DO WHAT YOU EXPECT"
Fix info:
--------
Backport of the deprecation bug fix (WL#5265) for global variable
'THREAD_CONCURRENCY' from mysql-5.6 to mysql-5.5
Note: With this backport, certain additional deprecation warnings
would be reported under error conditions while setting the
global/session variables.
Problem:
When a system variable is being set to the DEFAULT value, the server
segfaults if there is no 'default' defined for that system variable.
For example, for the following statements server segfaults.
set session rand_seed1=DEFAULT;
set session rand_seed2=DEFAULT;
Analysis:
The class sys_var represents one system variable. The class set_var represents
one system variable that is to be updated. The class set_var contains two
pieces of information, the system variable to object (set_var::var) member
and the value to be updated (set_var::value).
When the given value is 'default', the set_var::value will be NULL.
To update a system variable the member set_var::update() will be called,
which in turn will call sys_var::update() or sys_var::set_default() depending
on whether a value has been provided or not.
If the sys_var::set_default() is called, then the default value is obtained
either from the session scope or the global scope. This default value is
stored in a local temporary set_var object and then passed on to the
sys_var::update() call. A local temporary set_var object is needed because
sys_var::set_default() does not take set_var as an argument.
In the given scenario, the set_var::update() called sys_var::set_default().
And this sys_var::set_default() obtains the default value and then calls
sys_var::update(). To pass this value to sys_var::update() a local set_var
object is being created. While creating this local set_var object, its member
set_var::var was incorrectly left as 0.
Solution:
Instead of creating a local set_var object, the sys_var::set_default() can take
the set_var object as an argument just like sys_var::update().
rb://1996 approved by Nirbhay and Ramil.
NUMBERS
If a system variable was declared as deprecated without mention of an
alternative, the message would look funny, e.g. for @@delayed_insert_limit:
Warning 1287 '@@delayed_insert_limit' is deprecated and
will be removed in MySQL .
The message was meant to display the version number, but it's not
possible to give one when declaring a system variable.
The fix does two things:
1) The definition of the message
ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT is changed so that it does
not display a version number. I.e. in English the message now reads:
Warning 1287 The syntax '@@delayed_insert_limit' is deprecated and
will be removed in a future version.
2) The message ER_WARN_DEPRECATED_SYNTAX_WITH_VER is discontinued in
favor of ER_WARN_DEPRECATED_SYNTAX for system variables. This change
was already done in versions 5.6 and above as part of wl#5265. This
part is simply back-ported from the worklog.
ARE NOT BEING HONORED
max_allowed_packet works in conjunction with net_buffer_length.
max_allowed_packet is an upper bound of net_buffer_length.
So it doesn't make sense to set the upper limit lower than the value.
Added a warning (using ER_UNKNOWN_ERRROR and a specific message)
when this is done (in the log at startup and when setting either
max_allowed_packet or the net_buffer_length variables)
Added a test case.
Fixed several tests that broke the above rule.
The problem was that server didn't check resulting size of prepared
statement argument which was set using mysql_send_long_data() API.
By calling mysql_send_long_data() several times it was possible
to create overly big string and thus force server to allocate
memory for it. There was no way to limit this allocation.
The solution is to add check for size of result string against
value of max_long_data_size start-up parameter. When intermediate
string exceeds max_long_data_size value an appropriate error message
is emitted.
We can't use existing max_allowed_packet parameter for this purpose
since its value is limited by 1GB and therefore using it as a limit
for data set through mysql_send_long_data() API would have been an
incompatible change. Newly introduced max_long_data_size parameter
gets value from max_allowed_packet parameter unless its value is
specified explicitly. This new parameter is marked as deprecated
and will be eventually replaced by max_allowed_packet parameter.
Value of max_long_data_size parameter can be set only at server
startup.
A separate fix for 5.1 (as 5.1 and 5.5 have seriously
differged in the related pieces of the code).
A patch for 5.5 was approved earlier.
Problem: ucs2 was correctly disallowed in "SET NAMES" only,
while mysql_real_connect() and mysql_change_user() still allowed
to use ucs2, which made server crash.
Fix: disallow ucs2 in mysql_real_connect() and mysql_change_user().
@ sql/sql_priv.h
- changing return type for thd_init_client_charset() to bool,
to return errors to the caller
@ sql/sql_var.cc
- using new function
@ sql/sql_connect.cc
- thd_client_charset_init:
in case of unsupported client character set send error and return true;
in case of success return false
- check_connection:
Return error if character set initialization failed
@ sql/sql_parse.cc
- check charset in the very beginnig of the CMD_CHANGE_USER handling code
@ tests/mysql_client_test.c
- adding tests
Problem: ucs2 was correctly disallowed in "SET NAMES" only,
while mysql_real_connect() and mysql_change_user() still allowed
to use ucs2, which made server crash.
Fix: disallow ucs2 in mysql_real_connect() and mysql_change_user().
@ sql/set_var.cc
Using new function.
@ sql/sql_acl.cc
- Return error if character set initialization failed
- Getting rid of pointer aliasing:
Initialize user_name to NULL, to avoid double free().
@ sql/sql_connect.cc
- in case of unsupported client character set send error and return true
- in case of success return false
@ sql/sql_connect.h
- changing return type for thd_init_client_charset() to bool,
to return errors to the caller
@ sql/sql_parse.h
- introducing a new function, to reuse in all places where we need
to check client character set.
@ tests/mysql_client_test.c
Adding test
memory reference
There are two issues present here.
1) There is a possibility that we test a byte beyond the
allocated buffer
2) We compare a byte that might never have been
initalized to see if it's 0.
The first issue is not triggered by existing code, but an
ASSERT has been added to safe-guard against introducing
new code that triggers it.
The second issue is what triggers the Valgrind warnings
reported in the bug report. A buffer is allocated in
class String to hold the value. This buffer is populated
by the character data constituting the string, but is not
zero-terminated in most cases. Testing if it is indeed
zero-terminated means that we check a byte that has never
been explicitly set, thus causing Valgrind to trigger.
Note that issue 2 is not a serious problem. The variable
is read, and if it's not zero, we will set it to zero.
There are no further consequences.
Note that this patch does not fix the underlying problems
with issue 1, as it is deemed too risky to fix at this
point (as noted in the bug report). As discussed in
the report, the c_ptr() method should probably be
replaced, but this requires a thorough analysis of the
~200 calls to the method.
Bug #55755 : Date STD variable signness breaks server on FreeBSD and OpenBSD
* Added a check to configure on the size of time_t
* Created a macro to check for a valid time_t that is safe to use with datetime
functions and store in TIMESTAMP columns.
* Used the macro consistently instead of the ad-hoc checks introduced by 52315
* Fixed compliation warnings on platforms where the size of time_t is smaller than
the size of a long (e.g. OpenBSD 4.8 64 amd64).
Bug #52315: utc_date() crashes when system time > year 2037
* Added a correct check for the timestamp range instead of just variable size check to
SET TIMESTAMP.
* Added overflow checking before converting to time_t.
* Using a correct localized error message in this case instead of the generic error.
* Added a test suite.
* fixed the checks so that they check for unsigned time_t as well. Used the checks
consistently across the source code.
* fixed the original test case to expect the new error code.
- Removed files specific to compiling on OS/2
- Removed files specific to SCO Unix packaging
- Removed "libmysqld/copyright", text is included in documentation
- Removed LaTeX headers for NDB Doxygen documentation
- Removed obsolete NDB files
- Removed "mkisofs" binaries
- Removed the "cvs2cl.pl" script
- Changed a few GPL texts to use "program" instead of "library"
Bug#55794: ulonglong options of mysqld show wrong values.
Port the few remaining system variables to the correct mechanism --
range-check in check-stage (and throw error or warning at that point
as needed and depending on STRICTness), update in update stage.
Fix some signedness errors when retrieving sysvar values for display.
Fix assorted warnings that are generated in optimized builds.
Most of it is silencing variables that are set but unused.
This patch also introduces the MY_ASSERT_UNREACHABLE macro
which helps the compiler to deduce that a certain piece of
code is unreachable.
thread-specific variables weren't set when we load error message files.
per-file comments:
libmysqld/lib_sql.cc
Bug#53251 mysql_library_init fails on second execution with embedded library
we need to call my_thread_init() once more. Normally it's called at the my_init()
stage but that doesn't happen on the second my_init() call.
sql/derror.cc
Bug#53251 mysql_library_init fails on second execution with embedded library
use default errors for the embedded server.
sql/mysqld.cc
Bug#53251 mysql_library_init fails on second execution with embedded library
unregister server errors in clean_up(). Without it the error list contains
that on the second mysql_server_init() which is not good.
sql/set_var.cc
Bug#53251 mysql_library_init fails on second execution with embedded library
sys_var::cleanup() call instead of the destructor
sql/set_var.h
Bug#53251 mysql_library_init fails on second execution with embedded library
sys_var::cleanup() introduced instead of the destructor
sql/sys_vars.h
Bug#53251 mysql_library_init fails on second execution with embedded library
Sys_var_charptr::cleanup() implemented
Before this fix, the server did not recognize 'short' (as in -a)
options but only 'long' (as in --ansi) options
in the startup command line, due to earlier changes in 5.5
introduced for the performance schema.
The root cause is that handle_options() did not honor the
my_getopt_skip_unknown flag when parsing 'short' options.
The fix changes handle_options(), so that my_getopt_skip_unknown is
honored in all cases.
Note that there are limitations to this,
see the added doxygen documentation in handle_options().
The current usage of handle_options() by the server to
parse early performance schema options fits within the limitations.
This has been enforced by an assert for PARSE_EARLY options, for safety.
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.
Apart strict-aliasing warnings, fix the remaining warnings
generated by GCC 4.4.4 -Wall and -Wextra flags.
One major source of warnings was the in-house function my_bcmp
which (unconventionally) took pointers to unsigned characters
as the byte sequences to be compared. Since my_bcmp and bcmp
are deprecated functions whose only difference with memcmp is
the return value, every use of the function is replaced with
memcmp as the special return value wasn't actually being used
by any caller.
There were also various other warnings, mostly due to type
mismatches, missing return values, missing prototypes, dead
code (unreachable) and ignored return values.
Some of the server implementations don't support dates later
than 2038 due to the internal time type being 32 bit.
Added checks so that the server will refuse dates that cannot
be handled by either throwing an error when setting date at
runtime or by refusing to start or shutting down the server if
the system date cannot be stored in my_time_t.
Server crashes on 64bit linux with 'double free or corruption'
message, on 32bit mysql-test-run silently fails on bootstrap
stage. The problem is that FreeState() is called twice
for init_settings struct in _db_end_ function.
The fix is to remove superfluous FreeState() call.
Additional fix:
fixed discrepancy of result file when
debug & valgrind options are enabled
for MTR.
Adding my_global.h first in all files using
NO_EMBEDDED_ACCESS_CHECKS.
Correcting a merge problem resulting from a changed definition
of check_some_access compared to the original patches.
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
SET autocommit=1 while XA transaction is active may
cause various side effects, including memory corruption
and server crash.
The problem is that SET autocommit=1 and further queries
attempt to commit local transaction, whereas XA transaction
is still active.
As local and XA transactions are mutually exclusive, this
patch forbids enabling autocommit mode while XA transaction
is active.
Fix Bug#50555 "handler commands crash server in my_hash_first()"
as a post-merge fix (the new handler tests are not passing
otherwise).
- in hash.c, don't call calc_hash if ! my_hash_inited().
- add tests and results for the test case for Bug#50555
Add a wait-for graph based deadlock detector to the
MDL subsystem.
Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and
bug #37346 "innodb does not detect deadlock between update and
alter table".
The first bug manifested itself as an unwarranted abort of a
transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER
statement, when this transaction tried to repeat use of a
table, which it has already used in a similar fashion before
ALTER started.
The second bug showed up as a deadlock between table-level
locks and InnoDB row locks, which was "detected" only after
innodb_lock_wait_timeout timeout.
A transaction would start using the table and modify a few
rows.
Then ALTER TABLE would come in, and start copying rows
into a temporary table. Eventually it would stumble on
the modified records and get blocked on a row lock.
The first transaction would try to do more updates, and get
blocked on thr_lock.c lock.
This situation of circular wait would only get resolved
by a timeout.
Both these bugs stemmed from inadequate solutions to the
problem of deadlocks occurring between different
locking subsystems.
In the first case we tried to avoid deadlocks between metadata
locking and table-level locking subsystems, when upgrading shared
metadata lock to exclusive one.
Transactions holding the shared lock on the table and waiting for
some table-level lock used to be aborted too aggressively.
We also allowed ALTER TABLE to start in presence of transactions
that modify the subject table. ALTER TABLE acquires
TL_WRITE_ALLOW_READ lock at start, and that block all writes
against the table (naturally, we don't want any writes to be lost
when switching the old and the new table). TL_WRITE_ALLOW_READ
lock, in turn, would block the started transaction on thr_lock.c
lock, should they do more updates. This, again, lead to the need
to abort such transactions.
The second bug occurred simply because we didn't have any
mechanism to detect deadlocks between the table-level locks
in thr_lock.c and row-level locks in InnoDB, other than
innodb_lock_wait_timeout.
This patch solves both these problems by moving lock conflicts
which are causing these deadlocks into the metadata locking
subsystem, thus making it possible to avoid or detect such
deadlocks inside MDL.
To do this we introduce new type-of-operation-aware metadata
locks, which allow MDL subsystem to know not only the fact that
transaction has used or is going to use some object but also what
kind of operation it has carried out or going to carry out on the
object.
This, along with the addition of a special kind of upgradable
metadata lock, allows ALTER TABLE to wait until all
transactions which has updated the table to go away.
This solves the second issue.
Another special type of upgradable metadata lock is acquired
by LOCK TABLE WRITE. This second lock type allows to solve the
first issue, since abortion of table-level locks in event of
DDL under LOCK TABLES becomes also unnecessary.
Below follows the list of incompatible changes introduced by
this patch:
- From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those
statements that acquire TL_WRITE_ALLOW_READ lock)
wait for all transactions which has *updated* the table to
complete.
- From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE
(i.e. all statements which acquire TL_WRITE table-level lock) wait
for all transaction which *updated or read* from the table
to complete.
As a consequence, innodb_table_locks=0 option no longer applies
to LOCK TABLES ... WRITE.
- DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort
statements or transactions which use tables being dropped or
renamed, and instead wait for these transactions to complete.
- Since LOCK TABLES WRITE now takes a special metadata lock,
not compatible with with reads or writes against the subject table
and transaction-wide, thr_lock.c deadlock avoidance algorithm
that used to ensure absence of deadlocks between LOCK TABLES
WRITE and other statements is no longer sufficient, even for
MyISAM. The wait-for graph based deadlock detector of MDL
subsystem may sometimes be necessary and is involved. This may
lead to ER_LOCK_DEADLOCK error produced for multi-statement
transactions even if these only use MyISAM:
session 1: session 2:
begin;
update t1 ... lock table t2 write, t1 write;
-- gets a lock on t2, blocks on t1
update t2 ...
(ER_LOCK_DEADLOCK)
- Finally, support of LOW_PRIORITY option for LOCK TABLES ... WRITE
was abandoned.
LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same
priority as the usual LOCK TABLE ... WRITE.
SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE in
the wait queue.
- We do not take upgradable metadata locks on implicitly
locked tables. So if one has, say, a view v1 that uses
table t1, and issues:
LOCK TABLE v1 WRITE;
FLUSH TABLE t1; -- (or just 'FLUSH TABLES'),
an error is produced.
In order to be able to perform DDL on a table under LOCK TABLES,
the table must be locked explicitly in the LOCK TABLES list.
Several items said to be deprecated in the 4.1 manual
have never been removed. This worklog adds deprecation
warnings when these items are used, and warns the user
that the items will be removed in MySQL 5.6.
A couple of previously deprecation decision have been
reversed (see single file comments)
It is well-known that due to concurrency issues, a slave can become
inconsistent when a transaction contains updates to both transaction and
non-transactional tables in statement and mixed modes.
In a nutshell, the current code-base tries to preserve causality among the
statements by writing non-transactional statements to the txn-cache which
is flushed upon commit. However, modifications done to non-transactional
tables on behalf of a transaction become immediately visible to other
connections but may not immediately get into the binary log and therefore
consistency may be broken.
In general, it is impossible to automatically detect causality/dependency
among statements by just analyzing the statements sent to the server. This
happen because dependency may be hidden in the application code and it is
necessary to know a priori all the statements processed in the context of
a transaction such as in a procedure. Moreover, even for the few cases that
we could automatically address in the server, the computation effort
required could make the approach infeasible.
So, in this patch we introduce the option
- "--binlog-direct-non-transactional-updates" that can be used to bypass
the current behavior in order to write directly to binary log statements
that change non-transactional tables.
- backported code that handles %f/%g arguments in
my_vsnprintf.c from 6.0
- backported %f/%g tests in unittest/mysys/my_vsnprintf-t.c
from 6.0
- replaced snprintf("%g") in sql/set_var.cc with my_gcvt()
- removed unnecessary "--replace-result"s for Windows in
mysql-test/suite/sys_vars/t/long_query_time_basic.test
- some test results adjustments
"HANDLER statements within a transaction might lead to deadlocks".
Introduce a notion of a sentinel to MDL_context. A sentinel
is a ticket that separates all tickets in the context into two
groups: before and after it. Currently we can have (and need) only
one designated sentinel -- it separates all locks taken by LOCK
TABLE or HANDLER statement, which must survive COMMIT and ROLLBACK
and all other locks, which must be released at COMMIT or ROLLBACK.
The tricky part is maintaining the sentinel up to date when
someone release its corresponding ticket. This can happen, e.g.
if someone issues DROP TABLE under LOCK TABLES (generally,
see all calls to release_all_locks_for_name()).
MDL_context::release_ticket() is modified to take care of it.
******
A fix and a test case for Bug#46224 "HANDLER statements within a
transaction might lead to deadlocks".
An attempt to mix HANDLER SQL statements, which are transaction-
agnostic, an open multi-statement transaction,
and DDL against the involved tables (in a concurrent connection)
could lead to a deadlock. The deadlock would occur when
HANDLER OPEN or HANDLER READ would have to wait on a conflicting
metadata lock. If the connection that issued HANDLER statement
also had other metadata locks (say, acquired in scope of a
transaction), a classical deadlock situation of mutual wait
could occur.
Incompatible change: entering LOCK TABLES mode automatically
closes all open HANDLERs in the current connection.
Incompatible change: previously an attempt to wait on a lock
in a connection that has an open HANDLER statement could wait
indefinitely/deadlock. After this patch, an error ER_LOCK_DEADLOCK
is produced.
The idea of the fix is to merge thd->handler_mdl_context
with the main mdl_context of the connection, used for transactional
locks. This makes deadlock detection possible, since all waits
with locks are "visible" and available to analysis in a single
MDL context of the connection.
Since HANDLER locks and transactional locks have a different life
cycle -- HANDLERs are explicitly open and closed, and so
are HANDLER locks, explicitly acquired and released, whereas
transactional locks "accumulate" till the end of a transaction
and are released only with COMMIT, ROLLBACK and ROLLBACK TO SAVEPOINT,
a concept of "sentinel" was introduced to MDL_context.
All locks, HANDLER and others, reside in the same linked list.
However, a selected element of the list separates locks with
different life cycle. HANDLER locks always reside at the
end of the list, after the sentinel. Transactional locks are
prepended to the beginning of the list, before the sentinel.
Thus, ROLLBACK, COMMIT or ROLLBACK TO SAVEPOINT, only
release those locks that reside before the sentinel. HANDLER locks
must be released explicitly as part of HANDLER CLOSE statement,
or an implicit close.
The same approach with sentinel
is also employed for LOCK TABLES locks. Since HANDLER and LOCK TABLES
statement has never worked together, the implementation is
made simple and only maintains one sentinel, which is used either
for HANDLER locks, or for LOCK TABLES locks.
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
