was also renamed to lock_object_name()
          as it now also used to take metadata locks on events.
        - Global_read_lock::set_explicit_lock_duration() was added which
          allows not to release locks used for GRL when leaving prelocked
          mode.
      sql/lock.h:
        - Renamed lock_routine_name() to lock_object_name() and changed
          its signature to allow its usage for events.
        - Removed broadcast_refresh() function. It is no longer needed
          with new GRL implementation.
      sql/log_event.cc:
        Release metadata locks with statement duration at the end
        of processing legacy event for LOAD DATA. This ensures that
        replication thread processing such event properly releases
        its protection against global read lock.
      sql/mdl.cc:
        Changed MDL subsystem to support new MDL-based implementation
        of global read lock.
        
        Added COMMIT and EVENTS namespaces for metadata locks. Changed
        thread state name for GLOBAL namespace to "Waiting for global
        read lock".
        
        Optimized MDL_map::find_or_insert() method to avoid taking
        m_mutex mutex when looking up MDL_lock objects for GLOBAL
        or COMMIT namespaces. We keep pre-created MDL_lock objects
        for these namespaces around and simply return pointers to
        these global objects when needed.
        
        Changed MDL_lock/MDL_scoped_lock to properly handle
        notification of insert delayed handler threads when FTWRL
        takes global S lock.
        
        Introduced concept of lock duration. In addition to locks with
        transaction duration which work in the way which is similar to
        how locks worked before (i.e. they are released at the end of
        transaction), locks with statement and explicit duration were
        introduced.
        Locks with statement duration are automatically released at the
        end of statement. Locks with explicit duration require explicit
        release and obsolete concept of transactional sentinel.
        
        * Changed MDL_request and MDL_ticket classes to support notion
          of duration.
        * Changed MDL_context to keep locks with different duration in
          different lists. Changed code handling ticket list to take
          this into account.
        * Changed methods responsible for releasing locks to take into
          account duration of tickets. Particularly public
          MDL_context::release_lock() method now only can release
          tickets with explicit duration (there is still internal
          method which allows to specify duration). To release locks
          with statement or transaction duration one have to use
          release_statement/transactional_locks() methods.
        * Concept of savepoint for MDL subsystem now has to take into
          account locks with statement duration. Consequently
          MDL_savepoint class was introduced and methods working with
          savepoints were updated accordingly.
        * Added methods which allow to set duration for one or all
          locks in the context.
      sql/mdl.h:
        Changed MDL subsystem to support new MDL-based implementation
        of global read lock.
        
        Added COMMIT and EVENTS namespaces for metadata locks.
        
        Introduced concept of lock duration. In addition to locks with
        transaction duration which work in the way which is similar to
        how locks worked before (i.e. they are released at the end of
        transaction), locks with statement and explicit duration were
        introduced.
        Locks with statement duration are automatically released at the
        end of statement. Locks with explicit duration require explicit
        release and obsolete concept of transactional sentinel.
        
        * Changed MDL_request and MDL_ticket classes to support notion
          of duration.
        * Changed MDL_context to keep locks with different duration in
          different lists. Changed code handling ticket list to take
          this into account.
        * Changed methods responsible for releasing locks to take into
          account duration of tickets. Particularly public
          MDL_context::release_lock() method now only can release
          tickets with explicit duration (there is still internal
          method which allows to specify duration). To release locks
          with statement or transaction duration one have to use
          release_statement/transactional_locks() methods.
        * Concept of savepoint for MDL subsystem now has to take into
          account locks with statement duration. Consequently
          MDL_savepoint class was introduced and methods working with
          savepoints were updated accordingly.
        * Added methods which allow to set duration for one or all
          locks in the context.
      sql/mysqld.cc:
        Removed global mutex and condition variables which were used
        by old implementation of GRL.
        Also we no longer need to initialize Events::LOCK_event_metadata
        mutex as it was replaced with metadata locks on events.
      sql/mysqld.h:
        Removed global variable, mutex and condition variables which
        were used by old implementation of GRL.
      sql/rpl_rli.cc:
        When slave thread closes tables which were open for handling
        of RBR events ensure that it releases global IX lock which
        was acquired as protection against GRL.
      sql/sp.cc:
        Adjusted code to the new signature of lock_object/routine_name(),
        to the fact that one now needs specify duration of lock when
        initializing MDL_request and to the fact that savepoints for MDL
        subsystem are now represented by MDL_savepoint class.
      sql/sp_head.cc:
        Ensure that statements in stored procedures release statement
        metadata locks and thus release their protectiong against GRL
        in proper moment in time.
        Adjusted code to the fact that one now needs specify duration
        of lock when initializing MDL_request.
      sql/sql_admin.cc:
        Adjusted code to the fact that one now needs specify duration
        of lock when initializing MDL_request.
      sql/sql_base.cc:
        - Implemented support for new approach to acquiring protection
          against global read lock. We no longer acquire such protection
          explicitly on the basis of statement flags. Instead we always
          rely on code which is responsible for acquiring metadata locks
          on object to be changed acquiring this protection. This is
          achieved by acquiring global IX metadata lock with statement
          duration. Code doing this also responsible for checking that
          current connection has no active GRL by calling an
          Global_read_lock::can_acquire_protection() method.
          Changed code in open_table() and lock_table_names()
          accordingly.
          Note that as result of this change DDL and DML on temporary
          tables is always compatible with GRL (before it was
          incompatible in some cases and compatible in other cases).
        - To speed-up code acquiring protection against GRL introduced
          m_has_protection_against_grl member in Open_table_context
          class. It indicates that protection was already acquired
          sometime during open_tables() execution and new attempts
          can be skipped.
        - Thanks to new GRL implementation calls to broadcast_refresh()
          became unnecessary and were removed.
        - Adjusted code to the fact that one now needs specify duration
          of lock when initializing MDL_request and to the fact that
          savepoints for MDL subsystem are now represented by
          MDL_savepoint class.
      sql/sql_base.h:
        Adjusted code to the fact that savepoints for MDL subsystem are
        now represented by MDL_savepoint class.
        Also introduced Open_table_context::m_has_protection_against_grl
        member which allows to avoid acquiring protection against GRL
        while opening tables if such protection was already acquired.
      sql/sql_class.cc:
        Changed THD::leave_locked_tables_mode() after transactional
        sentinel for metadata locks was obsoleted by introduction of
        locks with explicit duration.
      sql/sql_class.h:
        - Adjusted code to the fact that savepoints for MDL subsystem
          are now represented by MDL_savepoint class.
        - Changed Global_read_lock class according to changes in
          global read lock implementation:
          * wait_if_global_read_lock and start_waiting_global_read_lock
            are now gone. Instead code needing protection against GRL
            has to acquire global IX metadata lock with statement
            duration itself. To help it new can_acquire_protection()
            was introduced. Also as result of the above change
            m_protection_count member is gone too.
          * Added m_mdl_blocks_commits_lock member to store metadata
            lock blocking commits.
          * Adjusted code to the fact that concept of transactional
            sentinel was obsoleted by concept of lock duration.
        - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer
          necessary. New GRL implementation acquires protection
          against global read lock automagically when statement
          acquires metadata locks on tables or other objects it
          is going to change.
      sql/sql_db.cc:
        Adjusted code to the fact that one now needs specify duration
        of lock when initializing MDL_request.
      sql/sql_handler.cc:
        Removed call to broadcast_refresh() function. It is no longer
        needed with new GRL implementation.
        Adjusted code after introducing duration concept for metadata
        locks. Particularly to the fact transactional sentinel was
        replaced with explicit duration.
      sql/sql_handler.h:
        Renamed mysql_ha_move_tickets_after_trans_sentinel() to
        mysql_ha_set_explicit_lock_duration() after transactional
        sentinel was obsoleted by locks with explicit duration.
      sql/sql_insert.cc:
        Adjusted code handling delaying inserts after switching to
        new GRL implementation. Now connection thread initiating
        delayed insert has to acquire global IX lock in addition
        to metadata lock on table being inserted into. This IX lock
        protects against GRL and similarly to SW lock on table being
        inserted into has to be passed to handler thread in order to
        avoid deadlocks.
      sql/sql_lex.cc:
        LEX::protect_against_global_read_lock member is no longer
        necessary since protection against GRL is automatically
        taken by code acquiring metadata locks/opening tables.
      sql/sql_lex.h:
        LEX::protect_against_global_read_lock member is no longer
        necessary since protection against GRL is automatically
        taken by code acquiring metadata locks/opening tables.
      sql/sql_parse.cc:
        - Implemented support for new approach to acquiring protection
          against global read lock. We no longer acquire such protection
          explicitly on the basis of statement flags. Instead we always
          rely on code which is responsible for acquiring metadata locks
          on object to be changed acquiring this protection. This is
          achieved by acquiring global IX metadata lock with statement
          duration. This lock is automatically released at the end of
          statement execution.
        - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not
          to release metadata locks and thus protection against of GRL
          in the middle of statement execution.
        - Adjusted code to the fact that one now needs specify duration
          of lock when initializing MDL_request and to the fact that
          savepoints for MDL subsystem are now represented by
          MDL_savepoint class.
      sql/sql_prepare.cc:
        Adjusted code to the to the fact that savepoints for MDL
        subsystem are now represented by MDL_savepoint class.
      sql/sql_rename.cc:
        With new GRL implementation there is no need to explicitly
        acquire protection against GRL before renaming tables.
        This happens automatically in code which acquires metadata
        locks on tables being renamed.
      sql/sql_show.cc:
        Adjusted code to the fact that one now needs specify duration
        of lock when initializing MDL_request and to the fact that
        savepoints for MDL subsystem are now represented by
        MDL_savepoint class.
      sql/sql_table.cc:
        - With new GRL implementation there is no need to explicitly
          acquire protection against GRL before dropping tables.
          This happens automatically in code which acquires metadata
          locks on tables being dropped.
        - Changed mysql_alter_table() not to release lock on new table
          name explicitly and to rely on automatic release of locks
          at the end of statement instead. This was necessary since
          now MDL_context::release_lock() is supported only for locks
          for explicit duration.
      sql/sql_trigger.cc:
        With new GRL implementation there is no need to explicitly
        acquire protection against GRL before changing table triggers.
        This happens automatically in code which acquires metadata
        locks on tables which triggers are to be changed.
      sql/sql_update.cc:
        Fix bug exposed by GRL testing. During prepare phase acquire
        only S metadata locks instead of SW locks to keep prepare of
        multi-UPDATE compatible with concurrent LOCK TABLES WRITE
        and global read lock.
      sql/sql_view.cc:
        With new GRL implementation there is no need to explicitly
        acquire protection against GRL before creating view.
        This happens automatically in code which acquires metadata
        lock on view to be created.
      sql/sql_yacc.yy:
        LEX::protect_against_global_read_lock member is no longer
        necessary since protection against GRL is automatically
        taken by code acquiring metadata locks/opening tables.
      sql/table.cc:
        Adjusted code to the fact that one now needs specify duration
        of lock when initializing MDL_request.
      sql/table.h:
        Adjusted code to the fact that one now needs specify duration
        of lock when initializing MDL_request.
      sql/transaction.cc:
        Replaced custom implementation of global read lock with
        one based on metadata locks. Consequently when doing
        commit instead of calling method of Global_read_lock
        class to acquire protection against GRL we simply acquire
        IX in COMMIT namespace.
        Also adjusted code to the fact that MDL savepoint is now
        represented by MDL_savepoint class.
      6bf6272f
  2. 08 Nov, 2010 7 commits
  3. 07 Nov, 2010 3 commits
    • Dmitry Shulga's avatar
      7cd6bb26
    • Dmitry Shulga's avatar
      A fix and a test case for Bug#47924 -main.log_tables times out · 8f237f58
      Dmitry Shulga authored
      sporadically.
      
      The cause of the sporadic time out was a leaking protection
      against the global read lock, taken by the RENAME statement,
      and not released in case of an error occurred during RENAME.
      The leaking protection counter would lead to the value of
      protect_against_global_read never dropping to 0.
      Consequently FLUSH TABLES in all connections, including the
      one that leaked the protection, could not proceed.
       
      The fix is to ensure that all branchesin RENAME code properly
      release GRL protection.
      
      mysql-test/r/log_tables.result:
        Added results for test for bug#47924.
      mysql-test/t/log_tables.test:
        Added test for bug#47924.
      sql/sql_rename.cc:
        mysql_rename_tables() modified: replaced return from function
        to goto to clean up code block in case of error.
      8f237f58
    • He Zhenxing's avatar
  4. 05 Nov, 2010 8 commits
  5. 04 Nov, 2010 6 commits
    • Jorgen Loland's avatar
      Bug#57882 - Item_func_conv_charset::val_str(String*): · f0ce6787
      Jorgen Loland authored
                  Assertion `fixed == 1' failed
      
      Followup patch. Test case relied on system variable that is
      only available if replication is compiled in. Replaced with
      variable available in all builds.
      
      mysql-test/r/errors.result:
        Test case relied on system variable that is only available if
        replication is compiled in. Replaced with variable available in
        all builds.
      mysql-test/t/errors.test:
        Test case relied on system variable that is only available if
        replication is compiled in. Replaced with variable available in
        all builds.
      f0ce6787
    • smenon's avatar
      merge · a9a6cd13
      smenon authored
      a9a6cd13
    • smenon's avatar
      Bug #57746: Win directory of source distribution - out-of-date files / support for new files · 0752b54a
      smenon authored
      (win/README updated with some more changes)
      0752b54a
    • Mats Kindahl's avatar
      BUG#57108: mysqld crashes when I attempt to install plugin · f8d2154c
      Mats Kindahl authored
      If a relative path is supplied to option --defaults-file or
      --defaults-extra-file, the server will crash when executing
      an INSTALL PLUGIN command. The reason is that the defaults
      file is initially read relative the current working directory
      when the server is started, but when INSTALL PLUGIN is executed,
      the server has changed working directory to the data directory.
      Since there is no check that the call to my_load_defaults()
      inside mysql_install_plugin(), the subsequence call to
      free_defaults() will crash the server.
      
      This patch fixes the problem by:
      
      - Prepending the current working directory to the file name when
        a relative path is given to the --defaults-file or --defaults-
        extra-file option the first time my_load_defaults() is called,
        which is just after the server has started in main().
      
      - Adding a check of the return value of my_load_defaults() inside
        mysql_install_plugin() and aborting command (with an error) if
        an error is returned.
      
      - It also adds a check of the return value for load_defaults in
        lib_sql.cc for the embedded server since that was missing.
      
      To test that the relative files for the options --defaults-file and
      --defaults-extra-file is handled properly, mysql-test-run.pl is also
      changed to not add a --defaults-file option if one is provided in the
      tests *.opt file.
      f8d2154c
    • Jorgen Loland's avatar
      Bug#57882 - Item_func_conv_charset::val_str(String*): · 64bee6fd
      Jorgen Loland authored
                  Assertion `fixed == 1' failed
      
      (also fixes duplicate bug 57515)
      
      agg_item_set_converter() (item.cc) handles conversion of 
      character sets by creating a new Item. fix_fields() is then 
      called on this newly created item. Prior to this patch, it was
      not checked whether fix_fields() was successful or not. Thus, 
      agg_item_set_converter() would return success even when an 
      error occured. This patch makes it return error (TRUE) if 
      fix_fields() fails.
      
      mysql-test/r/errors.result:
        Add test for BUG#57882
      mysql-test/t/errors.test:
        Add test for BUG#57882
      sql/item.cc:
        Make agg_item_set_converter() return with error if fix_fields() 
        on the newly created converted item fails.
      64bee6fd
    • He Zhenxing's avatar
      BUG#47027 delegates_init() failure is not user friendly (usability issue) · 6429e7d3
      He Zhenxing authored
            
      Function delegetas_init() did not report proper error messages
      when there are failures, which made it hard to know where the problem
      occurred.
      
      Fixed the problem by adding specific error message for every possible
      place that can fail. And since these failures are supposed to never
      happen, ask the user to report a bug if they happened.
      6429e7d3
  6. 03 Nov, 2010 9 commits
  7. 02 Nov, 2010 5 commits
  8. 01 Nov, 2010 1 commit