There were two problems here:
1. misleading error message
2. abusing KILL QUERY in the test case
1. The server reported "'DELETE FROM t1' failed: 1689: Wait on a lock was
aborted due to a pending exclusive lock", while the proper error message
should be "'DELETE FROM t1' failed: 1317: Query execution was interrupted".
The problem is that the server has two different flags for
signalling that a query is being killed: THD::killed and
mysys_var::abort. The test case triggers a race: sometimes
mysys_var::abort is set earlier than THD::killed. That leads
to the following situation:
- thr_lock() checks mysys_var::abort and returns error status,
since mysys_var::abort is set;
- the caller (mysql_lock_tables()) gets an error from thr_lock(),
but THD::killed is not set, so it decides that thr_lock() couldn't
get a lock due to a pending exclusive lock.
This is a known issue with the server and it's not going to be fixed soon.
5.5 differs from 5.1 here as follows: when thr_lock() returns an error:
- 5.1 continues trying thr_lock() until success;
- 5.5 propagates the error
2. The test case uses KILL QUERY is a highly concurent environment.
The fix is to wait for the dying statement to rest in peace before
executing another DELETE FROM t1.
Clarified error messages related to unsafe statements:
- avoid the internal technical term "row injection"
- use 'binary log' instead of 'binlog'
- avoid the word 'unsafeness'
Fix for bug #46947 "Embedded SELECT without FOR UPDATE is
causing a lock", with after-review fixes.
SELECT statements with subqueries referencing InnoDB tables
were acquiring shared locks on rows in these tables when they
were executed in REPEATABLE-READ mode and with statement or
mixed mode binary logging turned on.
This was a regression which were introduced when fixing
bug 39843.
The problem was that for tables belonging to subqueries
parser set TL_READ_DEFAULT as a lock type. In cases when
statement/mixed binary logging at open_tables() time this
type of lock was converted to TL_READ_NO_INSERT lock at
open_tables() time and caused InnoDB engine to acquire
shared locks on reads from these tables. Although in some
cases such behavior was correct (e.g. for subqueries in
DELETE) in case of SELECT it has caused unnecessary locking.
This patch tries to solve this problem by rethinking our
approach to how we handle locking for SELECT and subqueries.
Now we always set TL_READ_DEFAULT lock type for all cases
when we read data. When at open_tables() time this lock
is interpreted as TL_READ_NO_INSERT or TL_READ depending
on whether this statement as a whole or call to function
which uses particular table should be written to the
binary log or not (if yes then statement should be properly
serialized with concurrent statements and stronger lock
should be acquired).
Test coverage is added for both InnoDB and MyISAM.
This patch introduces an "incompatible" change in locking
scheme for subqueries used in SELECT ... FOR UPDATE and
SELECT .. IN SHARE MODE.
In 4.1 the server would use a snapshot InnoDB read for
subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE
statements, regardless of whether the binary log is on or off.
If the user required a different type of read (i.e. locking read),
he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE
clause for each individual subquery.
On of the patches for 5.0 broke this behaviour (which was not documented
or tested), and started to use locking reads fora all subqueries in SELECT ...
FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour.
Stored routine DDL statements use statement-based replication
regardless of the current binlog format. The problem here was
that if a DDL statement failed during metadata lock acquisition
or opening of mysql.proc, the binlog format would not be reset
before returning. So the following DDL or DML statements are
binlogged with a wrong binlog format, which causes the slave
to stop.
The problem can be resolved by grabbing an exclusive MDL lock firstly
instead of clearing the current binlog format. So that the binlog
format will not be affected when the lock grab returns directly with
an error. The same way is taken to open a proc table for update.
parallel mode
The failure has nothing to do with parallel, but rather on the
order the tests are executed. In this case, the test
binlog_tmp_table (lets call it test2) was not ensuring that the
binary logs would be reset when it started. Later the test issues
a mysqlbinlog .../master-bin.000002 | mysql ... If the test that
was executed before this one (lets call it test1) had issued a
flush logs, then the file in use in test1 (master-bin.000002)
would not actually match the one that was expected. Eventually,
this would cause the statements logged in test1 to be replayed,
instead of the ones logged in the beginning of test2.
We fix this by:
1. adding RESET MASTER to the beginning of binlog_tmp_table
2. setting dynamically the file to use in binlog_tmp_table
Only #1 was needed, but the two make the tests cases more robust.
The problem is that message resource (message.rc) is compiled as part of static library
sql.lib rather than with executable mysqld.exe. resource files do not work in static
libraries.
The fix is to add message.rc to mysqld.exe source files list.
Statements with CONNECTION_ID were forced to be kept in the transactional
cache and by consequence non-transactional changes that were supposed to
be flushed ahead of the transaction were kept in the transactional cache.
This happened because after BUG#51894 any statement whose thd's
thread_specific_used was set was kept in the transactional cache. The idea
was to keep changes on temporary tables in the transactional cache. However,
the thread_specific_used was set not only for statements that accessed
temporary tables but also when the CONNECTION_ID was used.
To fix the problem, we created a new variable to keep track of updates
to temporary tables.
The bug was a side effect of WL#5030 (fix header files) and
WL#5161 (CMake).
The problem was that CMake-generated config.h (and my_config.h
as a copy of it) had a header guard. GNU autotools-generated
[my_]config.h did not. During WL#5030 the order of header files
was changed, so the following started to happen (using GNU autotools,
in embedded server):
- my_config.h included, defining HAVE_OPENSSL
- my_global.h included, un-defining HAVE_OPENSSL
- zlib.h included, including config.h,
defining HAVE_OPENSSL again.
The fix is to check HAVE_OPENSSL in conjuction with EMBEDDED_LIBRARY.
More common fix would be to define a macros as HAVE_OPENSSL && !EMBEDDED_LIBRARY
and use it instead of HAVE_OPENSSL.
The bug was a side effect of WL#5030 (fix header files) and
WL#5161 (CMake).
The problem was that CMake-generated config.h (and my_config.h
as a copy of it) had a header guard. GNU autotools-generated
[my_]config.h did not. During WL#5030 the order of header files
was changed, so the following started to happen (using GNU autotools,
in embedded server):
- my_config.h included, defining HAVE_OPENSSL
- my_global.h included, un-defining HAVE_OPENSSL
- zlib.h included, including config.h,
defining HAVE_OPENSSL again.
The fix is to change the order of header file, moving zlib.h
to the top of the header list. More proper fix would be to wrap
unguarded auto-generated [my_]config.h by guarded non-generated
header file.
transaction
BUG#52616 Temp table prevents switch binlog format from STATEMENT to ROW
Before the WL#2687 and BUG#46364, every non-transactional change that happened
after a transactional change was written to trx-cache and flushed upon
committing the transaction. WL#2687 and BUG#46364 changed this behavior and
non-transactional changes are now written to the binary log upon committing
the statement.
A binary log event is identified as transactional or non-transactional through
a flag in the Log_event which is set taking into account the underlie storage
engine on what it is stems from. In the current bug, this flag was not being
set properly when the DROP TEMPORARY TABLE was executed.
However, while fixing this bug we figured out that changes to temporary tables
should be always written to the trx-cache if there is an on-going transaction.
Otherwise, binlog events in the reversed order would be produced.
Regarding concurrency, keeping changes to temporary tables in the trx-cache is
also safe as temporary tables are only visible to the owner connection.
In this patch, we classify the following statements as unsafe:
1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam
On the other hand, the following statements are classified as safe:
1 - INSERT INTO t_innodb SELECT * FROM t_myisam_temp
2 - INSERT INTO t_myisam_temp SELECT * FROM t_innodb
The patch also guarantees that transactions that have a DROP TEMPORARY are
always written to the binary log regardless of the mode and the outcome:
commit or rollback. In particular, the DROP TEMPORARY is extended with the
IF EXISTS clause when the current statement logging format is set to row.
Finally, the patch allows to switch from STATEMENT to MIXED/ROW when there
are temporary tables but the contrary is not possible.
This assertion could be triggered during execution of OPTIMIZE TABLE for
InnoDB tables. As part of optimize for InnoDB tables, the table is recreated
and then opened again. If the reopen failed for any reason, the assertion
would be triggered. This could for example be caused by a concurrent DROP
TABLE executed by a different connection. The reason for the assertion was
that any failures during reopening were ignored.
This patch fixes the problem by making sure that the result of reopening the
table is checked and that any error messages are sent to the client.
Test case added to innodb_mysql_sync.test.
This was a deadlock between CREATE/ALTER/DROP EVENT and a query
accessing both the mysql.event table and I_S.GLOBAL_VARIABLES.
The root of the problem was that the LOCK_event_metadata mutex was
used to both protect the "event_scheduler" global system variable
and the internal event data structures used by CREATE/ALTER/DROP EVENT.
The deadlock would occur if CREATE/ALTER/DROP EVENT held
LOCK_event_metadata while trying to open the mysql.event table,
at the same time as the query had mysql.event open, trying to
lock LOCK_event_metadata to access "event_scheduler".
This bug was fixed in the scope of Bug#51160 by using only
LOCK_global_system_variables to protect "event_scheduler".
This makes it so that the query above won't lock LOCK_event_metadata,
thereby preventing this deadlock from occuring.
This patch contains no code changes.
Test case added to lock_sync.test.
my_global.h first
We may end up with a compilation failure on certain platforms
because zlib.h is included before my_global.h.
Fixed by moving zlib.h inclusion down after my_global.h.
e.g.MYSQL_AUDIT_GENERAL_ERROR
General audit API (MYSQL_AUDIT_GENERAL_CLASS) didn't expose event
subclass to plugins.
This patch exposes event subclass to plugins via
struct mysql_event_general::event_subclass.
This change is not compatible with existing general audit plugins.
Audit interface major version has been incremented.
even if myisam-recover is OFF
The problem was that a corrupted MyISAM table was auto repaired
even if the myisam_recover_options server variable (or the
myisam_recover option) was set to OFF.
The reason was that the auto_repair() function, which is supposed
to say if auto repair is to be used, did not use the server variable
setting correctly. This bug was a regression introduced by WL#4738.
This patch fixes the problem by making sure auto_repair() returns
FALSE if myisam_recover_options is set to OFF.
Test case added to myisam.test.
The problem was that the code that works with stored routines was present
in mysql_system_tables.sql. This is wrong because until upgrade is finished,
stored routines may be (and were) not available.
The fix is to move that code to the end of mysql_system_tables_fix.sql.
