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1531 Commits

Author SHA1 Message Date
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
Konstantin Osipov
248625d910 A fix and a test case for Bug#56540 "Exception (crash) in
sql_show.cc during rqg_info_schema test on Windows".

Ensure we do not access freed memory when filling
information_schema.views when one of the views
could not be properly opened.



mysql-test/r/information_schema.result:
  Update results - a fix for Bug#56540.
mysql-test/t/information_schema.test:
  Add a test case for Bug#56540
sql/sql_base.cc:
  Push an error into the Diagnostics area
  when we return an error.
  This directs get_all_tables() to the execution
  branch which doesn't involve 'process_table()'
  when no table/view was opened.
sql/sql_show.cc:
  Do not try to access underlying table fields
  when opening of a view failed. The underlying
  table is closed in that case, and accessing
  its fields may lead to dereferencing a damaged 
  pointer.
2010-10-14 20:56:56 +04:00
Jon Olav Hauglid
5a57a45c66 Follow-up for Bug #55930 Assertion `thd->transaction.stmt.is_empty()
|| thd->in_sub_stmt || (thd->state..

Don't rollback statement transactions if we are in a sub-statement.
This could for example happen for open_ltable() when opening the
general log during execution of a stored procedure.
2010-10-14 11:02:37 +02:00
Jon Olav Hauglid
b5be2fbc8d Bug #55930 Assertion `thd->transaction.stmt.is_empty() ||
thd->in_sub_stmt || (thd->state..

OPTIMIZE TABLE is not directly supported by InnoDB. Instead,
recreate and analyze of the table is done. After recreate,
the table is closed and locks are released before the table
is reopened and locks re-acquired for the analyze phase.

This assertion was triggered if OPTIMIZE TABLE failed to
acquire thr_lock locks before starting the analyze phase.
The assertion tests (among other things) that there no
active statement transaction. However, as part of acquiring
the thr_lock lock, external_lock() is called for InnoDB
tables and this causes a statement transaction to be started.
If thr_multi_lock() later fails (e.g. due to timeout),
the failure handling code causes this assert to be triggered.

This patch fixes the problem by doing rollback of the
current statement transaction in case open_ltable (used by
OPTIMIZE TABLE) fails to acquire thr_lock locks.

Test case added to lock_sync.test.
2010-10-13 16:15:28 +02:00
Dmitry Lenev
476939cb45 Reverted a temporary workaround for bug #56405 "Deadlock
in the MDL deadlock detector".

It is no longer needed as a better fix for this bug has
been pushed.
2010-09-30 17:29:12 +04:00
Jon Olav Hauglid
bf55d1fcf0 Merge from mysql-5.5-bugteam to mysql-5.5-runtime 2010-09-30 12:43:43 +02:00
Dmitry Lenev
48de6a60d2 Fix compile warning about passing NULL to non-pointer
argument of inline_mysql_mutex_init in sql_base.cc.

When initializing LOCK_dd_owns_lock_open mutex pass
correct PSI key instead of NULL value.

mysql-test/suite/perfschema/r/dml_setup_instruments.result:
  Updated test results after adding P_S instrumentation
  for LOCK_dd_owns_lock_open.
sql/sql_base.cc:
  When initializing LOCK_dd_owns_lock_open mutex pass
  correct PSI key instead of NULL value.
2010-09-24 20:26:24 +04:00
Dmitry Lenev
e86bbbda55 Fix for bug #56251 "Deadlock with INSERT DELAYED and MERGE
tables".

Attempting to issue an INSERT DELAYED statement for a MERGE
table might have caused a deadlock if it happened as part of
a transaction or under LOCK TABLES, and there was a concurrent
DDL or LOCK TABLES ... WRITE statement which tried to lock one
of its underlying tables.

The problem occurred when a delayed insert handler thread tried
to open a MERGE table and discovered that to do this it had also
to open all underlying tables and hence acquire metadata
locks on them. Since metadata locks on the underlying tables were
not pre-acquired by the connection thread executing INSERT DELAYED,
attempts to do so might lead to waiting. In this case the
connection thread had to wait for the delayed insert thread.
If the thread which was preventing the lock on the underlying table
from being acquired had to wait for the connection thread (due to
this or other metadata locks), a deadlock occurred. 
This deadlock was not detected by the MDL deadlock detector since 
waiting for the handler thread by the connection thread is not
represented in the wait-for graph.

This patch solves the problem by ensuring that the delayed
insert handler thread never tries to open underlying tables 
of a MERGE table. Instead open_tables() is aborted right after
the parent table is opened and a ER_DELAYED_NOT_SUPPORTED 
error is emitted (which is passed to the connection thread and
ultimately to the user).

mysql-test/r/merge.result:
  Added test for bug #56251 "Deadlock with INSERT DELAYED and
  MERGE tables".
mysql-test/t/merge.test:
  Added test for bug #56251 "Deadlock with INSERT DELAYED and
  MERGE tables".
sql/sql_base.cc:
  Changed open_n_lock_single_table() to take prelocking strategy
  as an argument instead of always using DML_prelocking_strategy.
sql/sql_base.h:
  Changed open_n_lock_single_table() to take prelocking strategy
  as an argument instead of always using DML_prelocking_strategy.
  Added a version of this function which is compatible with old
  signature.
sql/sql_insert.cc:
  When opening MERGE table in delayed insert thread stop and emit
  ER_DELAYED_NOT_SUPPORTED right after opening main table and
  before opening underlying tables. This ensures that we won't
  try to acquire metadata lock on underlying tables which might
  lead to a deadlock.
  This is achieved by using special prelocking strategy which
  abort open_tables() process as soon as we discover that we
  have opened table with engine which doesn't support delayed
  inserts.
2010-09-15 18:15:31 +04:00
Dmitry Lenev
65a438d87a Fix for bug #55273 "FLUSH TABLE tm WITH READ LOCK for Merge
table causes assert failure".

Attempting to use FLUSH TABLE table_list WITH READ LOCK
statement for a MERGE table led to an assertion failure if
one of its children was not present in the list of tables
to be flushed. The problem was not visible in non-debug builds.

The assertion failure was caused by the fact that in such
situations FLUSH TABLES table_list WITH READ LOCK implementation
tried to use (e.g. lock) such child tables without acquiring
metadata lock on them. This happened because when opening tables
we assumed metadata locks on all tables were already acquired
earlier during statement execution and a such assumption was
false for MERGE children.

This patch fixes the problem by ensuring at open_tables() time
that we try to acquire metadata locks on all tables to be opened. 
For normal tables such requests are satisfied instantly since
locks are already acquired for them. For MERGE children metadata
locks are acquired in normal fashion.

Note that FLUSH TABLES merge_table WITH READ LOCK will lock for
read both the MERGE table and its children but will flush only 
the MERGE table. To flush children one has to mention them in table
list explicitly. This is expected behavior and it is consistent with
usage patterns for this statement (e.g. in mysqlhotcopy script).

mysql-test/r/flush.result:
  Added test case for bug #55273 "FLUSH TABLE tm WITH READ LOCK
  for Merge table causes assert failure".
mysql-test/t/flush.test:
  Added test case for bug #55273 "FLUSH TABLE tm WITH READ LOCK
  for Merge table causes assert failure".
sql/sql_base.cc:
  Changed lock_table_names() to support newly introduced
  MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK flag.
sql/sql_base.h:
  Introduced MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK flag for
  open_tables() and lock_table_names() which allows to skip
  acquiring of global and schema-scope locks when SNW, SNRW or
  X metadata locks are acquired.
sql/sql_reload.cc:
  Changed "FLUSH TABLES table_list WITH READ LOCK" code not to
  cause assert about missing metadata locks when MERGE table is
  flushed without one of its underlying tables.
  To achieve this we no longer call open_and_lock_tables() with
  MYSQL_OPEN_HAS_MDL_LOCK flag so this function automatically
  acquires metadata locks on MERGE children if such lock has
  not been already acquired at earlier stage. Instead we call
  this function with MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK flag to
  suppress acquiring of global IX lock in order to keep FLUSH
  TABLES  table_list WITH READ LOCK compatible with FLUSH TABLE
  WITH READ LOCK.
  Also changed implementation to use lock_table_names() function
  for pre-acquiring of metadata locks instead of custom code.
  To implement this change moved setting of open_type member for
  table list elements to parser.
sql/sql_yacc.yy:
  Now we set acceptable type of table for FLUSH TABLES table_list
  WITH READ LOCK at parsing time instead of execution time.
2010-09-09 18:29:14 +04:00
Dmitry Lenev
f052fa3aad A temporary workaround for bug #56405 "Deadlock in the
MDL deadlock detector".

Deadlock could have occurred when workload containing mix
of DML, DDL and FLUSH TABLES statements affecting same
set of tables was executed in heavily concurrent environment.

This deadlock occurred when several connections tried to
perform deadlock detection in metadata locking subsystem.
The first connection started traversing wait-for graph,
encountered sub-graph representing wait for flush, acquired
LOCK_open and dived into sub-graph inspection. When it has
encounterd sub-graph corresponding to wait for metadata lock
and blocked while trying to acquire rd-lock on
MDL_lock::m_rwlock (*) protecting this subgraph, since some
other thread had wr-lock on it. When this wr-lock was released
it could have happened (if there was other pending wr-lock
against this rwlock) that rd-lock from the first connection
was left unsatisfied but at the same time new rd-lock request
from the second connection sneaked in and was satisfied (for
this to be possible second rd- request should come exactly
after wr-lock is released but before pending wr-lock manages
to grab rwlock, which is possible both on Linux and in our
own rwlock implementation). If this second connection
continued traversing wait-for graph and encountered sub-graph
representing wait for flush it tried to acquire LOCK_open
and thus deadlock was created.

This patch tries to workaround this problem but not allowing
deadlock detector to lock LOCK_open mutex if some other thread
doing deadlock detection already owns it and current search
depth is greater than 0. Instead deadlock is reported.

Other possible solutions are either known to have negative
effects on performance or require much more time for proper
implementation and testing.

No test case is provided as this bug is very hard to repeat
in MTR environment but is repeatable with the help of RQG
tests.

sql/mdl.cc:
  Moved Deadlock_detection_visitor::m_current_search_depth to
  parent class to make it available in
  TABLE_SHARE::visit_subgraph().
  Added MDL_wait_for_graph_visitor::abort_traversal() method
  which allows to abort traversal of a wait-for graph and
  report a deadlock.
sql/mdl.h:
  Moved Deadlock_detection_visitor::m_current_search_depth to
  parent class to make it available in
  TABLE_SHARE::visit_subgraph().
  Added MDL_wait_for_graph_visitor::abort_traversal() method
  which allows to abort traversal of a wait-for graph and
  report a deadlock.
sql/sql_base.cc:
  Added dd_owns_lock_open counter and mutex protecting it to
  track number of connections which do deadlock detection and
  own or try to acquire LOCK_open.
sql/sql_base.h:
  Added dd_owns_lock_open counter and mutex protecting it to
  track number of connections which do deadlock detection and
  own or try to acquire LOCK_open.
sql/table.cc:
  Workaround bug #56405 but not allowing MDL deadlock detector
  to lock LOCK_open mutex if some other thread doing deadlock
  detection already owns it and current search depth is greater
  than 0. Instead report deadlock.
2010-09-06 21:29:02 +04:00
Alexander Nozdrin
cc0925f5d9 Bug#27480 (Extend CREATE TEMPORARY TABLES privilege
to allow temp table operations) -- prerequisite patch #3.

Rename open_temporary_table() to open_table_uncached().
open_temporary_table() will be introduced in following patches
to open temporary tables for a statement.
2010-08-31 14:03:36 +04:00
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
4fcb173c41 Bug#27480 (Extend CREATE TEMPORARY TABLES privilege
to allow temp table operations) -- prerequisite patch #1.
  
Move a piece of code that initialiazes TABLE instance
after it was successfully opened into a separate function.
This function will be reused in the following patches.
2010-08-27 12:39:01 +04:00
Jon Olav Hauglid
02863b4180 Merge from mysql-5.5-runtime to mysql-5.5-bugfixing. 2010-08-20 10:24:32 +02:00
Jon Olav Hauglid
bbaae9a2dc Bug #55973 Assertion `thd->transaction.stmt.is_empty()'
on CREATE TABLE .. SELECT I_S.PART

This assert was triggered if an InnoDB table was created using
CREATE TABLE ... AS SELECT where the query used an I_S table, and
a view existed in the database. It would also be triggered for
any statement changing an InnoDB table (e.g. INSERT, UPDATE, DELETE)
which had a subquery referencing an I_S table.

The assert was triggered if open_normal_and_derived_tables() failed
and a statement transaction had been started. This will usually not
happen as tables are opened before a statement transaction is started.
However, e.g. CREATE TABLE ... AS SELECT starts a transaction in order
to insert tuples into the new table. And if the subquery references
an I_S table, all current tables and views can be opened in order to
fill the I_S table on the fly. If a view is discovered, open will fail
as it is instructed to open tables only (OPEN_TABLE_ONLY). This would
cause the assert to be triggered.

The assert was added in the patch for Bug#52044 and was therefore
not in any released versions of the server.

This patch fixes the problem by adjusting the assert to take into
consideration the possibility of tables being opened as part of
an I_S query. This is similar to what is already done for 
close_tables_for_reopen().

Test case added to information_schema_inno.test.
2010-08-20 09:16:26 +02:00
Alfranio Correia
ac6026ce27 BUG#53452 Inconsistent behavior of binlog_direct_non_transactional_updates with
temp table
            
This patch introduces two key changes in the replication's behavior.
            
Firstly, it reverts part of BUG#51894 which puts any update to temporary tables
into the trx-cache. Now, updates to temporary tables are handled according to
the type of their engines as a regular table.
            
Secondly, an unsafe mixed statement, (i.e. a statement that access transactional
table as well non-transactional or temporary table, and writes to any of them),
are written into the trx-cache in order to minimize errors in the execution when
the statement logging format is in use.
            
Such changes has a direct impact on which statements are classified as unsafe
statements and thus part of BUG#53259 is reverted.
2010-08-20 03:59:58 +01:00
Jon Olav Hauglid
41caa7f483 Bug #56085 Embedded server tests fails with assert in
check_if_table_exists()

This assert was triggered when the server tried to load plugins
while running in embedded server mode. In embedded server mode,
check_if_table_exists() was used to check if mysql.plugin existed
so that ER_NO_SUCH_TABLE could be silently ignored.
The problem was that this check was done without acquiring a metadata
lock on mysql.plugin first. This triggered the assert.

This patch fixes the problem by removing the call to
check_if_table_exists() from plugin_load(). Instead an error handler
which traps ER_NO_SUCH_TABLE is installed before trying to open
mysql.plugin when running in embedded server mode.

No test coverage added since this assert was triggered by 
existing tests running in embedded server mode.


sql/sql_base.cc:
  Renamed Prelock_error_handler to No_such_table_error_handler
  and moved the declaration to sql_base.h to make it usable
  in plugin_load().
sql/sql_base.h:
  Renamed Prelock_error_handler to No_such_table_error_handler
  and moved the declaration to sql_base.h to make it usable
  in plugin_load().
sql/sql_plugin.cc:
  Removed call to check_if_table_exists() used to check for mysql.plugin 
  in plugin_load() for embedded server. Instead install error handler
  which traps ER_NO_SUCH_TABLE during open_and_lock_tables().
2010-08-19 11:33:37 +02:00
Jon Olav Hauglid
f2123f34e3 Merge from mysql-5.5-bugfixing to mysql-5.5-runtime 2010-08-18 13:55:37 +02:00
Jon Olav Hauglid
eb498cce4d Manual merge from mysql-5.5-bugfixing to mysql-5.5-runtime. 2010-08-18 13:29:04 +02:00
unknown
d0d8bbed5e WL#5370 Keep forward-compatibility when changing
'CREATE TABLE IF NOT EXISTS ... SELECT' behaviour
BUG#47132, BUG#47442, BUG49494, BUG#23992 and BUG#48814 will disappear
automatically after the this patch.
BUG#55617 is fixed by this patch too.
            
This is the 5.5 part.
It implements:
- 'CREATE TABLE IF NOT EXISTS ... SELECT' statement will not insert
  anything and binlog anything if the table already exists.
  It only generate a warning that table already exists.
- A couple of test cases for the behavior changing.
2010-08-18 17:35:41 +08:00
Mattias Jonsson
daf0e6b725 Bug#53676: Unexpected errors and possible table
corruption on ADD PARTITION and LOCK TABLE
Bug#53770: Server crash at handler.cc:2076 on
           LOAD DATA after timed out COALESCE PARTITION

5.5 fix for:
Bug#51042: REORGANIZE PARTITION can leave table in an
           inconsistent state in case of crash
Needs to be back-ported to 5.1

5.5 fix for:
Bug#50418: DROP PARTITION does not interact with
           transactions

Main problem was non-persistent operations done
before meta-data lock was taken (53770+53676).
And 53676 needed to keep the table/partitions opened and locked
while copying the data to the new partitions.

Also added thorough tests to spot some additional bugs
in the ddl_log code, which could result in bad state
between the .frm and partitions.

Collapsed patch, includes all fixes required from the reviewers.

mysql-test/r/partition_innodb.result:
  updated result with new test
mysql-test/suite/parts/inc/partition_crash.inc:
  crash test include file
mysql-test/suite/parts/inc/partition_crash_add.inc:
  test all states in fast_alter_partition_table
  ADD PARTITION branch
mysql-test/suite/parts/inc/partition_crash_change.inc:
  test all states in fast_alter_partition_table
  CHANGE PARTITION branch
mysql-test/suite/parts/inc/partition_crash_drop.inc:
  test all states in fast_alter_partition_table
  DROP PARTITION branch
mysql-test/suite/parts/inc/partition_fail.inc:
  recovery test including injecting errors
mysql-test/suite/parts/inc/partition_fail_add.inc:
  test all states in fast_alter_partition_table
  ADD PARTITION branch
mysql-test/suite/parts/inc/partition_fail_change.inc:
  test all states in fast_alter_partition_table
  CHANGE PARTITION branch
mysql-test/suite/parts/inc/partition_fail_drop.inc:
  test all states in fast_alter_partition_table
  DROP PARTITION branch
mysql-test/suite/parts/inc/partition_mgm_crash.inc:
  include file that runs all crash and failure injection tests.
mysql-test/suite/parts/r/partition_debug_innodb.result:
  new test result file
mysql-test/suite/parts/r/partition_debug_myisam.result:
  new test result file
mysql-test/suite/parts/r/partition_special_innodb.result:
  updated result
mysql-test/suite/parts/r/partition_special_myisam.result:
  updated result
mysql-test/suite/parts/t/partition_debug_innodb-master.opt:
  opt file for using with crashing tests of partitioned innodb
mysql-test/suite/parts/t/partition_debug_innodb.test:
  partitioned innodb test that require debug builds
mysql-test/suite/parts/t/partition_debug_myisam-master.opt:
  opt file for using with crashing tests of partitioned myisam
mysql-test/suite/parts/t/partition_debug_myisam.test:
  partitioned myisam test that require debug builds
mysql-test/suite/parts/t/partition_special_innodb-master.opt:
  added innodb-file-per-table to easier verify partition status on disk
mysql-test/suite/parts/t/partition_special_innodb.test:
  added test case
mysql-test/suite/parts/t/partition_special_myisam.test:
  added test case
mysql-test/t/partition_innodb.test:
  added test case
sql/sql_base.cc:
  Moved alter_close_tables to sql_partition.cc
sql/sql_base.h:
  removed some non existing and duplicated functions.
sql/sql_partition.cc:
  fast_alter_partition_table:
  Spletted abort_and_upgrad_lock_and_close_table
  to its parts (wait_while_table_is_used and
  alter_close_tables) and always have
  wait_while_table_is_used before any persistent
  operations (including logs, which will be executed
  on failure) and alter_close_tables after
  create/read/write operations and before
  drop operations.
  
  moved alter_close_tables here from sql_base.cc
  
  Added error injections for better test coverage.
  
  write_log_final_change_partition:
  fixed a log_entry linking bug (delete_frm was not
  linked to change/drop partition)
  and drop partition must be executed before
  change partition (change partition can rename a
  partition to an old name, like REORG p1 INTO (p1,p2).
  
  write_log_add_change_partition:
  need to use drop_frm first, and relinking that entry
  and reusing its execute entry.
sql/sql_table.cc:
  added initialization of next_active_log_entry.
sql/table.h:
  removed a duplicate declaration.
2010-08-13 09:50:25 +02:00
Konstantin Osipov
82759db0cc Remove dead code.
sql/sql_base.h:
  Remove an unused parameter.
sql/sql_servers.cc:
  Remove an unused parameter.
2010-08-12 20:44:41 +04:00
Konstantin Osipov
29c4873ad5 Commit on behalf of Dmitry Lenev.
Merge his patch for Bug#52044 into 5.5, and apply 
review comments.
2010-08-12 17:50:23 +04:00
Konstantin Osipov
265a6edd23 A pre-requisite patch for the fix for Bug#52044.
Implement a few simple asserts in my_rwlock_t locks.

include/my_pthread.h:
  Declare two simple assert functions.
include/mysql/psi/mysql_thread.h:
  Add wrappers for new assert functions.
mysys/thr_rwlock.c:
  Add asserts.
sql/sql_base.cc:
  Silence a compiler warning for the case when
  SAFE_MUTEX is not ON.
2010-08-11 01:12:01 +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
Dmitry Lenev
8d0dc9b58b Part of fix for bug#52044 "FLUSH TABLES WITH READ LOCK and
FLUSH TABLES <list> WITH READ LOCK are incompatible" to
be pushed as separate patch.

Replaced thread state name "Waiting for table", which was
used by threads waiting for a metadata lock or table flush, 
with a set of names which better reflect types of resources
being waited for.

Also replaced "Table lock" thread state name, which was used 
by threads waiting on thr_lock.c table level lock, with more
elaborate "Waiting for table level lock", to make it 
more consistent with other thread state names.

Updated test cases and their results according to these 
changes.

Fixed sys_vars.query_cache_wlock_invalidate_func test to not
to wait for timeout of wait_condition.inc script.

mysql-test/r/query_cache.result:
  Added test coverage for query_cache_wlock_invalidate
  behavior for implicitly locked tables.
mysql-test/suite/sys_vars/r/query_cache_wlock_invalidate_func.result:
  Fixed sys_vars.query_cache_wlock_invalidate_func test to not
  to wait for timeout of wait_condition.inc script. Reverted
  changes to test which introduced timeout and replaced waiting
  condition with a more appropriate one.
  Test coverage for query_cache_wlock_invalidate behavior for
  implicitly locked tables was added to query_cache.test.
mysql-test/suite/sys_vars/t/query_cache_wlock_invalidate_func.test:
  Fixed sys_vars.query_cache_wlock_invalidate_func test to not
  to wait for timeout of wait_condition.inc script. Reverted
  changes to test which introduced timeout and replaced waiting
  condition with a more appropriate one.
  Test coverage for query_cache_wlock_invalidate behavior for
  implicitly locked tables was added to query_cache.test.
mysql-test/t/query_cache.test:
  Added test coverage for query_cache_wlock_invalidate
  behavior for implicitly locked tables.
mysys/thr_lock.c:
  Replaced "Table lock" thread state name, which was used by 
  threads waiting on thr_lock.c table level lock, with more
  elaborate "Waiting for table level lock", to make it 
  consistent with thread state names which are used while
  waiting for metadata locks and table flush.
sql/mdl.cc:
  Replaced thread state name "Waiting for table", which was
  used by threads waiting for a metadata lock or table flush, 
  with a set of names which better reflect types of resources
  being waited for. 
  
  To implement this:
  - Adjusted MDL_wait::timed_wait() to take thread state name
    as parameter.
  - Introduced method of MDL_key class which allows to get
    thread state name to be used while waiting for resource
    corresponding to the key and changed code to use it.
    Added array translating namespaces to thread state names
    as part of this change.
sql/mdl.h:
  To implement this:
  - Adjusted MDL_wait::timed_wait() to take thread state name
    as parameter.
  - Introduced method of MDL_key class which allows to get
    thread state name to be used while waiting for resource
    corresponding to the key and changed code to use it.
    Added array translating namespaces to thread state names
    as part of this change.
sql/sql_base.cc:
  Replaced thread state name "Waiting for table", which was
  used by threads waiting for table flush, with a more elaborate
  "Waiting for table flush".
2010-08-06 15:29:37 +04:00
Konstantin Osipov
a91a5ee3bf Cleanup: remove unused declarations from sql_base.h.
sql/sql_base.cc:
  Update a comment to not refer to a non-existing
  function.
sql/sql_base.h:
  Remove unused declarations (bad merge with the header
  files split worklog).
sql/sql_test.cc:
  Cleanup: remove unused declarations.
2010-08-04 20:29:13 +04:00
Alexander Nozdrin
32f3ab7933 Auto-merge from mysql-trunk-merge. 2010-07-29 16:32:11 +04:00
Konstantin Osipov
d85c628180 Merge trunk-bugfixing -> trunk-runtime. 2010-07-29 14:18:13 +04:00
Dmitry Lenev
00496b7acd Fix for bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH
TABLES <list> WITH READ LOCK are incompatible".

The problem was that FLUSH TABLES <list> WITH READ LOCK
which was issued when other connection has acquired global
read lock using FLUSH TABLES WITH READ LOCK was blocked
and has to wait until global read lock is released.

This issue stemmed from the fact that FLUSH TABLES <list>
WITH READ LOCK implementation has acquired X metadata locks
on tables to be flushed. Since these locks required acquiring
of global IX lock this statement was incompatible with global
read lock.

This patch addresses problem by using SNW metadata type of
lock for tables to be flushed by FLUSH TABLES <list> WITH
READ LOCK. It is OK to acquire them without global IX lock
as long as we won't try to upgrade those locks. Since SNW
locks allow concurrent statements using same table FLUSH
TABLE <list> WITH READ LOCK now has to wait until old
versions of tables to be flushed go away after acquiring
metadata locks. Since such waiting can lead to deadlock
MDL deadlock detector was extended to take into account
waits for flush and resolve such deadlocks.

As a bonus code in open_tables() which was responsible for
waiting old versions of tables to go away was refactored.
Now when we encounter old version of table in open_table()
we don't back-off and wait for all old version to go away,
but instead wait for this particular table to be flushed.
Such approach supported by deadlock detection should reduce
number of scenarios in which FLUSH TABLES aborts concurrent
multi-statement transactions.

Note that active FLUSH TABLES <list> WITH READ LOCK still
blocks concurrent FLUSH TABLES WITH READ LOCK statement
as the former keeps tables open and thus prevents the
latter statement from doing flush.

mysql-test/include/handler.inc:
  Adjusted test case after changing status which is set
  when FLUSH TABLES waits for tables to be flushed from
  "Flushing tables" to "Waiting for table".
mysql-test/r/flush.result:
  Added test which checks that "flush tables <list> with
  read lock" is compatible with active "flush tables with
  read lock" but not vice-versa. This test also covers
  bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES
  <list> WITH READ LOCK are incompatible".
mysql-test/r/mdl_sync.result:
  Added scenarios in which wait for table to be flushed
  causes deadlocks to the coverage of MDL deadlock detector.
mysql-test/suite/perfschema/r/dml_setup_instruments.result:
  Adjusted test results after removal of COND_refresh
  condition variable.
mysql-test/suite/perfschema/r/server_init.result:
  Adjusted test and its results after removal of COND_refresh
  condition variable.
mysql-test/suite/perfschema/t/server_init.test:
  Adjusted test and its results after removal of COND_refresh
  condition variable.
mysql-test/t/flush.test:
  Added test which checks that "flush tables <list> with
  read lock" is compatible with active "flush tables with
  read lock" but not vice-versa. This test also covers
  bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES
  <list> WITH READ LOCK are incompatible".
mysql-test/t/kill.test:
  Adjusted test case after changing status which is set
  when FLUSH TABLES waits for tables to be flushed from
  "Flushing tables" to "Waiting for table".
mysql-test/t/lock_multi.test:
  Adjusted test case after changing status which is set
  when FLUSH TABLES waits for tables to be flushed from
  "Flushing tables" to "Waiting for table".
mysql-test/t/mdl_sync.test:
  Added scenarios in which wait for table to be flushed
  causes deadlocks to the coverage of MDL deadlock detector.
sql/ha_ndbcluster.cc:
  Adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/ha_ndbcluster_binlog.cc:
  Adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/lock.cc:
  Removed COND_refresh condition variable. See comment
  for sql_base.cc for details.
sql/mdl.cc:
  Now MDL deadlock detector takes into account information
  about waits for table flushes when searching for deadlock.
  To implement this change:
  - Declaration of enum_deadlock_weight and
    Deadlock_detection_visitor were moved to mdl.h header
    to make them available to the code in table.cc which
    implements deadlock detector traversal through edges
    of waiters graph representing waiting for flush.
  - Since now MDL_context may wait not only for metadata
    lock but also for table to be flushed an abstract
    Wait_for_edge class was introduced. Its descendants
    MDL_ticket and Flush_ticket incapsulate specifics
    of inspecting waiters graph when following through
    edge representing wait of particular type.
  
  We no longer require global IX metadata lock when acquiring
  SNW or SNRW locks. Such locks are needed only when metadata
  locks of these types are upgraded to X locks. This allows
  to use SNW locks in FLUSH TABLES <list> WITH READ LOCK
  implementation and keep the latter compatible with global
  read lock.
sql/mdl.h:
  Now MDL deadlock detector takes into account information
  about waits for table flushes when searching for deadlock.
  To implement this change:
  - Declaration of enum_deadlock_weight and
    Deadlock_detection_visitor were moved to mdl.h header
    to make them available to the code in table.cc which
    implements deadlock detector traversal through edges
    of waiters graph representing waiting for flush.
  - Since now MDL_context may wait not only for metadata
    lock but also for table to be flushed an abstract
    Wait_for_edge class was introduced. Its descendants
    MDL_ticket and Flush_ticket incapsulate specifics
    of inspecting waiters graph when following through
    edge representing wait of particular type.
  - Deadlock_detection_visitor now has m_table_shares_visited
    member which allows to support recursive locking for
    LOCK_open. This is required when deadlock detector
    inspects waiters graph which contains several edges
    representing waits for flushes or needs to come through
    the such edge more than once.
sql/mysqld.cc:
  Removed COND_refresh condition variable. See comment
  for sql_base.cc for details.
sql/mysqld.h:
  Removed COND_refresh condition variable. See comment
  for sql_base.cc for details.
sql/sql_base.cc:
  Changed approach to how threads are waiting for table
  to be flushed. Now thread that wants to wait for old
  table to go away subscribes for notification by adding
  Flush_ticket to table's share and waits using
  MDL_context::m_wait object. Once table gets flushed
  (i.e. all tables are closed and table share is ready
  to be destroyed) all such waiters are notified
  individually.
  Thanks to this change MDL deadlock detector can take
  such waits into account.
  
  To implement this/as result of this change:
  - tdc_wait_for_old_versions() was replaced with
    tdc_wait_for_old_version() which waits for individual
    old share to go away and which is called by open_table()
    after finding out that share is outdated. We don't
    need to perform back-off before such waiting thanks
    to the fact that deadlock detector now sees such waits.
  - As result Open_table_ctx::m_mdl_requests became
    unnecessary and was removed. We no longer allocate
    copies of MDL_request objects on MEM_ROOT when
    MYSQL_OPEN_FORCE_SHARED/SHARED_HIGH_PRIO flags are
    in effect.
  - close_cached_tables() and tdc_wait_for_old_version()
    share code which implements waiting for share to be
    flushed - the both use TABLE_SHARE::wait_until_flush()
    method. Thanks to this close_cached_tables() supports
    timeouts and has extra parameter for this.
  - Open_table_context::OT_MDL_CONFLICT enum element was
    renamed to OT_CONFLICT as it is now also used in cases
    when back-off is required to resolve deadlock caused
    by waiting for flush and not metadata lock.
  - In cases when we discover that current connection tries
    to open tables from different generation we now simply
    back-off and restart process of opening tables. To
    support this Open_table_context::OT_REOPEN_TABLES enum
    element was added.
  - COND_refresh condition variable became unnecessary and
    was removed.
  - mysql_notify_thread_having_shared_lock() no longer wakes
    up connections waiting for flush as all such connections
    can be waken up by deadlock detector if necessary.
sql/sql_base.h:
  - close_cached_tables() now has one more parameter -
    timeout for waiting for table to be flushed.
  - Open_table_context::OT_MDL_CONFLICT enum element was
    renamed to OT_CONFLICT as it is now also used in cases
    when back-off is required to resolve deadlock caused
    by waiting for flush and not metadata lock.
    Added new OT_REOPEN_TABLES enum element to be used in
    cases when we need to restart open tables process even
    in the middle of transaction.
  - Open_table_ctx::m_mdl_requests became unnecessary and
    was removed.
sql/sql_class.h:
  Added assert ensuring that we won't use LOCK_open mutex
  with THD::enter_cond(). Otherwise deadlocks can arise in
  MDL deadlock detector.
sql/sql_parse.cc:
  Changed FLUSH TABLES <list> WITH READ LOCK to take SNW
  metadata locks instead of X locks on tables to be flushed.
  Since we no longer require global IX lock to be taken
  when SNW locks are taken this makes this statement
  compatible with FLUSH TABLES WITH READ LOCK statement.
  Since SNW locks allow other connections to have table
  opened FLUSH TABLES <list> WITH READ LOCK now has to
  wait during open_tables() for old version to go away.
  Such waits can lead to deadlocks which will be detected
  by MDL deadlock detector which now takes waits for table
  to be flushed into account.
  
  Also adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/sql_yacc.yy:
  FLUSH TABLES <list> WITH READ LOCK now needs only SNW
  metadata locks on tables.
sql/sys_vars.cc:
  Adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/table.cc:
  Implemented new approach to how threads are waiting for
  table to be flushed. Now thread that wants to wait for
  old table to go away subscribes for notification by
  adding Flush_ticket to table's share and waits using
  MDL_context::m_wait object. Once table gets flushed
  (i.e. all tables are closed and table share is ready
  to be destroyed) all such waiters are notified
  individually. This change allows to make such waits
  visible inside of MDL deadlock detector.
  To do it:
  
  - Added list of waiters/Flush_tickets to TABLE_SHARE
    class.
  - Changed free_table_share() to postpone freeing of
    share memory until last waiter goes away and to
    wake up subscribed waiters.
  - Added TABLE_SHARE::wait_until_flushed() method which
    implements subscription to the list of waiters for
    table to be flushed and waiting for this event.
  
  Implemented interface which allows to expose waits for
  flushes to MDL deadlock detector:
  
  - Introduced Flush_ticket class a descendant of
    Wait_for_edge class.
  - Added TABLE_SHARE::find_deadlock() method which allows
    deadlock detector to find out what contexts are still
    using old version of table in question (i.e. to find
    out what contexts are waited for by owner of
    Flush_ticket).
sql/table.h:
  In order to support new strategy of waiting for table flush
  (see comment for table.cc for details) added list of
  waiters/Flush_tickets to TABLE_SHARE class.
  
  Implemented interface which allows to expose waits for
  flushes to MDL deadlock detector:
  - Introduced Flush_ticket class a descendant of
    Wait_for_edge class.
  - Added TABLE_SHARE::find_deadlock() method which allows
    deadlock detector to find out what contexts are still
    using old version of table in question (i.e. to find
    out what contexts are waited for by owner of
    Flush_ticket).
2010-07-27 17:34:58 +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
Luis Soares
9a714c935f BUG#55387: binlog.binlog_tmp_table crashes the server
sporadically

There are two problems:

1. When closing temporary tables, during the THD clean up - and
   after the session connection was already closed, there is a
   chance we can push an error into the THD diagnostics area, if
   the writing of the implicit DROP event to the binary log fails
   for some reason. As a consequence an assertion can be
   triggered, because at that point the diagnostics area is
   already set.

2. Using push_warning with MYSQL_ERROR::WARN_LEVEL_ERROR is a 
   bug.

Given that close_temporary_tables is mostly called from
THD::cleanup - ie, with the session already closed, we fix
problem #1 by allowing the diagnostics area to be
overwritten. There is one other place in the code that calls
close_temporary_tables - while applying Start_log_event_v3. To
cover that case, we make close_temporary_tables to return the
error, thus, propagating upwards in the stack.

To fix problem #2, we replace push_warning with sql_print_error.

sql/log_event.cc:
  Added handling of error returned by close_temporary_tables to
  Start_log_event_v3::do_apply_event.
sql/sql_base.cc:
  Three changes to close_temporary_tables:
  1. it returns a boolean now (instead of void)
  2. it uses sql_print_error instead of push_warning when writing to
     binary log fails
  3. we set can_overwrite_status before writing to the binary log,
     thence not risking triggering an assertion by any other push
     into diagnostics area happening inside mysql_bin_log.write.
sql/sql_base.h:
  Changed the interface of close_temporary_tables so that it returns
  bool instead of void.
2010-07-22 16:56:50 +01:00
Davi Arnaut
182599dd13 Merge of mysql-5.1-bugteam into mysql-trunk-merge. 2010-07-20 16:30:10 -03:00
Davi Arnaut
9a5fa17fd3 Bug#45288: pb2 returns a lot of compilation warnings on linux
Fix warnings flagged by the new warning option -Wunused-but-set-variable
that was added to GCC 4.6 and that is enabled by -Wunused and -Wall. The
option causes a warning whenever a local variable is assigned to but is
later unused. It also warns about meaningless pointer dereferences.

client/mysql.cc:
  Meaningless pointer dereferences.
client/mysql_upgrade.c:
  Check whether reading from the file succeeded.
extra/comp_err.c:
  Unused.
extra/yassl/src/yassl_imp.cpp:
  Skip instead of reading data that is discarded.
include/my_pthread.h:
  Variable is only used in debug builds.
include/mysys_err.h:
  Add new error messages.
mysys/errors.c:
  Add new error message for permission related functions.
mysys/mf_iocache.c:
  Variable is only checked under THREAD.
mysys/my_copy.c:
  Raise a error if chmod or chown fails.
mysys/my_redel.c:
  Raise a error if chmod or chown fails.
regex/engine.c:
  Use a equivalent variable for the assert.
server-tools/instance-manager/instance_options.cc:
  Unused.
sql/field.cc:
  Unused.
sql/item.cc:
  Unused.
sql/log.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
  
  Adjust doxygen comment to the right function.
  
  Pass message lenght to log function.
sql/mysqld.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
sql/partition_info.cc:
  Unused.
sql/slave.cc:
  No need to set pointer to the address of '\0'.
sql/spatial.cc:
  Unused. Left for historical purposes.
sql/sql_acl.cc:
  Unused.
sql/sql_base.cc:
  Pointers are always set to the same variables.
sql/sql_parse.cc:
  End statement if reading fails.
  
  Store the buffer after it has actually been updated.
sql/sql_repl.cc:
  No need to set pointer to the address of '\0'.
sql/sql_show.cc:
  Put variable under the same ifdef block.
sql/udf_example.c:
  Set null pointer flag appropriately.
storage/csv/ha_tina.cc:
  Meaningless dereferences.
storage/example/ha_example.cc:
  Return the error since it's available.
storage/myisam/mi_locking.c:
  Remove unused and dead code.
2010-07-20 15:07:36 -03:00
Jon Olav Hauglid
7467ee7bc6 merge from mysql-trunk-bugfixing 2010-07-19 10:27:53 +02:00
Davi Arnaut
711c318c07 Merge of mysql-trunk-bugfixing into mysql-trunk-merge. 2010-07-15 10:47:50 -03:00
Dmitry Lenev
a6a8e10c79 A pre-requisite for patch fixing bug #52044 "FLUSH TABLES
WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are
incompatible", which adds information about waits caused by 
FLUSH TABLES statement to deadlock detector in MDL subsystem.

Remove API supporting caching of pointers to TABLE_SHARE 
object in MDL subsystem and all code related to it. 

The problem was that locking requirements of code 
implementing this API conflicted with locking requirements 
of code which adds information about waits caused by flushes 
to deadlock detector in MDL subsystem (the former needed to
lock LOCK_open or its future equivalent while having 
write-lock on MDL_lock's rwlock, and the latter needs to be 
able to read-lock MDL_lock rwlock while owning LOCK_open or 
its future equivalent).

Since caching of pointers to TABLE_SHARE objects in MDL 
subsystem didn't bring expected performance benefits we 
decided to remove caching API rather than try to come up 
with some complex solution for this problem.
2010-07-13 22:01:54 +04:00
Jon Olav Hauglid
f45523188e merge from mysql-trunk-bugfixing 2010-07-13 10:39:24 +02:00
Davi Arnaut
f56dd32bf7 Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.

Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.

Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost. 

The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.

Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.

client/mysqldump.c:
  Pass my_free directly as its signature is compatible with the
  callback type -- which wasn't the case for free_table_ent.
2010-07-08 18:20:08 -03:00
Davi Arnaut
5641fb64b4 Merge of mysql-5.1-bugteam into mysql-trunk-merge. 2010-07-02 16:38:04 -03:00
Davi Arnaut
0eb26fdfa8 Bug#53445: Build with -Wall and fix warnings that it generates
Apart strict-aliasing warnings, fix the remaining warnings
generated by GCC 4.4.4 -Wall and -Wextra flags.

One major source of warnings was the in-house function my_bcmp
which (unconventionally) took pointers to unsigned characters
as the byte sequences to be compared. Since my_bcmp and bcmp
are deprecated functions whose only difference with memcmp is
the return value, every use of the function is replaced with
memcmp as the special return value wasn't actually being used
by any caller.

There were also various other warnings, mostly due to type
mismatches, missing return values, missing prototypes, dead
code (unreachable) and ignored return values.

BUILD/SETUP.sh:
  Remove flags that are implied by -Wall and -Wextra.
  Do not warn about unused parameters in C++.
BUILD/check-cpu:
  Print only the compiler version instead of verbose banner.
  Although the option is gcc specific, the check was only
  being used for GCC specific checks anyway.
client/mysql.cc:
  bcmp is no longer defined.
client/mysqltest.cc:
  Pass a string to function expecting a format string.
  Replace use of bcmp with memcmp.
cmd-line-utils/readline/Makefile.am:
  Always define _GNU_SOURCE when compiling GNU readline.
  Required to make certain prototypes visible.
cmd-line-utils/readline/input.c:
  Condition for the code to be meaningful.
configure.in:
  Remove check for bcmp.
extra/comp_err.c:
  Use appropriate type.
extra/replace.c:
  Replace use of bcmp with memcmp.
extra/yassl/src/crypto_wrapper.cpp:
  Do not ignore the return value of fgets. Retrieve the file
  position if fgets succeed -- if it fails, the function will
  bail out and return a error.
extra/yassl/taocrypt/include/blowfish.hpp:
  Use a single array instead of accessing positions of the sbox_
  through a subscript to pbox_.
extra/yassl/taocrypt/include/runtime.hpp:
  One definition of such functions is enough.
extra/yassl/taocrypt/src/aes.cpp:
  Avoid potentially ambiguous conditions.
extra/yassl/taocrypt/src/algebra.cpp:
  Rename arguments to avoid shadowing related warnings.
extra/yassl/taocrypt/src/blowfish.cpp:
  Avoid potentially ambiguous conditions.
extra/yassl/taocrypt/src/integer.cpp:
  Do not define type within a anonymous union.
  Use a variable to return a value instead of
  leaving the result in a register -- compiler
  does not know the logic inside the asm.
extra/yassl/taocrypt/src/misc.cpp:
  Define handler for pure virtual functions.
  Remove unused code.
extra/yassl/taocrypt/src/twofish.cpp:
  Avoid potentially ambiguous conditions.
extra/yassl/testsuite/test.hpp:
  Function must have C language linkage.
include/m_string.h:
  Remove check which relied on bcmp being defined -- they weren't
  being used as bcmp is only visible when _BSD_SOURCE is defined.
include/my_bitmap.h:
  Remove bogus helpers which were used only in a few files and
  were causing warnings about dead code.
include/my_global.h:
  Due to G++ bug, always silence false-positive uninitialized
  variables warnings when compiling C++ code with G++.
  Remove bogus helper.
libmysql/Makefile.shared:
  Remove built-in implementation of bcmp.
mysql-test/lib/My/SafeProcess/safe_process.cc:
  Cast pid to largest possible type for a process identifier.
mysys/mf_loadpath.c:
  Leave space of the ending nul.
mysys/mf_pack.c:
  Replace bcmp with memcmp.
mysys/my_bitmap.c:
  Dead code removal.
mysys/my_gethwaddr.c:
  Remove unused variable.
mysys/my_getopt.c:
  Silence bogus uninitialized variable warning.
  Do not cast away the constant qualifier.
mysys/safemalloc.c:
  Cast to expected type.
mysys/thr_lock.c:
  Silence bogus uninitialized variable warning.
sql/field.cc:
  Replace bogus helper with a more appropriate logic which is
  used throughout the code.
sql/item.cc:
  Remove bogus logical condition which always evaluates to TRUE.
sql/item_create.cc:
  Simplify code to avoid signedness related warnings.
sql/log_event.cc:
  Replace use of bcmp with memcmp.
  No need to use helpers for simple bit operations.
sql/log_event_old.cc:
  Replace bmove_align with memcpy.
sql/mysqld.cc:
  Move use declaration of variable to the ifdef block where it
  is used. Remove now-unnecessary casts and arguments.
sql/set_var.cc:
  Replace bogus helpers with simple and classic bit operations.
sql/slave.cc:
  Cast to expected type and silence bogus warning.
sql/sql_class.h:
  Don't use enum values as bit flags, the supposed type safety is
  bogus as the combined bit flags are not a value in the enumeration.
sql/udf_example.c:
  Only declare variable when necessary.
sql/unireg.h:
  Replace use of bmove_align with memcpy.
storage/innobase/os/os0file.c:
  Silence bogus warning.
storage/myisam/mi_open.c:
  Remove bogus cast, DBUG_DUMP expects a pointer to unsigned
  char.
storage/myisam/mi_page.c:
  Remove bogus cast, DBUG_DUMP expects a pointer to unsigned
  char.
strings/bcmp.c:
  Remove built-in bcmp.
strings/ctype-ucs2.c:
  Silence bogus warning.
tests/mysql_client_test.c:
  Use a appropriate type as expected by simple_command().
2010-07-02 15:30:47 -03:00
Dmitry Lenev
10582e2abe A follow-up for 5.5 version of fix for bug#54360 "Deadlock
DROP/ALTER/CREATE DATABASE with open HANDLER".

Remove wait_for_condition() which became unused after 
database locks were replaced with MDL scoped locks.
If one needs functionality provided by this call one can 
always use THD::enter_cond()/exit_cond() methods.

Also removed an unused include from sql_db.cc and updated 
comment describing one of used includes to reflect current
situation.
2010-07-01 18:58:47 +04:00
Jon Olav Hauglid
9ff272fbbd A 5.5 version of the fix for Bug #54360 "Deadlock DROP/ALTER/CREATE
DATABASE with open HANDLER"

Remove LOCK_create_db, database name locks, and use metadata locks instead.
This exposes CREATE/DROP/ALTER DATABASE statements to the graph-based
deadlock detector in MDL, and paves the way for a safe, deadlock-free
implementation of RENAME DATABASE.

Database DDL statements will now take exclusive metadata locks on
the database name, while table/view/routine DDL statements take
intention exclusive locks on the database name. This prevents race
conditions between database DDL and table/view/routine DDL.
(e.g. DROP DATABASE with concurrent CREATE/ALTER/DROP TABLE)

By adding database name locks, this patch implements
WL#4450 "DDL locking: CREATE/DROP DATABASE must use database locks" and
WL#4985 "DDL locking: namespace/hierarchical locks".

The patch also changes code to use init_one_table() where appropriate.
The new lock_table_names() function requires TABLE_LIST::db_length to
be set correctly, and this is taken care of by init_one_table().

This patch also adds a simple template to help work with 
the mysys HASH data structure.

Most of the patch was written by Konstantin Osipov.
2010-07-01 15:53:46 +02:00
Konstantin Osipov
c3b1a5751a Salvage comments added by Ingo while working on
Bug#52114 and Bug#50788.
The bugs themselves are regressions that are introduced
by an incomplete fix for Bug#36171 and will not be pushed.
2010-06-29 18:28:36 +04:00
Konstantin Osipov
52f361ecb8 A fix for Bug#54811 "Assert in mysql_lock_have_duplicate()".
Remove mysql_lock_have_duplicate(), since now we always
have TABLE_LIST objects for MyISAMMRG children
in lex->query_tables and keep it till the end of the
statement (sub-statement).


mysql-test/r/merge.result:
  Update results (Bug#54811).
mysql-test/t/merge-big.test:
  Update to new wait state.
mysql-test/t/merge.test:
  Add a test case for Bug#54811.
sql/lock.cc:
  Remove a function that is now unused.
sql/lock.h:
  Remove a function that is now unused.
sql/sql_base.cc:
  Don't try to search for duplicate table among THR_LOCK objects, TABLE_LIST list contains all used tables.
2010-06-29 18:01:33 +04:00
Luis Soares
e0ece40b64 BUG#54842: DROP TEMPORARY TABLE not binlogged after manual
switching binlog format to ROW

BUG 52616 fixed the case which the user would switch from STMT to
ROW binlog format, but the server would silently ignore it. After
that fix thd->is_current_stmt_binlog_format_row() reports correct
value at logging time and events are logged in ROW (as expected)
instead of STMT as they were previously and wrongly logged.

However, the fix was only partially complete, because on
disconnect, at THD cleanup, the implicit logging of temporary
tables is conditionally performed. If the binlog_format==ROW and
thd->is_current_stmt_binlog_format_row() is true then DROPs are
not logged. Given that the user can switch from STMT to ROW, this
is wrong because the server cannot tell, just by relying on the
ROW binlog format, that the tables have been dropped before. This
is effectively similar to the MIXED scenario when a switch from
STMT to ROW is triggered.

We fix this by removing this condition from
close_temporary_tables.

mysql-test/extra/binlog_tests/drop_temp_table.test:
  Added binlog test case.
mysql-test/suite/binlog/r/binlog_row_drop_tmp_tbl.result:
  Result changes because:
  - there is a missing drop on three temporary tables
  - it now contains results for the test added
mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
  Result now contains the implicit drop for the temporary table.
mysql-test/suite/binlog/r/binlog_stm_drop_tmp_tbl.result:
  Result file changed because it now contains results for added
  test case.
mysql-test/suite/rpl/r/rpl_drop_temp.result:
  Result file changed because it now contains results for added
  test case.
mysql-test/suite/rpl/t/rpl_drop_temp.test:
  Added replication test case.
sql/sql_base.cc:
  Removed the condition that would make the server to skip
  logging implicit drops when ROW binary log format mode was 
  in use.
  Additionally, deployed DBUG_ENTER/RETURN macros.
2010-06-29 11:54:58 +01:00
Jon Olav Hauglid
9b5d1d98da Bug #53757 assert in mysql_truncate_by_delete
The assert was triggered if a connection executing TRUNCATE
on a InnoDB table was killed during open_tables.

This bug was fixed in the scope of Bug #45643
"InnoDB does not support replication of TRUNCATE TABLE".

This patch adds test coverage to innodb_mysql_sync.test.
2010-06-25 09:07:18 +02:00
Konstantin Osipov
429454f76e A new implementation for the TABLE_SHARE cache in MDL
subsystem. Fix a number of caveates that the previous
implementation suffered from, including unprotected
access to shared data and lax resource accounting
(share->ref_count) that could lead to deadlocks.

The new implementation still suffers from a number
of potential deadlocks in some edge cases, and this is 
still not enabled by default. Especially since performance
testing has shown that it gives only marginable (not even 
exceeding measuring accuracy) improvements.

@todo: 
- Remove calls to close_cached_tables() with REFRESH_FAST,
and have_lock, because they break the MDL cache. 
- rework FLUSH TABLES <list> to not use close_cached_tables()
- make sure that whenever we set TABLE_SHARE::version to
0 we free MDL cache references to it.


sql/mdl.cc:
  We may cache references to TABLE_SHARE objects in 
  MDL_lock objects for tables. Create a separate
  MDL_lock class to represent a table.
sql/mdl.h:
  Adjust the MDL caching API to avoid races.
sql/sql_base.cc:
  Move all caching functionality close together.
  Implement a solution for deadlocks caused by 
  close_cached_tables() when MDL cache is enabled (incomplete).
sql/sql_yacc.yy:
  Adjust FLUSH rule to do the necessary initialization of
  TABLE_LIST elements used in for FLUSH TABLES <list>, and thus
  work OK with flush_mdl_cache() function.
2010-06-18 20:14:10 +04:00
Konstantin Osipov
33c57e2f9e WL#5419 "LOCK_open scalability: make tdc_refresh_version
an atomic counter"

Split the large LOCK_open section in open_table(). 
Do not call open_table_from_share() under LOCK_open.
Remove thd->version.

This fixes
Bug#50589 "Server hang on a query evaluated using a temporary 
table"
Bug#51557 "LOCK_open and kernel_mutex are not happy together"
Bug#49463 "LOCK_table and innodb are not nice when handler 
instances are created".

This patch has effect on storage engines that rely on
ha_open() PSEA method being called under LOCK_open.
In particular:

1) NDB is broken and left unfixed. NDB relies on LOCK_open
being kept as part of ha_open(), since it uses auto-discovery.
While previously the NDB open code was race-prone, now
it simply fails on asserts.

2) HEAP engine had a race in ha_heap::open() when
a share for the same table could be added twice
to the list of shares, or a dangling reference to a share
stored in HEAP handler. This patch aims to address this
problem by 'pinning' the newly created share in the 
internal HEAP engine share list until at least one
handler instance is created using that share.


include/heap.h:
  Add members to HP_CREATE_INFO.
  Declare heap_release_share().
sql/lock.cc:
  Remove thd->version, use thd->open_tables->s->version instead.
sql/repl_failsafe.cc:
  Remove thd->version.
sql/sql_base.cc:
  - close_thread_table(): move handler cleanup code outside the critical section protected by LOCK_open.
  - remove thd->version
  - split the large critical section in open_table() that
  opens a new table from share and is protected by LOCK_open
  into 2 critical sections, thus reducing the critical path.
  - make check_if_table_exists() acquire LOCK_open internally.
  - use thd->open_tables->s->version instead of thd->refresh_version to make sure that all tables in
  thd->open_tables are in the same refresh series.
sql/sql_base.h:
  Add declaration for check_if_table_exists().
sql/sql_class.cc:
  Remove init_open_tables_state(), it's now equal to
  reset_open_tables_state().
sql/sql_class.h:
  Remove thd->version, THD::init_open_tables_state().
sql/sql_plugin.cc:
  Use table->m_needs_reopen to mark the table as stale
  rather than manipulate with thd->version, which is no more.
sql/sql_udf.cc:
  Use table->m_needs_reopen to mark the table as stale
  rather than manipulate with thd->version, which is no more.
sql/table.h:
  Remove an unused variable.
sql/tztime.cc:
  Use table->m_needs_reopen to mark the table as stale
  rather than manipulate with thd->version, which is no more.
storage/heap/CMakeLists.txt:
  Add heap tests to cmake build files.
storage/heap/ha_heap.cc:
  Fix a race when ha_heap::ha_open() could insert two 
  HP_SHARE objects into the internal share list or store
  a dangling reference to a share in ha_heap instance,
  or wrongly set implicit_emptied.
storage/heap/hp_create.c:
  Optionally pin a newly created share in the list of shares
  by increasing its open_count. This is necessary to 
  make sure that a newly created share doesn't disappear while
  a HP_INFO object is being created to reference it.
storage/heap/hp_open.c:
  When adding a new HP_INFO object to the list of objects
  in the heap share, make sure the open_count is not increased
  twice.
storage/heap/hp_test1.c:
  Adjust the test to new function signatures.
storage/heap/hp_test2.c:
  Adjust the test to new function signatures.
2010-06-11 19:28:18 +04:00
Konstantin Osipov
90a87cd52d A pre-requisite for WL#5419 "LOCK_open scalability:
make tdc_refresh_version an 
atomic counter".
Backport the trivial changes from mysql-trunk-iplus.
2010-06-10 15:43:32 +04:00