TO POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
ALTER TABLE MODIFY/CHANGE ... FIRST did nothing except renaming
columns if new version of the table had exactly the same
structure as the old one (i.e. as result of such statement, names
of columns changed their order as specified but data in columns
didn't). The same thing happened for ALTER TABLE DROP COLUMN/ADD
COLUMN statements which were supposed to produce new version of
table with exactly the same structure as the old version of table.
I.e. in the latter case the result was the same as if old column
was renamed instead of being dropped and new column with default
as value being created.
Both these problems were caused by the fact that ALTER TABLE
implementation incorrectly interpreted both these situations as
simple renaming of columns and assumed that in-place ALTER TABLE
algorithm could have been used for them.
This patch fixes this problem by ensuring that in cases when some
column is moved to the first position or some column is dropped
the default ALTER TABLE algorithm involving table copying is
always used. This is achieved by detecting such situations in
mysql_prepare_alter_table() and setting Alter_info::change_level
to ALTER_TABLE_DATA_CHANGED for them.
mysql-test/r/alter_table.result:
Added test for bug #12652385 - "61493: REORDERING COLUMNS TO
POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
mysql-test/t/alter_table.test:
Added test for bug #12652385 - "61493: REORDERING COLUMNS TO
POSITION FIRST CAN CAUSE DATA TO BE CORRUPTED".
sql/sql_table.cc:
Changed mysql_prepare_alter_table() to detect situations in
which we some column moved to the first position or some column
is dropped and ensure that such ALTER TABLE statements won't
be carried out using in-place algorithm. The latter could have
happened before this patch if new version of table had the same
structure as the old one (except the column names).
Bug 12430414 - THE TEST PERFSCHEMA.SELECTS.TEST CAN AFFECT SUCCEEDING TESTS
Bug 12430599 - THE TEST PERFSCHEMA.ONE_THREAD_PER_CON. CAN AFFECT SUCCEEDING TESTS
Bug 12431153 - THE TEST PERFSCHEMA.PFS_UPGRADE CAN AFFECT SUCCEEDING TEST
GRADUALLY IF A TRIGGER EXISTS".
This bug manifested itself in two ways:
- Firstly execution of any data-changing statement which
required prelocking (i.e. involved stored function or
trigger) as part of transaction slowed down a bit all
subsequent statements in this transaction. So performance
in transaction which periodically involved such statements
gradually degraded over time.
- Secondly execution of any data-changing statement which
required prelocking as part of transaction prevented
concurrent FLUSH TABLES WITH READ LOCK from proceeding
until the end of transaction instead of end of particular
statement.
The problem was caused by incorrect handling of metadata lock
used in FTWRL implementation for statements requiring prelocked
mode.
Each statement which changes data acquires global IX lock
with STATEMENT duration. This lock is supposed to block
concurrent FTWRL from proceeding until the statement ends.
When entering prelocked mode, durations of all metadata locks
acquired so far were changed to EXPLICIT, to prevent
substatements from releasing these locks. When prelocked mode
was left, durations of metadata locks were changed to
TRANSACTIONAL (with a few exceptions) so they can be properly
released at the end of transaction.
Unfortunately, this meant that the global IX lock blocking
FTWRL with STATEMENT duration was moved to TRANSACTIONAL
duration after execution of statement requiring prelocking.
Since each subsequent statement that required prelocking and
tried to acquire global IX lock with STATEMENT duration got
a new instance of MDL_ticket, which was later moved to
TRANSACTIONAL duration, this led to unwarranted growth of
number of tickets with TRANSACITONAL duration in this
connection's MDL_context. As result searching for other
tickets in it became slow and acquisition of other metadata
locks by this transaction started to hog CPU.
Moreover, this also meant that after execution of statement
requiring prelocking concurrent FTWRL was blocked
until the end of transaction instead of end of statement.
This patch solves this problem by not moving locks to EXPLICIT
duration when thread enters prelocked mode (unless it is a real
LOCK TABLES mode). This step turned out to be not really
necessary as substatements don't try to release metadata locks.
Consequently, the global IX lock blocking FTWRL keeps its
STATEMENT duration and is properly released at the end of
statement and the above issue goes away.
mysql-test/r/flush.result:
Added test for bug #12641342 - "61401: UPDATE PERFORMANCE
DEGRADES GRADUALLY IF A TRIGGER EXISTS".
mysql-test/t/flush.test:
Added test for bug #12641342 - "61401: UPDATE PERFORMANCE
DEGRADES GRADUALLY IF A TRIGGER EXISTS".
sql/mdl.h:
Added comment describing various types of metadata lock
duration.
sql/sql_class.cc:
Since we no longer change duration of metadata locks to EXPLICIT
when entering prelocked mode (unless it is a real LOCK TABLES)
there is no need to restore proper duration of the locks when
leaving prelocked mode.
sql/sql_class.h:
Do not change duration of metadata locks to EXPLICIT when
entering prelocking mode (unless it is a real LOCK TABLES).
This allows to avoid problems with restoring correct duration
when leaving this mode. It is possible to do this as
substatements won't release metadata locks in any case.
sql/sql_parse.cc:
Added assert checking that we won't release metadata locks
when in substatement.
Issue:
------
New test case mysql_embedded.test was failing on pb2.
Description:
------------
To run this test case executable libmysqld/examples/mysql_embedded is required.
But as per /libmysqld/examples/cmake_install.cmake this executable doesn't get
copied to <install_dir> when mysql is installed at <install_dir>.That is the
reason it was passing in my local branch and failed on pb2 when pushed.
Solution;
---------
Added code in mysql-test-run.pl, which will try to see if this file exists.If
It doesn't exist, test case will be skipped with a skip message. New code in
mysql-test-run.pl looks only for directory libmysqld/examples/mysql_embedded
because this is the only place where this file could/does exist.
mysql-test/mysql-test-run.pl:
Added new variable for mysql_embedded executable.
mysql-test/t/disabled.def:
enabled mysql_embedded.test which was disabled earlier.
mysql-test/t/mysql_embedded.test:
Modified test case to first verify if mysql_embedded executable exists. If
it does not, skip the test.
UPDATED TWICE
For multi update it is not allowed to update a column
of a table if that table is accessed through multiple aliases
and either
1) the updated column is used as partitioning key
2) the updated column is part of the primary key
and the primary key is clustered
This check is done in unsafe_key_update().
The bug was that for case 2), it was checked whether
updated_column_number == table_share->primary_key
However, the primary_key variable is the index number of the
primary key, not a column number.
Prior to this bugfix, the first column was wrongly believed to be
the primary key. The columns covered by an index is found in
table->key_info[idx_number]->key_part. The bugfix is to check if
any of the columns in the keyparts of the primary key are
updated.
The user-visible effect is that for storage engines with
clustered primary key (e.g. InnoDB but not MyISAM) queries
like
"UPDATE t1 AS A JOIN t2 AS B SET A.primkey=..."
will now error with
"ERROR HY000: Primary key/partition key update is not allowed
since the table is updated both as 'A' and 'B'."
instead of
"ERROR 1032 (HY000): Can't find record in 't1_tb'"
even if primkey is not the first column in the table. This
was the intended behavior of bugfix 11764529.
mysql-test/r/multi_update.result:
Add test for bug#11882110
mysql-test/r/multi_update_innodb.result:
Add test for bug#11882110
mysql-test/t/multi_update.test:
Add test for bug#11882110
mysql-test/t/multi_update_innodb.test:
Add test for bug#11882110
sql/sql_update.cc:
unsafe_key_update() wrongly checked if the primary key index
number was the same as updated column number. Now it is checked
whether any of the columns making up the primary key is updated.
sql/table.h:
Fix comment on TABLE_SHARE::primary_key. Incorrect comment
was introduced by an earlier merge conflict (as per dlenev)
Issue:
When libmysqld/example/mysql_embedded is executed, it was getting abort. Its a
regression as it was working in 5.1 and failed in 5.5. Issue is there because
remaining_argc/remaining_argv were not getting assigned correctly in
init_embedded_server() which were being used later in init_common_variable().
Solution:
Rectified code to pass correct argc/argv to be used in init_common_variable().
libmysqld/lib_sql.cc:
Rectified remaining_argc/remaining_argv assignment.
mysql-test/r/mysql_embedded.result:
Result file for the test case added.
mysql-test/t/mysql_embedded.test:
Added test case to verify libmysqld/example/mysql_embedded works.
This test case was failing on 5.5 and trunk for two reasons.
1) It waited for the "Waiting for table level lock" process
state while this state was renamed "Waiting for table
metadata lock" with the introduction of MDL in 5.5.
2) SET GLOBAL query_cache_size= 100000; gave a warning since
query_cache_size is supposed to be multiples of 1024.
This patch fixes these two issues and re-enables the test case.
RESULT CONSISTED OF MORE THAN ONE ROW
MySQL converts incorrect DATEs and DATETIMEs to '0000-00-00' on
insertion by default. This means that this sequence is possible:
CREATE TABLE t1(date_notnull DATE NOT NULL);
INSERT INTO t1 values (NULL);
SELECT * FROM t1;
0000-00-00
At the same time, ODBC drivers do not (or at least did not in the
90's) understand the DATE and DATETIME value '0000-00-00'. Thus,
to be able to query for the value 0000-00-00 it was decided in
MySQL 4.x (or maybe even before that) that for the special case
of DATE/DATETIME NOT NULL columns, the query "SELECT ... WHERE
date_notnull IS NULL" should return rows with date_notnull ==
'0000-00-00'. This is documented misbehavior that we do not want
to change.
The hack used to make MySQL return these rows is to convert
"date_notnull IS NULL" to "date_notnull = 0". This is, however,
only done if the table date_notnull belongs to is not an inner
table of an outer join. The rationale for this seems to be that
if there is no join match for the row in the outer table,
null-complemented rows would otherwise not be returned because
the null-complemented DATE value is actually NULL. On the other
hand, this means that the "return rows with 0000-00-00 when the
query asks for IS NULL"-hack is not in effect for outer joins.
In this bug, we have a LEFT JOIN that does not misbehave like
the documentation says it should. The fix is to rewrite
"date_notnull IS NULL" to "date_notnull IS NULL OR
date_notnull = 0"
if dealing with an OUTER JOIN, otherwise
"date_notnull IS NULL" to "date_notnull = 0"
as was done before.
Note:
The bug was originally reported as different result on first
and second execution of SP. The reason was that during first
execution the query was correctly rewritten to an inner join
due to a null-rejecting predicate. On second execution the
"IS NULL" -> "= 0" rewrite was done because there was no outer
join. The real problem, though, was incorrect date/datetime
IS NULL handling for OUTER JOINs.
mysql-test/r/type_datetime.result:
Add test for BUG#12561818
mysql-test/t/type_datetime.test:
Add test for BUG#12561818
sql/sql_select.cc:
Special handling of NULL for DATE/DATETIME NOT NULL columns:
In the case of outer join,
"date_notnull IS NULL"
is now rewritten to
"date_notnull IS NULL OR date_notnull = 0"
SYNTAX TRIGGERS IN ANY WAY
Table with triggers which were using deprecated (5.0-only) syntax became
unavailable for any DML and DDL after upgrade to 5.1 version of server.
Attempt to execute any statement on such a table resulted in parsing
error reported. Since this included DROP TRIGGER and DROP TABLE
statements (actually, the latter was allowed but was not functioning
properly for such tables) it was impossible to fix the problem without
manual operations on .TRG and .TRN files in data directory.
The problem was that failure to parse trigger body (due to 5.0-only
syntax) when opening trigger file for a table prevented the table
from being open. This made all operations on the table impossible
(except DROP TABLE which due to peculiarity in its implementation
dropped the table but left trigger files around).
This patch solves this problem by silencing error which occurs when
we parse trigger body during table open. Error message is preserved
for the future use and table is marked as having a broken trigger.
We also try to analyze parse tree to recover trigger name, which
will be needed in order to drop the broken trigger. DML statements
which invoke triggers on the table marked as having broken trigger
are prohibited and emit saved error message. The same happens for
DDL which change triggers except DROP TRIGGER and DROP TABLE which
try their best to do what was requested. Table becomes no longer
marked as having broken trigger when last such trigger is dropped.
mysql-test/r/trigger-compat.result:
Add results for test case for bug#45235
mysql-test/t/trigger-compat.test:
Add test case for bug#45235.
sql/sp_head.cc:
Added protection against MEM_ROOT double restoring to
sp_head::restore_thd_mem_root() method. Since this
method can be sometimes called twice during parsing
of stored routine (the first time during normal flow
of parsing, and the second time when a syntax error
is detected) we need to shortcut execution of the
method to avoid damaging MEM_ROOT by the second
consecutive call to this method.
sql/sql_trigger.cc:
Added error handler Deprecated_trigger_syntax_handler to
catch non-OOM errors during parsing of trigger body.
Added handling of parse errors into method
Table_triggers_list::check_n_load().
sql/sql_trigger.h:
Added new members to handle broken triggers and error messages.
THE EVENT STATUS.
Any ALTER EVENT statement on a disabled event enabled it back
(unless this ALTER EVENT statement explicitly disabled the event).
The problem was that during processing of an ALTER EVENT statement
value of status field was overwritten unconditionally even if new
value was not specified explicitly. As a consequence this field
was set to default value for status which corresponds to ENABLE.
The solution is to check if status field was explicitly specified in
ALTER EVENT statement before assigning new value to status field.
mysql-test/r/events_bugs.result:
test's result for Bug#11764334 was added.
mysql-test/t/events_bugs.test:
new test for Bug#11764334 was added.
sql/event_db_repository.cc:
mysql_event_fill_row() was modified: set value for status field
in events tables only in case if statement CREATE EVENT
is being processed or if this value was set in ALTER EVENT
statement.
Event_db_repository::create_event was modified: removed redundant
setting of status field after return from call to mysql_event_fill_row().
sql/event_parse_data.h:
Event_parse_data structure was modified: added flag
status_changed that is set to true if status's value
was changed in ALTER EVENT statement.
sql/sql_yacc.yy:
Set flag status_changed if status was set in ALTER EVENT
statement.
STATEMENTS FAIL".
Attempt to execute CREATE TABLE LIKE statement on a MyISAM
table with INDEX or DATA DIRECTORY options specified as a
source resulted in "MyISAM table '...' is in use..." error.
According to our documentation such a statement should create
a copy of source table with DATA/INDEX DIRECTORY options
omitted.
The problem was that new implementation of CREATE TABLE LIKE
statement in 5.5 tried to copy value of INDEX and DATA DIRECTORY
parameters from the source table. Since in description of source
table this parameters also included name of this table, attempt
to create target table with these parameter led to file name
conflict and error.
This fix addresses the problem by preserving documented and
backward-compatible behavior. I.e. by ensuring that contents
of DATA/INDEX DIRECTORY clauses for the source table is
ignored when target table is created.
mysql-test/r/symlink.result:
Added test for bug #11759990 - "52354: 'CREATE TABLE ..
LIKE ... ' STATEMENTS FAIL".
mysql-test/t/symlink.test:
Added test for bug #11759990 - "52354: 'CREATE TABLE ..
LIKE ... ' STATEMENTS FAIL".
sql/sql_table.cc:
Changed CREATE TABLE LIKE implementation to ignore contents
of DATA/INDEX DIRECTORY clauses for source table when target
table is created. This is documented and backward-compatible
behavior.
FUNCTION DOES NOT EXIST IF NOT-PRIV USER RECONNECTS".
The bug itself was fixed by the same patch as bug@11747137
"30977: CONCURRENT STATEMENT USING STORED FUNCTION AND DROP
FUNCTION BREAKS SBR".
Problem: in case of wrong data insert into indexed GEOMETRY fields
(e.g. NULL value for a not NULL field) MyISAM reported
"ERROR 126 (HY000): Incorrect key file for table; try to repair it"
due to misuse of the key deletion function.
Fix: always use R-tree key functions for R-tree based indexes
and B-tree key functions for B-tree based indexes.
mysql-test/r/gis-rtree.result:
Bug#11764487: myisam corruption with insert ignore and invalid spatial data
- test result.
mysql-test/t/gis-rtree.test:
Bug#11764487: myisam corruption with insert ignore and invalid spatial data
- test case.
storage/myisam/mi_update.c:
Bug#11764487: myisam corruption with insert ignore and invalid spatial data
- handling update errors check for HA_ERR_NULL_IN_SPATIAL as well to be
consistent with mi_write();
- always use keyinfo->ck_delete()/ck_insert() instead of _mi_ck_delete()/_mi_ck_write()
to handle index properly, as it may be of B-tree or R-tree type.
storage/myisam/mi_write.c:
Bug#11764487: myisam corruption with insert ignore and invalid spatial data
- always use keyinfo->ck_delete() instead of _mi_ck_delete() to handle
index properly, as it may be of B-tree or R-tree type.
FAIL IN EMBEDDED SERVER
FreeBSD 64 bit needs the FP_X_DNML to fpsetmask() to prevent exceptions from
propagating into mysql (as a threaded application).
However fpsetmask() itself is deprecated in favor of fedisableexcept().
1. Fixed the #ifdef to check for FP_X_DNML instead of i386.
2. Added a configure.in check for fedisableexcept() and, if present,
this function is called insted of the fpsetmask().
No need for new tests, as the existing tests cover this already.
Removed the affected tests from the experimental list.
SECONDARY INDEX IN INNODB
This is a follow-up patch.
This patch moves part of the new test coverage to a test
file that is only run on debug builds since it used debug-
only features and therefore broke the test case on
release builds.
SECONDARY INDEX IN INNODB
The patches for Bug#11751388 and Bug#11784056 enabled concurrent
reads while creating secondary indexes in InnoDB. However, they
introduced a regression. This regression occured if ALTER TABLE
failed after the index had been added, for example during the
lock upgrade needed to update .FRM. If this happened, InnoDB
and the server got out of sync with regards to which indexes
actually existed. Therefore the patch for Bug#11815600 again
disabled concurrent reads.
This patch re-enables concurrent reads. The original regression
is fixed by splitting the ADD INDEX operation into two parts.
First the new index is created but not made active. This is
done while concurrent reads are allowed. The second part of
the operation makes the index active (or reverts the change).
This is done after lock upgrade, which prevents the original
regression.
In order to implement this change, the patch changes the storage
API for in-place index creation. handler::add_index() is split
into two functions, handler_add_index() and
handler::final_add_index(). The former for creating indexes without
making them visible and the latter for commiting (i.e. making
visible) new indexes or reverting the changes.
Large parts of this patch were written by Marko Mäkelä.
Test case added to innodb_mysql_lock.test.
With this change, the index prefix column length lifted from 767 bytes
to 3072 bytes if "innodb_large_prefix" is set to "true".
rb://603 approved by Marko
The test case problem stemmed from the fact that a debug sync
signal is a global variable that persists until overwritten
by a new signal. This means that if two different signals
are raised in sequence, a thread waiting for the first signal
might miss it if the second signal sets the global variable
before the thread wakes up.
The solution is to deliver a subsequent signal only after the
waiting thread has received it.
mysql-test/t/query_cache_debug.test:
Wait for signal to be delivered.
will create multiple running events.
A CREATE IF NOT EXIST on an event that existed and was enabled caused
multiple instances of the event to run. Disabling the event didn't help.
If the event was dropped, the event stopped running, but when created
again, multiple instances of the event were still running. The only way
to get out of this situation was to restart the server.
The problem was that Event_db_repository::create_event() didn't return
enough information to discriminate between situation when event didn't
exist and was created and when event did exist and was not created
(but a warning was emitted). As result in the latter case event
was added to in-memory queue of events second time. And this led to
unwarranted multiple executions of the same event.
The solution is to add out-parameter to Event_db_repository::create_event()
method which will signal that event was not created because it already
exists and so it should not be added to the in-memory queue.
mysql-test/r/events_bugs.result:
Added results for test for Bug#12546938.
mysql-test/t/events_bugs.test:
Added test for Bug#12546938.
sql/event_db_repository.cc:
Event_db_repository::create_event was modified: set newly added out-parameter
event_already_exists to true value if event wasn't created because event
already existed and IF NOT EXIST clause was present.
sql/event_db_repository.h:
Added out-parameter 'event_already_exists' to create_event() method.
sql/events.cc:
Events::create_event was modified: insert new element into
event queue only if event was actually created.
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
Attempt to update an InnoDB temporary table under LOCK TABLES
led to assertion failure in both debug and production builds
if this temporary table was explicitly locked for READ. The
same scenario works fine for MyISAM temporary tables.
The assertion failure was caused by discrepancy between lock
that was requested on the rows of temporary table at LOCK TABLES
time and by update operation. Since SQL-layer requested a
read-lock at LOCK TABLES time InnoDB engine assumed that upcoming
statements which are going to be executed under LOCK TABLES will
only read table and therefore should acquire only S-lock.
An update operation broken this assumption by requesting X-lock.
Possible approaches to fixing this problem are:
1) Skip locking of temporary tables as locking doesn't make any
sense for connection-local objects.
2) Prohibit changing of temporary table locked by LOCK TABLES ...
READ.
Unfortunately both of these approaches have drawbacks which make
them unviable for stable versions of server.
So this patch takes another approach and changes code in such way
that LOCK TABLES for a temporary table will always request write
lock. In 5.5 version of this patch switch from read lock to write
lock is done on SQL-layer.
mysql-test/suite/innodb/r/innodb_mysql.result:
Added test for bug #11762012 - "54553: INNODB ASSERTS IN
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
mysql-test/suite/innodb/t/innodb_mysql.test:
Added test for bug #11762012 - "54553: INNODB ASSERTS IN
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
sql/sql_parse.cc:
Since a temporary table locked by LOCK TABLES can be updated even
if it was only locked for read we always request TL_WRITE locks
for such tables at LOCK TABLES time. This allows to avoid
discrepancy between locks acquired at LOCK TABLES time and by
a statement executed under LOCK TABLES. Such a discrepancy has
caused problems for InnoDB storage engine.
To support this change a part of code implementing LOCK TABLES
has been moved to a helper function.
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
Attempt to update an InnoDB temporary table under LOCK TABLES
led to assertion failure in both debug and production builds
if this temporary table was explicitly locked for READ. The
same scenario works fine for MyISAM temporary tables.
The assertion failure was caused by discrepancy between lock
that was requested on the rows of temporary table at LOCK TABLES
time and by update operation. Since SQL-layer requested a
read-lock at LOCK TABLES time InnoDB engine assumed that upcoming
statements which are going to be executed under LOCK TABLES will
only read table and therefore should acquire only S-lock.
An update operation broken this assumption by requesting X-lock.
Possible approaches to fixing this problem are:
1) Skip locking of temporary tables as locking doesn't make any
sense for connection-local objects.
2) Prohibit changing of temporary table locked by LOCK TABLES ...
READ.
Unfortunately both of these approaches have drawbacks which make
them unviable for stable versions of server.
So this patch takes another approach and changes code in such way
that LOCK TABLES for a temporary table will always request write
lock. In 5.1 version of this patch switch from read lock to write
lock is done inside of InnoDBs handler methods as doing it on
SQL-layer causes compatibility troubles with FLUSH TABLES WITH
READ LOCK.
mysql-test/suite/innodb/r/innodb_mysql.result:
Added test for bug #11762012 - "54553: INNODB ASSERTS IN
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
mysql-test/suite/innodb/t/innodb_mysql.test:
Added test for bug #11762012 - "54553: INNODB ASSERTS IN
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
mysql-test/suite/innodb_plugin/r/innodb_mysql.result:
Added test for bug #11762012 - "54553: INNODB ASSERTS IN
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
mysql-test/suite/innodb_plugin/t/innodb_mysql.test:
Added test for bug #11762012 - "54553: INNODB ASSERTS IN
HA_INNOBASE::UPDATE_ROW, TEMPORARY TABLE, TABLE LOCK".
storage/innobase/handler/ha_innodb.cc:
Assume that a temporary table locked by LOCK TABLES can be updated
even if it was only locked for read and therefore an X-lock should
be always requested for such tables.
storage/innodb_plugin/handler/ha_innodb.cc:
Assume that a temporary table locked by LOCK TABLES can be updated
even if it was only locked for read and therefore an X-lock should
be always requested for such tables.
Problem: MYSQL_BIN_LOG::reset_logs acquires mutexes in wrong order.
The correct order is first LOCK_thread_count and then LOCK_log. This function
does it the other way around. This leads to deadlock when run in parallel
with a thread that takes the two locks in correct order. For example, a thread
that disconnects will take the locks in the correct order.
Fix: change order of the locks in MYSQL_BIN_LOG::reset_logs:
first LOCK_thread_count and then LOCK_log.
mysql-test/suite/binlog/r/binlog_reset_master.result:
added result file
mysql-test/suite/binlog/t/binlog_reset_master.test:
Added test case that demonstrates deadlock because of wrong mutex order.
The deadlock is between two threads:
- RESET MASTER acquires mutexes in wrong order.
- client thread shutdown code acquires mutexes in right order.
Actually, this test case does not produce deadlock in 5.1, probably
the client thread shutdown code does not hold both mutexes at the same
time. However, the bug existed in 5.1 (mutexes are taken in the wrong
order) so we push the test case to 5.1 too, to prevent future
regressions.
sql/log.cc:
Change mutex acquisition to the correct order:
first LOCK_thread_count, then LOCK_log.
sql/mysqld.cc:
Add debug code to synchronize test case.
Assertion happens due to missing NULL value check in
Item_func_round::fix_length_and_dec() function.
The fix: added NULL value check for second parameter.
mysql-test/r/func_math.result:
test case
mysql-test/t/func_math.test:
test case
sql/item_func.cc:
added NULL value check for second parameter.
