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708 commits

Author SHA1 Message Date
Michael Widenius
52090a4434 Code cleanup to get fewer reallocs() during execution. 
- Changed TABLE->alias to String to get fewer reallocs when alias are used.
- Preallocate some buffers

Changed some String->c_ptr() -> String->ptr() when \0 is not needed.
Fixed wrong usage of String->ptr() when we need a \0 terminated string.
Use my_strtod() instead of my_atof() to avoid having to add \0 to string.
c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
zr 

sql/event_db_repository.cc:
  Update usage of TABLE->alias
sql/event_scheduler.cc:
  c_ptr() -> c_ptr_safe()
sql/events.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/field.cc:
  Update usage of TABLE->alias
sql/field.h:
  Update usage of TABLE->alias
sql/ha_partition.cc:
  Update usage of TABLE->alias
sql/handler.cc:
  Update usage of TABLE->alias
  Fixed wrong usage of str.ptr()
sql/item.cc:
  Fixed error where code wrongly assumed string was \0 terminated.
sql/item_func.cc:
  c_ptr() -> c_ptr_safe()
  Update usage of TABLE->alias
sql/item_sum.h:
  Use my_strtod() instead of my_atof() to avoid having to add \0 to string
sql/lock.cc:
  Update usage of TABLE->alias
sql/log.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/log_event.cc:
  c_ptr_quick() -> ptr() as \0 was not needed
sql/opt_range.cc:
  ptr() -> c_ptr() as \0 is needed
sql/opt_subselect.cc:
  Update usage of TABLE->alias
sql/opt_table_elimination.cc:
  Update usage of TABLE->alias
sql/set_var.cc:
  ptr() -> c_ptr() as \0 is needed
  c_ptr() -> c_ptr_safe()
sql/sp.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/sp_rcontext.cc:
  
  Update usage of TABLE->alias
sql/sql_base.cc:
  Preallocate buffers
  Update usage of TABLE->alias
sql/sql_class.cc:
  Fix arguments to sprintf() to work even if string is not \0 terminated
sql/sql_insert.cc:
  Update usage of TABLE->alias
  c_ptr() -> ptr() as \0 was not needed
sql/sql_load.cc:
  Preallocate buffers
  Trivial optimizations
sql/sql_parse.cc:
  Trivial optimization
sql/sql_plugin.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/sql_select.cc:
  Update usage of TABLE->alias
sql/sql_show.cc:
  Update usage of TABLE->alias
sql/sql_string.h:
  Added move() function to move allocated memory from one object to another.
sql/sql_table.cc:
  Update usage of TABLE->alias
  c_ptr() -> c_ptr_safe()
sql/sql_test.cc:
  ptr() -> c_ptr_safe()
sql/sql_trigger.cc:
  Update usage of TABLE->alias
  c_ptr() -> c_ptr_safe()
sql/sql_update.cc:
  Update usage of TABLE->alias
sql/sql_view.cc:
  ptr() -> c_ptr_safe()
sql/sql_yacc.yy:
  ptr() -> c_ptr()
sql/table.cc:
  
  Update usage of TABLE->alias
sql/table.h:
  Changed TABLE->alias to String to get fewer reallocs when alias are used.
storage/federatedx/ha_federatedx.cc:
  Use c_ptr_safe() to ensure strings are \0 terminated.
storage/maria/ha_maria.cc:
  Update usage of TABLE->alias
storage/myisam/ha_myisam.cc:
  Update usage of TABLE->alias
storage/xtradb/row/row0sel.c:
  Ensure that null bits in record are properly reset.
  (Old code didn't work as row_search_for_mysql() can be called twice while reading fields from one row.
 2010-11-24 00:08:48 +02:00
Michael Widenius
b52020221e Merge with MySQL 5.1.52 2010-11-23 23:39:59 +02:00
Dmitry Lenev
6bf6272fda Patch that refactors global read lock implementation and fixes 
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.
 2010-11-11 20:11:05 +03:00
Dmitry Lenev
378cdc58c1 Patch that refactors global read lock implementation and fixes 
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.
 2010-11-11 20:11:05 +03:00
Michael Widenius
20acfbf30d Fix for: LP #634955: Assert in _ma_update_at_original_place() 
Added locking of lock mutex when updating status in external_unlock() for Aria and MyISAM tables.
Fixed that 'source' command doesn't cause mysql command line tool to exit on error.
DEBUG_EXECUTE() and DEBUG_EVALUATE_IF() should not execute things based on wildcards. (Allows one to run --debug with mysql-test-run scripts that uses @debug)
Fixed several core dump, deadlock and crashed table bugs in handling of LOCK TABLE with MERGE tables:
- Added priority of locks to avoid crashes with MERGE tables.
- Added thr_lock_merge() to allow one to merge two results of thr_lock().
Fixed 'not found row' bug in REPLACE with Aria tables.
Mark MyISAM tables that are part of MERGE with HA_OPEN_MERGE_TABLE and set the locks to have priority THR_LOCK_MERGE_PRIV.
- By sorting MERGE tables last in thr_multi_unlock() it's safer to release and relock them many times (can happen when TRIGGERS are created)
Avoid printing (null) in debug file (to easier find out wrong NULL pointer usage with %s).



client/mysql.cc:
  Fixed that 'source' command doesn't cause mysql command line tool to exit on error.
client/mysqltest.cc:
  Don't send NULL to fn_format(). (Can cause crash on Solaris when using --debug)
dbug/dbug.c:
  DEBUG_EXECUTE() and DEBUG_EVALUATE_IF() should not execute things based on wildcards.
include/my_base.h:
  Added flag to signal if one opens a MERGE table.
  Added extra() command to signal that one is not part of a MERGE table anymore.
include/thr_lock.h:
  Added priority for locks (needed to fix bug in thr_lock when using MERGE tables)
  Added option to thr_unlock() if get_status() should be called.
  Added prototype for thr_merge_locks().
mysql-test/mysql-test-run.pl:
  Ignore crashed table warnings for tables named 'crashed'.
mysql-test/r/merge.result:
  Renamed triggers to make debugging easier.
  Added some CHECK TABLES to catch errors earlier.
  Additional tests.
mysql-test/r/merge_debug.result:
  Test of error handling when reopening MERGE tables.
mysql-test/r/udf_query_cache.result:
  Added missing flush status
mysql-test/suite/parts/r/partition_repair_myisam.result:
  Update results
mysql-test/t/merge.test:
  Renamed triggers to make debugging easier.
  Added some CHECK TABLES to catch errors earlier.
  Additional tests.
mysql-test/t/merge_debug.test:
  Test of error handling when reopening MERGE tables.
mysql-test/t/udf_query_cache.test:
  Added missing flush status
mysys/my_getopt.c:
  Removed not used variable
mysys/my_symlink2.c:
  Changed (null) to (NULL) to make it easier to find NULL arguments to DBUG_PRINT() functions.
  (On linux, NULL to sprintf is printed 'null')
mysys/thr_lock.c:
  Added priority of locks to avoid crashes with MERGE tables.
  Added thr_lock_merge() to allow one to merge two results of thr_lock().
  - This is needed for MyISAM as all locked table must share the same status. If not, you will not see newly inserted rows in other instances of the table.
  If calling thr_unlock() with THR_UNLOCK_UPDATE_STATUS, call update_status() and restore_status() for the locks. This is needed in some rare cases where we call thr_unlock() followed by thr_lock() without calling external_unlock/external_lock in between.
  Simplify loop in thr_multi_lock().
  Added 'start_trans', which is called at end of thr_multi_lock() when all locks are taken.
  - This was needed by Aria to ensure that transaction is started when we got all locks, not at get_status(). Without this, some rows could not be visible when we lock two tables at the same time, causing REPLACE using two tables to fail unexpectedly.
sql/handler.cc:
  Add an assert() in handler::print_error() for "impossible errors" (like table is crashed) when --debug-assert-if-crashed-table is used.
sql/lock.cc:
  Simplify mysql_lock_tables() code if get_lock_data() returns 0 locks.
  Added new parameter to thr_multi_unlock()
  In mysql_unlock_read_tables(), call first externa_unlock(), then thr_multi_unlock();  This is same order as we do in mysql_unlock_tables().
  Don't abort locks in mysql_lock_abort() for merged tables when a MERGE table is deleted; Would cause a spin lock.
  Added call to thr_merge_locks() in mysql_lock_merge() to ensure consistency in thr_locks().
  - New locks of same type and table is stored after the old lock to ensure that we get the status from the original lock.
sql/mysql_priv.h:
  Added debug_assert_if_crashed_table
sql/mysqld.cc:
  Added --debug-assert-if-crashed-table
sql/parse_file.cc:
  Don't print '(null)' in DBUG_PRINT of no dir given
sql/set_var.cc:
  Increase default size of buffer for @debug variable.
sql/sql_base.cc:
  In case of error from reopen_table() in reopen_tables(), call unlock_open_table() and restart loop.
  - This fixed bug when we twice deleted same table from open_cache.
  Don't take name lock for already name locked table in open_unireg_entry().
  - Fixed bug when doing repair in reopen_table().
  - In detach_merge_children(), always detach if 'clear_refs' is given. We can't trust parent->children_attached as this function can be called twice, first time with clear_refs set to 0.
sql/sql_class.cc:
  Changed printing of (null) to "" in set_thd_proc_info()
sql/sql_parse.cc:
  Added DBUG
sql/sql_trigger.cc:
  Don't call unlink_open_table() if reopen_table() fails as the table may already be freed.
storage/maria/ma_bitmap.c:
  Fixed DBUG_ASSERT() in allocate_tail()
storage/maria/ma_blockrec.c:
  Fixed wrong calculation of row length for very small rows in undo_row_update().
  - Fixes ASSERT() when doing undo.
storage/maria/ma_blockrec.h:
  Added _ma_block_start_trans() and _ma_block_start_trans_no_versioning()
storage/maria/ma_locking.c:
  Call _ma_update_status_with_lock() when releasing write locks.
  - Fixes potential problem with updating status without the proper lock.
storage/maria/ma_open.c:
  Changed to use start_trans() instead of get_status() to ensure that we see all rows in all locked tables when we got the locks.
  - Fixed 'not found row' bug in REPLACE with Aria tables.
storage/maria/ma_state.c:
  Added _ma_update_status_with_lock() and _ma_block_start_trans().
  This is to ensure that we see all rows in all locked tables when we got the locks.
storage/maria/ma_state.h:
  Added _ma_update_status_with_lock()
storage/maria/ma_write.c:
  More DBUG_PRINT
storage/myisam/mi_check.c:
  Fixed error message
storage/myisam/mi_extra.c:
  Added HA_EXTRA_DETACH_CHILD:
  - Detach MyISAM table to not be part of MERGE table (remove flag & lock priority).
storage/myisam/mi_locking.c:
  Call mi_update_status_with_lock() when releasing write locks.
  - Fixes potential problem with updating status without the proper lock.
  Change to use new HA_OPEN_MERGE_TABLE flag to test if MERGE table.
  Added mi_fix_status(), called by thr_merge().
storage/myisam/mi_open.c:
  Added marker if part of MERGE table.
  Call mi_fix_status() in thr_lock() for transactional tables.
storage/myisam/myisamdef.h:
  Change my_once_flag to uint, as it stored different values than just 0/1
  Added 'open_flag' to store state given to mi_open()
storage/myisammrg/ha_myisammrg.cc:
  Add THR_LOCK_MERGE_PRIV to THR_LOCK_DATA to get MERGE locks sorted after other types of locks.
storage/myisammrg/myrg_locking.c:
  Remove windows specific code.
storage/myisammrg/myrg_open.c:
  Use HA_OPEN_MERGE_TABLE to mi_open().
  Set HA_OPEN_MERGE_TABLE for linked MyISAM tables.
storage/xtradb/buf/buf0buf.c:
  Fixed compiler warning
storage/xtradb/buf/buf0lru.c:
  Initialize variable that could be used not initialized.
 2010-11-02 17:22:57 +02:00
Jon Olav Hauglid
bf55d1fcf0 Merge from mysql-5.5-bugteam to mysql-5.5-runtime 2010-09-30 12:43:43 +02:00
Jon Olav Hauglid
a53f61e6e8 Merge from mysql-5.5-bugteam to mysql-5.5-runtime 2010-09-30 12:43:43 +02:00
Jon Olav Hauglid
a302953bf7 Bug #56595 RENAME TABLE causes assert on OS X 
The problem was that RENAME TABLE caused an assert if the system variable
lower_case_table_names was 2 (default on Mac OS X) and the old table name
was given in upper case. This caused lowercase_table2.test to fail.

The assert checks that an exclusive metadata lock is held by the connection
trying to do RENAME TABLE - specificially during updates of table triggers.
The assert was triggered since the check is case sensitive and the lock
was held on the normalized (lower case) version of the table name.

This patch fixes the problem by making sure a normalized version of the
table name is used for the metadata lock check, while using a non-normalized
version of the table name for the rename of trigger files. The same is done
for ALTER TABLE ... RENAME.

Regression testing for the bug itself is already covered by
lowercase_table2.test. Additional coverage added to lowercase_fs_off.test.
 2010-09-16 11:11:13 +02:00
Jon Olav Hauglid
f14d947c98 Bug #56595 RENAME TABLE causes assert on OS X 
The problem was that RENAME TABLE caused an assert if the system variable
lower_case_table_names was 2 (default on Mac OS X) and the old table name
was given in upper case. This caused lowercase_table2.test to fail.

The assert checks that an exclusive metadata lock is held by the connection
trying to do RENAME TABLE - specificially during updates of table triggers.
The assert was triggered since the check is case sensitive and the lock
was held on the normalized (lower case) version of the table name.

This patch fixes the problem by making sure a normalized version of the
table name is used for the metadata lock check, while using a non-normalized
version of the table name for the rename of trigger files. The same is done
for ALTER TABLE ... RENAME.

Regression testing for the bug itself is already covered by
lowercase_table2.test. Additional coverage added to lowercase_fs_off.test.
 2010-09-16 11:11:13 +02:00
Dmitry Shulga
029cc52c88 Auto-merge from mysql-5.1-bugteam. 2010-09-07 16:00:41 +07:00
Dmitry Shulga
417092560c Auto-merge from mysql-5.1-bugteam. 2010-09-07 16:00:41 +07:00
Dmitry Shulga
d6f6db6f4c Fixed bug #55421 - Protocol::end_statement(): Assertion `0' on 
multi-table UPDATE IGNORE.
The problem was that if there was an active SELECT statement
during trigger execution, an error risen during the execution
may cause a crash. The fix is to temporary reset LEX::current_select
before trigger execution and restore it afterwards. This way
errors risen during the trigger execution are processed as
if there was no active SELECT.

mysql-test/r/trigger_notembedded.result:
  added test case result for bug #55421.
mysql-test/t/trigger_notembedded.test:
  added test case for bug #55421.
sql/sql_trigger.cc:
  Reset thd->lex->current_select before start trigger execution
  and restore its original value after execution is finished.
  This is neccessery in order to set error status in 
  diagnostic_area in case of trigger execution failure.
 2010-09-07 15:53:46 +07:00
Dmitry Shulga
70807d1473 Fixed bug #55421 - Protocol::end_statement(): Assertion `0' on 
multi-table UPDATE IGNORE.
The problem was that if there was an active SELECT statement
during trigger execution, an error risen during the execution
may cause a crash. The fix is to temporary reset LEX::current_select
before trigger execution and restore it afterwards. This way
errors risen during the trigger execution are processed as
if there was no active SELECT.
 2010-09-07 15:53:46 +07:00
Michael Widenius
a4fff491eb Fix that one can run mysql_upgrade with long table names 
Fall back to use ALTER TABLE for engines that doesn't support REPAIR when doing repair for upgrade.
Nicer output from mysql_upgrade and mysql_check
Updated all arrays that used NAME_LEN to use SAFE_NAME_LEN to ensure that we don't break things accidently as names can now have a #mysql50# prefix.

client/mysql_upgrade.c:
  If we are using verbose, also run mysqlcheck in verbose mode.
client/mysqlcheck.c:
  Add more information if running in verbose mode
  Print 'Needs upgrade' instead of complex error if table needs to be upgraded
  Don't write connect information if verbose is not 2 or above
mysql-test/r/drop.result:
  Updated test and results as we now support full table names
mysql-test/r/grant.result:
  Now you get a correct error message if using #mysql with paths
mysql-test/r/show_check.result:
  Update results as table names can temporarly be bigger than NAME_LEN (during upgrade)
mysql-test/r/upgrade.result:
  Test upgrade for long table names.
mysql-test/suite/funcs_1/r/is_tables_is.result:
  Updated old test result (had note been updated in a while)
mysql-test/t/drop.test:
  Updated test and results as we now support full table names
mysql-test/t/grant.test:
  Now you get a correct error message if using #mysql with paths
mysql-test/t/upgrade.test:
  Test upgrade for long table names.
sql/ha_partition.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/item.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/log_event.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/mysql_priv.h:
  Added SAFE_NAME_LEN
sql/rpl_filter.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sp.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sp_head.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_acl.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_base.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_connect.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_parse.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_prepare.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_select.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_show.cc:
  NAME_LEN -> SAFE_NAME_LEN
  Enlarge table names for SHOW TABLES to also include optional #mysql50#
sql/sql_table.cc:
  Fall back to use ALTER TABLE for engines that doesn't support REPAIR when doing repair for upgrade.
sql/sql_trigger.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_udf.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/sql_view.cc:
  NAME_LEN -> SAFE_NAME_LEN
sql/table.cc:
  Fixed check_table_name() to not count #mysql50# as part of name
  If #mysql50# is part of the name, don't allow path characters in name.
 2010-09-03 19:20:30 +03:00
Alexander Nozdrin
65c5e8dcbf Bug#27480 (Extend CREATE TEMPORARY TABLES privilege 
to allow temp table operations) -- prerequisite patch #2.

Introduce a new form of find_temporary_table() function:
find_temporary_table() by a table key. It will be used
in further patches.

Replace find_temporary_table(table_list->db, table_list->name)
by more appropiate find_temporary_table(table_list) across
the codebase.
 2010-08-31 13:52:56 +04:00
Alexander Nozdrin
2e462c8f99 Bug#27480 (Extend CREATE TEMPORARY TABLES privilege 
to allow temp table operations) -- prerequisite patch #2.

Introduce a new form of find_temporary_table() function:
find_temporary_table() by a table key. It will be used
in further patches.

Replace find_temporary_table(table_list->db, table_list->name)
by more appropiate find_temporary_table(table_list) across
the codebase.
 2010-08-31 13:52:56 +04:00
Konstantin Osipov
523066987d A fix for Bug#41158 "DROP TABLE holds LOCK_open during unlink()". 
Remove acquisition of LOCK_open around file system operations,
since such operations are now protected by metadata locks.
Rework table discovery algorithm to not require LOCK_open.

No new tests added since all MDL locking operations are covered
in lock.test and mdl_sync.test, and as long as these tests
pass despite the increased concurrency, consistency must be
unaffected.

mysql-test/t/disabled.def:
  Disable NDB tests due to Bug#55799.
sql/datadict.cc:
  No longer necessary to protect ha_create_table() with
  LOCK_open. Serial execution is now ensured by metadata
  locks.
sql/ha_ndbcluster.cc:
  Do not manipulate with LOCK_open in cluster code.
sql/ha_ndbcluster_binlog.cc:
  Do not manipulate with LOCK_open in cluster code.
sql/ha_ndbcluster_binlog.h:
  Update function signature.
sql/handler.cc:
  Implement ha_check_if_table_exists().
  @todo: some engines provide ha_table_exists_in_engine()
  handlerton call, for those we perhaps shouldn't
  call ha_discover(), to be more efficient.
  Since currently it's only NDB, postpone till
  integration with NDB.
sql/handler.h:
  Declare ha_check_if_table_exists() function.
sql/mdl.cc:
  Remove an obsolete comment.
sql/sql_base.cc:
  Update to a new signature of close_cached_tables():
  from now on we always call it without LOCK_open.
  Update comments.
  Remove get_table_share_with_create(), we should
  not attempt to create a table under LOCK_open.
  Introduce get_table_share_with_discover() instead,
  which would request a back off action if the table
  exists in engine.
  Remove acquisition of LOCK_open for 
  data dictionary operations, such as check_if_table_exists().
  Do not use get_table_share_with_create/discover for views,
  where it's not needed.
  Make tdc_remove_table() optionally acquire LOCK_open
  to simplify usage of this function.
  Use the right mutex in the partitioning code when
  manipulating with thd->open_tables.
sql/sql_base.h:
  Update signatures of changes functions.
sql/sql_insert.cc:
  Do not wrap quick_rm_table() with LOCK_open acquisition, 
  this is unnecessary.
sql/sql_parse.cc:
  Update to the new calling convention of tdc_remove_table().
  Update to the new signature of close_cached_tables().
  Update comments.
sql/sql_rename.cc:
  Update to the new calling convention of tdc_remove_table().
  Remove acquisition of LOCK_open around filesystem
  operations.
sql/sql_show.cc:
  Remove get_trigger_table_impl().
  Do not acquire LOCK_open for a dirty read of the trigger
  file.
sql/sql_table.cc:
  Do not acquire LOCK_open for filesystem operations.
sql/sql_trigger.cc:
  Do not require LOCK_open for trigger file I/O.
sql/sql_truncate.cc:
  Update to the new signature of tdc_remove_table().
sql/sql_view.cc:
  Do not require LOCK_open for view I/O.
  Use tdc_remove_table() to expel view share.
  Update comments.
sql/sys_vars.cc:
  Update to the new signature of close_cached_tables().
 2010-08-09 22:33:47 +04:00
Konstantin Osipov
f8bfa3287d A fix for Bug#41158 "DROP TABLE holds LOCK_open during unlink()". 
Remove acquisition of LOCK_open around file system operations,
since such operations are now protected by metadata locks.
Rework table discovery algorithm to not require LOCK_open.

No new tests added since all MDL locking operations are covered
in lock.test and mdl_sync.test, and as long as these tests
pass despite the increased concurrency, consistency must be
unaffected.
 2010-08-09 22:33:47 +04:00
Konstantin Osipov
36290c0923 A pre-requisite patch for the fix for Bug#52044. 
This patch also fixes Bug#55452 "SET PASSWORD is
replicated twice in RBR mode".

The goal of this patch is to remove the release of 
metadata locks from close_thread_tables().
This is necessary to not mistakenly release
the locks in the course of a multi-step
operation that involves multiple close_thread_tables()
or close_tables_for_reopen().

On the same token, move statement commit outside 
close_thread_tables().

Other cleanups:
Cleanup COM_FIELD_LIST.
Don't call close_thread_tables() in COM_SHUTDOWN -- there
are no open tables there that can be closed (we leave
the locked tables mode in THD destructor, and this
close_thread_tables() won't leave it anyway).

Make open_and_lock_tables() and open_and_lock_tables_derived()
call close_thread_tables() upon failure.
Remove the calls to close_thread_tables() that are now
unnecessary.

Simplify the back off condition in Open_table_context.

Streamline metadata lock handling in LOCK TABLES 
implementation.

Add asserts to ensure correct life cycle of 
statement transaction in a session.

Remove a piece of dead code that has also become redundant
after the fix for Bug 37521.

mysql-test/r/variables.result:
  Update results: set @@autocommit and statement transaction/
  prelocked mode.
mysql-test/r/view.result:
  A harmless change in CHECK TABLE <view> status for a broken view.
  If previously a failure to prelock all functions used in a view 
  would leave the connection in LTM_PRELOCKED mode, now we call
  close_thread_tables() from open_and_lock_tables()
  and leave prelocked mode, thus some check in mysql_admin_table() that
  works only in prelocked/locked tables mode is no longer activated.
mysql-test/suite/rpl/r/rpl_row_implicit_commit_binlog.result:
  Fixed Bug#55452 "SET PASSWORD is replicated twice in
  RBR mode": extra binlog events are gone from the
  binary log.
mysql-test/t/variables.test:
  Add a test case: set autocommit and statement transaction/prelocked
  mode.
sql/event_data_objects.cc:
  Simplify code in Event_job_data::execute().
  Move sp_head memory management to lex_end().
sql/event_db_repository.cc:
  Move the release of metadata locks outside
  close_thread_tables().
  Make sure we call close_thread_tables() when
  open_and_lock_tables() fails and remove extra
  code from the events data dictionary.
  Use close_mysql_tables(), a new internal
  function to properly close mysql.* tables
  in the data dictionary.
  Contract Event_db_repository::drop_events_by_field,
  drop_schema_events into one function.
  When dropping all events in a schema,
  make sure we don't mistakenly release all
  locks acquired by DROP DATABASE. These
  include locks on the database name
  and the global intention exclusive
  metadata lock.
sql/event_db_repository.h:
  Function open_event_table() does not require an instance 
  of Event_db_repository.
sql/events.cc:
  Use close_mysql_tables() instead of close_thread_tables()
  to bootstrap events, since the latter no longer
  releases metadata locks.
sql/ha_ndbcluster.cc:
  - mysql_rm_table_part2 no longer releases
  acquired metadata locks. Do it in the caller.
sql/ha_ndbcluster_binlog.cc:
  Deploy the new protocol for closing thread
  tables in run_query() and ndb_binlog_index
  code.
sql/handler.cc:
  Assert that we never call ha_commit_trans/
  ha_rollback_trans in sub-statement, which
  is now the case.
sql/handler.h:
  Add an accessor to check whether THD_TRANS object
  is empty (has no transaction started).
sql/log.cc:
  Update a comment.
sql/log_event.cc:
  Since now we commit/rollback statement transaction in 
  mysql_execute_command(), we need a mechanism to communicate
  from Query_log_event::do_apply_event() to mysql_execute_command()
  that the statement transaction should be rolled back, not committed.
  Ideally it would be a virtual method of THD. I hesitate
  to make THD a virtual base class in this already large patch.
  Use a thd->variables.option_bits for now.
  
  Remove a call to close_thread_tables() from the slave IO
  thread. It doesn't open any tables, and the protocol
  for closing thread tables is more complicated now.
  
  Make sure we properly close thread tables, however, 
  in Load_data_log_event, which doesn't
  follow the standard server execution procedure
  with mysql_execute_command().
  @todo: this piece should use Server_runnable
  framework instead.
  Remove an unnecessary call to mysql_unlock_tables().
sql/rpl_rli.cc:
  Update Relay_log_info::slave_close_thread_tables()
  to follow the new close protocol.
sql/set_var.cc:
  Remove an unused header.
sql/slave.cc:
  Remove an unnecessary call to
  close_thread_tables().
sql/sp.cc:
  Remove unnecessary calls to close_thread_tables()
  from SP DDL implementation. The tables will
  be closed by the caller, in mysql_execute_command().
  When dropping all routines in a database, make sure
  to not mistakenly drop all metadata locks acquired
  so far, they include the scoped lock on the schema.
sql/sp_head.cc:
  Correct the protocol that closes thread tables
  in an SP instruction.
  Clear lex->sphead before cleaning up lex
  with lex_end to make sure that we don't
  delete the sphead twice. It's considered
  to be "cleaner" and more in line with
  future changes than calling delete lex->sphead
  in other places that cleanup the lex.
sql/sp_head.h:
  When destroying m_lex_keeper of an instruction,
  don't delete the sphead that all lex objects
  share. 
  @todo: don't store a reference to routine's sp_head
  instance in instruction's lex.
sql/sql_acl.cc:
  Don't call close_thread_tables() where the caller will
  do that for us.
  Fix Bug#55452 "SET PASSWORD is replicated twice in RBR 
  mode" by disabling RBR replication in change_password()
  function.
  Use close_mysql_tables() in bootstrap and ACL reload
  code to make sure we release all metadata locks.
sql/sql_base.cc:
  This is the main part of the patch:
  - remove manipulation with thd->transaction
  and thd->mdl_context from close_thread_tables().
  Now this function is only responsible for closing
  tables, nothing else.
  This is necessary to be able to easily use
  close_thread_tables() in procedures, that
  involve multiple open/close tables, which all
  need to be protected continuously by metadata
  locks.
  Add asserts ensuring that TABLE object
  is only used when is protected by a metadata lock.
  Simplify the back off condition of Open_table_context,
  we no longer need to look at the autocommit mode.
  Make open_and_lock_tables() and open_normal_and_derived_tables()
  close thread tables and release metadata locks acquired so-far 
  upon failure. This simplifies their usage.
  Implement close_mysql_tables().
sql/sql_base.h:
  Add declaration for close_mysql_tables().
sql/sql_class.cc:
  Remove a piece of dead code that has also become redundant
  after the fix for Bug 37521.
  The code became dead when my_eof() was made a non-protocol method,
  but a method that merely modifies the diagnostics area.
  The code became redundant with the fix for Bug#37521, when 
  we started to cal close_thread_tables() before
  Protocol::end_statement().
sql/sql_do.cc:
  Do nothing in DO if inside a substatement
  (the assert moved out of trans_rollback_stmt).
sql/sql_handler.cc:
  Add comments.
sql/sql_insert.cc:
  Remove dead code. 
  Release metadata locks explicitly at the
  end of the delayed insert thread.
sql/sql_lex.cc:
  Add destruction of lex->sphead to lex_end(),
  lex "reset" method called at the end of each statement.
sql/sql_parse.cc:
  Move close_thread_tables() and other related
  cleanups to mysql_execute_command()
  from dispatch_command(). This has become
  possible after the fix for Bug#37521.
  Mark federated SERVER statements as DDL.
  
  Next step: make sure that we don't store
  eof packet in the query cache, and move
  the query cache code outside mysql_parse.
  
  Brush up the code of COM_FIELD_LIST.
  Remove unnecessary calls to close_thread_tables().
  
  When killing a query, don't report "OK"
  if it was a suicide.
sql/sql_parse.h:
  Remove declaration of a function that is now static.
sql/sql_partition.cc:
  Remove an unnecessary call to close_thread_tables().
sql/sql_plugin.cc:
  open_and_lock_tables() will clean up
  after itself after a failure.
  Move close_thread_tables() above
  end: label, and replace with close_mysql_tables(),
  which will also release the metadata lock
  on mysql.plugin.
sql/sql_prepare.cc:
  Now that we no longer release locks in close_thread_tables()
  statement prepare code has become more straightforward.
  Remove the now redundant check for thd->killed() (used
  only by the backup project) from Execute_server_runnable.
  Reorder code to take into account that now mysql_execute_command()
  performs lex->unit.cleanup() and close_thread_tables().
sql/sql_priv.h:
  Add a new option to server options to interact
  between the slave SQL thread and execution
  framework (hack). @todo: use a virtual
  method of class THD instead.
sql/sql_servers.cc:
  Due to Bug 25705 replication of 
  DROP/CREATE/ALTER SERVER is broken.
  Make sure at least we do not attempt to 
  replicate these statements using RBR,
  as this violates the assert in close_mysql_tables().
sql/sql_table.cc:
  Do not release metadata locks in mysql_rm_table_part2,
  this is done by the caller.
  Do not call close_thread_tables() in mysql_create_table(),
  this is done by the caller. 
  Fix a bug in DROP TABLE under LOCK TABLES when,
  upon error in wait_while_table_is_used() we would mistakenly
  release the metadata lock on a non-dropped table.
  Explicitly release metadata locks when doing an implicit
  commit.
sql/sql_trigger.cc:
  Now that we delete lex->sphead in lex_end(),
  zero the trigger's sphead in lex after loading
  the trigger, to avoid double deletion.
sql/sql_udf.cc:
  Use close_mysql_tables() instead of close_thread_tables().
sql/sys_vars.cc:
  Remove code added in scope of WL#4284 which would
  break when we perform set @@session.autocommit along
  with setting other variables and using tables or functions.
  A test case added to variables.test.
sql/transaction.cc:
  Add asserts.
sql/tztime.cc:
  Use close_mysql_tables() rather than close_thread_tables().
 2010-07-27 14:25:53 +04:00
Konstantin Osipov
ec2c3bf2c1 A pre-requisite patch for the fix for Bug#52044. 
This patch also fixes Bug#55452 "SET PASSWORD is
replicated twice in RBR mode".

The goal of this patch is to remove the release of 
metadata locks from close_thread_tables().
This is necessary to not mistakenly release
the locks in the course of a multi-step
operation that involves multiple close_thread_tables()
or close_tables_for_reopen().

On the same token, move statement commit outside 
close_thread_tables().

Other cleanups:
Cleanup COM_FIELD_LIST.
Don't call close_thread_tables() in COM_SHUTDOWN -- there
are no open tables there that can be closed (we leave
the locked tables mode in THD destructor, and this
close_thread_tables() won't leave it anyway).

Make open_and_lock_tables() and open_and_lock_tables_derived()
call close_thread_tables() upon failure.
Remove the calls to close_thread_tables() that are now
unnecessary.

Simplify the back off condition in Open_table_context.

Streamline metadata lock handling in LOCK TABLES 
implementation.

Add asserts to ensure correct life cycle of 
statement transaction in a session.

Remove a piece of dead code that has also become redundant
after the fix for Bug 37521.
 2010-07-27 14:25:53 +04:00
Konstantin Osipov
cc6dabba37 Merge trunk-bugfixing -> trunk-runtime 2010-06-17 17:31:51 +04:00
Konstantin Osipov
484351d108 Merge trunk-bugfixing -> trunk-runtime 2010-06-17 17:31:51 +04:00
Alexey Kopytov
f84b3f5c21 Manual merge from mysql-5.1-bugteam to mysql-trunk-merge. 
conflicts:
   conflict      mysys/safemalloc.c
   conflict      sql/mysqld.cc
   conflict      sql/sp.cc
   conflict      sql/sql_lex.cc
   conflict      sql/sql_lex.h
   conflict      sql/sql_parse.cc
   conflict      sql/sql_prepare.cc
 2010-06-11 17:48:24 +04:00
Alexey Kopytov
eae3b4fe76 Manual merge from mysql-5.1-bugteam to mysql-trunk-merge. 
conflicts:
   conflict      mysys/safemalloc.c
   conflict      sql/mysqld.cc
   conflict      sql/sp.cc
   conflict      sql/sql_lex.cc
   conflict      sql/sql_lex.h
   conflict      sql/sql_parse.cc
   conflict      sql/sql_prepare.cc
 2010-06-11 17:48:24 +04:00
Alexey Kopytov
386929d3ae Manual merge from the bugfix tree. 
conflicts:
   conflict      sql/sql_parse.cc
 2010-06-11 16:52:06 +04:00
Alexey Kopytov
162e426238 Manual merge from the bugfix tree. 
conflicts:
   conflict      sql/sql_parse.cc
 2010-06-11 16:52:06 +04:00
Alexey Kopytov
e5cf56ef80 Manual merge from the bugfix tree. 
conflicts:
   conflict      sql/sql_parse.cc
 2010-06-11 14:51:21 +04:00
Alexey Kopytov
b497e2c6b2 Manual merge from the bugfix tree. 
conflicts:
   conflict      sql/sql_parse.cc
 2010-06-11 14:51:21 +04:00
Davi Arnaut
db2fe44c84 Merge of mysql-5.1-bugteam into mysql-trunk-merge. 2010-06-10 22:30:49 -03:00
Davi Arnaut
d6e003545a Merge of mysql-5.1-bugteam into mysql-trunk-merge. 2010-06-10 22:30:49 -03:00
Davi Arnaut
0f9ddfa9d8 Bug#42733: Type-punning warnings when compiling MySQL -- 
strict aliasing violations.

One somewhat major source of strict-aliasing violations and
related warnings is the SQL_LIST structure. For example,
consider its member function `link_in_list` which takes
a pointer to pointer of type T (any type) as a pointer to
pointer to unsigned char. Dereferencing this pointer, which
is done to reset the next field, violates strict-aliasing
rules and might cause problems for surrounding code that
uses the next field of the object being added to the list.

The solution is to use templates to parametrize the SQL_LIST
structure in order to deference the pointers with compatible
types. As a side bonus, it becomes possible to remove quite
a few casts related to acessing data members of SQL_LIST.

sql/handler.h:
  Use the appropriate template type argument.
sql/item.cc:
  Remove now-unnecessary cast.
sql/item_subselect.cc:
  Remove now-unnecessary casts.
sql/item_sum.cc:
  Use the appropriate template type argument.
  Remove now-unnecessary cast.
sql/mysql_priv.h:
  Move SQL_LIST structure to sql_list.h
  Use the appropriate template type argument.
sql/sp.cc:
  Remove now-unnecessary casts.
sql/sql_delete.cc:
  Use the appropriate template type argument.
  Remove now-unnecessary casts.
sql/sql_derived.cc:
  Remove now-unnecessary casts.
sql/sql_lex.cc:
  Remove now-unnecessary casts.
sql/sql_lex.h:
  SQL_LIST now takes a template type argument which must
  match the type of the elements of the list. Use forward
  declaration when the type is not available, it is used
  in pointers anyway.
sql/sql_list.h:
  Rename SQL_LIST to SQL_I_List. The template parameter is
  the type of object that is stored in the list.
sql/sql_olap.cc:
  Remove now-unnecessary casts.
sql/sql_parse.cc:
  Remove now-unnecessary casts.
sql/sql_prepare.cc:
  Remove now-unnecessary casts.
sql/sql_select.cc:
  Remove now-unnecessary casts.
sql/sql_show.cc:
  Remove now-unnecessary casts.
sql/sql_table.cc:
  Remove now-unnecessary casts.
sql/sql_trigger.cc:
  Remove now-unnecessary casts.
sql/sql_union.cc:
  Remove now-unnecessary casts.
sql/sql_update.cc:
  Remove now-unnecessary casts.
sql/sql_view.cc:
  Remove now-unnecessary casts.
sql/sql_yacc.yy:
  Remove now-unnecessary casts.
storage/myisammrg/ha_myisammrg.cc:
  Remove now-unnecessary casts.
 2010-06-10 17:45:22 -03:00
Davi Arnaut
53b8829682 Bug#42733: Type-punning warnings when compiling MySQL -- 
strict aliasing violations.

One somewhat major source of strict-aliasing violations and
related warnings is the SQL_LIST structure. For example,
consider its member function `link_in_list` which takes
a pointer to pointer of type T (any type) as a pointer to
pointer to unsigned char. Dereferencing this pointer, which
is done to reset the next field, violates strict-aliasing
rules and might cause problems for surrounding code that
uses the next field of the object being added to the list.

The solution is to use templates to parametrize the SQL_LIST
structure in order to deference the pointers with compatible
types. As a side bonus, it becomes possible to remove quite
a few casts related to acessing data members of SQL_LIST.
 2010-06-10 17:45:22 -03:00
Dmitry Lenev
ae1ae4bd63 Fix for bug #51263 "Deadlock between transactional 
SELECT and ALTER TABLE ...  REBUILD PARTITION".

ALTER TABLE on InnoDB table (including partitioned tables)
acquired exclusive locks on rows of table being altered.
In cases when there was concurrent transaction which did
locking reads from this table this sometimes led to a
deadlock which was not detected by MDL subsystem nor by
InnoDB engine (and was reported only after exceeding
innodb_lock_wait_timeout).

This problem stemmed from the fact that ALTER TABLE acquired
TL_WRITE_ALLOW_READ lock on table being altered. This lock
was interpreted as a write lock and thus for table being
altered handler::external_lock() method was called with
F_WRLCK as an argument. As result InnoDB engine treated
ALTER TABLE as an operation which is going to change data
and acquired LOCK_X locks on rows being read from old
version of table.

In case when there was a transaction which already acquired
SR metadata lock on table and some LOCK_S locks on its rows
(e.g. by using it in subquery of DML statement) concurrent
ALTER TABLE was blocked at the moment when it tried to
acquire LOCK_X lock before reading one of these rows.
The transaction's attempt to acquire SW metadata lock on
table being altered led to deadlock, since it had to wait
for ALTER TABLE to release SNW lock. This deadlock was not
detected and got resolved only after timeout expiring
because waiting were happening in two different subsystems.

Similar deadlocks could have occured in other situations.
This patch tries to solve the problem by changing ALTER TABLE
implementation to use TL_READ_NO_INSERT lock instead of
TL_WRITE_ALLOW_READ. After this step handler::external_lock()
is called with F_RDLCK as an argument and InnoDB engine
correctly interprets ALTER TABLE as operation which only
reads data from original version of table. Thanks to this
ALTER TABLE acquires only LOCK_S locks on rows it reads.
This, in its turn, causes inter-subsystem deadlocks to go
away, as all potential lock conflicts and thus deadlocks will
be limited to metadata locking subsystem:

- When ALTER TABLE reads rows from table being altered it
  can't encounter any locks which conflict with LOCK_S row
  locks. There should be no concurrent transactions holding
  LOCK_X row locks. Such a transaction should have been
  acquired SW metadata lock on table first which would have
  conflicted with ALTER's SNW lock.
- Vice versa, when DML which runs concurrently with ALTER
  TABLE tries to lock row it should be requesting only LOCK_S
  lock which is compatible with locks acquired by ALTER,
  as otherwise such DML must own an SW metadata lock on table
  which would be incompatible with ALTER's SNW lock.

mysql-test/r/innodb_mysql_lock2.result:
  Added test for bug #51263 "Deadlock between transactional
  SELECT and ALTER TABLE ... REBUILD PARTITION".
mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result:
  Since CREATE TRIGGER no longer acquires write lock on table
  it is no longer interpreted as an operation which modifies
  table data and therefore no longer fails if invoked for
  SBR-only engine in ROW mode.
mysql-test/suite/rpl_ndb/t/rpl_ndb_binlog_format_errors.test:
  Since CREATE TRIGGER no longer acquires write lock on table
  it is no longer interpreted as an operation which modifies
  table data and therefore no longer fails if invoked for
  SBR-only engine in ROW mode.
mysql-test/t/innodb_mysql_lock2.test:
  Added test for bug #51263 "Deadlock between transactional
  SELECT and ALTER TABLE ... REBUILD PARTITION".
sql/ha_partition.cc:
  When ALTER TABLE creates a new partition to be filled from
  other partition lock it in F_WRLCK mode instead of using
  mode which was used for locking the whole table (it is
  F_RDLCK now).
sql/lock.cc:
  Replaced conditions which used TL_WRITE_ALLOW_READ
  lock type with equivalent conditions using
  TL_WRITE_ALLOW_WRITE. This should allow to get rid
  of TL_WRITE_ALLOW_READ lock type eventually.
sql/mdl.cc:
  Updated outdated comment to reflect current situation.
sql/sql_base.cc:
  Replaced conditions which used TL_WRITE_ALLOW_READ
  lock type with equivalent conditions using
  TL_WRITE_ALLOW_WRITE. This should allow to get rid
  of TL_WRITE_ALLOW_READ lock type eventually.
sql/sql_table.cc:
  mysql_admin_table():
    Use TL_WRITE_ALLOW_WRITE lock type instead of
    TL_WRITE_ALLOW_READ to determine that we need to acquire
    upgradable metadata lock. This should allow to completely
    get rid of TL_WRITE_ALLOW_READ in long term.
  mysql_recreate_table():
    ALTER TABLE now requires TL_READ_NO_INSERT thr_lock.c lock
    instead of TL_WRITE_ALLOW_READ.
sql/sql_trigger.cc:
  Changed CREATE/DROP TRIGGER implementation to use
  TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock.
  The latter is no longer necessary since:
  a) We now can rely on metadata locks to achieve proper
     isolation between two DDL statements or DDL and DML
     statements.
  b) This statement does not change any data in table so there
     is no need to inform storage engine about it.
sql/sql_yacc.yy:
  Changed implementation of ALTER TABLE (and CREATE/DROP INDEX
  as a consequence) to use TL_READ_NO_INSERT lock instead of
  TL_WRITE_ALLOW_READ lock. This is possible since:
  a) We now can rely on metadata locks to achieve proper
     isolation between two DDL statements or DDL and DML
     statements.
  b) This statement only reads data in table being open.
     We write data only to the new version of table and
     then replace with it old version of table under
     X metadata lock.
  
  Thanks to this change InnoDB will no longer acquire LOCK_X
  locks on rows being read by ALTER TABLE (instead LOCK_S
  locks will be acquired) and thus cause of bug #51263
  "Deadlock between transactional SELECT and ALTER TABLE ...
  REBUILD PARTITION" is removed.
  
  Did the similar change for CREATE TRIGGER (see comments
  for sql_trigger.cc for details).
 2010-05-26 16:18:08 +04:00
Dmitry Lenev
c070e5a1ed Fix for bug #51263 "Deadlock between transactional 
SELECT and ALTER TABLE ...  REBUILD PARTITION".

ALTER TABLE on InnoDB table (including partitioned tables)
acquired exclusive locks on rows of table being altered.
In cases when there was concurrent transaction which did
locking reads from this table this sometimes led to a
deadlock which was not detected by MDL subsystem nor by
InnoDB engine (and was reported only after exceeding
innodb_lock_wait_timeout).

This problem stemmed from the fact that ALTER TABLE acquired
TL_WRITE_ALLOW_READ lock on table being altered. This lock
was interpreted as a write lock and thus for table being
altered handler::external_lock() method was called with
F_WRLCK as an argument. As result InnoDB engine treated
ALTER TABLE as an operation which is going to change data
and acquired LOCK_X locks on rows being read from old
version of table.

In case when there was a transaction which already acquired
SR metadata lock on table and some LOCK_S locks on its rows
(e.g. by using it in subquery of DML statement) concurrent
ALTER TABLE was blocked at the moment when it tried to
acquire LOCK_X lock before reading one of these rows.
The transaction's attempt to acquire SW metadata lock on
table being altered led to deadlock, since it had to wait
for ALTER TABLE to release SNW lock. This deadlock was not
detected and got resolved only after timeout expiring
because waiting were happening in two different subsystems.

Similar deadlocks could have occured in other situations.
This patch tries to solve the problem by changing ALTER TABLE
implementation to use TL_READ_NO_INSERT lock instead of
TL_WRITE_ALLOW_READ. After this step handler::external_lock()
is called with F_RDLCK as an argument and InnoDB engine
correctly interprets ALTER TABLE as operation which only
reads data from original version of table. Thanks to this
ALTER TABLE acquires only LOCK_S locks on rows it reads.
This, in its turn, causes inter-subsystem deadlocks to go
away, as all potential lock conflicts and thus deadlocks will
be limited to metadata locking subsystem:

- When ALTER TABLE reads rows from table being altered it
  can't encounter any locks which conflict with LOCK_S row
  locks. There should be no concurrent transactions holding
  LOCK_X row locks. Such a transaction should have been
  acquired SW metadata lock on table first which would have
  conflicted with ALTER's SNW lock.
- Vice versa, when DML which runs concurrently with ALTER
  TABLE tries to lock row it should be requesting only LOCK_S
  lock which is compatible with locks acquired by ALTER,
  as otherwise such DML must own an SW metadata lock on table
  which would be incompatible with ALTER's SNW lock.
 2010-05-26 16:18:08 +04:00
Dmitry Lenev
bee0f214fd Pre-requisite patch for bug #51263 "Deadlock between 
transactional SELECT and ALTER TABLE ... REBUILD PARTITION".

The goal of this patch is to decouple type of metadata
lock acquired for table by open_tables() from type of
table-level lock to be acquired on it.

To achieve this we change approach to how we determine what
type of metadata lock should be acquired on table to be open.
Now instead of inferring it at open_tables() time from flags
and type of table-level lock we rely on that type of metadata
lock is properly set at parsing time and is not changed
further.

sql/ha_ndbcluster.cc:
  Now one needs to properly initialize table list element's
  MDL_request object before calling mysql_rm_table_part2().
sql/lock.cc:
  lock_table_names() no longer initializes table list elements'
  MDL_request objects. Now proper initialization of these
  requests is a responsibility of the caller.
sql/lock.h:
  Removed MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag which became
  unnecessary. Thanks to the fact that we don't reset type of
  requests for metadata locks between re-executions we now can
  figure out that upgradable locks are requested by simply
  looking at their type which were set in the parser. As result
  this flag became redundant.
sql/mdl.h:
  Added version of new operator which simplifies allocation of
  MDL_request objects on a MEM_ROOT.
sql/sp_head.cc:
  Added comment explaining why it is OK to infer type of
  metadata lock to request from type of table-level lock
  for prelocking.
  Added enum_mdl_type argument to sp_add_to_query_tables()
  to simplify its usage in trigger implementation.
sql/sp_head.h:
  Added enum_mdl_type argument to sp_add_to_query_tables()
  to simplify its usage in trigger implementation.
sql/sql_base.cc:
  - open_table_get_mdl_lock():
    Preserve type of MDL_request for table list element which
    was set in the parser by creating MDL_request objects on
    memory root if MYSQL_OPEN_FORCE_SHARED_MDL or
    MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL flag were specified.
    Thanks to this and to the fact that we no longer reset
    type of requests for metadata locks between re-executions
    we no longer need to acquire exclusive metadata lock on
    table to be created in a special way. This lock is acquired
    by code handling acquiring of upgradable locks.
    Also changed signature/calling convention for this function
    to simplify its usage.
  - Accordingly special lock strategy for table list elements
    which was used for such locks became unnecessary and was
    removed. Other strategies were renamed.
  - Since we no longer have guarantee that MDL_request object
    which were not satisfied due to lock conflict belongs to
    table list element Open_table_context class and its methods
    were extended to remember pointer to MDL_request which has
    caused problem at request_backoff_action() time and use it
    in recover_from_failed_open(). Similar approach is used
    for cases when problem from which we need to recover is
    not related to MDL but to the table itself. In this case
    we store pointer to the element of table list.
  - Changed open_tables()/open_tables_check_upgradable_mdl()/
    open_tables_acquire_upgradable_mdl() not to rely on
    MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag to understand when
    upgradable metadata locks should be acquired and not to
    infer type of MDL lock from type of table-level lock.
    Instead we assume that type of MDL to be acquired was set
    in the parser (we can do this as type of MDL_request is
    no longer reset between re-executions).
sql/sql_class.h:
  Since we no longer have guarantee that MDL_request object
  which were not satisfied due to lock conflict belongs to
  table list element Open_table_context class and its methods
  were extended to remember pointer to MDL_request which has
  caused problem at request_backoff_action() time and use it
  in recover_from_failed_open(). Similar approach is used
  for cases when problem from which we need to recover is
  not related to MDL but to the table itself. In this case
  we store pointer to the element of table list.
sql/sql_db.cc:
  Now one needs to properly initialize table list element's
  MDL_request object before calling mysql_rm_table_part2()
  or mysql_rename_tables().
sql/sql_lex.cc:
  st_select_lex/st_select_lex_node::add_table_to_list() method
  now has argument which allows specify type of metadata lock
  to be requested for table list element being added.
sql/sql_lex.h:
  - st_select_lex/st_select_lex_node::add_table_to_list()
    method now has argument which specifies type of metadata
    lock to be requested for table list element being added.
    This allows to explicitly set type of MDL lock to be
    acquired for a DDL statement in parser. It is also more
    future-proof than inferring type of MDL request from type
    of table-level lock.
  - Added Yacc_state::m_mdl_type member which specifies which
    type of metadata lock should be requested for tables to be
    added to table list by a grammar rule in cases when the same
    rule is used in several statements requiring different kinds
    of metadata locks.
sql/sql_parse.cc:
  - st_select_lex::add_table_to_list() method now has argument
    which specifies type of metadata lock to be requested for
    table list element being added. This allows to explicitly
    set type of MDL lock to be acquired for a DDL statement in
    parser. It is also more future-proof than inferring type of
    MDL request from type of table-level lock.
  - EXCLUSIVE_DOWNGRADABLE_MDL lock strategy has a new name -
    OTLS_DOWNGRADE_IF_EXISTS.
  - Adjusted LOCK TABLES implementation to the fact that we no
    longer infer type of metadata lock to be acquired from table
    level lock and that type of MDL request is set at parsing.
    And thus MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag became
    unnecessary.
sql/sql_prepare.cc:
  TABLE_LIST's lock strategy SHARED_MDL was renamed to OTLS_NONE
  as now it means that metadata lock should not be changed during
  call to open_table() (if it has been already acquired) and is
  also used for exclusive metadata lock.
sql/sql_show.cc:
  st_select_lex::add_table_to_list() method now has argument
  which specifies type of metadata lock to be requested for
  table list element being added.
sql/sql_table.cc:
  - Adjusted mysql_admin_table()'s code to the fact that
    open_tables() no longer determines what kind of metadata
    lock should be obtained basing on type of table-level
    lock and flags. Instead type of metadata lock for table
    to be open should be set before calling open_tables().
  - Changed mysql_alter_table() code to the facts:
    a) that now it is responsibility of caller to properly
    initalize MDL_request in table list elements before calling
    lock_table_names()
    b) and that MYSQL_OPEN_TAKE_UPGRADABLE_MDL is no longer
    necessary since type of metadata lock to be obtained
    at open_tables() time is set during parsing.
  - Changed code of mysql_recreate_table() to properly set
    type of metadata and table-level lock to be obtained
    by mysql_alter_table() which it calls.
sql/sql_trigger.cc:
  Instead of relying on MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag to
  force open_tables() to take an upgradable lock we now specify
  exact type of lock to be taken when constructing table list
  element for table to be open for CREATE/DROP TRIGGER.
sql/sql_view.cc:
  We no longer use TABLE_LIST::EXCLUSIVE_MDL strategy to force
  open_tables() to take an exclusive metadata lock on view to
  be created. Instead we rely on parser setting proper type of
  metadata lock to request and open_tables() acquiring it.
  This became possible thanks to the fact that we no longer
  reset type of MDL_request between statement re-executions.
sql/sql_yacc.yy:
  Instead of inferring type of MDL_request for table to be
  open from type of table-level lock and flags passed to
  open_tables() we now explicitly specify them at parsing.
  This became possible thanks to the fact that we no longer
  reset type of MDL_request between statement re-executions.
  In future this should allow to decouple type of metadata
  lock from type of table-level lock.
  The only exception to this approach is statements implemented
  through mysql_admin_table() which re-uses same table list
  element several times with different types of table-level
  and metadata locks.
  We now also properly initialize MDL_request objects for table
  list elements which are later passed to lock_table_names()
  function.
sql/table.cc:
  Do not reset type of MDL_request between statement
  re-executions. This became unnecessesary as we no longer
  change type of MDL_request residing in table list element.
  In its turn this change allows to set type of MDL_request
  only once - at parsing time.
sql/table.h:
  Got rid of TABLE_LIST::EXCLUSIVE_MDL lock strategy.
  Now we can specify that we need to acquire exclusive lock
  on table to be processed by open_tables() through setting
  an appropriate type of MDL_request at parsing time (this
  became possible thanks to the fact that we no longer reset
  types of MDL_request's belonging to table list elements
  between statement re-execution).
  Strategy SHARED_MDL was renamed to OTLS_NONE as now it
  means that metadata lock should not be changed during call
  to open_table() (if it has been already acquired) and is
  also used for exclusive metadata lock.
  Strategy EXCLUSIVE_DOWNGRADABLE_MDL was renamed to
  OTLS_DOWNGRADE_IF_EXISTS.
 2010-05-25 16:35:01 +04:00
Dmitry Lenev
a3c080be7a Pre-requisite patch for bug #51263 "Deadlock between 
transactional SELECT and ALTER TABLE ... REBUILD PARTITION".

The goal of this patch is to decouple type of metadata
lock acquired for table by open_tables() from type of
table-level lock to be acquired on it.

To achieve this we change approach to how we determine what
type of metadata lock should be acquired on table to be open.
Now instead of inferring it at open_tables() time from flags
and type of table-level lock we rely on that type of metadata
lock is properly set at parsing time and is not changed
further.
 2010-05-25 16:35:01 +04:00
Alexey Kopytov
c2ebb0ac88 Bug #42064: low memory crash when importing hex strings, in 
Item_hex_string::Item_hex_string

The status of memory allocation in the Lex_input_stream (called
from the Parser_state constructor) was not checked which led to
a parser crash in case of the out-of-memory error.

The solution is to introduce new init() member function in
Parser_state and Lex_input_stream so that status of memory
allocation can be returned to the caller.

mysql-test/r/error_simulation.result:
  Added a test case for bug #42064.
mysql-test/t/error_simulation.test:
  Added a test case for bug #42064.
mysys/my_alloc.c:
  Added error injection code for the regression test.
mysys/my_malloc.c:
  Added error injection code for the regression test.
mysys/safemalloc.c:
  Added error injection code for the regression test.
sql/event_data_objects.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/mysqld.cc:
  Added error injection code for the regression test.
sql/sp.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_lex.cc:
  Moved memory allocation from constructor to the separate init()
  member function.
  Added error injection code for the regression test.
sql/sql_lex.h:
  Moved memory allocation from constructor to the separate init()
  member function.
sql/sql_parse.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_partition.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_prepare.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_trigger.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_view.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures..
sql/thr_malloc.cc:
  Added error injection code for the regression test.
 2010-05-21 15:23:48 +04:00
Alexey Kopytov
779e2a9686 Bug #42064: low memory crash when importing hex strings, in 
Item_hex_string::Item_hex_string

The status of memory allocation in the Lex_input_stream (called
from the Parser_state constructor) was not checked which led to
a parser crash in case of the out-of-memory error.

The solution is to introduce new init() member function in
Parser_state and Lex_input_stream so that status of memory
allocation can be returned to the caller.
 2010-05-21 15:23:48 +04:00
Konstantin Osipov
1ab519d91f Committing on behalf or Dmitry Lenev: 
Fix for bug #46947 "Embedded SELECT without FOR UPDATE is
causing a lock", with after-review fixes.

SELECT statements with subqueries referencing InnoDB tables
were acquiring shared locks on rows in these tables when they
were executed in REPEATABLE-READ mode and with statement or
mixed mode binary logging turned on.

This was a regression which were introduced when fixing
bug 39843.

The problem was that for tables belonging to subqueries
parser set TL_READ_DEFAULT as a lock type. In cases when
statement/mixed binary logging at open_tables() time this
type of lock was converted to TL_READ_NO_INSERT lock at
open_tables() time and caused InnoDB engine to acquire
shared locks on reads from these tables. Although in some
cases such behavior was correct (e.g. for subqueries in
DELETE) in case of SELECT it has caused unnecessary locking.

This patch tries to solve this problem by rethinking our
approach to how we handle locking for SELECT and subqueries.
Now we always set TL_READ_DEFAULT lock type for all cases
when we read data. When at open_tables() time this lock
is interpreted as TL_READ_NO_INSERT or TL_READ depending
on whether this statement as a whole or call to function
which uses particular table should be written to the
binary log or not (if yes then statement should be properly
serialized with concurrent statements and stronger lock
should be acquired).

Test coverage is added for both InnoDB and MyISAM.

This patch introduces an "incompatible" change in locking
scheme for subqueries used in SELECT ... FOR UPDATE and
SELECT .. IN SHARE MODE.
In 4.1 the server would use a snapshot InnoDB read for 
subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE
statements, regardless of whether the binary log is on or off.
If the user required a different type of read (i.e. locking read),
he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE
clause for each individual subquery.
On of the patches for 5.0 broke this behaviour (which was not documented
or tested), and started to use locking reads fora all subqueries in SELECT ... 
FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour.

mysql-test/include/check_concurrent_insert.inc:
  Added auxiliary script which allows to check if statement
  reading table allows concurrent inserts in it.
mysql-test/include/check_no_concurrent_insert.inc:
  Added auxiliary script which allows to check that statement
  reading table doesn't allow concurrent inserts in it.
mysql-test/include/check_no_row_lock.inc:
  Added auxiliary script which allows to check if statement
  reading table doesn't take locks on its rows.
mysql-test/include/check_shared_row_lock.inc:
  Added auxiliary script which allows to check if statement
  reading table takes shared locks on some of its rows.
mysql-test/r/bug39022.result:
  After bug #46947 'Embedded SELECT without FOR UPDATE is
  causing a lock' was fixed test case for bug 39022 has to
  be adjusted in order to trigger execution path on which
  original problem was encountered.
mysql-test/r/innodb_mysql_lock2.result:
  Added coverage for handling of locking in various cases when
  we read data from InnoDB tables (includes test case for
  bug #46947 'Embedded SELECT without FOR UPDATE is causing a
  lock').
mysql-test/r/lock_sync.result:
  Added coverage for handling of locking in various cases when
  we read data from MyISAM tables.
mysql-test/t/bug39022.test:
  After bug #46947 'Embedded SELECT without FOR UPDATE is
  causing a lock' was fixed test case for bug 39022 has to
  be adjusted in order to trigger execution path on which
  original problem was encountered.
mysql-test/t/innodb_mysql_lock2.test:
  Added coverage for handling of locking in various cases when
  we read data from InnoDB tables (includes test case for
  bug #46947 'Embedded SELECT without FOR UPDATE is causing a
  lock').
mysql-test/t/lock_sync.test:
  Added coverage for handling of locking in various cases when
  we read data from MyISAM tables.
sql/log_event.cc:
  Since LEX::lock_option member was removed we no longer can
  rely on its value in Load_log_event::print_query() to
  determine that log event correponds to LOAD DATA CONCURRENT
  statement (this was not correct in all situations anyway).
  A new Load_log_event's member was introduced as a replacement.
  It is initialized at event object construction time and
  explicitly indicates whether LOAD DATA was concurrent.
sql/log_event.h:
  Since LEX::lock_option member was removed we no longer can
  rely on its value in Load_log_event::print_query() to
  determine that log event correponds to LOAD DATA CONCURRENT
  statement (this was not correct in all situations anyway).
  A new Load_log_event's member was introduced as a replacement.
  It is initialized at event object construction time and
  explicitly indicates whether LOAD DATA was concurrent.
sql/sp_head.cc:
  sp_head::reset_lex():
    Before parsing substatement reset part of parser state
    which needs this (e.g. set Yacc_state::m_lock_type to
    default value).
sql/sql_acl.cc:
  Since LEX::reset_n_backup_query_tables_list() now also
  resets LEX::sql_command member (as it became part of
  Query_tables_list class) we have to restore it in cases
  when while working with proxy Query_table_list we assume
  that LEX::sql_command still corresponds to original SQL
  command being executed (for example, when we are logging
  statement to the binary log while having Query_tables_list
  reset and backed up).
sql/sql_base.cc:
  Changed read_lock_type_for_table() to return a weak TL_READ
  type of lock in cases when we are executing statement which
  won't update tables directly and table doesn't belong to
  statement's prelocking list and thus can't be used by a
  stored function. It is OK to do so since in this case table
  won't be used by statement or function call which will be
  written to the binary log, so serializability requirements
  for it can be relaxed.
  One of results from this change is that SELECTs on InnoDB
  tables no longer takes shared row locks for tables which
  are used in subqueries (i.e. bug #46947 is fixed).
  Another result is that for similar SELECTs on MyISAM tables
  concurrent inserts are allowed.
  In order to implement this change signature of
  read_lock_type_for_table() function was changed to take
  pointers to Query_tables_list and TABLE_LIST objects.
sql/sql_base.h:
  - Function read_lock_type_for_table() now takes pointers
    to Query_tables_list and TABLE_LIST elements as its
    arguments since to correctly determine lock type it needs
    to know what statement is being performed and whether table
    element for which lock type to be determined belongs to
    prelocking list.
sql/sql_lex.cc:
  - Removed LEX::lock_option and st_select_lex::lock_option
    members. Places in parser that were using them now use
    Yacc_state::m_lock_type instead.
  - To emphasize that LEX::sql_command member is used during
    process of opening and locking of tables it was moved to
    Query_tables_list class. It is now reset by
    Query_tables_list::reset_query_tables_list() method.
sql/sql_lex.h:
  - Removed st_select_lex::lock_option member as there is no
    real need for per-SELECT lock type (HIGH_PRIORITY option
    should apply to the whole statement. FOR UPDATE/LOCK IN
    SHARE MODE clauses can be handled without this member).
    The main effect which was achieved by introduction of this
    member, i.e. using TL_READ_DEFAULT lock type for
    subqueries, is now achieved by setting LEX::lock_option
    (or rather its replacement - Yacc_state::m_lock_type) to
    TL_READ_DEFAULT in almost all cases.
  - To emphasize that LEX::sql_command member is used during
    process of opening and locking of tables it was moved to
    Query_tables_list class.
  - Replaced LEX::lock_option with Yacc_state::m_lock_type
    in order to emphasize that this value is relevant only
    during parsing. Unlike for LEX::lock_option the default
    value for Yacc_state::m_lock_type is TL_READ_DEFAULT.
    Note that for cases when it is OK to take a "weak" read
    lock (e.g. simple SELECT) this lock type will be converted
    to TL_READ at open_tables() time. So this change won't
    cause negative change in behavior for such statements.
    OTOH this change ensures that, for example, for SELECTs
    which are used in stored functions TL_READ_NO_INSERT lock
    is taken when necessary and as result calls to such stored
    functions can be written to the binary log with correct
    serialization.
sql/sql_load.cc:
  Load_log_event constructor now requires a parameter that
  indicates whether LOAD DATA is concurrent.
sql/sql_parse.cc:
  LEX::lock_option was replaced with Yacc_state::m_lock_type.
  And instead of resetting the latter implicitly in
  mysql_init_multi_delete() we do it explicitly in the
  places in parser which call this function.
sql/sql_priv.h:
  - To be able more easily distinguish high-priority SELECTs
    in st_select_lex::print() method added flag for
    HIGH_PRIORITY option.
sql/sql_select.cc:
  Changed code not to rely on LEX::lock_option to determine
  that it is high-priority SELECT. It was replaced with
  Yacc_state::m_lock_type which is accessible only at
  parse time. So instead of LEX::lock_option we now rely
  on a newly introduced flag for st_select_lex::options -
  SELECT_HIGH_PRIORITY.
sql/sql_show.cc:
  Since LEX::reset_n_backup_query_tables_list() now also
  resets LEX::sql_command member (as it became part of
  Query_tables_list class) we have to restore it in cases
  when while working with proxy Query_table_list we assume
  that LEX::sql_command still corresponds to original SQL
  command being executed.
sql/sql_table.cc:
  Since LEX::reset_query_tables_list() now also resets
  LEX::sql_command member (as it became part of
  Query_tables_list class) we have to restore value of this
  member when this method is called by mysql_admin_table(),
  to make this code safe for re-execution.
sql/sql_trigger.cc:
  Since LEX::reset_n_backup_query_tables_list() now also
  resets LEX::sql_command member (as it became part of
  Query_tables_list class) we have to restore it in cases
  when while working with proxy Query_table_list we assume
  that LEX::sql_command still corresponds to original SQL
  command being executed (for example, when we are logging
  statement to the binary log while having Query_tables_list
  reset and backed up).
sql/sql_update.cc:
  Function read_lock_type_for_table() now takes pointers
  to Query_tables_list and TABLE_LIST elements as its
  arguments since to correctly determine lock type it needs
  to know what statement is being performed and whether table
  element for which lock type to be determined belongs to
  prelocking list.
sql/sql_yacc.yy:
  - Removed st_select_lex::lock_option member as there is no
    real need for per-SELECT lock type (HIGH_PRIORITY option
    should apply to the whole statement. FOR UPDATE/LOCK IN
    SHARE MODE clauses can be handled without this member).
    The main effect which was achieved by introduction of this
    member, i.e. using TL_READ_DEFAULT lock type for
    subqueries, is now achieved by setting LEX::lock_option
    (or rather its replacement - Yacc_state::m_lock_type) to
    TL_READ_DEFAULT in almost all cases.
  - Replaced LEX::lock_option with Yacc_state::m_lock_type
    in order to emphasize that this value is relevant only
    during parsing. Unlike for LEX::lock_option the default
    value for Yacc_state::m_lock_type is TL_READ_DEFAULT.
    Note that for cases when it is OK to take a "weak" read
    lock (e.g. simple SELECT) this lock type will be converted
    to TL_READ at open_tables() time. So this change won't
    cause negative change in behavior for such statements.
    OTOH this change ensures that, for example, for SELECTs
    which are used in stored functions TL_READ_NO_INSERT lock
    is taken when necessary and as result calls to such stored
    functions can be written to the binary log with correct
    serialization.
  - To be able more easily distinguish high-priority SELECTs
    in st_select_lex::print() method we now use new flag
    in st_select_lex::options bit-field.
 2010-04-28 14:04:11 +04:00
Konstantin Osipov
8280fdd3c3 Committing on behalf or Dmitry Lenev: 
Fix for bug #46947 "Embedded SELECT without FOR UPDATE is
causing a lock", with after-review fixes.

SELECT statements with subqueries referencing InnoDB tables
were acquiring shared locks on rows in these tables when they
were executed in REPEATABLE-READ mode and with statement or
mixed mode binary logging turned on.

This was a regression which were introduced when fixing
bug 39843.

The problem was that for tables belonging to subqueries
parser set TL_READ_DEFAULT as a lock type. In cases when
statement/mixed binary logging at open_tables() time this
type of lock was converted to TL_READ_NO_INSERT lock at
open_tables() time and caused InnoDB engine to acquire
shared locks on reads from these tables. Although in some
cases such behavior was correct (e.g. for subqueries in
DELETE) in case of SELECT it has caused unnecessary locking.

This patch tries to solve this problem by rethinking our
approach to how we handle locking for SELECT and subqueries.
Now we always set TL_READ_DEFAULT lock type for all cases
when we read data. When at open_tables() time this lock
is interpreted as TL_READ_NO_INSERT or TL_READ depending
on whether this statement as a whole or call to function
which uses particular table should be written to the
binary log or not (if yes then statement should be properly
serialized with concurrent statements and stronger lock
should be acquired).

Test coverage is added for both InnoDB and MyISAM.

This patch introduces an "incompatible" change in locking
scheme for subqueries used in SELECT ... FOR UPDATE and
SELECT .. IN SHARE MODE.
In 4.1 the server would use a snapshot InnoDB read for 
subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE
statements, regardless of whether the binary log is on or off.
If the user required a different type of read (i.e. locking read),
he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE
clause for each individual subquery.
On of the patches for 5.0 broke this behaviour (which was not documented
or tested), and started to use locking reads fora all subqueries in SELECT ... 
FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour.
 2010-04-28 14:04:11 +04:00
Mats Kindahl
46bd78b9ee WL#5030: Splitting mysql_priv.h 
Adding my_global.h first in all files using
NO_EMBEDDED_ACCESS_CHECKS.

Correcting a merge problem resulting from a changed definition
of check_some_access compared to the original patches.
 2010-04-07 13:58:40 +02:00
Mats Kindahl
0768deeb27 WL#5030: Splitting mysql_priv.h 
Adding my_global.h first in all files using
NO_EMBEDDED_ACCESS_CHECKS.

Correcting a merge problem resulting from a changed definition
of check_some_access compared to the original patches.
 2010-04-07 13:58:40 +02:00
Mats Kindahl
23d8586dbf WL#5030: Split and remove mysql_priv.h 
This patch:

- Moves all definitions from the mysql_priv.h file into
  header files for the component where the variable is
  defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h
 2010-03-31 16:05:33 +02:00
Mats Kindahl
e409d6f69c WL#5030: Split and remove mysql_priv.h 
This patch:

- Moves all definitions from the mysql_priv.h file into
  header files for the component where the variable is
  defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h
 2010-03-31 16:05:33 +02:00
Alexander Nozdrin
b3018e8613 Manual merge from mysql-trunk-merge. 
Conflicts:
  - client/mysql.cc
  - client/mysqldump.c
  - configure.in
  - mysql-test/r/csv.result
  - mysql-test/r/func_time.result
  - mysql-test/r/show_check.result
  - mysql-test/r/sp-error.result
  - mysql-test/r/sp.result
  - mysql-test/r/sp_trans.result
  - mysql-test/r/type_blob.result
  - mysql-test/r/type_timestamp.result
  - mysql-test/r/warnings.result
  - mysql-test/suite/rpl/r/rpl_sp.result
  - sql/mysql_priv.h
  - sql/mysqld.cc
  - sql/sp.cc
  - sql/sql_base.cc
  - sql/sql_table.cc
  - sql/sql_trigger.cc
  - sql/sql_view.cc
  - sql/table.h
  - sql/share/errmsg.txt
  - mysql-test/suite/sys_vars/r/log_bin_trust_routine_creators_basic.result
 2010-02-24 16:52:27 +03:00
Alexander Nozdrin
04b8cb1882 Manual merge from mysql-trunk-merge. 
Conflicts:
  - client/mysql.cc
  - client/mysqldump.c
  - configure.in
  - mysql-test/r/csv.result
  - mysql-test/r/func_time.result
  - mysql-test/r/show_check.result
  - mysql-test/r/sp-error.result
  - mysql-test/r/sp.result
  - mysql-test/r/sp_trans.result
  - mysql-test/r/type_blob.result
  - mysql-test/r/type_timestamp.result
  - mysql-test/r/warnings.result
  - mysql-test/suite/rpl/r/rpl_sp.result
  - sql/mysql_priv.h
  - sql/mysqld.cc
  - sql/sp.cc
  - sql/sql_base.cc
  - sql/sql_table.cc
  - sql/sql_trigger.cc
  - sql/sql_view.cc
  - sql/table.h
  - sql/share/errmsg.txt
  - mysql-test/suite/sys_vars/r/log_bin_trust_routine_creators_basic.result
 2010-02-24 16:52:27 +03:00
Alexey Kopytov
0afa209018 Manual merge of mysql-5.1-bugteam to mysql-trunk-merge. 2010-02-22 00:33:11 +03:00
Alexey Kopytov
8c31c4d16c Manual merge of mysql-5.1-bugteam to mysql-trunk-merge. 2010-02-22 00:33:11 +03:00
Konstantin Osipov
00dc9a6e70 Merge next-mr -> next-4284. 
Cherry-pick a fix Bug#37148 from next-mr, to preserve
file ids of the added files, and ensure that all the necessary
changes have been pulled.

Since initially Bug#37148 was null-merged into 6.0,
the changeset that is now being cherry-picked was likewise
null merged into next-4284.

Now that Bug#37148 has been reapplied to 6.0, try to make
it work with next-4284. This is also necessary to be able
to pull other changes from 5.1-rep into next-4284.

To resolve the merge issues use this changeset applied
to 6.0:
revid:jperkin@sun.com-20091216103628-ylhqf7s6yegui2t9
revno: 3776.1.1
committer: He Zhenxing <zhenxing.he@sun.com>
branch nick: 6.0-codebase-bugfixing
timestamp: Thu 2009-12-17 17:02:50 +0800
message:
  Fix merge problem with Bug#37148
 2010-02-04 23:15:47 +03:00
Konstantin Osipov
06e1a73af6 Merge next-mr -> next-4284. 
Cherry-pick a fix Bug#37148 from next-mr, to preserve
file ids of the added files, and ensure that all the necessary
changes have been pulled.

Since initially Bug#37148 was null-merged into 6.0,
the changeset that is now being cherry-picked was likewise
null merged into next-4284.

Now that Bug#37148 has been reapplied to 6.0, try to make
it work with next-4284. This is also necessary to be able
to pull other changes from 5.1-rep into next-4284.

To resolve the merge issues use this changeset applied
to 6.0:
revid:jperkin@sun.com-20091216103628-ylhqf7s6yegui2t9
revno: 3776.1.1
committer: He Zhenxing <zhenxing.he@sun.com>
branch nick: 6.0-codebase-bugfixing
timestamp: Thu 2009-12-17 17:02:50 +0800
message:
  Fix merge problem with Bug#37148
 2010-02-04 23:15:47 +03:00