Cherry-pick a fix Bug#37148 from next-mr, to preserve
file ids of the added files, and ensure that all the necessary
changes have been pulled.
Since initially Bug#37148 was null-merged into 6.0,
the changeset that is now being cherry-picked was likewise
null merged into next-4284.
Now that Bug#37148 has been reapplied to 6.0, try to make
it work with next-4284. This is also necessary to be able
to pull other changes from 5.1-rep into next-4284.
To resolve the merge issues use this changeset applied
to 6.0:
revid:jperkin@sun.com-20091216103628-ylhqf7s6yegui2t9
revno: 3776.1.1
committer: He Zhenxing <zhenxing.he@sun.com>
branch nick: 6.0-codebase-bugfixing
timestamp: Thu 2009-12-17 17:02:50 +0800
message:
Fix merge problem with Bug#37148
Removed local variables which became unused when we
have switched to new approach for CREATE TABLE LIKE
(i.e. abondoned .FRM file copying) and were causing
warnings during compilation.
m_tickets.front() == m_trans_sentinel'".
Debug build of server crashed due to assert failure in MDL
subsystem when one tried to execute multi-table REPAIR or
OPTIMIZE in autocommit=0 mode.
The assert failure occured when multi-table REPAIR or OPTIMIZE
started processing of second table from its table list and
tried to acquire upgradable metadata lock on this table.
The cause of the assert failure were MDL locks left over from
processing of previous table. It turned out that in autocommit=0
mode close_thread_tables() which happens at the end of table
processing doesn't release metadata locks.
This fix solves problem by releasing locks explicitly using
MDL_context::release_trans_locks() call.
mysql-test/r/repair.result:
Added test for bug #50784 "MDL: Assertion `m_tickets.is_empty() ||
m_tickets.front() == m_trans_sentinel'".
mysql-test/t/repair.test:
Added test for bug #50784 "MDL: Assertion `m_tickets.is_empty() ||
m_tickets.front() == m_trans_sentinel'".
sql/sql_table.cc:
Ensure that metadata locks are released after multi-table REPAIR/
OPTIMIZE/... processes each table. close_thread_tables() which is
called after processing each table doesn't release metadata locks
if we are in autocommit=0 mode. So this have to be done
explicitly by calling MDL_context::release_trans_locks().
There was two problems:
The first was the symptom, caused by bad error handling in
ha_partition. It did not handle print_error etc. when
having no partitions (when used by dummy handler).
The second was the real problem that when dropping tables
it reused the table type (storage engine) from when the lock
was asked for, not the table type that it had when gaining
the exclusive name lock. So that it tried to delete tables
from wrong storage engines.
Solutions for the first problem was to accept some handler
calls to the partitioning handler even if it was not setup
with any partitions, and also if possible fallback
to use the base handler's default functions.
Solution for the second problem was to remove the optimization
to reuse the definition from the cache, instead always check
the frm-file when holding the LOCK_open mutex
(updated with a fix for a debug print crash and better
comments as required by reviewer, and removed optimization
to avoid reading the frm-file).
mysql-test/r/partition_debug_sync.result:
Bug#42438: Crash ha_partition::change_table_ptr
New result file using DEBUG_SYNC for deterministic results.
mysql-test/t/partition_debug_sync.test:
Bug#42438: Crash ha_partition::change_table_ptr
New test file using DEBUG_SYNC for deterministic results.
sql/ha_partition.cc:
Bug#42438: Crash ha_partition::change_table_ptr
allow some handler calls, used by error handling, even when
no partitions are setup. Fallback to default handling if possible.
sql/sql_base.cc:
Bug#42438: Crash ha_partition::change_table_ptr
Added DEBUG_SYNC point for deterministic test cases.
sql/sql_table.cc:
Bug#42438: Crash ha_partition::change_table_ptr
Always use the table type written in the .frm-file
(i.e. the current table type) when deleting a table.
Moved the check for log-table to not depend of the cache.
Added DEBUG_SYNC points for deterministic test cases.
Add a wait-for graph based deadlock detector to the
MDL subsystem.
Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and
bug #37346 "innodb does not detect deadlock between update and
alter table".
The first bug manifested itself as an unwarranted abort of a
transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER
statement, when this transaction tried to repeat use of a
table, which it has already used in a similar fashion before
ALTER started.
The second bug showed up as a deadlock between table-level
locks and InnoDB row locks, which was "detected" only after
innodb_lock_wait_timeout timeout.
A transaction would start using the table and modify a few
rows.
Then ALTER TABLE would come in, and start copying rows
into a temporary table. Eventually it would stumble on
the modified records and get blocked on a row lock.
The first transaction would try to do more updates, and get
blocked on thr_lock.c lock.
This situation of circular wait would only get resolved
by a timeout.
Both these bugs stemmed from inadequate solutions to the
problem of deadlocks occurring between different
locking subsystems.
In the first case we tried to avoid deadlocks between metadata
locking and table-level locking subsystems, when upgrading shared
metadata lock to exclusive one.
Transactions holding the shared lock on the table and waiting for
some table-level lock used to be aborted too aggressively.
We also allowed ALTER TABLE to start in presence of transactions
that modify the subject table. ALTER TABLE acquires
TL_WRITE_ALLOW_READ lock at start, and that block all writes
against the table (naturally, we don't want any writes to be lost
when switching the old and the new table). TL_WRITE_ALLOW_READ
lock, in turn, would block the started transaction on thr_lock.c
lock, should they do more updates. This, again, lead to the need
to abort such transactions.
The second bug occurred simply because we didn't have any
mechanism to detect deadlocks between the table-level locks
in thr_lock.c and row-level locks in InnoDB, other than
innodb_lock_wait_timeout.
This patch solves both these problems by moving lock conflicts
which are causing these deadlocks into the metadata locking
subsystem, thus making it possible to avoid or detect such
deadlocks inside MDL.
To do this we introduce new type-of-operation-aware metadata
locks, which allow MDL subsystem to know not only the fact that
transaction has used or is going to use some object but also what
kind of operation it has carried out or going to carry out on the
object.
This, along with the addition of a special kind of upgradable
metadata lock, allows ALTER TABLE to wait until all
transactions which has updated the table to go away.
This solves the second issue.
Another special type of upgradable metadata lock is acquired
by LOCK TABLE WRITE. This second lock type allows to solve the
first issue, since abortion of table-level locks in event of
DDL under LOCK TABLES becomes also unnecessary.
Below follows the list of incompatible changes introduced by
this patch:
- From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those
statements that acquire TL_WRITE_ALLOW_READ lock)
wait for all transactions which has *updated* the table to
complete.
- From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE
(i.e. all statements which acquire TL_WRITE table-level lock) wait
for all transaction which *updated or read* from the table
to complete.
As a consequence, innodb_table_locks=0 option no longer applies
to LOCK TABLES ... WRITE.
- DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort
statements or transactions which use tables being dropped or
renamed, and instead wait for these transactions to complete.
- Since LOCK TABLES WRITE now takes a special metadata lock,
not compatible with with reads or writes against the subject table
and transaction-wide, thr_lock.c deadlock avoidance algorithm
that used to ensure absence of deadlocks between LOCK TABLES
WRITE and other statements is no longer sufficient, even for
MyISAM. The wait-for graph based deadlock detector of MDL
subsystem may sometimes be necessary and is involved. This may
lead to ER_LOCK_DEADLOCK error produced for multi-statement
transactions even if these only use MyISAM:
session 1: session 2:
begin;
update t1 ... lock table t2 write, t1 write;
-- gets a lock on t2, blocks on t1
update t2 ...
(ER_LOCK_DEADLOCK)
- Finally, support of LOW_PRIORITY option for LOCK TABLES ... WRITE
was abandoned.
LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same
priority as the usual LOCK TABLE ... WRITE.
SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE in
the wait queue.
- We do not take upgradable metadata locks on implicitly
locked tables. So if one has, say, a view v1 that uses
table t1, and issues:
LOCK TABLE v1 WRITE;
FLUSH TABLE t1; -- (or just 'FLUSH TABLES'),
an error is produced.
In order to be able to perform DDL on a table under LOCK TABLES,
the table must be locked explicitly in the LOCK TABLES list.
mysql-test/include/handler.inc:
Adjusted test case to trigger an execution path on which bug 41110
"crash with handler command when used concurrently with alter
table" and bug 41112 "crash in mysql_ha_close_table/get_lock_data
with alter table" were originally discovered. Left old test case
which no longer triggers this execution path for the sake of
coverage.
Added test coverage for HANDLER SQL statements and type-aware
metadata locks.
Added a test for the global shared lock and HANDLER SQL.
Updated tests to take into account that the old simple deadlock
detection heuristics was replaced with a graph-based deadlock
detector.
mysql-test/r/debug_sync.result:
Updated results (see debug_sync.test).
mysql-test/r/handler_innodb.result:
Updated results (see handler.inc test).
mysql-test/r/handler_myisam.result:
Updated results (see handler.inc test).
mysql-test/r/innodb-lock.result:
Updated results (see innodb-lock.test).
mysql-test/r/innodb_mysql_lock.result:
Updated results (see innodb_mysql_lock.test).
mysql-test/r/lock.result:
Updated results (see lock.test).
mysql-test/r/lock_multi.result:
Updated results (see lock_multi.test).
mysql-test/r/lock_sync.result:
Updated results (see lock_sync.test).
mysql-test/r/mdl_sync.result:
Updated results (see mdl_sync.test).
mysql-test/r/sp-threads.result:
SHOW PROCESSLIST output has changed due to the fact that waiting
for LOCK TABLES WRITE now happens within metadata locking
subsystem.
mysql-test/r/truncate_coverage.result:
Updated results (see truncate_coverage.test).
mysql-test/suite/funcs_1/datadict/processlist_val.inc:
SELECT FROM I_S.PROCESSLIST output has changed due to fact that
waiting for LOCK TABLES WRITE now happens within metadata locking
subsystem.
mysql-test/suite/funcs_1/r/processlist_val_no_prot.result:
SELECT FROM I_S.PROCESSLIST output has changed due to fact that
waiting for LOCK TABLES WRITE now happens within metadata locking
subsystem.
mysql-test/suite/rpl/t/rpl_sp.test:
Updated to a new SHOW PROCESSLIST state name.
mysql-test/t/debug_sync.test:
Use LOCK TABLES READ instead of LOCK TABLES WRITE as the latter
no longer allows to trigger execution path involving waiting on
thr_lock.c lock and therefore reaching debug sync-point covered
by this test.
mysql-test/t/innodb-lock.test:
Adjusted test case to the fact that innodb_table_locks=0 option is
no longer supported, since LOCK TABLES WRITE handles all its
conflicts within MDL subsystem.
mysql-test/t/innodb_mysql_lock.test:
Added test for bug #37346 "innodb does not detect deadlock between
update and alter table".
mysql-test/t/lock.test:
Added test coverage which checks the fact that we no longer support
DDL under LOCK TABLES on tables which were locked implicitly.
Adjusted existing test cases accordingly.
mysql-test/t/lock_multi.test:
Added test for bug #46272 "MySQL 5.4.4, new MDL: unnecessary
deadlock". Adjusted other test cases to take into account the
fact that waiting for LOCK TABLES ... WRITE now happens within MDL
subsystem.
mysql-test/t/lock_sync.test:
Since LOCK TABLES ... WRITE now takes SNRW metadata lock for
tables locked explicitly we have to implicitly lock InnoDB tables
(through view) to trigger the table-level lock conflict between
TL_WRITE and TL_WRITE_ALLOW_WRITE.
mysql-test/t/mdl_sync.test:
Added basic test coverage for type-of-operation-aware metadata
locks. Also covered with tests some use cases involving HANDLER
statements in which a deadlock could arise.
Adjusted existing tests to take type-of-operation-aware MDL into
account.
mysql-test/t/multi_update.test:
Update to a new SHOW PROCESSLIST state name.
mysql-test/t/truncate_coverage.test:
Adjusted test case after making LOCK TABLES WRITE to wait until
transactions that use the table to be locked are completed.
Updated to the changed name of DEBUG_SYNC point.
sql/handler.cc:
Global read lock functionality has been
moved into a class.
sql/lock.cc:
Global read lock functionality has been
moved into a class.
Updated code to use the new MDL API.
sql/mdl.cc:
Introduced new type-of-operation aware metadata locks.
To do this:
- Changed MDL_lock to use one list for waiting requests and one
list for granted requests. For each list, added a bitmap
that holds information what lock types a list contains.
Added a helper class MDL_lock::List to manipulate with granted
and waited lists while keeping the bitmaps in sync
with list contents.
- Changed lock-compatibility functions to use bitmaps that
define compatibility.
- Introduced a graph based deadlock detector inspired by
waiting_threads.c from Maria implementation.
- Now that we have a deadlock detector, and no longer have
a global lock to protect individual lock objects, but rather
use an rw lock per object, removed redundant code for upgrade,
and the global read lock. Changed the MDL API to
no longer require the caller to acquire the global
intention exclusive lock by means of a separate method.
Removed a few more methods that became redundant.
- Removed deadlock detection heuristic, it has been made
obsolete by the deadlock detector.
- With operation-type-aware metadata locks, MDL subsystem has
become aware of potential conflicts between DDL and open
transactions. This made it possible to remove calls to
mysql_abort_transactions_with_shared_lock() from acquisition
paths for exclusive lock and lock upgrade. Now we can simply
wait for these transactions to complete without fear of
deadlock. Function mysql_lock_abort() has also become
unnecessary for all conflicting cases except when a DDL
conflicts with a connection that has an open HANDLER.
sql/mdl.h:
Introduced new type-of-operation aware metadata locks.
Introduced a graph based deadlock detector and supporting
methods.
Added comments.
God rid of redundant API calls.
Renamed m_lt_or_ha_sentinel to m_trans_sentinel,
since now it guards the global read lock as well as
LOCK TABLES and HANDLER locks.
sql/mysql_priv.h:
Moved the global read lock functionality into a
class.
Added MYSQL_OPEN_FORCE_SHARED_MDL flag which forces
open_tables() to take MDL_SHARED on tables instead of
metadata locks specified in the parser. We use this to
allow PREPARE run concurrently in presence of
LOCK TABLES ... WRITE.
Added signature for find_table_for_mdl_ugprade().
sql/set_var.cc:
Global read lock functionality has been
moved into a class.
sql/sp_head.cc:
When creating TABLE_LIST elements for prelocking or
system tables set the type of request for metadata
lock according to the operation that will be performed
on the table.
sql/sql_base.cc:
- Updated code to use the new MDL API.
- In order to avoid locks starvation we take upgradable
locks all at once. As result implicitly locked tables no
longer get an upgradable lock. Consequently DDL and FLUSH
TABLES for such tables is prohibited.
find_write_locked_table() was replaced by
find_table_for_mdl_upgrade() function.
open_table() was adjusted to return TABLE instance with
upgradable ticket when necessary.
- We no longer wait for all locks on OT_WAIT back off
action -- only on the lock that caused the wait
conflict. Moreover, now we distinguish cases when we
have to wait due to conflict in MDL and old version
of table in TDC.
- Upate mysql_notify_threads_having_share_locks()
to only abort thr_lock.c waits of threads that
have open HANDLERs, since lock conflicts with only
these threads now can lead to deadlocks not detectable
by the MDL deadlock detector.
- Remove mysql_abort_transactions_with_shared_locks()
which is no longer needed.
sql/sql_class.cc:
Global read lock functionality has been moved into a class.
Re-arranged code in THD::cleanup() to simplify assert.
sql/sql_class.h:
Introduced class to incapsulate global read lock
functionality.
Now sentinel in MDL subsystem guards the global read lock
as well as LOCK TABLES and HANDLER locks. Adjusted code
accordingly.
sql/sql_db.cc:
Global read lock functionality has been moved into a class.
sql/sql_delete.cc:
We no longer acquire upgradable metadata locks on tables
which are locked by LOCK TABLES implicitly. As result
TRUNCATE TABLE is no longer allowed for such tables.
Updated code to use the new MDL API.
sql/sql_handler.cc:
Inform MDL_context about presence of open HANDLERs.
Since HANLDERs break MDL protocol by acquiring table-level
lock while holding only S metadata lock on a table MDL
subsystem should take special care about such contexts (Now
this is the only case when mysql_lock_abort() is used).
sql/sql_parse.cc:
Global read lock functionality has been moved into a class.
Do not take upgradable metadata locks when opening tables
for CREATE TABLE SELECT as it is not necessary and limits
concurrency.
When initializing TABLE_LIST objects before adding them
to the table list set the type of request for metadata lock
according to the operation that will be performed on the
table.
We no longer acquire upgradable metadata locks on tables
which are locked by LOCK TABLES implicitly. As result FLUSH
TABLES is no longer allowed for such tables.
sql/sql_prepare.cc:
Use MYSQL_OPEN_FORCE_SHARED_MDL flag when opening
tables during PREPARE. This allows PREPARE to run
concurrently in presence of LOCK TABLES ... WRITE.
sql/sql_rename.cc:
Global read lock functionality has been moved into a class.
sql/sql_show.cc:
Updated code to use the new MDL API.
sql/sql_table.cc:
Global read lock functionality has been moved into a class.
We no longer acquire upgradable metadata locks on tables
which are locked by LOCK TABLES implicitly. As result DROP
TABLE is no longer allowed for such tables.
Updated code to use the new MDL API.
sql/sql_trigger.cc:
Global read lock functionality has been moved into a class.
We no longer acquire upgradable metadata locks on tables
which are locked by LOCK TABLES implicitly. As result
CREATE/DROP TRIGGER is no longer allowed for such tables.
Updated code to use the new MDL API.
sql/sql_view.cc:
Global read lock functionality has been moved into a class.
Fixed results of wrong merge that led to misuse of GLR API.
CREATE VIEW statement is not a commit statement.
sql/table.cc:
When resetting TABLE_LIST objects for PS or SP re-execution
set the type of request for metadata lock according to the
operation that will be performed on the table. Do the same
in auxiliary function initializing metadata lock requests
in a table list.
sql/table.h:
When initializing TABLE_LIST objects set the type of request
for metadata lock according to the operation that will be
performed on the table.
sql/transaction.cc:
Global read lock functionality has been moved into a class.
Rename method as to not hide a base.
Reorder attributes initialization.
Remove unused variable.
Rework code to silence a warning due to assignment used as truth value.
sql/item_strfunc.cc:
Rename method as to not hide a base.
sql/item_strfunc.h:
Rename method as to not hide a base.
sql/log_event.cc:
Reorder attributes initialization.
sql/rpl_injector.cc:
Rework code to silence a warning due to assignment used as truth value.
sql/rpl_record.cc:
Remove unused variable.
sql/sql_db.cc:
Rework code to silence a warning due to assignment used as truth value.
sql/sql_parse.cc:
Rework code to silence a warning due to assignment used as truth value.
sql/sql_table.cc:
Rework code to silence a warning due to assignment used as truth value.
condition variable per context instead of one mutex and one conditional
variable for the whole subsystem.
This should increase concurrency in this subsystem.
It also opens the way for further changes which are necessary to solve
such bugs as bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock"
and bug #37346 "innodb does not detect deadlock between update and alter
table".
Two other notable changes done by this patch:
- MDL subsystem no longer implicitly acquires global intention exclusive
metadata lock when per-object metadata lock is acquired. Now this has
to be done by explicit calls outside of MDL subsystem.
- Instead of using separate MDL_context for opening system tables/tables
for purposes of I_S we now create MDL savepoint in the main context
before opening tables and rollback to this savepoint after closing
them. This means that it is now possible to get ER_LOCK_DEADLOCK error
even not inside a transaction. This might happen in unlikely case when
one runs DDL on one of system tables while also running DDL on some
other tables. Cases when this ER_LOCK_DEADLOCK error is not justified
will be addressed by advanced deadlock detector for MDL subsystem which
we plan to implement.
mysql-test/include/handler.inc:
Adjusted handler_myisam.test and handler_innodb.test to the fact that
exclusive metadata locks on tables are now acquired according to
alphabetical order of fully qualified table names instead of order
in which tables are mentioned in statement.
mysql-test/r/handler_innodb.result:
Adjusted handler_myisam.test and handler_innodb.test to the fact that
exclusive metadata locks on tables are now acquired according to
alphabetical order of fully qualified table names instead of order
in which tables are mentioned in statement.
mysql-test/r/handler_myisam.result:
Adjusted handler_myisam.test and handler_innodb.test to the fact that
exclusive metadata locks on tables are now acquired according to
alphabetical order of fully qualified table names instead of order
in which tables are mentioned in statement.
mysql-test/r/mdl_sync.result:
Adjusted mdl_sync.test to the fact that exclusive metadata locks on
tables are now acquired according to alphabetical order of fully
qualified table names instead of order in which tables are mentioned
in statement.
mysql-test/t/mdl_sync.test:
Adjusted mdl_sync.test to the fact that exclusive metadata locks on
tables are now acquired according to alphabetical order of fully
qualified table names instead of order in which tables are mentioned
in statement.
sql/events.cc:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result code
opening/closing system tables was changed to use Open_tables_backup
instead of Open_table_state class as well.
sql/ha_ndbcluster.cc:
Since manipulations with open table state no longer install proxy
MDL_context it does not make sense to perform them in order to
satisfy assert in mysql_rm_tables_part2(). Removed them per agreement
with Cluster team. This has not broken test suite since scenario in
which deadlock can occur and assertion fails is not covered by tests.
sql/lock.cc:
MDL subsystem no longer implicitly acquires global intention exclusive
metadata lock when per-object exclusive metadata lock is acquired.
Now this has to be done by explicit calls outside of MDL subsystem.
sql/log.cc:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result code
opening/closing system tables was changed to use Open_tables_backup
instead of Open_table_state class as well.
sql/mdl.cc:
Changed metadata locking subsystem to use mutex per lock and condition
variable per context instead of one mutex and one conditional variable
for the whole subsystem.
Changed approach to handling of global metadata locks. Instead of
implicitly acquiring intention exclusive locks when user requests
per-object upgradeable or exclusive locks now we require them to be
acquired explicitly in the same way as ordinary metadata locks.
In fact global lock are now ordinary metadata locks in new GLOBAL
namespace.
To implement these changes:
- Removed LOCK_mdl mutex and COND_mdl condition variable.
- Introduced MDL_lock::m_mutex mutexes which protect individual lock
objects.
- Replaced mdl_locks hash with MDL_map class, which has hash for
MDL_lock objects as a member and separate mutex which protects this
hash. Methods of this class allow to find(), find_or_create() or
remove() MDL_lock objects in concurrency-friendly fashion (i.e.
for most common operation, find_or_create(), we don't acquire
MDL_lock::m_mutex while holding MDL_map::m_mutex. Thanks to MikaelR
for this idea and benchmarks!). Added three auxiliary members to
MDL_lock class (m_is_destroyed, m_ref_usage, m_ref_release) to
support this concurrency-friendly behavior.
- Introduced MDL_context::m_ctx_wakeup_cond condition variable to be
used for waiting until this context's pending request can be
satisfied or its thread has to perform actions to resolve potential
deadlock. Context which want to wait add ticket corresponding to the
request to an appropriate queue of waiters in MDL_lock object so
they can be noticed when other contexts change state of lock and be
awaken by them by signalling on MDL_context::m_ctx_wakeup_cond.
As consequence MDL_ticket objects has to be used for any waiting
in metadata locking subsystem including one which happens in
MDL_context::wait_for_locks() method.
Another consequence is that MDL_context is no longer copyable and
can't be saved/restored when working with system tables.
- Made MDL_lock an abstract class, which delegates specifying exact
compatibility matrix to its descendants. Added MDL_global_lock child
class for global lock (The old is_lock_type_compatible() method
became can_grant_lock() method of this class). Added MDL_object_lock
class to represent per-object lock (The old MDL_lock::can_grant_lock()
became its method). Choice between two classes happens based on MDL
namespace in MDL_lock::create() method.
- Got rid of MDL_lock::type member as its meaning became ambigous for
global locks.
- To simplify waking up of contexts waiting for lock split waiting queue
in MDL_lock class in two queues. One for pending requests for exclusive
(including intention exclusive) locks and another for requests for
shared locks.
- Added virtual wake_up_waiters() method to MDL_lock, MDL_global_lock and
MDL_object_lock classes which allows to wake up waiting contexts after
state of lock changes. Replaced old duplicated code with calls to this
method.
- Adjusted MDL_context::try_acquire_shared_lock()/exclusive_lock()/
global_shared_lock(), MDL_ticket::upgrade_shared_lock_to_exclusive_lock()
and MDL_context::release_ticket() methods to use MDL_map and
MDL_lock::m_mutex instead of single LOCK_mdl mutex and wake up
waiters according to the approach described above. The latter method
also was renamed to MDL_context::release_lock().
- Changed MDL_context::try_acquire_shared_lock()/exclusive_lock() and
release_lock() not to handle global locks. They are now supposed to
be taken explicitly like ordinary metadata locks.
- Added helper MDL_context::try_acquire_global_intention_exclusive_lock()
and acquire_global_intention_exclusive_lock() methods.
- Moved common code from MDL_context::acquire_global_shared_lock() and
acquire_global_intention_exclusive_lock() to new method -
MDL_context::acquire_lock_impl().
- Moved common code from MDL_context::try_acquire_shared_lock(),
try_acquire_global_intention_exclusive_lock()/exclusive_lock()
to MDL_context::try_acquire_lock_impl().
- Since acquiring of several exclusive locks can no longer happen under
single LOCK_mdl mutex the approach to it had to be changed. Now we do
it in one by one fashion. This is done in alphabetical order to avoid
deadlocks. Changed MDL_context::acquire_exclusive_locks() accordingly
(as part of this change moved code responsible for acquiring single
exclusive lock to new MDL_context::acquire_exclusive_lock_impl()
method).
- Since we no longer have single LOCK_mdl mutex which protects all
MDL_context::m_is_waiting_in_mdl members using these members to
determine if we have really awaken context holding conflicting
shared lock became inconvinient. Got rid of this member and changed
notify_shared_lock() helper function and process of acquiring
of/upgrading to exclusive lock not to rely on such information.
Now in MDL_context::acquire_exclusive_lock_impl() and
MDL_ticket::upgrade_shared_lock_to_exclusive_lock() we simply
re-try to wake up threads holding conflicting shared locks after
small time out.
- Adjusted MDL_context::can_wait_lead_to_deadlock() and
MDL_ticket::has_pending_conflicting_lock() to use per-lock
mutexes instead of LOCK_mdl. To do this introduced
MDL_lock::has_pending_exclusive_lock() method.
sql/mdl.h:
Changed metadata locking subsystem to use mutex per lock and condition
variable per context instead of one mutex and one conditional variable
for the whole subsystem. In order to implement this change:
- Added MDL_key::cmp() method to be able to sort MDL_key objects
alphabetically. Changed length fields in MDL_key class to uint16
as 16-bit is enough for length of any key.
- Changed MDL_ticket::get_ctx() to return pointer to non-const
object in order to be able to use MDL_context::awake() method
for such contexts.
- Got rid of unlocked versions of can_wait_lead_to_deadlock()/
has_pending_conflicting_lock() methods in MDL_context and
MDL_ticket. We no longer has single mutex which protects all
locks. Thus one always has to use versions of these methods
which acquire per-lock mutexes.
- MDL_request_list type of list now counts its elements.
- Added MDL_context::m_ctx_wakeup_cond condition variable to be used
for waiting until this context's pending request can be satisfied
or its thread has to perform actions to resolve potential deadlock.
Added awake() method to wake up context from such wait.
Addition of condition variable made MDL_context uncopyable.
As result we no longer can save/restore MDL_context when working
with system tables. Instead we create MDL savepoint before opening
those tables and rollback to it once they are closed.
- MDL_context::release_ticket() became release_lock() method.
- Added auxiliary MDL_context::acquire_exclusive_lock_impl() method
which does all necessary work to acquire exclusive lock on one object
but should not be used directly as it does not enforce any asserts
ensuring that no deadlocks are possible.
- Since we no longer need to know if thread trying to acquire exclusive
lock managed to wake up any threads having conflicting shared locks
(as, anyway, we will try to wake up such threads again shortly)
- MDL_context::m_is_waiting_in_mdl member became unnecessary and
notify_shared_lock() no longer needs to be friend of MDL_context.
Changed approach to handling of global metadata locks. Instead of
implicitly acquiring intention exclusive locks when user requests
per-object upgradeable or exclusive locks now we require them to be
acquired explicitly in the same way as ordinary metadata locks.
- Added new GLOBAL namespace for such locks.
- Added new type of lock to be requested MDL_INTENTION_EXCLISIVE.
- Added MDL_context::try_acquire_global_intention_exclusive_lock()
and acquire_global_intention_exclusive_lock() methods.
- Moved common code from MDL_context::acquire_global_shared_lock()
and acquire_global_intention_exclusive_lock() to new method -
MDL_context::acquire_lock_impl().
- Moved common code from MDL_context::try_acquire_shared_lock(),
try_acquire_global_intention_exclusive_lock()/exclusive_lock()
to MDL_context::try_acquire_lock_impl().
- Added helper MDL_context::is_global_lock_owner() method to be
able easily to find what kind of global lock this context holds.
- MDL_context::m_has_global_shared_lock became unnecessary as
global read lock is now represented by ordinary ticket.
- Removed assert in MDL_context::set_lt_or_ha_sentinel() which became
false for cases when we execute LOCK TABLES under global read lock
mode.
sql/mysql_priv.h:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result calls
opening/closing system tables were changed to use Open_tables_backup
instead of Open_table_state class as well.
sql/sp.cc:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result code
opening/closing system tables was changed to use Open_tables_backup
instead of Open_table_state class as well.
sql/sp.h:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result code
opening/closing system tables was changed to use Open_tables_backup
instead of Open_table_state class as well.
sql/sql_base.cc:
close_thread_tables():
Since we no longer use separate MDL_context for opening system
tables we need to avoid releasing all transaction locks when
closing system table. Releasing metadata lock on system table
is now responsibility of THD::restore_backup_open_tables_state().
open_table_get_mdl_lock(),
Open_table_context::recover_from_failed_open():
MDL subsystem no longer implicitly acquires global intention exclusive
metadata lock when per-object upgradable or exclusive metadata lock is
acquired. So this have to be done explicitly from these calls.
Changed Open_table_context class to store MDL_request object for
global intention exclusive lock acquired when opening tables.
open_table():
Do not release metadata lock if we have failed to open table as
this lock might have been acquired by one of previous statements
in transaction, and therefore should not be released.
open_system_tables_for_read()/close_system_tables()/
open_performance_schema_table():
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result code
opening/closing system tables was changed to use Open_tables_backup
instead of Open_table_state class as well.
close_performance_schema_table():
Got rid of duplicated code.
sql/sql_class.cc:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. Also releasing
metadata lock on system table is now responsibility of
THD::restore_backup_open_tables_state().
Adjusted assert in THD::cleanup() to take into account fact that now
we also use MDL sentinel for global read lock.
sql/sql_class.h:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. As result:
- 'mdl_context' member was moved out of Open_tables_state to THD class.
enter_locked_tables_mode()/leave_locked_tables_mode() had to follow.
- Methods of THD responsible for saving/restoring open table state were
changed to use Open_tables_backup class which in addition to
Open_table_state has a member for this savepoint.
Changed Open_table_context class to store MDL_request object for
global intention exclusive lock acquired when opening tables.
sql/sql_delete.cc:
MDL subsystem no longer implicitly acquires global intention exclusive
metadata lock when per-object exclusive metadata lock is acquired.
Now this has to be done by explicit calls outside of MDL subsystem.
sql/sql_help.cc:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result code
opening/closing system tables was changed to use Open_tables_backup
instead of Open_table_state class as well.
sql/sql_parse.cc:
Adjusted assert reload_acl_and_cache() to the fact that global read
lock now takes full-blown metadata lock.
sql/sql_plist.h:
Added support for element counting to I_P_List list template.
One can use policy classes to specify if such counting is needed
or not needed for particular list.
sql/sql_show.cc:
Instead of using separate MDL_context for opening tables for I_S
purposes we now create MDL savepoint in the main context before
opening tables and rollback to this savepoint after closing them.
To support this and similar change for system tables methods of
THD responsible for saving/restoring open table state were changed
to use Open_tables_backup class which in addition to Open_table_state
has a member for this savepoint. As result code opening/closing tables
for I_S purposes was changed to use Open_tables_backup instead of
Open_table_state class as well.
sql/sql_table.cc:
mysql_rm_tables_part2():
Since now global intention exclusive metadata lock is ordinary
metadata lock we no longer can rely that by releasing MDL locks
on all tables we will release all locks acquired by this routine.
So in non-LOCK-TABLES mode we have to release all locks acquired
explicitly.
prepare_for_repair(), mysql_alter_table():
MDL subsystem no longer implicitly acquires global intention
exclusive metadata lock when per-object exclusive metadata lock
is acquired. Now this has to be done by explicit calls outside of
MDL subsystem.
sql/tztime.cc:
Instead of using separate MDL_context for opening system tables we now
create MDL savepoint in the main context before opening such tables
and rollback to this savepoint after closing them. To support this
change methods of THD responsible for saving/restoring open table
state were changed to use Open_tables_backup class which in addition
to Open_table_state has a member for this savepoint. As result code
opening/closing system tables was changed to use Open_tables_backup
instead of Open_table_state class as well.
Also changed code not to use special mechanism for open system tables
when it is not really necessary.
REORGANIZE PARTITION
There were several problems which lead to this this,
all related to bad error handling.
1) There was several bugs preventing the ddl-log to be used for
cleaning up created files on error.
2) The error handling after the copy partition rows did not close
and unlock the tables, resulting in deletion of partitions
which were in use, which lead InnoDB to put the partition to
drop in a background queue.
sql/ha_partition.cc:
Bug#47343: InnoDB fails to clean-up after lock wait timeout on
REORGANIZE PARTITION
Better error handling, if partition has been created/opened/locked
then make sure it is unlocked and closed before returning error.
The delete of the newly created partition is handled by the ddl-log.
sql/sql_parse.cc:
Bug#47343: InnoDB fails to clean-up after lock wait timeout on
REORGANIZE PARTITION
Fix a bug found when experimenting, thd could really be NULL here,
as mentioned in the function header.
sql/sql_partition.cc:
Bug#47343: InnoDB fails to clean-up after lock wait timeout on
REORGANIZE PARTITION
Used the correct .frm shadow name to put into the ddl-log.
Really use the ddl-log to handle errors.
sql/sql_table.cc:
Bug#47343: InnoDB fails to clean-up after lock wait timeout on
REORGANIZE PARTITION
Fixes of the ddl-log when used as error recovery (no crash).
When executing an entry from memory (not read from disk)
the name_len was not set correctly.
Conflicts:
Text conflict in .bzr-mysql/default.conf
Text conflict in mysql-test/extra/rpl_tests/rpl_loaddata.test
Text conflict in mysql-test/r/mysqlbinlog2.result
Text conflict in mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result
Text conflict in mysql-test/suite/binlog/r/binlog_unsafe.result
Text conflict in mysql-test/suite/rpl/r/rpl_insert_id.result
Text conflict in mysql-test/suite/rpl/r/rpl_loaddata.result
Text conflict in mysql-test/suite/rpl/r/rpl_stm_auto_increment_bug33029.result
Text conflict in mysql-test/suite/rpl/r/rpl_udf.result
Text conflict in mysql-test/suite/rpl/t/rpl_slow_query_log.test
Text conflict in sql/field.h
Text conflict in sql/log.cc
Text conflict in sql/log_event.cc
Text conflict in sql/log_event_old.cc
Text conflict in sql/mysql_priv.h
Text conflict in sql/share/errmsg.txt
Text conflict in sql/sp.cc
Text conflict in sql/sql_acl.cc
Text conflict in sql/sql_base.cc
Text conflict in sql/sql_class.h
Text conflict in sql/sql_db.cc
Text conflict in sql/sql_delete.cc
Text conflict in sql/sql_insert.cc
Text conflict in sql/sql_lex.cc
Text conflict in sql/sql_lex.h
Text conflict in sql/sql_load.cc
Text conflict in sql/sql_table.cc
Text conflict in sql/sql_update.cc
Text conflict in sql/sql_view.cc
Conflict adding files to storage/innobase. Created directory.
Conflict because storage/innobase is not versioned, but has versioned children. Versioned directory.
Conflict adding file storage/innobase. Moved existing file to storage/innobase.moved.
Conflict adding files to storage/innobase/handler. Created directory.
Conflict because storage/innobase/handler is not versioned, but has versioned children. Versioned directory.
Contents conflict in storage/innobase/handler/ha_innodb.cc
3655 Jon Olav Hauglid 2009-10-19
Bug #30977 Concurrent statement using stored function and DROP FUNCTION
breaks SBR
Bug #48246 assert in close_thread_table
Implement a fix for:
Bug #41804 purge stored procedure cache causes mysterious hang for many
minutes
Bug #49972 Crash in prepared statements
The problem was that concurrent execution of DML statements that
use stored functions and DDL statements that drop/modify the same
function might result in incorrect binary log in statement (and
mixed) mode and therefore break replication.
This patch fixes the problem by introducing metadata locking for
stored procedures and functions. This is similar to what is done
in Bug#25144 for views. Procedures and functions now are
locked using metadata locks until the transaction is either
committed or rolled back. This prevents other statements from
modifying the procedure/function while it is being executed. This
provides commit ordering - guaranteeing serializability across
multiple transactions and thus fixes the reported binlog problem.
Note that we do not take locks for top-level CALLs. This means
that procedures called directly are not protected from changes by
simultaneous DDL operations so they are executed at the state they
had at the time of the CALL. By not taking locks for top-level
CALLs, we still allow transactions to be started inside
procedures.
This patch also changes stored procedure cache invalidation.
Upon a change of cache version, we no longer invalidate the entire
cache, but only those routines which we use, only when a statement
is executed that uses them.
This patch also changes the logic of prepared statement validation.
A stored procedure used by a prepared statement is now validated
only once a metadata lock has been acquired. A version mismatch
causes a flush of the obsolete routine from the cache and
statement reprepare.
Incompatible changes:
1) ER_LOCK_DEADLOCK is reported for a transaction trying to access
a procedure/function that is locked by a DDL operation in
another connection.
2) Procedure/function DDL operations are now prohibited in LOCK
TABLES mode as exclusive locks must be taken all at once and
LOCK TABLES provides no way to specifiy procedures/functions to
be locked.
Test cases have been added to sp-lock.test and rpl_sp.test.
Work on this bug has very much been a team effort and this patch
includes and is based on contributions from Davi Arnaut, Dmitry
Lenev, Magne Mæhre and Konstantin Osipov.
mysql-test/r/ps_ddl.result:
Update results (Bug#30977).
mysql-test/r/ps_ddl1.result:
Update results (Bug#30977).
mysql-test/r/sp-error.result:
Update results (Bug#30977).
mysql-test/r/sp-lock.result:
Update results (Bug#30977).
mysql-test/suite/rpl/r/rpl_sp.result:
Update results (Bug#30977).
mysql-test/suite/rpl/t/rpl_sp.test:
Add a test case for Bug#30977.
mysql-test/t/ps_ddl.test:
Update comments. We no longer re-prepare a prepared statement
when a stored procedure used in top-level CALL is changed.
mysql-test/t/ps_ddl1.test:
Modifying stored procedure p1 no longer invalidates prepared
statement "call p1" -- we can re-use the prepared statement
without invalidation.
mysql-test/t/sp-error.test:
Use a constant for an error value.
mysql-test/t/sp-lock.test:
Add test coverage for Bug#30977.
sql/lock.cc:
Implement lock_routine_name() - a way to acquire an
exclusive metadata lock (ex- name-lock) on
stored procedure/function.
sql/sp.cc:
Change semantics of sp_cache_routine() -- now it has an option
to make sure that the routine that is cached is up to date (has
the latest sp cache version).
Add sp_cache_invalidate() to sp_drop_routine(), where it was
missing (a bug!).
Acquire metadata locks for SP DDL (ALTER/CREATE/DROP). This is
the core of the fix for Bug#30977.
Since caching and cache invalidation scheme was changed, make
sure we don't invalidate the SP cache in the middle of a stored
routine execution. At the same time, make sure we don't access
stale data due to lack of invalidation.
For that, change ALTER FUNCTION/PROCEDURE to not use the cache,
and SHOW PROCEDURE CODE/SHOW CREATE PROCEDURE/FUNCTION to always
read an up to date version of the routine from the cache.
sql/sp.h:
Add a helper wrapper around sp_cache_routine().
sql/sp_cache.cc:
Implement new sp_cache_version() and sp_cache_flush_obsolete().
Now we flush stale routines individually, rather than all at once.
sql/sp_cache.h:
Update signatures of sp_cache_version() and sp_cache_flush_obsolete().
sql/sp_head.cc:
Add a default initialization of sp_head::m_sp_cache_version.
Remove a redundant sp_head::create().
sql/sp_head.h:
Add m_sp_cache_version to sp_head class - we now
keep track of every routine in the stored procedure cache, rather than
of the entire cache.
sql/sql_base.cc:
Implement prelocking for stored routines. Validate stored
routines after they were locked.
Flush obsolete routines upon next access, one by one, not all at once
(Bug#41804).
Style fixes.
sql/sql_class.h:
Rename a Open_table_context method.
sql/sql_parse.cc:
Make sure stored procedures DDL commits the active transaction
(issues an implicit commit before and after).
Remove sp_head::create(), a pure redundancy.
Move the semantical check during alter routine inside sp_update_routine() code in order to:
- avoid using SP cache during update, it may be obsolete.
- speed up and simplify the update procedure.
Remove sp_cache_flush_obsolete() calls, we no longer flush the entire
cache, ever, stale routines are flushed before next use, one at a time.
sql/sql_prepare.cc:
Move routine metadata validation to open_and_process_routine().
Fix Bug#49972 (don't swap flags at reprepare).
Reset Sroutine_hash_entries in reinit_stmt_before_use().
Remove SP cache invalidation, it's now done by open_tables().
sql/sql_show.cc:
Fix a warning: remove an unused label.
sql/sql_table.cc:
Reset mdl_request.ticket for tickets acquired for routines inlined
through a view, in CHECK TABLE statement, to satisfy an MDL assert.
sql/sql_update.cc:
Move the cleanup of "translation items" to close_tables_for_reopen(),
since it's needed in all cases when we back off, not just
the back-off in multi-update. This fixes a bug when the server
would crash on attempt to back off when opening tables
for a statement that uses information_schema tables.
Conflicts:
Conflict adding files to server-tools. Created directory.
Conflict because server-tools is not versioned, but has versioned children. Versioned directory.
Conflict adding files to server-tools/instance-manager. Created directory.
Conflict because server-tools/instance-manager is not versioned, but has versioned children. Versioned directory.
Contents conflict in server-tools/instance-manager/instance_map.cc
Contents conflict in server-tools/instance-manager/listener.cc
Contents conflict in server-tools/instance-manager/options.cc
Contents conflict in server-tools/instance-manager/user_map.cc
"HANDLER statements within a transaction might lead to deadlocks".
Introduce a notion of a sentinel to MDL_context. A sentinel
is a ticket that separates all tickets in the context into two
groups: before and after it. Currently we can have (and need) only
one designated sentinel -- it separates all locks taken by LOCK
TABLE or HANDLER statement, which must survive COMMIT and ROLLBACK
and all other locks, which must be released at COMMIT or ROLLBACK.
The tricky part is maintaining the sentinel up to date when
someone release its corresponding ticket. This can happen, e.g.
if someone issues DROP TABLE under LOCK TABLES (generally,
see all calls to release_all_locks_for_name()).
MDL_context::release_ticket() is modified to take care of it.
******
A fix and a test case for Bug#46224 "HANDLER statements within a
transaction might lead to deadlocks".
An attempt to mix HANDLER SQL statements, which are transaction-
agnostic, an open multi-statement transaction,
and DDL against the involved tables (in a concurrent connection)
could lead to a deadlock. The deadlock would occur when
HANDLER OPEN or HANDLER READ would have to wait on a conflicting
metadata lock. If the connection that issued HANDLER statement
also had other metadata locks (say, acquired in scope of a
transaction), a classical deadlock situation of mutual wait
could occur.
Incompatible change: entering LOCK TABLES mode automatically
closes all open HANDLERs in the current connection.
Incompatible change: previously an attempt to wait on a lock
in a connection that has an open HANDLER statement could wait
indefinitely/deadlock. After this patch, an error ER_LOCK_DEADLOCK
is produced.
The idea of the fix is to merge thd->handler_mdl_context
with the main mdl_context of the connection, used for transactional
locks. This makes deadlock detection possible, since all waits
with locks are "visible" and available to analysis in a single
MDL context of the connection.
Since HANDLER locks and transactional locks have a different life
cycle -- HANDLERs are explicitly open and closed, and so
are HANDLER locks, explicitly acquired and released, whereas
transactional locks "accumulate" till the end of a transaction
and are released only with COMMIT, ROLLBACK and ROLLBACK TO SAVEPOINT,
a concept of "sentinel" was introduced to MDL_context.
All locks, HANDLER and others, reside in the same linked list.
However, a selected element of the list separates locks with
different life cycle. HANDLER locks always reside at the
end of the list, after the sentinel. Transactional locks are
prepended to the beginning of the list, before the sentinel.
Thus, ROLLBACK, COMMIT or ROLLBACK TO SAVEPOINT, only
release those locks that reside before the sentinel. HANDLER locks
must be released explicitly as part of HANDLER CLOSE statement,
or an implicit close.
The same approach with sentinel
is also employed for LOCK TABLES locks. Since HANDLER and LOCK TABLES
statement has never worked together, the implementation is
made simple and only maintains one sentinel, which is used either
for HANDLER locks, or for LOCK TABLES locks.
mysql-test/include/handler.inc:
Add test coverage for Bug#46224 "HANDLER statements within a
transaction might lead to deadlocks".
Extended HANDLER coverage to cover a mix of HANDLER, transactions
and DDL statements.
mysql-test/r/handler_innodb.result:
Update results (Bug#46224).
mysql-test/r/handler_myisam.result:
Update results (Bug#46224).
sql/lock.cc:
Remove thd->some_tables_deleted, it's never used.
sql/log_event.cc:
No need to check for thd->locked_tables_mode,
it's done inside release_transactional_locks().
sql/mdl.cc:
Implement the concept of HANDLER and LOCK TABLES "sentinel".
Implement a method to clone an acquired ticket.
Do not return tickets beyond the sentinel when acquiring
locks, create a copy.
Remove methods to merge and backup MDL_context, they are now
not used (Hurra!). This opens a path to a proper constructor
and destructor of class MDL_context (to be done in a separate
patch).
Modify find_ticket() to provide information about where
the ticket position is with regard to the sentinel.
sql/mdl.h:
Add declarations necessary for the implementation of the concept
of "sentinel", a dedicated ticket separating transactional and
non-transactional locks.
sql/mysql_priv.h:
Add mark_tmp_table_for_reuse() declaration,
a function to "close" a single session (temporary) table.
sql/sql_base.cc:
Remove thd->some_tables_deleted.
Modify deadlock-prevention asserts and deadlock detection
heuristics to take into account that from now on HANDLER locks
reside in the same locking context.
Add broadcast_refresh() to mysql_notify_thread_having_shared_lock():
this is necessary for the case when a thread having a shared lock
is asleep in tdc_wait_for_old_versions(). This situation is only
possible with HANDLER t1 OPEN; FLUSH TABLE (since all over code paths
that lead to tdc_wait_for_old_versions() always have an
empty MDL_context). Previously the server would simply deadlock
in this situation.
sql/sql_class.cc:
Remove now unused member "THD::some_tables_deleted".
Move mysql_ha_cleanup() a few lines above in THD::cleanup()
to make sure that all handlers are closed when it's time to
destroy the MDL_context of this connection.
Remove handler_mdl_context and handler_tables.
sql/sql_class.h:
Remove THD::handler_tables, THD::handler_mdl_context,
THD::some_tables_deleted.
sql/sql_handler.cc:
Remove thd->handler_tables.
Remove thd->handler_mdl_context.
Rewrite mysql_ha_open() to have no special provision for MERGE
tables, now that we don't have to manipulate with thd->handler_tables
it's easy to do.
Remove dead code.
Fix a bug in mysql_ha_flush() when we would always flush
a temporary HANDLER when mysql_ha_flush() is called (actually
mysql_ha_flush() never needs to flush temporary tables).
sql/sql_insert.cc:
Update a comment, no more thd->some_tables_deleted.
sql/sql_parse.cc:
Implement an incompatible change: entering LOCK TABLES closes
active HANDLERs, if any.
Now that we have a sentinel, we don't need to check
for thd->locked_tables_mode when releasing metadata locks in
COMMIT/ROLLBACK.
sql/sql_plist.h:
Add new (now necessary) methods to the list class.
sql/sql_prepare.cc:
Make sure we don't release HANDLER locks when rollback to a
savepoint, set to not keep locks taken at PREPARE.
sql/sql_servers.cc:
Update to a new signature of MDL_context::release_all_locks().
sql/sql_table.cc:
Remove thd->some_tables_deleted.
sql/transaction.cc:
Add comments.
Make sure rollback to (MDL) savepoint works under LOCK TABLES and
with HANDLER tables.
Bug#16565 mysqld --help --verbose does not order variablesBug#20413 sql_slave_skip_counter is not shown in show variables
Bug#20415 Output of mysqld --help --verbose is incomplete
Bug#25430 variable not found in SELECT @@global.ft_max_word_len;
Bug#32902 plugin variables don't know their names
Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
Bug#34829 No default value for variable and setting default does not raise error
Bug#34834 ? Is accepted as a valid sql mode
Bug#34878 Few variables have default value according to documentation but error occurs
Bug#34883 ft_boolean_syntax cant be assigned from user variable to global var.
Bug#37187 `INFORMATION_SCHEMA`.`GLOBAL_VARIABLES`: inconsistent status
Bug#40988 log_output_basic.test succeeded though syntactically false.
Bug#41010 enum-style command-line options are not honoured (maria.maria-recover fails)
Bug#42103 Setting key_buffer_size to a negative value may lead to very large allocations
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
Bug#44797 plugins w/o command-line options have no disabling option in --help
Bug#46314 string system variables don't support expressions
Bug#46470 sys_vars.max_binlog_cache_size_basic_32 is broken
Bug#46586 When using the plugin interface the type "set" for options caused a crash.
Bug#47212 Crash in DBUG_PRINT in mysqltest.cc when trying to print octal number
Bug#48758 mysqltest crashes on sys_vars.collation_server_basic in gcov builds
Bug#49417 some complaints about mysqld --help --verbose output
Bug#49540 DEFAULT value of binlog_format isn't the default value
Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
Bug#49644 init_connect and \0
Bug#49645 init_slave and multi-byte characters
Bug#49646 mysql --show-warnings crashes when server dies
CMakeLists.txt:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
client/mysql.cc:
don't crash with --show-warnings when mysqld dies
config/ac-macros/plugins.m4:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
include/my_getopt.h:
comments
include/my_pthread.h:
fix double #define
mysql-test/mysql-test-run.pl:
run sys_vars suite by default
properly recognize envirinment variables (e.g. MTR_MAX_SAVE_CORE) set to 0
escape gdb command line arguments
mysql-test/suite/sys_vars/r/rpl_init_slave_func.result:
init_slave+utf8 bug
mysql-test/suite/sys_vars/t/rpl_init_slave_func.test:
init_slave+utf8 bug
mysys/my_getopt.c:
Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
Bug#46586 When using the plugin interface the type "set" for options caused a crash.
Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
mysys/typelib.c:
support for flagset
sql/ha_ndbcluster.cc:
backport from telco tree
sql/item_func.cc:
Bug#49644 init_connect and \0
Bug#49645 init_slave and multi-byte characters
sql/sql_builtin.cc.in:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
sql/sql_plugin.cc:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
Bug#32902 plugin variables don't know their names
Bug#44797 plugins w/o command-line options have no disabling option in --help
sql/sys_vars.cc:
all server variables are defined here
storage/myisam/ft_parser.c:
remove unnecessary updates of param->quot
storage/myisam/ha_myisam.cc:
myisam_* variables belong here
strings/my_vsnprintf.c:
%o and %llx
unittest/mysys/my_vsnprintf-t.c:
%o and %llx tests
vio/viosocket.c:
bugfix: fix @@wait_timeout to work with socket timeouts (vs. alarm thread)
The problem is a somewhat common misusage of the strmake function.
The strmake(dst, src, len) function writes at most /len/ bytes to
the string pointed to by src, not including the trailing null byte.
Hence, if /len/ is the exact length of the destination buffer, a
one byte buffer overflow can occur if the length of the source
string is equal to or greater than /len/.
client/mysqldump.c:
Make room for the trailing null byte.
libmysql/libmysql.c:
Add comment, there is enough room in the buffer.
Increase buffer length, two strings are concatenated.
libmysqld/lib_sql.cc:
Make room for the trailing null byte.
mysys/default.c:
Make room for the trailing null bytes.
mysys/mf_pack.c:
Make room for the trailing null byte.
server-tools/instance-manager/commands.cc:
Copy only if overflow isn't possible in both cases.
server-tools/instance-manager/listener.cc:
Make room for the trailing null byte.
sql/log.cc:
Make room for the trailing null byte.
sql/sp_pcontext.h:
Cosmetic fix.
sql/sql_acl.cc:
MAX_HOSTNAME already specifies space for the trailing null byte.
sql/sql_parse.cc:
Make room for the trailing null byte.
sql/sql_table.cc:
Make room for the trailing null byte.
with temporary table and partitions
It was possible to create temporary partitioned tables
via create table ... like ... (which is not allowed with
create temporary table). This lead to a new HA_EXTRA flag
(HA_EXTRA_MMAP) was sent to the partitioning handler,
which was caught on an assert in debug builds.
Solution was to check for partitioned tables when
doing create table ... like ... and disallow it.
mysql-test/r/partition_error.result:
Bug#49477: Assertion `0' failed in ha_partition.cc:5530
with temporary table and partitions
Added result
mysql-test/t/partition_error.test:
Bug#49477: Assertion `0' failed in ha_partition.cc:5530
with temporary table and partitions
Added test
sql/sql_table.cc:
Bug#49477: Assertion `0' failed in ha_partition.cc:5530
with temporary table and partitions
Added check to prevent creation of partitioned temporary
tables.
Only copy .par file for partitioned tables.
-----------------------------------------------------------
2497.392.1 Michael Widenius 2008-08-19
Fixes for Bug #38016 Maria: trying to access freed memory when
committing a transaction.
Don't write out states if they haven't changed.
sql/sql_table.cc:
Call extra(HA_EXTRA_PREPARE_FOR_RENAME) before renaming a table.
Bug #46654 False deadlock on concurrent DML/DDL with partitions,
inconsistent behavior
The problem was that if one connection is running a multi-statement
transaction which involves a single partitioned table, and another
connection attempts to alter the table, the first connection gets
ER_LOCK_DEADLOCK and cannot proceed anymore, even when the ALTER TABLE
statement in another connection has timed out or failed.
The reason for this was that the prepare phase for ALTER TABLE for
partitioned tables removed all instances of the table from the table
definition cache before it started waiting on the lock. The transaction
running in the first connection would notice this and report ER_LOCK_DEADLOCK.
This patch changes the prep_alter_part_table() ALTER TABLE code so that
tdc_remove_table() is no longer called. Instead, only the TABLE instance
changed by prep_alter_part_table() is marked as needing reopen.
The patch also removes an unnecessary call to tdc_remove_table() from
mysql_unpack_partition() as the changed TABLE object is destroyed by the
caller at a later point.
Test case added in partition_sync.test.
Bug#42546 Backup: RESTORE fails, thinking it finds an existing table
The problem occured when a MDL locking conflict happened for a non-existent
table between a CREATE and a INSERT statement. The code for CREATE
interpreted this lock conflict to mean that the table existed,
which meant that the statement failed when it should not have.
The problem could occur for CREATE TABLE, CREATE TABLE LIKE and
ALTER TABLE RENAME.
This patch fixes the problem for CREATE TABLE and CREATE TABLE LIKE.
It is based on code backported from the mysql-6.1-fk tree written
by Dmitry Lenev. CREATE now uses normal open_and_lock_tables() code
to acquire exclusive locks. This means that for the test case in the bug
description, CREATE will wait until INSERT completes so that it can
get the exclusive lock. This resolves the reported bug.
The patch also prohibits CREATE TABLE and CREATE TABLE LIKE under
LOCK TABLES. Note that this is an incompatible change and must
be reflected in the documentation. Affected test cases have been
updated.
mdl_sync.test contains tests for CREATE TABLE and CREATE TABLE LIKE.
Fixing the issue for ALTER TABLE RENAME is beyond the scope of this
patch. ALTER TABLE cannot be prohibited from working under LOCK TABLES
as this could seriously impact customers and a proper fix would require
a significant rewrite.
------------------------------------------------------------
revno: 2617.68.25
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-next-bg-pre2-2
timestamp: Wed 2009-09-16 18:26:50 +0400
message:
Follow-up for one of pre-requisite patches for fixing bug #30977
"Concurrent statement using stored function and DROP FUNCTION
breaks SBR".
Made enum_mdl_namespace enum part of MDL_key class and removed MDL_
prefix from the names of enum members. In order to do the latter
changed name of PROCEDURE symbol to PROCEDURE_SYM (otherwise macro
which was automatically generated for this symbol conflicted with
MDL_key::PROCEDURE enum member).
Introduce a counter for protection against global read lock on thread level.
The functions for protection against global read lock sometimes need a local
variable to signal when the protection is set, and hence need to be released.
It would be better to control this behaviour via a counter on the THD struct,
telling how many times the protection has been claimed by the current thread.
A side-effect of the fix is that if protection is claimed twice for a thread,
only a simple increment is required for the second claim, instead of a
mutex-protected increment of the global variable protect_against_global_read_lock.
sql/lock.cc:
Count how many times that we have claimed protection against global read lock.
Assert that we really have the protection when releasing it.
Added comments to all functions operating on global_read_lock.
sql/sql_class.cc:
Added the counter variable global_read_lock_protection.
sql/sql_class.h:
Added the counter variable global_read_lock_protection.
sql/sql_parse.cc:
Replaced test on local variable need_start_waiting with test on
thd->global_read_lock_protection.
sql/sql_table.cc:
Replaced test on local variable need_start_waiting with test on
thd->global_read_lock_protection.
sql/sql_trigger.cc:
Inserted test on thd->global_read_lock_protection.
Bug #48248 assert in MDL_ticket::upgrade_shared_lock_to_exclusive
The assert would happen if REPAIR TABLE was used on a table already
locked by LOCK TABLES READ. REPAIR mistakenly tried to upgrade the
read-lock to exclusive, thereby triggering the assert.
The cause of the problem was that REPAIR TABLE ignored errors
from opening and locking tables. This is by design, as REPAIR
can be used to broken tables that cannot be opened. However,
repair also ignored logical errors such as the inability to
exclusivly lock a table due to conflicting LOCK TABLES.
This patch fixes the problem by not ignoring errors from
opening and locking tables if inside LOCK TABLES mode.
In LOCK TABLES we already know that the table can be opened,
so that the failure to open must be a logical error.
Test added to repair.test.
A pre-requisite patch for Bug#30977 "Concurrent statement using
stored function and DROP FUNCTION breaks SBR".
This patch changes the MDL API by introducing a namespace for
lock keys: MDL_TABLE for tables and views and MDL_PROCEDURE
for stored procedures and functions. The latter is needed for
the fix for Bug#30977.
