The task is to
(a) add a comment on indexes and
(b) increase the maximum length of column, table and the new index comments.
The patch committed on behalf of Yoshinori Matsunobu (Yoshinori.Matsunobu@Sun.COM).
an INFORMATION_SCHEMA table
When a prepared statement using a merged view containing an information
schema table was executed, a metadata lock of the view was not taken.
This meant that it was possible for concurrent view DDL to execute,
thereby breaking the binary log. For example, it was possible
for DROP VIEW to appear in the binary log before a query using the view.
This also happened when a statement in a stored routine was executed a
second time.
For such views, the information schema table is merged into the view
during the prepare phase (or first execution of a statement in a routine).
The problem was that we took a short cut and were not executing full-blown
view opening during subsequent executions of the statement. As a result,
a metadata lock on the view was not taken to protect the view definition.
This patch resolves the problem by making sure a metadata lock is taken
for views even after information schema tables are merged into them.
Test cased added to view.test.
The problem was that a shared InnoDB row lock was taken when executing
SELECT statements inside a stored function as a part of a transaction
using REPEATABLE READ. This prevented other transactions from updating
the row.
InnoDB uses multi-versioning and consistent nonlocking reads. SELECTs
should therefore not acquire locks and block other transactions
wishing to do updates.
This bug is no longer repeatable with the changes introduced in the scope
of metadata locking.
Test case added to innodb_mysql.test.
WL#5154 was a task for formally deprecating and removing items that
were mentioned in the manual as having been deprecated since MySQL
4.1 or 5.0, but that had never been removed.
Since WL#5154 was created, examination of mysqld.cc, mysql.cc, and
mysqldump.c reveals additional deprecations not mentioned in the
manual. (In some cases, the items are simply not mentioned in the
5.1+ manuals.)
This is a follow-on task to deprecate and remove these additional
items.
The deprecation happened in MySQL 5.1, and the options/variables
are now removed from the code.
client/mysql.cc:
--no-tee is now removed
client/mysqldump.c:
--all is now removed
-a now points to --create-options
sql/mysqld.cc:
delay-key-write-for-all-tables is removed
--enable-locking is removed
--log-update is removed
--skip-locking is removed
--skip-symlink is removed
--sql-bin-update-same is removed
--warnings is removed
--record-buffer is removed
A set of program options and variables was deprecated in
MySQL 5.1, and is hereby removed.
client/mysql.cc:
--no-auto-rehash (-A) is no longer deprecated
--no-named-commands (-g) is now removed
--skip-line-numbers (-L) is no longer deprecated
--set-variable (-O) is now removed
--no-pager is now removed
client/mysqlbinlog.cc:
--position is now removed (use --start-position)
-j is now equivalent with --start-position
client/mysqldump.c:
--first-slave is now removed
--no-set-names (-N) is now removed
--set-variable (-O) is now removed
mysql-test/include/default_mysqld.cnf:
default-character-set is removed as an option
character-set-server is equivalent.
mysql-test/t/bug47671-master.opt:
default-character-set option is removed
character-set-server is equivalent
mysql-test/t/ctype_latin1_de-master.opt:
default-character-set option is removed
character-set-server is equivalent
mysql-test/t/ctype_ucs2_def-master.opt:
default-collation is removed
collation-server is equicalent
scripts/mysqld_multi.sh:
--config-file has been superseded by
--defaults-extra-file
sql/mysql_priv.h:
Removed the version number in the deprecation
warning text, as decided by ServerPT.
sql/mysqld.cc:
--default-character-set (-C) is removed
--default-collation is removed
--log-long-format (-0) is removed
--safe-show-database is removed
--set-variable (-O) is removed
sql/sql_yacc.yy:
The FRAC_SECOND keyword is removed
sql/sys_vars.cc:
The sql_log_update system variable is removed
If a prepared statement used both a MyISAMMRG table and a stored
function or trigger, execution could fail with "No such table"
error or crash.
The error would come from a failure of the MyISAMMRG engine
to meet the expectations of the prelocking algorithm,
in particular maintain lex->query_tables_own_last pointer
in sync with lex->query_tables_last pointer/the contents
of lex->query_tables. When adding merge children, the merge
engine would extend the table list. Then, when adding
prelocked tables, the prelocking algorithm would use a pointer
to the last merge child to assign to lex->query_tables_own_last.
Then, when merge children were removed at the end of
open_tables(), lex->query_tables_own_last
was not updated, and kept pointing
to a removed merge child.
The fix ensures that query_tables_own_last is always in
sync with lex->query_tables_last.
This is a regression introduced by WL#4144 and present only
in next-4284 tree and 6.0.
mysql-test/r/merge.result:
Update results (Bug#47648).
mysql-test/t/merge.test:
Add a test case for Bug#47648.
Update the result file to reflect a fix of another bug
in MyISAMMRG code: not maintaining lex->query_tables_own_last
allowed a stored function or trigger to modify a merge table
which was already updated by the main statement.
It is not allowed for other storage engines, and should
not be allowed for MyISAMMRG.
storage/myisammrg/ha_myisammrg.cc:
When adding children to the list of tables to open,
make sure that we properly set lex->query_tables_own_last.
When removing the children, update lex->query_tables_own_last
if necessary.
This patch removes the unused server variable
"table_lock_wait_timeout".
mysql-test/r/variables.result:
Updated the test for Bug#28580 to reflect that
"table_lock_wait_timeout" no longer exists.
mysql-test/t/variables.test:
Updated the test for Bug#28580 to reflect that
"table_lock_wait_timeout" no longer exists.
TEMPORARY + HANDLER + LOCK + SP".
Server crashed when one:
1) Opened HANDLER or acquired global read lock
2) Then locked one or several temporary tables with
LOCK TABLES statement (but no base tables).
3) Then issued any statement causing commit (explicit
or implicit).
4) Issued statement which should have closed HANDLER
or released global read lock.
The problem was that when entering LOCK TABLES mode in the
scenario described above we incorrectly set transactional
MDL sentinel to zero. As result during commit all metadata
locks were released (including lock for open HANDLER or
global metadata shared lock). Indeed, attempt to release
metadata lock for the second time which happened during
HANLDER CLOSE or during release of GLR caused crash.
This patch fixes problem by changing MDL_context's
set_trans_sentinel() method to set sentinel to correct
value (it should point to the most recent ticket).
mysql-test/include/handler.inc:
Added test for bug #51136 "Crash in pthread_rwlock_rdlock on
TEMPORARY + HANDLER + LOCK + SP".
mysql-test/r/flush.result:
Updated test results (see flush.test).
mysql-test/r/handler_innodb.result:
Updated test results (see include/handler.inc).
mysql-test/r/handler_myisam.result:
Updated test results (see include/handler.inc).
mysql-test/t/flush.test:
Added additional coverage for bug #51136 "Crash in
pthread_rwlock_rdlock on TEMPORARY + HANDLER + LOCK +
SP".
sql/mdl.h:
When setting new value of transactional sentinel use
pointer to the most recent ticket instead of value
returned by MDL_context::mdl_savepoint().
This allows to handle correctly situation when the new
value of sentinel should be the same as its current value
(MDL_context::mdl_savepoint() returns NULL in this case).
DDL workload".
When a RENAME TABLE or LOCK TABLE ... WRITE statement which
mentioned the same table several times were aborted during
the process of acquring metadata locks (due to deadlock
which was discovered or because of KILL statement) server
might have crashed.
When attempt to acquire all locks requested had failed we
went through the list of requests and released locks which
we have managed to acquire by that moment one by one. Since
in the scenario described above list of requests contained
duplicates this led to releasing the same ticket twice and
a crash as result.
This patch solves the problem by employing different approach
to releasing locks in case of failure to acquire all locks
requested.
Now we take a MDL savepoint before starting acquiring locks
and simply rollback to it if things go bad.
mysql-test/r/lock_multi.result:
Updated test results (see lock_multi.test).
mysql-test/t/lock_multi.test:
Added test case for bug #51134 "Crash in MDL_lock::destroy
on a concurrent DDL workload".
sql/mdl.cc:
MDL_context::acquire_locks():
When attempt to acquire all locks requested has failed do
not go through the list of requests and release locks which
we have managed to acquire one by one.
Since list of requests can contain duplicates such approach
may lead to releasing the same ticket twice and a crash as
result.
Instead use the following approach - take a MDL savepoint
before starting acquiring locks and simply rollback to it
if things go bad.
function with distinct.
Loose index scan is used to find MIN/MAX values using appropriate index and
thus allow to avoid grouping. For each found row it updates non-aggregated
fields with values from row with found MIN/MAX value.
Without loose index scan non-aggregated fields are copied by end_send_group
function. With loose index scan there is no need in end_send_group and
end_send is used instead. Non-aggregated fields still need to be copied and
this was wrongly implemented in QUICK_GROUP_MIN_MAX_SELECT::get_next.
WL#3220 added a case when loose index scan can be used with end_send_group to
optimize calculation of aggregate functions with distinct. In this case
the row found by QUICK_GROUP_MIN_MAX_SELECT::get_next might belong to a next
group and copying it will produce wrong result.
Update of non-aggregated fields is moved to the end_send function from
QUICK_GROUP_MIN_MAX_SELECT::get_next.
mysql-test/r/group_min_max.result:
Added a test case for the bug#50539.
mysql-test/t/group_min_max.test:
Added a test case for the bug#50539.
sql/opt_range.cc:
Bug#50539: Wrong result when loose index scan is used for an aggregate
function with distinct.
Update of non-aggregated fields is moved to the end_send function from
QUICK_GROUP_MIN_MAX_SELECT::get_next.
sql/sql_select.cc:
Bug#50539: Wrong result when loose index scan is used for an aggregate
function with distinct.
Update of non-aggregated fields is moved to the end_send function from
QUICK_GROUP_MIN_MAX_SELECT::get_next.
failed in enter_locked_tables_mode".
Server was aborted due to assertion failure when one tried to
execute statement requiring prelocking (i.e. firing triggers
or using stored functions) while having open HANDLERs.
The problem was that THD::enter_locked_tables_mode() method
which was called at the beginning of execution of prelocked
statement assumed there are no open HANDLERs. It had to do
so because corresponding THD::leave_locked_tables_mode()
method was unable to properly restore MDL sentinel when
leaving LOCK TABLES/prelocked mode in the presence of open
HANDLERs.
This patch solves this problem by changing the latter method
to properly restore MDL sentinel and thus removing need for
this assumption. As a side-effect, it lifts unjustified
limitation by allowing to keep HANDLERs open when entering
LOCK TABLES mode.
mysql-test/include/handler.inc:
Adjusted tests after making LOCK TABLES not to close
open HANDLERs. Added coverage for bug #50908
"Assertion `handler_tables_hash.records == 0' failed
in enter_locked_tables_mode".
mysql-test/r/handler_innodb.result:
Updated test results (see include/handler.inc).
mysql-test/r/handler_myisam.result:
Updated test results (see include/handler.inc).
sql/mysql_priv.h:
Introduced mysql_ha_move_tickets_after_trans_sentinel()
routine which allows to move tickets for metadata locks
corresponding to open HANDLERs after transaction sentinel.
sql/sql_class.cc:
Changed THD::leave_locked_tables_mode() to correctly restore
MDL sentinel value in the presence of open HANDLERs.
sql/sql_class.h:
Removed assert from THD::enter_locked_tables_mode() as we
no longer have to close HANDLERs when entering LOCK TABLES
or prelocked modes. Instead we keep them open and correctly
restore MDL sentinel value after leaving them.
Removal of assert also fixes problem from the bug report.
sql/sql_handler.cc:
Introduced mysql_ha_move_tickets_after_trans_sentinel()
routine which allows to move tickets for metadata locks
corresponding to open HANDLERs after transaction sentinel.
sql/sql_parse.cc:
We no longer have to close HANDLERs when entering LOCK TABLES
mode. Instead we keep them open and simply correctly restore
MDL sentinel value after leaving this mode.
causing crashes!
Adding a SPATIAL INDEX on a non-geometrical column caused a
segmentation fault when the table was subsequently
inserted into.
A test was added in mysql_prepare_create_table to explicitly
check whether non-geometrical columns are used in a
spatial index, and throw an error if so.
mysql-test/t/gis.test:
Added test cases to verify that only geometrical
columns can get a spatial index.
In addition, verify that only a single geom.
column can participate in a spatial index.
corruption and crash results
An index creation statement where the index key
is larger/wider than the column it references
should throw an error.
A statement like:
CREATE TABLE t1 (a CHAR(1), PRIMARY KEY (A(255)))
did not error, but a segmentation fault followed when
an insertion was attempted on the table
The partial key validiation clause has been
restructured to (hopefully) better document which
uses of partial keys are valid.
This patch introduces timeouts for metadata locks.
The timeout is specified in seconds using the new dynamic system
variable "lock_wait_timeout" which has both GLOBAL and SESSION
scopes. Allowed values range from 1 to 31536000 seconds (= 1 year).
The default value is 1 year.
The new server parameter "lock-wait-timeout" can be used to set
the default value parameter upon server startup.
"lock_wait_timeout" applies to all statements that use metadata locks.
These include DML and DDL operations on tables, views, stored procedures
and stored functions. They also include LOCK TABLES, FLUSH TABLES WITH
READ LOCK and HANDLER statements.
The patch also changes thr_lock.c code (table data locks used by MyISAM
and other simplistic engines) to use the same system variable.
InnoDB row locks are unaffected.
One exception to the handling of the "lock_wait_timeout" variable
is delayed inserts. All delayed inserts are executed with a timeout
of 1 year regardless of the setting for the global variable. As the
connection issuing the delayed insert gets no notification of
delayed insert timeouts, we want to avoid unnecessary timeouts.
It's important to note that the timeout value is used for each lock
acquired and that one statement can take more than one lock.
A statement can therefore block for longer than the lock_wait_timeout
value before reporting a timeout error. When lock timeout occurs,
ER_LOCK_WAIT_TIMEOUT is reported.
Test case added to lock_multi.test.
include/my_pthread.h:
Added macros for comparing two timespec structs.
include/thr_lock.h:
Introduced timeouts for thr_lock.c locks.
mysql-test/r/mysqld--help-notwin.result:
Updated result file with the new server variable.
mysql-test/r/mysqld--help-win.result:
Updated result file with the new server variable.
mysql-test/suite/sys_vars/r/lock_wait_timeout_basic.result:
Added basic test for the new server variable.
mysql-test/suite/sys_vars/t/lock_wait_timeout_basic.test:
Added basic test for the new server variable.
mysys/thr_lock.c:
Introduced timeouts for thr_lock.c locks.
sql/mdl.cc:
Introduced timeouts for metadata locks.
sql/mdl.h:
Introduced timeouts for metadata locks.
sql/sql_base.cc:
Introduced timeouts in tdc_wait_for_old_versions().
sql/sql_class.h:
Added new server variable lock_wait_timeout.
sql/sys_vars.cc:
Added new server variable lock_wait_timeout.
rqg_mdl_stability".
When start of statement's waiting on a metadata lock
created more than one loop in waiters graph server might
have entered deadlock condition.
The problem was that in the case described above MDL deadlock
detector had to perform several searches for deadlock but
forgot to reset Deadlock_detection_context before performing
new search.
Failure to do so has broken assumption in code resposible for
choosing victim that if Deadlock_detection_context::victim
is set we also have read lock on m_waiting_for_lock for this
context. As result this lock could have been unlocked more
times than it was acquired which corrupted rwlock's state
which led to server deadlock.
This fix ensures that such reset is done before each attempt
to find a deadlock.
mysql-test/r/mdl_sync.result:
Added test for bug #50998 "Deadlock in MDL code during test
rqg_mdl_stability" as well as coverage for the case when
addition of statement waiting for metadata lock adds several
loops in the waiters graph and therefore several searches
for deadlock should be performed by MDL deadlock detector.
mysql-test/t/mdl_sync.test:
Added test for bug #50998 "Deadlock in MDL code during test
rqg_mdl_stability" as well as coverage for the case when
addition of statement waiting for metadata lock adds several
loops in the waiters graph and therefore several searches
for deadlock should be performed by MDL deadlock detector.
sql/mdl.cc:
Ensure that in cases when MDL deadlock detector had to
perform several searches for deadlock because several loops
in waiters graph are possible we reset
Deadlock_detection_context before performing each search.
Failure to do so has broken assumption in code resposible
for choosing victim that if Deadlock_detection_context::victim
is set we also have read lock on m_waiting_for_lock for this
context. As result this lock could have been unlocked more
times than it was acquired which corrupted rwlock's state
(no one was able to acquire write lock on it anymore).
and MDL".
Concurrent execution of a multi-DELETE statement and ALTER
TABLE statement which affected one of the tables used in
the multi-DELETE sometimes led to deadlock.
Similar deadlocks might have occured when one performed
INSERT/UPDATE/DELETE on a view and concurrently executed
ALTER TABLE for the view's underlying table, or when one
concurrently executed TRUNCATE TABLE for InnoDB table and
ALTER TABLE for the same table.
These deadlocks were caused by a discrepancy between types of
metadata and thr_lock.cc locks acquired by those statements.
What happened was that multi-DELETE/TRUNCATE/DML-through-the-
view statement in the first connection acquired SR lock on a
table, then ALTER TABLE would come in in the second connection
and acquire SNW metadata lock and TL_WRITE_ALLOW_READ
thr_lock.c lock and then would start waiting for the first
connection during lock upgrade. After that the statement in
the first connection would try to acquire TL_WRITE lock on
table and would start waiting for the second connection,
creating a deadlock.
This patch solves this problem by ensuring that we acquire
SW metadata lock in all cases in which we acquiring write
thr_lock.c lock. This guarantees that deadlocks like the
one described above won't occur since all lock conflicts
in such situation are resolved within MDL subsystem.
This patch also adds assert which should guarantee that
such situations won't arise in future.
mysql-test/r/lock_multi.result:
Added main test for bug #50913 "Deadlock between
open_and_lock_tables_derived and MDL".
mysql-test/r/mdl_sync.result:
Added additional coverage for bug #50913 "Deadlock
between open_and_lock_tables_derived and MDL".
mysql-test/t/lock_multi.test:
Added main test for bug #50913 "Deadlock between
open_and_lock_tables_derived and MDL".
mysql-test/t/mdl_sync.test:
Added additional coverage for bug #50913 "Deadlock
between open_and_lock_tables_derived and MDL".
sql/lock.cc:
Added assert that enforces that when we are locking
a non-temporary table we have an appropriate type of
metadata lock on this table.
sql/mysql_priv.h:
Added separate flag for open_tables() to be able specify that
SH metadata locks on table to be open should be acquired.
We can no longer use MYSQL_LOCK_IGNORE_FLUSH flag for this
as in addition to use in I_S implementation it is also used
for opening system tables. Since in the latter case we also
acquire thr_lock.c locks using SH metadata lock in it instead
of SR or SW locks may lead to deadlock.
sql/sql_base.cc:
When opening tables don't interpret MYSQL_LOCK_IGNORE_FLUSH
flag as request to acquire SH metadata locks. This flag is
also used for opening system tables for which we also take
thr_lock.c locks and thus proper metadata lock to take in
this case is SR or SW lock (otherwise deadlocks can occur).
In cases when SH lock is really required (e.g. when tables
are open by I_S implementation) we rely on that newly
introduced MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL flag is
used.
sql/sql_delete.cc:
mysql_truncate_by_delete():
Adjust type of metadata lock to be requested after changing
type of thr_lock.c lock for table list element from one
which was set in parser to TL_WRITE.
This removes discrepancy between types of these locks which
allowed deadlocks to creep in.
sql/sql_handler.cc:
When closing table which was open by HANDLER statement clear
TABLE::open_by_handler flag. This allows to use this flag as
a reliable indication that TABLE instance was open by HANDLER
statement in assert which was added to mysql_lock_tables().
sql/sql_parse.cc:
multi_delete_set_locks_and_link_aux_tables():
Adjust type of metadata lock to be requested after changing
type of thr_lock.c lock for table list element from one
which was set in parser to TL_WRITE.
This removes discrepancy between types of these locks which
allowed deadlocks to creep in.
sql/sql_show.cc:
Use newly introduced MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL
flag in order to acquire SH metadata locks when opening tables
in I_S implementation.
sql/sql_update.cc:
Added comment explaining why in multi-update after deciding
that we need weaker thr_lock.c lock on a table we don't
downgrade metadata lock on it.
sql/sql_view.cc:
When merging view into main statement adjust type of metadata
lock to be requested after changing type of thr_lock.c lock
for table. This removes discrepancy between types of these
locks which allowed deadlocks to creep in.
mysql-test/t/disabled.def:
Restore disabled ssl tests: SSL certificates were updated.
Disable sp_sync.test, the test case can't work in next-4284.
mysql-test/t/partition_innodb.test:
Disable parsing of the test case for Bug#47343,
the test can not work in next-4284.
mysql-test/t/ps_ddl.test:
Update results (CREATE TABLE IF NOT EXISTS takes
into account existence of the temporary table).
