~40% bugfixed(*) applied
~40$ bugfixed reverted (incorrect or we're not buggy)
~20% bugfixed applied, despite us being not buggy
(*) only changes in the server code, e.g. not cmakefiles
SHOW PROCESSLIST, SHOW BINLOGS
Problem: A deadlock was occurring when 4 threads were
involved in acquiring locks in the following way
Thread 1: Dump thread ( Slave is reconnecting, so on
Master, a new dump thread is trying kill
zombie dump threads. It acquired thread's
LOCK_thd_data and it is about to acquire
mysys_var->current_mutex ( which LOCK_log)
Thread 2: Application thread is executing show binlogs and
acquired LOCK_log and it is about to acquire
LOCK_index.
Thread 3: Application thread is executing Purge binary logs
and acquired LOCK_index and it is about to
acquire LOCK_thread_count.
Thread 4: Application thread is executing show processlist
and acquired LOCK_thread_count and it is
about to acquire zombie dump thread's
LOCK_thd_data.
Deadlock Cycle:
Thread 1 -> Thread 2 -> Thread 3-> Thread 4 ->Thread 1
The same above deadlock was observed even when thread 4 is
executing 'SELECT * FROM information_schema.processlist' command and
acquired LOCK_thread_count and it is about to acquire zombie
dump thread's LOCK_thd_data.
Analysis:
There are four locks involved in the deadlock. LOCK_log,
LOCK_thread_count, LOCK_index and LOCK_thd_data.
LOCK_log, LOCK_thread_count, LOCK_index are global mutexes
where as LOCK_thd_data is local to a thread.
We can divide these four locks in two groups.
Group 1 consists of LOCK_log and LOCK_index and the order
should be LOCK_log followed by LOCK_index.
Group 2 consists of other two mutexes
LOCK_thread_count, LOCK_thd_data and the order should
be LOCK_thread_count followed by LOCK_thd_data.
Unfortunately, there is no specific predefined lock order defined
to follow in the MySQL system when it comes to locks across these
two groups. In the above problematic example,
there is no problem in the way we are acquiring the locks
if you see each thread individually.
But If you combine all 4 threads, they end up in a deadlock.
Fix:
Since everything seems to be fine in the way threads are taking locks,
In this patch We are changing the duration of the locks in Thread 4
to break the deadlock. i.e., before the patch, Thread 4
('show processlist' command) mysqld_list_processes()
function acquires LOCK_thread_count for the complete duration
of the function and it also acquires/releases
each thread's LOCK_thd_data.
LOCK_thread_count is used to protect addition and
deletion of threads in global threads list. While show
process list is looping through all the existing threads,
it will be a problem if a thread is exited but there is no problem
if a new thread is added to the system. Hence a new mutex is
introduced "LOCK_thd_remove" which will protect deletion
of a thread from global threads list. All threads which are
getting exited should acquire LOCK_thd_remove
followed by LOCK_thread_count. (It should take LOCK_thread_count
also because other places of the code still thinks that exit thread
is protected with LOCK_thread_count. In this fix, we are changing
only 'show process list' query logic )
(Eg: unlink_thd logic will be protected with
LOCK_thd_remove).
Logic of mysqld_list_processes(or file_schema_processlist)
will now be protected with 'LOCK_thd_remove' instead of
'LOCK_thread_count'.
Now the new locking order after this patch is:
LOCK_thd_remove -> LOCK_thd_data -> LOCK_log ->
LOCK_index -> LOCK_thread_count
Problem:
When log_warnings is greater than 1, master prints binlog
dump thread information in mysqld.1.err file.
The information contains slave server id, binlog file and
binlog position. The slave server id is uint32 and the print
format was wrongly specifified (%d instead of %u).
Hence a server id which is more than 2 billion is getting
printed with a negative value.
Eg: Start binlog_dump to slave_server(-1340259414),
pos(mysql-bin.001663, 325187493)
Fix: Changed the uint32 format to %u.
Since event types can be >=128 and are read from a (possibly signed) char
pointer, we need to cast to unsigned char before extending to int, or we will
get an incorrect negative number. This was done in the main code path already,
but there is a rare case where we check for new events first without a lock
and then again with the lock. If the second check succeeds because a new event
turns up at just the right time, then we took a code path that was missing the
correct unsigned char cast, leading to incorrect handling of events for old
slave servers and possibly other grief.
(This was found from a sporadic failure in Buildbot of test case
rpl_mariadb_slave_capability).
NO ERRORS REPORTED
Problem:
=======
Errors from my_b_fill are ignored. MYSQL_BIN_LOG::write_cache
code assumes that 0 returned from my_b_fill always means
end-of-cache, but that is incorrect. It can result in error
and the error is ignored. Other callers of my_b_fill don't
check for error: my_b_copy_to_file, maybe my_b_gets.
Fix:
===
An error handler is already present to check the "cache"
error that is reported during "MYSQL_BIN_LOG::write_cache"
call. Hence error handlers are added for "my_b_copy_to_file"
and "my_b_gets".
During my_b_fill() function call, when the cache read fails
info->error= -1 is set. Hence a check for "info->error"
is added for the above to callers upon their return.
mysys/mf_iocache2.c:
Added a check for "cache->error" and simulation of cache read failure
mysys/my_read.c:
Simulation of read failure
sql/log_event.cc:
Added debug simulation
sql/sql_repl.cc:
Added a check for cache error
In method mysql_binlog_send, right after detecting a EOF in the
read event loop, and before deciding if we should change to a new
binlog file there is a execution window where new events can be
written to the binlog and a rotation can happen. When reaching
the test, the function will then change to a new binlog file
ignoring all the events written in this window. This will result
in events not being replicated.
Only when the binlog is detected as deactivated in the event loop
of the dump thread, can we really know that no more events
remain. For this reason, this test is now made under the log lock
in the beginning of the event loop when reading the events.
FROM MYSQL_BINLOG_SEND
As part Bug #11747416 A DISK FULL MAKES BINARY LOG CORRUPT,
reading the variable "binlog_can_be_corrupted" was removed
In the existing code the value of this variable is only set,
never read. And also this issue causing compiler warnings.
So the variable is completely redundant and should be removed.
sql/sql_repl.cc:
Removing dead code
Give error for wrong parameters to CHANGE MASTER
Extend MASTER_PASSWORD and MASTER_HOST lengths
mysql-test/suite/rpl/r/rpl_password_boundaries.result:
Test length of MASTER_PASSWORD, MASTER_HOST and MASTER_USER
mysql-test/suite/rpl/r/rpl_semi_sync.result:
Use different password than user name for better test coverage
mysql-test/suite/rpl/t/rpl_password_boundaries.test:
Test length of MASTER_PASSWORD, MASTER_HOST and MASTER_USER
mysql-test/suite/rpl/t/rpl_semi_sync.test:
Use different password than user name for better test coverage
sql/rpl_mi.h:
Extend MASTER_PASSWORD and MASTER_HOST lengths
sql/sql_repl.cc:
Give error for wrong parameters to CHANGE MASTER
sql/sql_repl.h:
Extend MASTER_PASSWORD and MASTER_HOST lengths
=== Problem ===
The test is dependent on binlog positions and checks
to see if the command 'START SLAVE' functions correctly
with the 'UNTIL' clause added to it. The 'UNTIL' clause
is added to specify that the slave should start and run
until the SQL thread reaches a given point in the master
binary log or in the slave relay log.
The test uses hard coded values for MASTER_LOG_POS and
RELAY_LOG_POS, instead of extracting it using
query_get_value() function. There is a test
'rpl.rpl_row_until' which does the similar thing but uses
query_get_value() function to set the values of
MASTER_LOG_POS/ RELAY_LOG_POS. To be precise,
rpl.rpl_row_until is a modified version of
engines/func.rpl_row_until.test.
The use of hard coded values may lead the slave to stop at a position
which may differ from the expected position in the binlog file,
an example being the failure of engines/funcs.rpl_row_until in
mysql-5.1 given as:
"query 'select * from t2' failed. Table 'test.t2' doesn't exist".
In this case, the slave actually ran a couple of extra commands
as a result of which the slave first deleted the table and then
ran a select query on table, leading to the above mentioned failure.
=== Fix ===
1) Fixed the code for failure seen in rpl.rpl_row_until.
This test was also failing although the symptoms of
failure were different.
2) Copied the contents from rpl.rpl_row_until into
into engines/funcs.rpl.rpl_row_until.
3) Updated engines/funcs.rpl_row_until.result accordingly.
mysql-test/suite/engines/funcs/r/rpl_row_until.result:
modified to accomodate the changes in corresponding
test file.
mysql-test/suite/engines/funcs/t/disabled.def:
removed from the list of disabled tests.
mysql-test/suite/engines/funcs/t/rpl_row_until.test:
fixed rpl.rpl_row_until and copied its content to
engines/funcs.rpl_row_until. The reason being both
are same tests but rpl.rpl_row_until is an
updated version.
mysql-test/suite/rpl/t/disabled.def:
removed from the list of disabled tests.
sql/sql_repl.cc:
Added a check to catch an improper combination
of arguements passed to 'START SLAVE UNTIL'. Earlier,
START SLAVE UNTIL MASTER_LOG_FILE='master-bin.000001',
MASTER_LOG_POS=561, RELAY_LOG_POS=12;
passed. It is now detected and an error is reported.
two tests still fail:
main.innodb_icp and main.range_vs_index_merge_innodb
call records_in_range() with both range ends being open
(which triggers an assert)
Problem
========
Replication breaks in the cases if the event length exceeds
the size of master Dump thread's max_allowed_packet.
The reason why this failure is occuring is because the event length is
more than the total size of the max_allowed_packet, on addition of the
max_event_header length exceeds the max_allowed_packet of the DUMP thread.
This causes the Dump thread to break replication and throw an error.
That can happen e.g with row-based replication in Update_rows event.
Fix
====
The problem is fixed in 2 steps:
1.) The Dump thread limit to read event is increased to the upper limit
i.e. Dump thread reads whatever gets logged in the binary log.
2.) On the slave side we increase the the max_allowed_packet for the
slave's threads (IO/SQL) by increasing it to 1GB.
This is done using the new server option (slave_max_allowed_packet)
included, is used to regulate the max_allowed_packet of the
slave thread (IO/SQL) by the DBA, and facilitates the sending of
large packets from the master to the slave.
This causes the large packets to be received by the slave and apply
it successfully.
sql/log_event.cc:
The max_allowed_packet is not evaluated to the new option
slave_max_allowed_packet after the fix.
sql/log_event.h:
Added the new option in the log_event.h file.
sql/mysqld.cc:
Added a new option to the server.
sql/slave.cc:
Increasing the session max_allowed_packet to a large value,
i.e. not taking global(max_allowed) into consideration, for the slave's threads.
sql/sql_repl.cc:
The dump thread's max_allowed_packet is set to the upper limit
which makes it independent and it now reads whatever gets
logged in the binary log.
Problem
========
Replication breaks in the cases if the event length exceeds
the size of master Dump thread's max_allowed_packet.
The reason why this failure is occuring is because the event length is
more than the total size of the max_allowed_packet, on addition of the
max_event_header length exceeds the max_allowed_packet of the DUMP thread.
This causes the Dump thread to break replication and throw an error.
That can happen e.g with row-based replication in Update_rows event.
Fix
====
The problem is fixed in 2 steps:
1.) The Dump thread limit to read event is increased to the upper limit
i.e. Dump thread reads whatever gets logged in the binary log.
2.) On the slave side we increase the the max_allowed_packet for the
slave's threads (IO/SQL) by increasing it to 1GB.
This is done using the new server option (slave_max_allowed_packet)
included, is used to regulate the max_allowed_packet of the
slave thread (IO/SQL) by the DBA, and facilitates the sending of
large packets from the master to the slave.
This causes the large packets to be received by the slave and apply
it successfully.
sql/log_event.cc:
The max_allowed_packet is not evaluated to the new option
slave_max_allowed_packet after the fix.
sql/log_event.h:
Added the new option in the log_event.h file.
sql/mysqld.cc:
Added a new option to the server.
sql/slave.cc:
Increasing the session max_allowed_packet to a large value,
i.e. not taking global(max_allowed) into consideration, for the slave's threads.
sql/sql_repl.cc:
The dump thread's max_allowed_packet is set to the upper limit
which makes it independent and it now reads whatever gets
logged in the binary log.
IN THE ERROR LOG
Problem:
Using mysqlbinlog with the --read-from-remote-server option as shown below
prints a message in error log for each call. This happens for 5.5 and above
versions
mysqlbinlog -uroot -p --read-from-remote-server --host=localhost test
Message in error log file is given below:
120312 10:27:57 [Note] Start binlog_dump to slave_server(0), pos(test, 4)
The problem is that it can fill up the error log if the command is called
very often.
Analysis:
The below mentioned print function is called from "mysql_binlog_send" function
which causes the "Start binlog_dump..." string to be printed in error log file.
sql_print_information("Start binlog_dump to master_thread_id(%lu)
slave_server(%d)..."
Fix:
A condition has been added in such a way that the 'sql_print_information'
will be invoked only when the "log_warnings" variable is set to >1
otherwise don't call the 'sql_print_information' function.
Problem
========
SQL statements close to the size of max_allowed_packet produce binary
log events larger than max_allowed_packet.
The reason why this failure is occuring is because the event length is
more than the total size of the max_allowed_packet + max_event_header
length. Now since the event length exceeds this size master Dump
thread is unable to send the packet on to the slave.
That can happen e.g with row-based replication in Update_rows event.
Fix
====
The problem was fixed by increasing the max_allowed_packet for the
slave's threads (IO/SQL) by increasing it to 1GB.
This is done using the new server option included which is used to
regulate the max_allowed_packet of the slave thread (IO/SQL).
This causes the large packets to be received by the slave and apply
it successfully.
sql/log_event.h:
Added the new option in the log_event.h file.
sql/mysqld.cc:
Added a new option to the server.
sql/slave.cc:
Increasing the session max_allowed_packet to a large value ,
i.e. not taking global(max_allowed) into consideration, for the slave's threads.
PROBLEM:
Threads end-up in deadlock due to locks acquired as described
below,
con1: Run Query on a table.
It is important that this SELECT must back-off while
trying to open the t1 and enter into wait_for_condition().
The SELECT then is blocked trying to lock mysys_var->mutex
which is held by con3. The very significant fact here is
that mysys_var->current_mutex will still point to LOCK_open,
even if LOCK_open is no longer held by con1 at this point.
con2: Try dropping table used in con1 or query some table.
It will hold LOCK_open and be blocked trying to lock
kernel_mutex held by con4.
con3: Try killing the query run by con1.
It will hold THD::LOCK_thd_data belonging to con1 while
trying to lock mysys_var->current_mutex belonging to con1.
But current_mutex will point to LOCK_open which is held
by con2.
con4: Get innodb engine status
It will hold kernel_mutex, trying to lock THD::LOCK_thd_data
belonging to con1 which is held by con3.
So while technically only con2, con3 and con4 participate in the
deadlock, con1's mysys_var->current_mutex pointing to LOCK_open
is a vital component of the deadlock.
CYCLE = (THD::LOCK_thd_data -> LOCK_open ->
kernel_mutex -> THD::LOCK_thd_data)
FIX:
LOCK_thd_data has responsibility of protecting,
1) thd->query, thd->query_length
2) VIO
3) thd->mysys_var (used by KILL statement and shutdown)
4) THD during thread delete.
Among above responsibilities, 1), 2)and (3,4) seems to be three
independent group of responsibility. If there is different LOCK
owning responsibility of (3,4), the above mentioned deadlock cycle
can be avoid. This fix introduces LOCK_thd_kill to handle
responsibility (3,4), which eliminates the deadlock issue.
Note: The problem is not found in 5.5. Introduction MDL subsystem
caused metadata locking responsibility to be moved from TDC/TC to
MDL subsystem. Due to this, responsibility of LOCK_open is reduced.
As the use of LOCK_open is removed in open_table() and
mysql_rm_table() the above mentioned CYCLE does not form.
Revision ID for changes,
open_table() = dlenev@mysql.com-20100727133458-m3ua9oslnx8fbbvz
mysql_rm_table() = jon.hauglid@oracle.com-20101116100012-kxep9txz2fxy3nmw
The function mysql_show_binlog_events has a local stack variable
'LOG_INFO linfo;', which is assigned to thd->current_linfo, however
this variable goes out of scope and is destroyed before clean
thd->current_linfo.
The problem is solved by moving 'LOG_INFO linfo;' to function scope.
mysql-test/suite/innodb/t/group_commit_crash.test:
remove autoincrement to avoid rbr being used for insert ... select
mysql-test/suite/innodb/t/group_commit_crash_no_optimize_thread.test:
remove autoincrement to avoid rbr being used for insert ... select
mysys/my_addr_resolve.c:
a pointer to a buffer is returned to the caller -> the buffer cannot be on the stack
mysys/stacktrace.c:
my_vsnprintf() is ok here, in 5.5
nes prefixed with .\ or ./
- Add my_basename() to mysys.
- Do not compile files that are not needed on Windows (my_addr_resolve, an
d safemalloc related stuff it it is not used)
Avoids linker warnings about compilation of essentially empty files.
A follow-up patch corrects max sizes of printed strings and changes llstr() to %lld.
Credits go to Davi who provided a great feedback.
sql/share/errmsg-utf8.txt:
Max size for the whole message is 512 so a part of - like '%-.512s' should be less,
reduction to 320 is safe and with good chances won't cut off a part of a rather log
message in Last_IO_Error = 'Got fatal error 1236 ...'
sql/sql_repl.cc:
llstr() is replaced by %lld.
The server crashes when receiving a COM_BINLOG_DUMP command with a position of 0 or
larger than the file size.
The execution proceeds to an error block having the last read replication coordinates
pointer be NULL and its dereferencing crashed the server.
Fixed with making "public" previously used only for heartbeat coordinates.
mysql-test/extra/rpl_tests/rpl_start_stop_slave.test:
regression test for bug#3593869-64035 is added.
mysql-test/suite/rpl/r/rpl_cant_read_event_incident.result:
results updated (error mess format is changed).
mysql-test/suite/rpl/r/rpl_log_pos.result:
results updated (error mess format is changed).
mysql-test/suite/rpl/r/rpl_manual_change_index_file.result:
results updated (error mess format is changed).
mysql-test/suite/rpl/r/rpl_packet.result:
results updated (error mess format is changed).
mysql-test/suite/rpl/r/rpl_stm_start_stop_slave.result:
results updated (error mess format is changed).
mysql-test/suite/rpl/t/rpl_stm_start_stop_slave.test:
Slave is stopped by bug#3593869-64035 tests so
-let $rpl_only_running_threads= 1 is set prior to rpl_end.
sql/share/errmsg-utf8.txt:
Increasing the max length of explanatory message to 512.
sql/sql_repl.cc:
Making `coord' to carry the last read from binlog event coordinates
regardless of heartbeat.
Renaming, small cleanup and simplifying the code after if (coord) becomes unnecessary.
Adding yet another 3rd pair of coordinates - the starting replication -
into error text.
There was memory leak when running some tests on PB2.
The reason of the failure is an early return from change_master()
that was supposed to deallocate a dyn-array.
Actually the same bug58915 was fixed in trunk with relocating the dyn-array
destruction into THD::cleanup_after_query() which can't be bypassed.
The current patch backports magne.mahre@oracle.com-20110203101306-q8auashb3d7icxho
and adds two optimizations: were done: the static buffer for the dyn-array to base on,
and the array initialization is called precisely when it's necessary rather than
per each CHANGE-MASTER as before.
mysql-test/suite/rpl/t/rpl_empty_master_host.test:
the test is binlog-format insensitive so it will be run with MIXED mode only.
mysql-test/suite/rpl/t/rpl_server_id_ignore.test:
the test is binlog-format insensitive so it will be run with MIXED mode only.
sql/sql_class.cc:
relocating the dyn-array
destruction into THD::cleanup_after_query().
sql/sql_lex.cc:
LEX.mi zero initialization is done in LEX().
sql/sql_lex.h:
Optimization for repl_ignore_server_ids to base on a static buffer
which size is chosen to fit to most common use cases.
sql/sql_repl.cc:
dyn-array destruction is relocated to THD::cleanup_after_query().
sql/sql_yacc.yy:
Refining logics of Lex->mi.repl_ignore_server_ids initialization.
The array is initialized once a corresponding option in CHANGE MASTER token sequence
is found.
Fix typo causing too low timeout value for wait_for_slave_param.inc.
Fix binlog checksums following 5.5 merge.
Make sure the rpl suite can run with --mysqld=--binlog-checksum=CRC32
Fix a number of problems in the code when checksums are enabled.
