STATUS OF ROLLBACKED TRANSACTION" and bug #17054007 - "TRANSACTION
IS NOT FULLY ROLLED BACK IN CASE OF INNODB DEADLOCK".
The problem in the first bug report was that although deadlock involving
metadata locks was reported using the same error code and message as InnoDB
deadlock it didn't rollback transaction like the latter. This caused
confusion to users as in some cases after ER_LOCK_DEADLOCK transaction
could have been restarted immediately and in some cases rollback was
required.
The problem in the second bug report was that although InnoDB deadlock
caused transaction rollback in all storage engines it didn't cause release
of metadata locks. So concurrent DDL on the tables used in transaction was
blocked until implicit or explicit COMMIT or ROLLBACK was issued in the
connection which got InnoDB deadlock.
The former issue has stemmed from the fact that when support for detection
and reporting metadata locks deadlocks was added we erroneously assumed
that InnoDB doesn't rollback transaction on deadlock but only last statement
(while this is what happens on InnoDB lock timeout actually) and so didn't
implement rollback of transactions on MDL deadlocks.
The latter issue was caused by the fact that rollback of transaction due
to deadlock is carried out by setting THD::transaction_rollback_request
flag at the point where deadlock is detected and performing rollback
inside of trans_rollback_stmt() call when this flag is set. And
trans_rollback_stmt() is not aware of MDL locks, so no MDL locks are
released.
This patch solves these two problems in the following way:
- In case when MDL deadlock is detect transaction rollback is requested
by setting THD::transaction_rollback_request flag.
- Code performing rollback of transaction if THD::transaction_rollback_request
is moved out from trans_rollback_stmt(). Now we handle rollback request
on the same level as we call trans_rollback_stmt() and release statement/
transaction MDL locks.
QUOTING IN REPLICATION
Problem: Misquoting or unquoted identifiers may lead to
incorrect statements to be logged to the binary log.
Fix: we use specialized functions to append quoted identifiers in
the statements generated by the server.
In sql_class.cc, 'row_count', of type 'ha_rows', was used as last argument for
ER_TRUNCATED_WRONG_VALUE_FOR_FIELD which is
"Incorrect %-.32s value: '%-.128s' for column '%.192s' at row %ld".
So 'ha_rows' was used as 'long'.
On SPARC32 Solaris builds, 'long' is 4 bytes and 'ha_rows' is 'longlong' i.e. 8 bytes.
So the printf-like code was reading only the first 4 bytes.
Because the CPU is big-endian, 1LL is 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x01
so the first four bytes yield 0. So the warning message had "row 0" instead of
"row 1" in test outfile_loaddata.test:
-Warning 1366 Incorrect string value: '\xE1\xE2\xF7' for column 'b' at row 1
+Warning 1366 Incorrect string value: '\xE1\xE2\xF7' for column 'b' at row 0
All error-messaging functions which internally invoke some printf-life function
are potential candidate for such mistakes.
One apparently easy way to catch such mistakes is to use
ATTRIBUTE_FORMAT (from my_attribute.h).
But this works only when call site has both:
a) the format as a string literal
b) the types of arguments.
So:
func(ER(ER_BLAH), 10);
will silently not be checked, because ER(ER_BLAH) is not known at
compile time (it is known at run-time, and depends on the chosen
language).
And
func("%s", a va_list argument);
has the same problem, as the *real* type of arguments is not
known at this site at compile time (it's known in some caller).
Moreover,
func(ER(ER_BLAH));
though possibly correct (if ER(ER_BLAH) has no '%' markers), will not
compile (gcc says "error: format not a string literal and no format
arguments").
Consequences:
1) ATTRIBUTE_FORMAT is here added only to functions which in practice
take "string literal" formats: "my_error_reporter" and "print_admin_msg".
2) it cannot be added to the other functions: my_error(),
push_warning_printf(), Table_check_intact::report_error(),
general_log_print().
To do a one-time check of functions listed in (2), the following
"static code analysis" has been done:
1) replace
my_error(ER_xxx, arguments for substitution in format)
with the equivalent
my_printf_error(ER_xxx,ER(ER_xxx), arguments for substitution in
format),
so that we have ER(ER_xxx) and the arguments *in the same call site*
2) add ATTRIBUTE_FORMAT to push_warning_printf(),
Table_check_intact::report_error(), general_log_print()
3) replace ER(xxx) with the hard-coded English text found in
errmsg.txt (like: ER(ER_UNKNOWN_ERROR) is replaced with
"Unknown error"), so that a call site has the format as string literal
4) this way, ATTRIBUTE_FORMAT can effectively do its job
5) compile, fix errors detected by ATTRIBUTE_FORMAT
6) revert steps 1-2-3.
The present patch has no compiler error when submitted again to the
static code analysis above.
It cannot catch all problems though: see Field::set_warning(), in
which a call to push_warning_printf() has a variable error
(thus, not replacable by a string literal); I checked set_warning() calls
by hand though.
See also WL 5883 for one proposal to avoid such bugs from appearing
again in the future.
The issues fixed in the patch are:
a) mismatch in types (like 'int' passed to '%ld')
b) more arguments passed than specified in the format.
This patch resolves mismatches by changing the type/number of arguments,
not by changing error messages of sql/share/errmsg.txt. The latter would be wrong,
per the following old rule: errmsg.txt must be as stable as possible; no insertions
or deletions of messages, no changes of type or number of printf-like format specifiers,
are allowed, as long as the change impacts a message already released in a GA version.
If this rule is not followed:
- Connectors, which use error message numbers, will be confused (by insertions/deletions
of messages)
- using errmsg.sys of MySQL 5.1.n with mysqld of MySQL 5.1.(n+1)
could produce wrong messages or crash; such usage can easily happen if
installing 5.1.(n+1) while /etc/my.cnf still has --language=/path/to/5.1.n/xxx;
or if copying mysqld from 5.1.(n+1) into a 5.1.n installation.
When fixing b), I have verified that the superfluous arguments were not used in the format
in the first 5.1 GA (5.1.30 'bteam@astra04-20081114162938-z8mctjp6st27uobm').
Had they been used, then passing them today, even if the message doesn't use them
anymore, would have been necessary, as explained above.
include/my_getopt.h:
this function pointer is used only with "string literal" formats, so we can add
ATTRIBUTE_FORMAT.
mysql-test/collections/default.experimental:
test should pass now
sql/derror.cc:
by having a format as string literal, ATTRIBUTE_FORMAT check becomes effective.
sql/events.cc:
Change justified by the following excerpt from sql/share/errmsg.txt:
ER_EVENT_SAME_NAME
eng "Same old and new event name"
ER_EVENT_SET_VAR_ERROR
eng "Error during starting/stopping of the scheduler. Error code %u"
sql/field.cc:
ER_TOO_BIG_SCALE 42000 S1009
eng "Too big scale %d specified for column '%-.192s'. Maximum is %lu."
ER_TOO_BIG_PRECISION 42000 S1009
eng "Too big precision %d specified for column '%-.192s'. Maximum is %lu."
ER_TOO_BIG_DISPLAYWIDTH 42000 S1009
eng "Display width out of range for column '%-.192s' (max = %lu)"
sql/ha_ndbcluster.cc:
ER_OUTOFMEMORY HY001 S1001
eng "Out of memory; restart server and try again (needed %d bytes)"
(sizeof() returns size_t)
sql/ha_ndbcluster_binlog.cc:
Too many arguments for:
ER_GET_ERRMSG
eng "Got error %d '%-.100s' from %s"
Patch by Jonas Oreland.
sql/ha_partition.cc:
print_admin_msg() is used only with a literal as format, so ATTRIBUTE_FORMAT
works.
sql/handler.cc:
ER_OUTOFMEMORY HY001 S1001
eng "Out of memory; restart server and try again (needed %d bytes)"
(sizeof() returns size_t)
sql/item_create.cc:
ER_TOO_BIG_SCALE 42000 S1009
eng "Too big scale %d specified for column '%-.192s'. Maximum is %lu."
ER_TOO_BIG_PRECISION 42000 S1009
eng "Too big precision %d specified for column '%-.192s'. Maximum is %lu."
'c_len' and 'c_dec' are char*, passed as %d !! We don't know their value
(as strtoul() failed), but they are likely big, so we use INT_MAX.
'len' is ulong.
sql/item_func.cc:
ER_WARN_DATA_OUT_OF_RANGE 22003
eng "Out of range value for column '%s' at row %ld"
ER_CANT_FIND_UDF
eng "Can't load function '%-.192s'"
sql/item_strfunc.cc:
ER_TOO_BIG_FOR_UNCOMPRESS
eng "Uncompressed data size too large; the maximum size is %d (probably, length of uncompressed data was corrupted)"
max_allowed_packet is ulong.
sql/mysql_priv.h:
sql_print_message_func is a function _pointer_.
sql/sp_head.cc:
ER_SP_RECURSION_LIMIT
eng "Recursive limit %d (as set by the max_sp_recursion_depth variable) was exceeded for routine %.192s"
max_sp_recursion_depth is ulong
sql/sql_acl.cc:
ER_PASSWORD_NO_MATCH 42000
eng "Can't find any matching row in the user table"
ER_CANT_CREATE_USER_WITH_GRANT 42000
eng "You are not allowed to create a user with GRANT"
sql/sql_base.cc:
ER_NOT_KEYFILE
eng "Incorrect key file for table '%-.200s'; try to repair it"
ER_TOO_MANY_TABLES
eng "Too many tables; MySQL can only use %d tables in a join"
MAX_TABLES is size_t.
sql/sql_binlog.cc:
ER_UNKNOWN_ERROR
eng "Unknown error"
sql/sql_class.cc:
ER_TRUNCATED_WRONG_VALUE_FOR_FIELD
eng "Incorrect %-.32s value: '%-.128s' for column '%.192s' at row %ld"
WARN_DATA_TRUNCATED 01000
eng "Data truncated for column '%s' at row %ld"
sql/sql_connect.cc:
ER_HANDSHAKE_ERROR 08S01
eng "Bad handshake"
ER_BAD_HOST_ERROR 08S01
eng "Can't get hostname for your address"
sql/sql_insert.cc:
ER_WRONG_VALUE_COUNT_ON_ROW 21S01
eng "Column count doesn't match value count at row %ld"
sql/sql_parse.cc:
ER_WARN_HOSTNAME_WONT_WORK
eng "MySQL is started in --skip-name-resolve mode; you must restart it without this switch for this grant to work"
ER_TOO_HIGH_LEVEL_OF_NESTING_FOR_SELECT
eng "Too high level of nesting for select"
ER_UNKNOWN_ERROR
eng "Unknown error"
sql/sql_partition.cc:
ER_OUTOFMEMORY HY001 S1001
eng "Out of memory; restart server and try again (needed %d bytes)"
sql/sql_plugin.cc:
ER_OUTOFMEMORY HY001 S1001
eng "Out of memory; restart server and try again (needed %d bytes)"
sql/sql_prepare.cc:
ER_OUTOFMEMORY HY001 S1001
eng "Out of memory; restart server and try again (needed %d bytes)"
ER_UNKNOWN_STMT_HANDLER
eng "Unknown prepared statement handler (%.*s) given to %s"
length value (for '%.*s') must be 'int', per the doc of printf()
and the code of my_vsnprintf().
sql/sql_show.cc:
ER_OUTOFMEMORY HY001 S1001
eng "Out of memory; restart server and try again (needed %d bytes)"
sql/sql_table.cc:
ER_TOO_BIG_FIELDLENGTH 42000 S1009
eng "Column length too big for column '%-.192s' (max = %lu); use BLOB or TEXT instead"
sql/table.cc:
ER_NOT_FORM_FILE
eng "Incorrect information in file: '%-.200s'"
ER_COL_COUNT_DOESNT_MATCH_PLEASE_UPDATE
eng "Column count of mysql.%s is wrong. Expected %d, found %d. Created with MySQL %d, now running %d. Please use mysql_upgrade to fix this error."
table->s->mysql_version is ulong.
sql/unireg.cc:
ER_TOO_LONG_TABLE_COMMENT
eng "Comment for table '%-.64s' is too long (max = %lu)"
ER_TOO_LONG_FIELD_COMMENT
eng "Comment for field '%-.64s' is too long (max = %lu)"
ER_TOO_BIG_ROWSIZE 42000
eng "Row size too large. The maximum row size for the used table type, not counting BLOBs, is %ld. You have to change some columns to TEXT or BLOBs"
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().
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).
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().
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.
multiquery packet).
Background:
- a query can contain multiple SQL statements;
- the server frees resources allocated to process a query when the
whole query is handled. In other words, resources allocated to process
one SQL statement from a multi-statement query are freed when all SQL
statements are handled.
The problem was that the parser allocated a buffer of size of the whole
query for each SQL statement in a multi-statement query. Thus, if a query
had many SQL-statements (so, the query was long), but each SQL statement
was short, ther parser tried to allocate huge amount of memory (number of
small SQL statements * length of the whole query).
The memory was allocated for a so-called "cpp buffer", which is intended to
store pre-processed SQL statement -- SQL text without version specific
comments.
The fix is to allocate memory for the "cpp buffer" once for all SQL
statements (once for a query).
This patch:
- Moves all definitions from the mysql_priv.h file into
header files for the component where the variable is
defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h
This patch prevents system threads and system table accesses from
using user-specified values for "lock_wait_timeout". Instead all
such accesses are done using the default value (1 year).
This prevents background tasks (such as replication, events,
accessing stored function definitions, logging, reading time-zone
information, etc.) from failing in cases where the global value
of "lock_wait_timeout" is set very low.
The patch also simplifies the open tables API. Rather than adding
another convenience function for opening and locking system tables,
this patch removes most of the existing convenience functions for
open_and_lock_tables_derived(). Before, open_and_lock_tables() was
a convenience function that enforced derived tables handling, while
open_and_lock_tables_derived() was the main function where derived
tables handling was optional. Now, this convencience function is
gone and the main function is renamed to open_and_lock_tables().
No test case added as it would have required the use of --sleep to
check that system threads and system tables have a different timeout
value from the user-specified "lock_wait_timeout" system variable.
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
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)
----------------------------------------------------------
revno: 2617.69.20
committer: Konstantin Osipov <kostja@sun.com>
branch nick: 5.4-4284-1-assert
timestamp: Thu 2009-08-13 18:29:55 +0400
message:
WL#4284 "Transactional DDL locking"
A review fix.
Since WL#4284 implementation separated MDL_request and MDL_ticket,
MDL_request becamse a utility object necessary only to get a ticket.
Store it by-value in TABLE_LIST with the intent to merge
MDL_request::key with table_list->table_name and table_list->db
in future.
Change the MDL subsystem to not require MDL_requests to
stay around till close_thread_tables().
Remove the list of requests from the MDL context.
Requests for shared metadata locks acquired in open_tables()
are only used as a list in recover_from_failed_open_table_attempt(),
which calls mdl_context.wait_for_locks() for this list.
To keep such list for recover_from_failed_open_table_attempt(),
introduce a context class (Open_table_context), that collects
all requests.
A lot of minor cleanups and simplications that became possible
with this change.
sql/event_db_repository.cc:
Remove alloc_mdl_requests(). Now MDL_request instance is a member
of TABLE_LIST, and init_one_table() initializes it.
sql/ha_ndbcluster_binlog.cc:
Remove now unnecessary declaration and initialization
of binlog_mdl_request.
sql/lock.cc:
No need to allocate MDL requests in lock_table_names() now.
sql/log.cc:
Use init_one_table() method, remove alloc_mdl_requests(),
which is now unnecessary.
sql/log_event.cc:
No need to allocate mdl_request separately now.
Use init_one_table() method.
sql/log_event_old.cc:
Update to the new signature of close_tables_for_reopen().
sql/mdl.cc:
Update try_acquire_exclusive_lock() to be more easy to use.
Function lock_table_name_if_not_cached() has been removed.
Make acquire_shared_lock() signature consistent with
try_acquire_exclusive_lock() signature.
Remove methods that are no longer used.
Update comments.
sql/mdl.h:
Implement an assignment operator that doesn't
copy MDL_key (MDL_key::operator= is private and
should remain private).
This is a hack to work-around assignment of TABLE_LIST
by value in several places. Such assignments violate
encapsulation, since only perform a shallow copy.
In most cases these assignments are a hack on their own.
sql/mysql_priv.h:
Update signatures of close_thread_tables() and close_tables_for_reopen().
sql/sp.cc:
Allocate TABLE_LIST in thd->mem_root.
Use init_one_table().
sql/sp_head.cc:
Use init_one_table().
Remove thd->locked_tables_root, it's no longer needed.
sql/sql_acl.cc:
Use init_mdl_requests() and init_one_table().
sql/sql_base.cc:
Update to new signatures of try_acquire_shared_lock() and
try_acquire_exclusive_lock().
Remove lock_table_name_if_not_cached().
Fix a bug in open_ltable() that would not return ER_LOCK_DEADLOCK
in case of a failed lock_tables() and a multi-statement
transaction.
Fix a bug in open_and_lock_tables_derived() that would
not return ER_LOCK_DEADLOCK in case of a multi-statement
transaction and a failure of lock_tables().
Move assignment of enum_open_table_action to a method of Open_table_context, a new class that maintains information
for backoff actions.
Minor rearrangements of the code.
Remove alloc_mdl_requests() in functions that work with system
tables: instead the patch ensures that callers always initialize
TABLE_LIST argument.
sql/sql_class.cc:
THD::locked_tables_root is no more.
sql/sql_class.h:
THD::locked_tables_root is no more.
Add a declaration for Open_table_context class.
sql/sql_delete.cc:
Update to use the simplified MDL API.
sql/sql_handler.cc:
TABLE_LIST::mdl_request is stored by-value now.
Ensure that mdl_request.ticket is NULL for every request
that is passed into MDL, to satisfy MDL asserts.
@ sql/sql_help.cc
Function open_system_tables_for_read() no longer initializes
mdl_requests.
Move TABLE_LIST::mdl_request initialization closer to
TABLE_LIST initialization.
sql/sql_help.cc:
Function open_system_tables_for_read() no longer initializes
mdl_requests.
Move TABLE_LIST::mdl_request initialization closer to
TABLE_LIST initialization.
sql/sql_insert.cc:
Remove assignment by-value of TABLE_LIST in
TABLEOP_HOOKS. We can't carry over a granted
MDL ticket from one table list to another.
sql/sql_parse.cc:
Change alloc_mdl_requests() -> init_mdl_requests().
@todo We can remove init_mdl_requests() altogether
in some places: all places that call add_table_to_list()
already have mdl requests initialized.
sql/sql_plugin.cc:
Use init_one_table().
THD::locked_tables_root is no more.
sql/sql_servers.cc:
Use init_one_table().
sql/sql_show.cc:
Update acquire_high_priority_shared_lock() to use
TABLE_LIST::mdl_request rather than allocate an own.
Fix get_trigger_table_impl() to use init_one_table(),
check for out of memory, follow the coding style.
sql/sql_table.cc:
Update to work with TABLE_LIST::mdl_request by-value.
Remove lock_table_name_if_not_cached().
The code that used to delegate to it is quite simple and
concise without it now.
sql/sql_udf.cc:
Use init_one_table().
sql/sql_update.cc:
Update to use the new signature of close_tables_for_reopen().
sql/table.cc:
Move re-setting of mdl_requests for prepared statements
and stored procedures from close_thread_tables() to
reinit_stmt_before_use().
Change alloc_mdl_requests() to init_mdl_requests().
init_mdl_requests() is a hack that can't be deleted
until we don't have a list-aware TABLE_LIST constructor.
Hopefully its use will be minimal
sql/table.h:
Change alloc_mdl_requests() to init_mdl_requests()
TABLE_LIST::mdl_request is stored by value.
sql/tztime.cc:
We no longer initialize mdl requests in open_system_tables_for*()
functions. Move this initialization closer to initialization
of the rest of TABLE_LIST members.
storage/myisammrg/ha_myisammrg.cc:
Simplify mdl_request initialization.
2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1
- initial changeset that introduced the fix for
Bug#989 and follow up fixes for all test suite failures
introduced in the initial changeset.
------------------------------------------------------------
revno: 2617.31.1
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Fri 2009-03-06 19:17:00 -0300
message:
Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order
WL#4284: Transactional DDL locking
Currently the MySQL server does not keep metadata locks on
schema objects for the duration of a transaction, thus failing
to guarantee the integrity of the schema objects being used
during the transaction and to protect then from concurrent
DDL operations. This also poses a problem for replication as
a DDL operation might be replicated even thought there are
active transactions using the object being modified.
The solution is to defer the release of metadata locks until
a active transaction is either committed or rolled back. This
prevents other statements from modifying the table for the
entire duration of the transaction. This provides commitment
ordering for guaranteeing serializability across multiple
transactions.
- Incompatible change:
If MySQL's metadata locking system encounters a lock conflict,
the usual schema is to use the try and back-off technique to
avoid deadlocks -- this schema consists in releasing all locks
and trying to acquire them all in one go.
But in a transactional context this algorithm can't be utilized
as its not possible to release locks acquired during the course
of the transaction without breaking the transaction commitments.
To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be
returned if a lock conflict is encountered during a transaction.
Let's consider an example:
A transaction has two statements that modify table t1, then table
t2, and then commits. The first statement of the transaction will
acquire a shared metadata lock on table t1, and it will be kept
utill COMMIT to ensure serializability.
At the moment when the second statement attempts to acquire a
shared metadata lock on t2, a concurrent ALTER or DROP statement
might have locked t2 exclusively. The prescription of the current
locking protocol is that the acquirer of the shared lock backs off
-- gives up all his current locks and retries. This implies that
the entire multi-statement transaction has to be rolled back.
- Incompatible change:
FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ
LOCK won't cause locked tables to be implicitly unlocked anymore.
mysql-test/extra/binlog_tests/drop_table.test:
Add test case for Bug#989.
mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/include/mix1.inc:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/include/mix2.inc:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/r/flush_block_commit.result:
Update test case result (WL#4284).
mysql-test/r/flush_block_commit_notembedded.result:
Update test case result (WL#4284).
mysql-test/r/innodb.result:
Update test case result (WL#4284).
mysql-test/r/innodb_mysql.result:
Update test case result (WL#4284).
mysql-test/r/lock.result:
Add test case result for an effect of WL#4284/Bug#989
(all locks should be released when a connection terminates).
mysql-test/r/mix2_myisam.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/r/not_embedded_server.result:
Update test case result (effects of WL#4284/Bug#989).
Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES.
mysql-test/r/partition_innodb_semi_consistent.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/r/partition_sync.result:
Temporarily disable the test case for Bug#43867,
which will be fixed by a subsequent backport.
mysql-test/r/ps.result:
Add a test case for effect of PREPARE on transactional
locks: we take a savepoint at beginning of PREAPRE
and release it at the end. Thus PREPARE does not
accumulate metadata locks (Bug#989/WL#4284).
mysql-test/r/read_only_innodb.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_row_drop_tbl.result:
Add a test case result (WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result:
Add a test case result (WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_unsafe.result:
A side effect of Bug#989 -- slightly different table map ids.
mysql-test/suite/binlog/t/binlog_row_drop_tbl.test:
Add a test case for WL#4284/Bug#989.
mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test:
Add a test case for WL#4284/Bug#989.
mysql-test/suite/binlog/t/binlog_stm_row.test:
Update to the new state name. This
is actually a follow up to another patch for WL#4284,
that changes Locked thread state to Table lock.
mysql-test/suite/ndb/r/ndb_index_ordered.result:
Remove result for disabled part of the test case.
mysql-test/suite/ndb/t/disabled.def:
Temporarily disable a test case (Bug#45621).
mysql-test/suite/ndb/t/ndb_index_ordered.test:
Disable a part of a test case (needs update to
reflect semantics of Bug#989).
mysql-test/suite/rpl/t/disabled.def:
Disable tests made meaningless by transactional metadata
locking.
mysql-test/suite/sys_vars/r/autocommit_func.result:
Add a commit (Bug#989).
mysql-test/suite/sys_vars/t/autocommit_func.test:
Add a commit (Bug#989).
mysql-test/t/flush_block_commit.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/t/flush_block_commit_notembedded.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
Add a test case for transaction-scope locks and the global
read lock (Bug#989/WL#4284).
mysql-test/t/innodb.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction
(effects of Bug#989/WL#4284).
mysql-test/t/lock.test:
Add a test case for Bug#989/WL#4284.
mysql-test/t/not_embedded_server.test:
Add a test case for Bug#989/WL#4284.
mysql-test/t/partition_innodb_semi_consistent.test:
Replace TRUNCATE with DELETE, to not issue
an implicit commit of a transaction, and not depend
on metadata locks.
mysql-test/t/partition_sync.test:
Temporarily disable the test case for Bug#43867,
which needs a fix to be backported from 6.0.
mysql-test/t/ps.test:
Add a test case for semantics of PREPARE and transaction-scope
locks: metadata locks on tables used in PREPARE are enclosed into a
temporary savepoint, taken at the beginning of PREPARE,
and released at the end. Thus PREPARE does not effect
what locks a transaction owns.
mysql-test/t/read_only_innodb.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction
(Bug#989/WL#4284).
Wait for the read_only statement to actually flush tables before
sending other concurrent statements that depend on its state.
mysql-test/t/xa.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction
(Bug#989/WL#4284).
sql/ha_ndbcluster_binlog.cc:
Backport bits of changes of ha_ndbcluster_binlog.cc
from 6.0, to fix the failing binlog test suite with
WL#4284. WL#4284 implementation does not work
with 5.1 implementation of ndbcluster binlog index.
sql/log_event.cc:
Release metadata locks after issuing a commit.
sql/mdl.cc:
Style changes (WL#4284).
sql/mysql_priv.h:
Rename parameter to match the name used in the definition (WL#4284).
sql/rpl_injector.cc:
Release metadata locks on commit (WL#4284).
sql/rpl_rli.cc:
Remove assert made meaningless, metadata locks are released
at the end of the transaction.
sql/set_var.cc:
Close tables and release locks if autocommit mode is set.
sql/slave.cc:
Release metadata locks after a rollback.
sql/sql_acl.cc:
Don't implicitly unlock locked tables. Issue a implicit commit
at the end and unlock tables.
sql/sql_base.cc:
Defer the release of metadata locks when closing tables
if not required to.
Issue a deadlock error if the locking protocol requires
that a transaction re-acquire its locks.
Release metadata locks when closing tables for reopen.
sql/sql_class.cc:
Release metadata locks if the thread is killed.
sql/sql_parse.cc:
Release metadata locks after implicitly committing a active
transaction, or after explicit commits or rollbacks.
sql/sql_plugin.cc:
Allocate MDL request on the stack as the use of the table
is contained within the function. It will be removed from
the context once close_thread_tables is called at the end
of the function.
sql/sql_prepare.cc:
The problem is that the prepare phase of the CREATE TABLE
statement takes a exclusive metadata lock lock and this can
cause a self-deadlock the thread already holds a shared lock
on the table being that should be created.
The solution is to make the prepare phase take a shared
metadata lock when preparing a CREATE TABLE statement. The
execution of the statement will still acquire a exclusive
lock, but won't cause any problem as it issues a implicit
commit.
After some discussions with stakeholders it has been decided that
metadata locks acquired during a PREPARE statement must be released
once the statement is prepared even if it is prepared within a multi
statement transaction.
sql/sql_servers.cc:
Don't implicitly unlock locked tables. Issue a implicit commit
at the end and unlock tables.
sql/sql_table.cc:
Close table and release metadata locks after a admin operation.
sql/table.h:
The problem is that the prepare phase of the CREATE TABLE
statement takes a exclusive metadata lock lock and this can
cause a self-deadlock the thread already holds a shared lock
on the table being that should be created.
The solution is to make the prepare phase take a shared
metadata lock when preparing a CREATE TABLE statement. The
execution of the statement will still acquire a exclusive
lock, but won't cause any problem as it issues a implicit
commit.
sql/transaction.cc:
Release metadata locks after the implicitly committed due
to a new transaction being started. Also, release metadata
locks acquired after a savepoint if the transaction is rolled
back to the save point.
The problem is that in some cases transaction-long metadata locks
could be released before the transaction was committed. This could
happen when a active transaction was ended by a "START TRANSACTION"
or "BEGIN" statement, in which case the metadata locks would be
released before the actual commit of the active transaction.
The solution is to defer the release of metadata locks to after the
transaction has been implicitly committed. No test case is provided
as the effort to provide one is too disproportional to the size of
the fix.
----------------------------------------------------------
revno: 2617.23.20
committer: Konstantin Osipov <kostja@sun.com>
branch nick: mysql-6.0-runtime
timestamp: Wed 2009-03-04 16:31:31 +0300
message:
WL#4284 "Transactional DDL locking"
Review comments: "Objectify" the MDL API.
MDL_request and MDL_context still need manual construction and
destruction, since they are used in environment that is averse
to constructors/destructors.
sql/mdl.cc:
Improve comments.
Add asserts to backup()/restore_from_backup()/merge() methods.
Fix an order bug in the error path of mdl_acquire_exclusive_locks():
we used to first free a ticket object, and only then exclude
it from the list of tickets.
------------------------------------------------------------
revno: 2617.23.18
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Mon 2009-03-02 18:18:26 -0300
message:
Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order
WL#4284: Transactional DDL locking
This is a prerequisite patch:
These changes are intended to split lock requests from granted
locks and to allow the memory and lifetime of granted locks to
be managed within the MDL subsystem. Furthermore, tickets can
now be shared and therefore are used to satisfy multiple lock
requests, but only shared locks can be recursive.
The problem is that the MDL subsystem morphs lock requests into
granted locks locks but does not manage the memory and lifetime
of lock requests, and hence, does not manage the memory of
granted locks either. This can be problematic because it puts the
burden of tracking references on the users of the subsystem and
it can't be easily done in transactional contexts where the locks
have to be kept around for the duration of a transaction.
Another issue is that recursive locks (when the context trying to
acquire a lock already holds a lock on the same object) requires
that each time the lock is granted, a unique lock request/granted
lock structure structure must be kept around until the lock is
released. This can lead to memory leaks in transactional contexts
as locks taken during the transaction should only be released at
the end of the transaction. This also leads to unnecessary wake
ups (broadcasts) in the MDL subsystem if the context still holds
a equivalent of the lock being released.
These issues are exacerbated due to the fact that WL#4284 low-level
design says that the implementation should "2) Store metadata locks
in transaction memory root, rather than statement memory root" but
this is not possible because a memory root, as implemented in mysys,
requires all objects allocated from it to be freed all at once.
This patch combines review input and significant code contributions
from Konstantin Osipov (kostja) and Dmitri Lenev (dlenev).
mysql-test/r/mdl_sync.result:
Add test case result.
mysql-test/t/mdl_sync.test:
Add test case for shared lock upgrade case.
sql/event_db_repository.cc:
Rename mdl_alloc_lock to mdl_request_alloc.
sql/ha_ndbcluster_binlog.cc:
Use new function names to initialize MDL lock requests.
sql/lock.cc:
Rename MDL functions.
sql/log_event.cc:
The MDL request now holds the table and database name data (MDL_KEY).
sql/mdl.cc:
Move the MDL key to the MDL_LOCK structure in order to make the
object suitable for allocation from a fixed-size allocator. This
allows the simplification of the lists in the MDL_LOCK object,
which now are just two, one for granted tickets and other for
waiting (upgraders) tickets.
Recursive requests for a shared lock on the same object can now
be granted using the same lock ticket. This schema is only used
for shared locks because that the only case that matters. This
is used to avoid waste of resources in case a context (connection)
already holds a shared lock on a object.
sql/mdl.h:
Introduce a metadata lock object key which is used to uniquely
identify lock objects.
Separate the structure used to represent pending lock requests
from the structure used to represent granted metadata locks.
Rename functions used to manipulate locks requests in order to
have a more consistent function naming schema.
sql/sp_head.cc:
Rename mdl_alloc_lock to mdl_request_alloc.
sql/sql_acl.cc:
Rename alloc_mdl_locks to alloc_mdl_requests.
sql/sql_base.cc:
Various changes to accommodate that lock requests are separated
from lock tickets (granted locks).
sql/sql_class.h:
Last acquired lock before the savepoint was set.
sql/sql_delete.cc:
Various changes to accommodate that lock requests are separated
from lock tickets (granted locks).
sql/sql_handler.cc:
Various changes to accommodate that lock requests are separated
from lock tickets (granted locks).
sql/sql_insert.cc:
Rename alloc_mdl_locks to alloc_mdl_requests.
sql/sql_parse.cc:
Rename alloc_mdl_locks to alloc_mdl_requests.
sql/sql_plist.h:
Typedef for iterator type.
sql/sql_plugin.cc:
Rename alloc_mdl_locks to alloc_mdl_requests.
sql/sql_servers.cc:
Rename alloc_mdl_locks to alloc_mdl_requests.
sql/sql_show.cc:
Various changes to accommodate that lock requests are separated
from lock tickets (granted locks).
sql/sql_table.cc:
Various changes to accommodate that lock requests are separated
from lock tickets (granted locks).
sql/sql_trigger.cc:
Save reference to the lock ticket so it can be downgraded later.
sql/sql_udf.cc:
Rename alloc_mdl_locks to alloc_mdl_requests.
sql/table.cc:
Rename mdl_alloc_lock to mdl_request_alloc.
sql/table.h:
Separate MDL lock requests from lock tickets (granted locks).
storage/myisammrg/ha_myisammrg.cc:
Rename alloc_mdl_locks to alloc_mdl_requests.
------------------------------------------------------------
revno: 2630.4.33
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w2
timestamp: Fri 2008-06-20 17:11:20 +0400
message:
WL#3726 "DDL locking for all metadata objects".
After-review fixes in progress.
Minimized dependency of mdl.cc on other modules (particularly
made it independant of mysql_priv.h) in order to be able
write unit tests for metadata locking subsystem.
sql/ha_ndbcluster_binlog.cc:
Use newly introduced MAX_MDLKEY_LENGTH constant for allocating
buffer for object key for metadata locking subsystem.
sql/log_event.cc:
Use newly introduced MAX_MDLKEY_LENGTH constant for allocating
buffer for object key for metadata locking subsystem.
sql/mdl.cc:
Removed dependency on THD class (and thus on mysql_priv.h)
by using direct access to members of st_my_thread_var instead
of accessing THD::killed/enter_cond()/exit_cond().
sql/mdl.h:
Added MAX_MDLKEY_LENGTH constant to be used for allocating
buffers for key for metadata locking subsystem.
Added declarations of server kernel functions used by metadata
locking subsystem to mdl.h in order to decrease dependency of
mdl.cc on other files.
sql/mysql_priv.h:
Moved declaration of notify_thread_having_shared_lock() to the
mdl.h (also renamed it to make clear in metadata locking code
that it is a callback to SQL-layer).
sql/sql_base.cc:
Renamed notify_thread_having_shared_lock() to make it clear
in metadata locking subsystem code that it is a callback
to SQL layer.
sql/sql_handler.cc:
Use newly introduced MAX_MDLKEY_LENGTH constant for allocating
buffer for object key for metadata locking subsystem.
sql/sql_show.cc:
Use newly introduced MAX_MDLKEY_LENGTH constant for allocating
buffer for object key for metadata locking subsystem.
----------------------------------------------------------
revno: 2630.4.26
committer: Konstantin Osipov <konstantin@mysql.com>
branch nick: mysql-6.0-prelocked_mode-to-push
timestamp: Fri 2008-06-06 23:19:04 +0400
message:
WL#3726: work on review comments.
Remove thd->locked_tables. Always store MYSQL_LOCK instances in
thd->lock.
Rename thd->prelocked_mode to thd->locked_tables_mode.
Use thd->locked_tables_mode to determine if we
are under LOCK TABLES. Update the code to not assume that
if thd->lock is set, LOCK TABLES mode is off.
Review comments.
sql/ha_ndbcluster_binlog.cc:
Don't unlock the lock under LOCK TABLES (safety).
sql/handler.cc:
There is no thd->locked_tables any more.
Update comments.
sql/lock.cc:
There is no thd->locked_tables any more.
sql/log.cc:
Rename thd->prelocked_mode to thd->locked_tables_mode.
sql/set_var.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sp_head.cc:
Rename thd->prelocked_mode to thd->locked_tables_mode.
sql/sql_base.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
Remove thd->locked_tables.
sql/sql_cache.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sql_class.cc:
Avoid code duplication.
Do not release the table locks prematurely if we're under LOCK TABLES.
Use thd->locked_tables_mode instead of thd->locked_tables.
sql/sql_class.h:
Remove thd->locked_tables.
Make prelocked mode a kind of LOCK TABLES mode.
Update comments.
sql/sql_cursor.cc:
Update comments.
sql/sql_insert.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
Rename thd->prelocked_mode to thd->locked_tables_mode.
sql/sql_load.cc:
Rename thd->prelocked_mode to thd->locked_tables_mode.
sql/sql_parse.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
Remove thd->locked_tables.
sql/sql_partition.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sql_rename.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sql_select.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sql_table.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sql_trigger.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sql_update.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
sql/sql_view.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
storage/myisam/ha_myisam.cc:
Use thd->locked_tables_mode to determine if we are under LOCK TABLES.
------------------------------------------------------------
revno: 2630.4.17
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w2
timestamp: Thu 2008-05-29 16:52:56 +0400
message:
WL#3726 "DDL locking for all metadata objects".
After review fixes in progress.
"The great correction of names".
Renamed MDL_LOCK and MDL_LOCK_DATA classes to make usage of
these names in metadata locking subsystem consistent with
other parts of server (i.e. thr_lock.cc). Now we MDL_LOCK_DATA
corresponds to request for a lock and MDL_LOCK to the lock
itself. Adjusted code in MDL subsystem and other places
using these classes accordingly.
Did similar thing for GLOBAL_MDL_LOCK_DATA class and also
changed name of its members to correspond to names of
MDL_LOCK_DATA members.
Finally got rid of usage of one letter variables in MDL
code since it makes code harder to search in (according
to reviewer).
------------------------------------------------------------
revno: 2630.4.11
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Tue 2008-05-27 21:31:53 +0400
message:
WL#3726 "DDL locking for all metadata objects".
After review fixes in progress.
Changed mysql_lock_tables() to be no longer responsible for
reopening table if waiting for the lock on it was aborted.
This allows to get rid of several annoying functions.
sql/ha_ndbcluster_binlog.cc:
lock_tables() now also accepts set of options to be passed to
mysql_lock_tables().
sql/lock.cc:
Changed mysql_lock_tables() always requests caller to reopen
table instead doing this on its own when waiting for lock was
aborted. This allows us to get rid of several functions which
were used in rare cases and significantly complicated our life.
sql/log_event_old.cc:
lock_tables() now also accepts set of options to be passed
to mysql_lock_tables().
sql/mysql_priv.h:
Now mysql_lock_tables() always requests caller to reopen
table instead doing this on its own when waiting for lock was
aborted. So we no longer need wait_for_tables() and
table_is_used() functions and MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN
flag.
open_and_lock_table_derived() and lock_tables() now accept
options to be passed to open_tables() and mysql_lock_tables()
calls.
sql/sql_base.cc:
Since now mysql_lock_tables() always requests caller to
reopen table instead doing this on its own when waiting for
lock was aborted we no longer need wait_for_tables(),
table_is_used() and close_old_data_files() functions.
open_and_lock_table_derived() and lock_tables() now accept
options to be passed to open_tables() and mysql_lock_tables()
calls. This was needed in order to get rid of redundant code
in open_system_tables_for_read() function.
sql/sql_handler.cc:
mysql_lock_tables() is now always requests reopen if waiting
for lock is aborted. MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN flag
was removed.
sql/sql_insert.cc:
handle_delayed_insert():
Since mysql_lock_tables() is no longer responsible for
reopening tables when waiting for lock was aborted we have
to handle such situation outside of this function. To simplify
this extracted code opening table for delayed insert thread to
separate method of Delayed_insert class.
sql/sql_update.cc:
lock_tables() now also accepts set of options to be passed
to mysql_lock_tables().
