• Konstantin Osipov's avatar
    Initial import of WL#3726 "DDL locking for all metadata objects". · e3b03d5d
    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.
    
    .bzrignore:
      Add libmysqld/mdl.cc
    libmysqld/CMakeLists.txt:
      Added mdl.cc to the list of files needed for building of libmysqld.
    libmysqld/Makefile.am:
      Added files implementing new meta-data locking subsystem to the server.
    mysql-test/include/handler.inc:
      Use separate connection for waiting while threads performing DDL
      operations conflicting with open HANDLER tables reach blocked
      state. This is required because now we check and close tables open
      by HANDLER statements in this connection conflicting with DDL in
      another each time open_tables() is called and thus select from I_S
      which is used for waiting will unblock DDL operations if issued
      from connection with open HANDLERs.
    mysql-test/r/create.result:
      Adjusted test case after change in implementation of CREATE TABLE
      ... SELECT.  We no longer have special check in open_table() which
      catches the case when we select from the table created. Instead we
      rely on unique_table() call which happens after opening and
      locking all tables.
    mysql-test/r/flush.result:
      FLUSH TABLES WITH READ LOCK can no longer happen under LOCK
      TABLES.  Updated test accordingly.
    mysql-test/r/flush_table.result:
      Under LOCK TABLES we no longer allow to do FLUSH TABLES for tables
      locked for read. Updated test accordingly.
    mysql-test/r/handler_innodb.result:
      Use separate connection for waiting while threads performing DDL
      operations conflicting with open HANDLER tables reach blocked
      state. This is required because now we check and close tables open
      by HANDLER statements in this connection conflicting with DDL in
      another each time open_tables() is called and thus select from I_S
      which is used for waiting will unblock DDL operations if issued
      from connection with open HANDLERs.
    mysql-test/r/handler_myisam.result:
      Use separate connection for waiting while threads performing DDL
      operations conflicting with open HANDLER tables reach blocked
      state. This is required because now we check and close tables open
      by HANDLER statements in this connection conflicting with DDL in
      another each time open_tables() is called and thus select from I_S
      which is used for waiting will unblock DDL operations if issued
      from connection with open HANDLERs.
    mysql-test/r/information_schema.result:
      Additional test for WL#3726 "DDL locking for all metadata
      objects".  Check that we use high-priority metadata lock requests
      when filling I_S tables.
      
      Rearrange tests to match 6.0 better (fewer merge conflicts).
    mysql-test/r/kill.result:
      Added tests checking that DDL and DML statements waiting for
      metadata locks can be interrupted by KILL command.
    mysql-test/r/lock.result:
      One no longer is allowed to do DROP VIEW under LOCK TABLES even if
      this view is locked by LOCK TABLES. The problem is that in such
      situation write locks on view are not mutually exclusive so
      upgrading metadata lock which is required for dropping of view
      will lead to deadlock.
    mysql-test/r/partition_column_prune.result:
      Update results (same results in 6.0), WL#3726
    mysql-test/r/partition_pruning.result:
      Update results (same results in 6.0), WL#3726
    mysql-test/r/ps_ddl.result:
      We no longer invalidate prepared CREATE TABLE ... SELECT statement
      if target table changes. This is OK since it is not strictly
      necessary.
      
      
      The first change is wrong, is caused by FLUSH TABLE
      now flushing all unused tables. This is a regression that
      Dmitri fixed in 6.0 in a follow up patch.
    mysql-test/r/sp.result:
      Under LOCK TABLES we no longer allow accessing views which were
      not explicitly locked. To access view we need to obtain metadata
      lock on it and doing this under LOCK TABLES may lead to deadlocks.
    mysql-test/r/view.result:
      One no longer is allowed to do DROP VIEW under LOCK TABLES even if
      this view is locked by LOCK TABLES. The problem is that in such
      situation even "write locks" on view are not mutually exclusive so
      upgrading metadata lock which is required for dropping of view
      will lead to deadlock
    mysql-test/r/view_grant.result:
      ALTER VIEW implementation was changed to open a view only after
      checking that user which does alter has appropriate privileges on
      it. This means that in case when user's privileges are
      insufficient for this we won't check that new view definer is the
      same as original one or user performing alter has SUPER privilege.
      Adjusted test case accordingly.
    mysql-test/r/view_multi.result:
      Added test case for bug#25144 "replication / binlog with view
      breaks".
    mysql-test/suite/rpl/t/disabled.def:
      Disable test for deprecated features (they don't work with new MDL).
    mysql-test/t/create.test:
      Adjusted test case after change in implementation of CREATE TABLE
      ... SELECT.  We no longer have special check in open_table() which
      catches the case when we select from the table created. Instead we
      rely on unique_table() call which happens after opening and
      locking all tables.
    mysql-test/t/disabled.def:
      Disable merge.test, subject of WL#4144
    mysql-test/t/flush.test:
      
      FLUSH TABLES WITH READ LOCK can no longer happen under LOCK
      TABLES.  Updated test accordingly.
    mysql-test/t/flush_table.test:
      Under LOCK TABLES we no longer allow to do FLUSH TABLES for tables
      locked for read. Updated test accordingly.
    mysql-test/t/information_schema.test:
      Additional test for WL#3726 "DDL locking for all metadata
      objects".  Check that we use high-priority metadata lock requests
      when filling I_S tables.
      
      Rearrange the results for easier merges with 6.0.
    mysql-test/t/kill.test:
      Added tests checking that DDL and DML statements waiting for
      metadata locks can be interrupted by KILL command.
    mysql-test/t/lock.test:
      One no longer is allowed to do DROP VIEW under LOCK TABLES even if
      this view is locked by LOCK TABLES. The problem is that in such
      situation write locks on view are not mutually exclusive so
      upgrading metadata lock which is required for dropping of view
      will lead to deadlock.
    mysql-test/t/lock_multi.test:
      Adjusted test case to the changes of status in various places
      caused by change in implementation FLUSH TABLES WITH READ LOCK,
      which is now takes global metadata lock before flushing tables and
      therefore waits on at these places.
    mysql-test/t/ps_ddl.test:
      We no longer invalidate prepared CREATE TABLE ... SELECT statement
      if target table changes. This is OK since it is not strictly
      necessary.
      
      
      The first change is wrong, is caused by FLUSH TABLE
      now flushing all unused tables. This is a regression that
      Dmitri fixed in 6.0 in a follow up patch.
    mysql-test/t/sp.test:
      Under LOCK TABLES we no longer allow accessing views which were
      not explicitly locked. To access view we need to obtain metadata
      lock on it and doing this under LOCK TABLES may lead to deadlocks.
    mysql-test/t/trigger_notembedded.test:
      Adjusted test case to the changes of status in various places
      caused by change in implementation FLUSH TABLES WITH READ LOCK,
      which is now takes global metadata lock before flushing tables and
      therefore waits on at these places.
    mysql-test/t/view.test:
      One no longer is allowed to do DROP VIEW under LOCK TABLES even if
      this view is locked by LOCK TABLES. The problem is that in such
      situation even "write locks" on view are not mutually exclusive so
      upgrading metadata lock which is required for dropping of view
      will lead to deadlock.
    mysql-test/t/view_grant.test:
      ALTER VIEW implementation was changed to open a view only after
      checking that user which does alter has appropriate privileges on
      it. This means that in case when user's privileges are
      insufficient for this we won't check that new view definer is the
      same as original one or user performing alter has SUPER privilege.
      Adjusted test case accordingly.
    mysql-test/t/view_multi.test:
      Added test case for bug#25144 "replication / binlog with view
      breaks".
    sql/CMakeLists.txt:
      Added mdl.cc to the list of files needed for building of server.
    sql/Makefile.am:
      Added files implementing new meta-data locking subsystem to the
      server.
    sql/event_db_repository.cc:
      
      Allocate metadata lock requests objects (MDL_LOCK) on execution
      memory root in cases when TABLE_LIST objects is also allocated
      there or on stack.
    sql/ha_ndbcluster.cc:
      Adjusted code to work nicely with new metadata locking subsystem.
      close_cached_tables() no longer has wait_for_placeholder argument.
      Instead of relying on this parameter and related behavior FLUSH
      TABLES WITH READ LOCK now takes global shared metadata lock.
    sql/ha_ndbcluster_binlog.cc:
      Adjusted code to work with new metadata locking subsystem.
      close_cached_tables() no longer has wait_for_placeholder argument.
      Instead of relying on this parameter and related behavior FLUSH
      TABLES WITH READ LOCK now takes global shared metadata lock.
    sql/handler.cc:
      update_frm_version():
        Directly update TABLE_SHARE::mysql_version member instead of
        going through all TABLE instances for this table (old code was a
        legacy from pre-table-definition-cache days).
    sql/lock.cc:
      Use new metadata locking subsystem. Threw away most of functions
      related to name locking as now one is supposed to use metadata
      locking API instead.  In lock_global_read_lock() and
      unlock_global_read_lock() in order to avoid problems with global
      read lock sneaking in at the moment when we perform FLUSH TABLES
      or ALTER TABLE under LOCK TABLES and when tables being reopened
      are protected only by metadata locks we also have to take global
      shared meta data lock.
    sql/log_event.cc:
      Adjusted code to work with new metadata locking subsystem.  For
      tables open by slave thread for applying RBR events allocate
      memory for lock request object in the same chunk of memory as
      TABLE_LIST objects for them. In order to ensure that we keep these
      objects around until tables are open always close tables before
      calling Relay_log_info::clear_tables_to_lock(). Use new auxiliary
      Relay_log_info::slave_close_thread_tables() method to enforce
      this.
    sql/log_event_old.cc:
      Adjusted code to work with new metadata locking subsystem.  Since
      for tables open by slave thread for applying RBR events memory for
      lock request object is allocated in the same chunk of memory as
      TABLE_LIST objects for them we have to ensure that we keep these
      objects around until tables are open. To ensure this we always
      close tables before calling
      Relay_log_info::clear_tables_to_lock(). To enfore this we use
      new auxiliary Relay_log_info::slave_close_thread_tables()
      method.
    sql/mdl.cc:
      Implemented new metadata locking subsystem and API described in
      WL3726 "DDL locking for all metadata objects".
    sql/mdl.h:
      Implemented new metadata locking subsystem and API described in
      WL3726 "DDL locking for all metadata objects".
    sql/mysql_priv.h:
      - close_thread_tables()/close_tables_for_reopen() now has one more
        argument which indicates that metadata locks should be released
        but not removed from the context in order to be used later in
        mdl_wait_for_locks() and tdc_wait_for_old_version().
      - close_cached_table() routine is no longer public.
      - Thread waiting in wait_while_table_is_used() can be now killed
        so this function returns boolean to make caller aware of such
        situation.
      - We no longer have  table cache as separate entity instead used
        and unused TABLE instances are linked to TABLE_SHARE objects in
        table definition cache.
      - Now third argument of open_table() is also used for requesting
        table repair or auto-discovery of table's new definition. So its
        type was changed from bool to enum.
      - Added tdc_open_view() function for opening view by getting its
        definition from disk (and table cache in future).
      - reopen_name_locked_table() no longer needs "link_in" argument as
        now we have exclusive metadata locks instead of dummy TABLE
        instances when this function is called.
      - find_locked_table() now takes head of list of TABLE instances
        instead of always scanning through THD::open_tables list. Also
        added find_write_locked_table() auxiliary.
      - reopen_tables(), close_cached_tables() no longer have
        mark_share_as_old and wait_for_placeholder arguments. Instead of
        relying on this parameters and related behavior FLUSH TABLES
        WITH READ LOCK now takes global shared metadata lock.
      - We no longer need drop_locked_tables() and
        abort_locked_tables().
      - mysql_ha_rm_tables() now always assume that LOCK_open is not
        acquired by caller.
      - Added notify_thread_having_shared_lock() callback invoked by
        metadata locking subsystem when acquiring an exclusive lock, for
        each thread that has a conflicting shared metadata lock.
      - Introduced expel_table_from_cache() as replacement for
        remove_table_from_cache() (the main difference is that this new
        function assumes that caller follows metadata locking protocol
        and never waits).
      - Threw away most of functions related to name locking. One should
        use new metadata locking subsystem and API instead.
    sql/mysqld.cc:
      Got rid of call initializing/deinitializing table cache since now
      it is embedded into table definition cache. Added calls for
      initializing/ deinitializing metadata locking subsystem.
    sql/rpl_rli.cc:
      Introduced auxiliary Relay_log_info::slave_close_thread_tables()
      method which is used for enforcing that we always close tables
      open for RBR before deallocating TABLE_LIST elements and MDL_LOCK
      objects for them.
    sql/rpl_rli.h:
      Introduced auxiliary Relay_log_info::slave_close_thread_tables()
      method which is used for enforcing that we always close tables
      open for RBR before deallocating TABLE_LIST elements and MDL_LOCK
      objects for them.
    sql/set_var.cc:
      close_cached_tables() no longer has wait_for_placeholder argument.
      Instead of relying on this parameter and related behavior FLUSH
      TABLES WITH READ LOCK now takes global shared metadata lock.
    sql/sp_head.cc:
      For tables added to the statement's table list by prelocking
      algorithm we allocate these objects either on the same memory as
      corresponding table list elements or on THD::locked_tables_root
      (if we are building table list for LOCK TABLES).
    sql/sql_acl.cc:
      Allocate metadata lock requests objects (MDL_LOCK) on execution
      memory root in cases when we use stack TABLE_LIST objects to open
      tables.  Got rid of redundant code by using unlock_locked_tables()
      function.
    sql/sql_base.cc:
      Changed code to use new MDL subsystem. Got rid of separate table
      cache.  Now used and unused TABLE instances are linked to the
      TABLE_SHAREs in table definition cache.
      
      check_unused():
        Adjusted code to the fact that we no longer have separate table
        cache.  Removed dead code.
      table_def_free():
        Free TABLE instances referenced from TABLE_SHARE objects before
        destroying table definition cache.
      get_table_share():
        Added assert which ensures that noone will be able to access
        table (and its share) without acquiring some kind of metadata
        lock first.
      close_handle_and_leave_table_as_lock():
        Adjusted code to the fact that TABLE instances now are linked to
        list in TABLE_SHARE.
      list_open_tables():
        Changed this function to use table definition cache instead of
        table cache.
      free_cache_entry():
        Unlink freed TABLE elements from the list of all TABLE instances
        for the table in TABLE_SHARE.
      kill_delayed_thread_for_table():
        Added auxiliary for killing delayed insert threads for
        particular table.
      close_cached_tables():
        Got rid of wait_for_refresh argument as we now rely on global
        shared metadata lock to prevent FLUSH WITH READ LOCK sneaking in
        when we are reopening tables. Heavily reworked this function to
        use new MDL code and not to rely on separate table cache entity.
      close_open_tables():
        We no longer have separate table cache.
      close_thread_tables():
        Release metadata locks after closing all tables. Added skip_mdl
        argument which allows us not to remove metadata lock requests
        from the context in case when we are going to use this requests
        later in mdl_wait_for_locks() and tdc_wait_for_old_versions().
      close_thread_table()/close_table_for_reopen():
        Since we no longer have separate table cache and all TABLE
        instances are linked to TABLE_SHARE objects in table definition
        cache we have to link/unlink TABLE object to/from appropriate
        lists in the share.
      name_lock_locked_table():
       Moved redundant code to find_write_locked_table() function and
        adjusted code to the fact that wait_while_table_is_used() can
        now return with an error if our thread is killed.
      reopen_table_entry():
        We no longer need "link_in" argument as with MDL we no longer
        call this function with dummy TABLE object pre-allocated and
        added to the THD::open_tables. Also now we add newly-open TABLE
        instance to the list of share's used TABLE instances.
      table_cache_insert_placeholder():
        Got rid of name-locking legacy.
      lock_table_name_if_not_cached():
        Moved to sql_table.cc the only place where it is used. It was
        also reimplemented using new MDL API.
      open_table():
        - Reworked this function to use new MDL subsystem.
        - Changed code to deal with table definition cache directly
          instead of going through separate table cache.
        - Now third argument is also used for requesting table repair
          or auto-discovery of table's new definition. So its type was
          changed from bool to enum.
      find_locked_table()/find_write_locked_table():
        Accept head of list of TABLE objects as first argument and use
        this list instead of always searching in THD::open_tables list.
        Also added auxiliary for finding write-locked locked tables.
      reopen_table():
        Adjusted function to work with new MDL subsystem and to properly
        manuipulate with lists of used/unused TABLE instaces in
        TABLE_SHARE.
      reopen_tables():
        Removed mark_share_as_old parameter. Instead of relying on it
        and related behavior FLUSH TABLES WITH READ LOCK now takes
        global shared metadata lock. Changed code after removing
        separate table cache.
      drop_locked_tables()/abort_locked_tables():
        Got rid of functions which are no longer needed.
        unlock_locked_tables():
        Moved this function from sql_parse.cc and changed it to release
        memory which was used for allocating metadata lock requests for
        tables open and locked by LOCK TABLES.
      tdc_open_view():
        Intoduced function for opening a view by getting its definition
        from disk (and table cache in future).
      reopen_table_entry():
        Introduced function for opening table definitions while holding
        exclusive metatadata lock on it.
      open_unireg_entry():
       Got rid of this function. Most of its functionality is relocated
        to open_table() and open_table_fini() functions, and some of it
        to reopen_table_entry() and tdc_open_view(). Also code
        resposible for auto-repair and auto-discovery of tables was
        moved to separate function.
      open_table_entry_fini():
        Introduced function which contains common actions which finalize
        process of TABLE object creation.
      auto_repair_table():
        Moved code responsible for auto-repair of table being opened
        here.
      handle_failed_open_table_attempt()
        Moved code responsible for handling failing attempt to open
        table to one place (retry due to lock conflict/old version,
        auto-discovery and repair).
      open_tables():
        - Flush open HANDLER tables if they have old version of if there
          is conflicting metadata lock against them (before this moment
          we had this code in open_table()).
        - When we open view which should be processed via derived table
          on the second execution of prepared statement or stored
          routine we still should call open_table() for it in order to
          obtain metadata lock on it and prepare its security context.
        - In cases when we discover that some special handling of
          failure to open table is needed call
          handle_failed_open_table_attempt() which handles all such
          scenarios.
      open_ltable():
        Handling of various special scenarios of failure to open a table
        was moved to separate handle_failed_open_table_attempt()
        function.
      remove_db_from_cache():
        Removed this function as it is no longer used.
      notify_thread_having_shared_lock():
        Added callback which is invoked by MDL subsystem when acquiring
        an exclusive lock, for each thread that has a conflicting shared
        metadata lock.
      expel_table_from_cache():
        Introduced function for removing unused TABLE instances. Unlike
        remove_table_from_cache() it relies on caller following MDL
        protocol and having appropriate locks when calling it and thus
        does not do any waiting if table is still in use.
      tdc_wait_for_old_version():
        Added function which allows open_tables() to wait in cases when
        we discover that we should back-off due to presence of old
        version of table.
      abort_and_upgrade_lock():
        Use new MDL calls.
      mysql_wait_completed_table():
        Got rid of unused function.
      open_system_tables_for_read/for_update()/performance_schema_table():
        Allocate MDL_LOCK objects on execution memory root in cases when
        TABLE_LIST objects for corresponding tables is allocated on
        stack.
      close_performance_schema_table():
        Release metadata locks after closing tables.
      ******
      Use I_P_List for free/used tables list in the table share.
    sql/sql_binlog.cc:
      Use Relay_log_info::slave_close_thread_tables() method to enforce
      that we always close tables open for RBR before deallocating
      TABLE_LIST elements and MDL_LOCK objects for them.
    sql/sql_class.cc:
      Added meta-data locking contexts as part of Open_tables_state
      context.  Also introduced THD::locked_tables_root memory root
      which is to be used for allocating MDL_LOCK objects for tables in
      LOCK TABLES statement (end of lifetime for such objects is UNLOCK
      TABLES so we can't use statement or execution root for them).
    sql/sql_class.h:
      Added meta-data locking contexts as part of Open_tables_state
      context.  Also introduced THD::locked_tables_root memory root
      which is to be used for allocating MDL_LOCK objects for tables in
      LOCK TABLES statement (end of lifetime for such objects is UNLOCK
      TABLES so we can't use statement or execution root for them).
      
      Note: handler_mdl_context and locked_tables_root and
      mdl_el_root will be removed by subsequent patches.
    sql/sql_db.cc:
      mysql_rm_db() does not really need to call remove_db_from_cache()
      as it drops each table in the database using
      mysql_rm_table_part2(), which performs all necessary operations on
      table (definition) cache.
    sql/sql_delete.cc:
      Use the new metadata locking API for TRUNCATE.
    sql/sql_handler.cc:
      Changed HANDLER implementation to use new metadata locking
      subsystem.  Note that MDL_LOCK objects for HANDLER tables are
      allocated in the same chunk of heap memory as TABLE_LIST object
      for those tables.
    sql/sql_insert.cc:
      mysql_insert():
        find_locked_table() now takes head of list of TABLE object as
        its argument instead of always scanning through THD::open_tables
        list.
      handle_delayed_insert():
        Allocate metadata lock request object for table open by delayed
        insert thread on execution memroot.  create_table_from_items():
        We no longer allocate dummy TABLE objects for tables being
        created if they don't exist. As consequence
        reopen_name_locked_table() no longer has link_in argument.
        open_table() now has one more argument which is not relevant for
        temporary tables.
    sql/sql_parse.cc:
      - Moved unlock_locked_tables() routine to sql_base.cc and made
        available it in other files. Got rid of some redundant code by
        using this function.
      - Replaced boolean TABLE_LIST::create member with enum
        open_table_type member.
      - Use special memory root for allocating MDL_LOCK objects for
        tables open and locked by LOCK TABLES (these object should live
        till UNLOCK TABLES so we can't allocate them on statement nor
        execution memory root). Also properly set metadata lock
        upgradability attribure for those tables.
      - Under LOCK TABLES it is no longer allowed to flush tables which
        are not write-locked as this breaks metadata locking protocol
        and thus potentially might lead to deadlock.
      - Added auxiliary adjust_mdl_locks_upgradability() function.
    sql/sql_partition.cc:
      Adjusted code to the fact that reopen_tables() no longer has
      "mark_share_as_old" argument. Got rid of comments which are no
      longer true.
    sql/sql_plist.h:
      Added I_P_List template class for parametrized intrusive doubly
      linked lists and I_P_List_iterator for corresponding iterator.
      Unlike for I_List<> list elements of such list can participate in
      several lists. Unlike List<> such lists are doubly-linked and
      intrusive.
    sql/sql_plugin.cc:
      Allocate metadata lock requests objects (MDL_LOCK) on execution
      memory root in cases when we use stack TABLE_LIST objects to open
      tables.
    sql/sql_prepare.cc:
      Replaced boolean TABLE_LIST::create member with enum
      open_table_type member.  This allows easily handle situation in
      which instead of opening the table we want only to take exclusive
      metadata lock on it.
    sql/sql_rename.cc:
      Use new metadata locking subsystem in implementation of RENAME
      TABLE.
    sql/sql_servers.cc:
      Allocate metadata lock requests objects (MDL_LOCK) on execution
      memory root in cases when we use stack TABLE_LIST objects to open
      tables. Got rid of redundant code by using unlock_locked_tables()
      function.
    sql/sql_show.cc:
      Acquire shared metadata lock when we are getting information for
      I_S table directly from TABLE_SHARE without doing full-blown table
      open.  We use high priority lock request in this situation in
      order to avoid deadlocks.
      Also allocate metadata lock requests objects (MDL_LOCK) on
      execution memory root in cases when TABLE_LIST objects are also
      allocated there
    sql/sql_table.cc:
      mysql_rm_table():
        Removed comment which is no longer relevant.
      mysql_rm_table_part2():
        Now caller of mysql_ha_rm_tables() should not own LOCK_open.
        Adjusted code to use new metadata locking subsystem instead of
        name-locks.
      lock_table_name_if_not_cached():
        Moved this function from sql_base.cc to this file and
        reimplemented it using metadata locking API.
      mysql_create_table():
        Adjusted code to use new MDL API.
      wait_while_table_is_used():
        Changed function to use new MDL subsystem. Made thread waiting
        in it killable (this also led to introduction of return value so
        caller can distinguish successful executions from situations
        when waiting was aborted).
      close_cached_tables():
        Thread waiting in this function is killable now. As result it
        has return value for distinguishing between succes and failure.
        Got rid of redundant boradcast_refresh() call.
      prepare_for_repair():
        Use MDL subsystem instead of name-locks.
      mysql_admin_table():
        mysql_ha_rm_tables() now always assumes that caller doesn't own
        LOCK_open.
      mysql_repair_table():
        We should mark all elements of table list as requiring
        upgradable metadata locks.
      mysql_create_table_like():
        Use new MDL subsystem instead of name-locks.
      create_temporary_tables():
        We don't need to obtain metadata locks when creating temporary
        table.
      mysql_fast_or_online_alter_table():
        Thread waiting in wait_while_table_is_used() is now killable.
      mysql_alter_table():
        Adjusted code to work with new MDL subsystem and to the fact
        that threads waiting in what_while_table_is_used() and
        close_cached_table() are now killable.
    sql/sql_test.cc:
      We no longer have separate table cache. TABLE instances are now
      associated with/linked to TABLE_SHARE objects in table definition
      cache.
    sql/sql_trigger.cc:
      Adjusted code to work with new metadata locking subsystem.  Also
      reopen_tables() no longer has mark_share_as_old argument (Instead
      of relying on this parameter and related behavior FLUSH TABLES
      WITH READ LOCK now takes global shared metadata lock).
    sql/sql_udf.cc:
      Allocate metadata lock requests objects (MDL_LOCK) on execution
      memory root in cases when we use stack TABLE_LIST objects to open
      tables.
    sql/sql_update.cc:
      Adjusted code to work with new meta-data locking subsystem.
    sql/sql_view.cc:
      Added proper meta-data locking to implementations of
      CREATE/ALTER/DROP VIEW statements. Now we obtain exclusive
      meta-data lock on a view before creating/ changing/dropping it.
      This ensures that all concurrent statements that use this view
      will finish before our statement will proceed and therefore we
      will get correct order of statements in the binary log.
      Also ensure that TABLE_LIST::mdl_upgradable attribute is properly
      propagated for underlying tables of view.
    sql/table.cc:
      Added auxiliary alloc_mdl_locks() function for allocating metadata
      lock request objects for all elements of table list.
    sql/table.h:
      TABLE_SHARE:
        Got rid of unused members. Introduced members for storing lists
        of used and unused TABLE objects for this share.
      TABLE:
        Added members for linking TABLE objects into per-share lists of
        used and unused TABLE instances. Added member for holding
        pointer to metadata lock for this table.
      TABLE_LIST:
        Replaced boolean TABLE_LIST::create member with enum
        open_table_type member.  This allows easily handle situation in
        which instead of opening the table we want only to take
        exclusive meta-data lock on it (we need this in order to handle
        ALTER VIEW and CREATE VIEW statements).
        Introduced new mdl_upgradable member for marking elements of
        table list for which we need to take upgradable shared metadata
        lock instead of plain shared metadata lock.  Added pointer for
        holding pointer to MDL_LOCK for the table.
      Added auxiliary alloc_mdl_locks() function for allocating metadata
      lock requests objects for all elements of table list.  Added
      auxiliary set_all_mdl_upgradable() function for marking all
      elements in table list as requiring upgradable metadata locks.
    storage/myisammrg/ha_myisammrg.cc:
      Allocate MDL_LOCK objects for underlying tables of MERGE table.
      To be reworked once Ingo pushes his patch for WL4144.
    e3b03d5d
flush_table.test 2.86 KB