LOCK_thd_data was used to protect both THD data and
ensure that the THD is not deleted while it was in use
This patch moves the THD delete protection to LOCK_thd_kill,
which already protects the THD for kill.
The benefits are:
- More well defined what LOCK_thd_data protects
- LOCK_thd_data usage is now much simpler and easier to verify
- Less chance of deadlocks in SHOW PROCESS LIST as there is less
chance of interactions between mutexes
- Remove not needed LOCK_thread_count from
thd_get_error_context_description()
- Fewer mutex taken for thd->awake()
Other things:
- Don't take mysys->var mutex in show processlist to check if thread
is kill marked
- thd->awake() now automatically takes the LOCK_thd_kill mutex
(Simplifies code)
- Apc uses LOCK_thd_kill instead of LOCK_thd_data
- Remove not used thd_rpl_is_parallel()
- Remove not used mysql_notify_thread_having_shared_lock()
- Remove not needed LOCK_thread_count from MYSQL_BIN_LOG::reset_logs()
- LOCK_thread_count is not protecting against rollback, so this
code and comment is not needed
- Remove mutex_locks in slave.cc that are not needed.
Added THD::assert_not_linked() to ensure that it was safe to remove
- Fixed not repeatable test load_data_stmt_view
- Updated binlog_killed to test removal of mutex
(thanks to Andrei Elkin for test)
- More code comments
This is about adding more options to force slave retries
Two new variables has been added:
slave_transaction_retry_errors
- Tells the slave thread to retry transaction for replication when a
query event returns an error from the provided list. Deadlock and
elapsed lock wait timeout errors are automatically added to this list
slave-transaction-retry-interval
- Interval of the slave SQL thread will retry a transaction
in case it failed with a deadlock or elapsed lock wait
timeout or listed in slave_transaction_retry_errors
Other changes:
- Simplifed code for slave_skip_errors (to be aligned with
slave_transaction_retry_errors)
- Renamed print_slave_skip_errors() to make_slave_skip_errors_printable()
- Remove printing error from init_slave_skip_errors as my_bitmap_init()
will do that if needed.
- Generalize has_temporary_error()
- Fix win64 pointer truncation warnings
(usually coming from misusing 0x%lx and long cast in DBUG)
- Also fix printf-format warnings
Make the above mentioned warnings fatal.
- fix pthread_join on Windows to set return value.
This fixes MDEV-7742 and MDEV-8305 (Allow user to specify if stored
procedures should be logged in the slow and general log)
New functionality:
- Added new variables log_slow_disable_statements and log_disable_statements
that can be used to disable logging of certain queries to slow and
general log. Currently supported options are 'admin', 'call', 'slave'
and 'sp'.
Defaults are as before. Only 'sp' (stored procedure statements) is
disabled for slow and general_log.
- Slow log to files now includes the following new information:
- When logging stored procedure statements the name of stored
procedure is logged.
- Number of created tmp_tables, tmp_disk_tables and the space used
by temporary tables.
- When logging 'call', the logged status now contains the sum of all
included statements. Before only 'time' was correct.
- Added filsort_priority_queue as an option for log_slow_filter (this
variable existed before, but was not exposed)
- Added support for BIT types in my_getopt()
Mapped some old variables to bitmaps (old variables can still be used)
- Variable 'log_queries_not_using_indexes' is mapped to
log_slow_filter='not_using_index'
- Variable 'log_slow_slave_statements' is mapped to
log_slow_disabled_statements='slave'
- Variable 'log_slow_admin_statements' is mapped to
log_slow_disabled_statements='admin'
- All the above variables are changed to session variables from global
variables
Other things:
- Simplified LOGGER::log_command. We don't need to check for super if
OPTION_LOG_OFF is set as this flag can only be set if one is a super
user.
- Removed some setting of enable_slow_log as it's guaranteed to be set by
mysql_parse()
- mysql_admin_table() now sets thd->enable_slow_log
- Added prepare_logs_for_admin_command() to reset thd->enable_slow_log if
needed.
- Added new functions to store, restore and add slow query status
- Added new functions to store and restore query start time
- Reorganized Sub_statement_state according to types
- Added code in dispatch_command() to ensure that
thd->reset_for_next_command() is always called for a query.
- Added thd->last_sql_command to simplify checking of what was the type
of the last command. Needed when logging to slow log as lex->sql_command
may have changed before slow logging is called.
- Moved QPLAN_TMP_... to where status for tmp tables are updated
- Added new THD variable, affected_rows, to be able to correctly log
number of affected rows to slow log.
- Added sql/mariadb.h file that should be included first by files in sql
directory, if sql_plugin.h is not used (sql_plugin.h adds SHOW variables
that must be done before my_global.h is included)
- Removed a lot of include my_global.h from include files
- Removed include's of some files that my_global.h automatically includes
- Removed duplicated include's of my_sys.h
- Replaced include my_config.h with my_global.h
Problem & Analysis: Slave's Receiver thread, Applier thread and worker
threads are created with LOCAL-INFILE option enabled. As the document
says https://dev.mysql.com/doc/refman/5.7/en/load-data-local.html,
there are some issues if a thread enables local infile.
This flag should be enabled with care. But for the above mentioned
internal threads, server is enabling it at the time of creation.
Fix: Further analysis on the code shows that none of threads really
need this flag to be enabled at any time as Slave never executes
"LOAD DATA LOCAL INFILE" after reading it from Relay log.
Applier thread removes "LOCAL" before start executing the query.
Problem was that in a circular replication setup the master remembers
position to events it has generated itself when reading from a slave.
If there are no new events in the queue from the slave, a
Gtid_list_log_event is generated to remember the last skipped event.
The problem happens if there is a network delay and we generate a
Gtid_list_log_event in the middle of the transaction, in which case there
will be an implicit comment and a new transaction with serverid=0 will be
logged.
The fix was to not generate any Gtid_list_log_events in the middle of a
transaction.
Do not silence uncertain cases, or fix any bugs.
The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.
Do not silence uncertain cases, or fix any bugs.
The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.
Intermediate commit.
Fix compilation failure with different my_atomic implementation.
The my_atomic_loadptr* takes void ** as first argument, so variables
updated with it needs to be void * (it is not legal C to cast
some_type ** to void **).
post-review fixes:
* move all ssl implementation related ifdefs/defines to one file
(ssl_compat.h)
* work around OpenSSL-1.1 desire to malloc every EVP context by
run-time checking that context allocated on the stack is big enough
(openssl.c)
* use newer version of the AWS SDK for OpenSSL 1.1
* use get_dh2048() function as generated by openssl 1.1
(viosslfactories.c)
Initial support
tested against OpenSSL 1.0.1, 1.0.2, 1.1.0, Yassl and LibreSSL
not working on Windows with native SChannel support, due to wrong cipher
mapping: Latter one requires push of CONC-241 fixes.
Please note that OpenSSL 0.9.8 and OpenSSL 1.1.0 will not work: Even if
the build succeeds, test cases will fail with various errors, especially
when using different tls libraries or versions for client and server.
Other things
- Ensure that ut_d() is set to EXPR if ut_ad() is DEBUG_ASSERT()
If not, we will get a crash in purge_sys_t::~purge_sys_t() as
this ut_ad() code expect's that the ut_d() codes has been executed
Benefits of this patch:
- Removed a lot of calls to strlen(), especially for field_string
- Strings generated by parser are now const strings, less chance of
accidently changing a string
- Removed a lot of calls with LEX_STRING as parameter (changed to pointer)
- More uniform code
- Item::name_length was not kept up to date. Now fixed
- Several bugs found and fixed (Access to null pointers,
access of freed memory, wrong arguments to printf like functions)
- Removed a lot of casts from (const char*) to (char*)
Changes:
- This caused some ABI changes
- lex_string_set now uses LEX_CSTRING
- Some fucntions are now taking const char* instead of char*
- Create_field::change and after changed to LEX_CSTRING
- handler::connect_string, comment and engine_name() changed to LEX_CSTRING
- Checked printf() related calls to find bugs. Found and fixed several
errors in old code.
- A lot of changes from LEX_STRING to LEX_CSTRING, especially related to
parsing and events.
- Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING*
- Some changes for char* to const char*
- Added printf argument checking for my_snprintf()
- Introduced null_clex_str, star_clex_string, temp_lex_str to simplify
code
- Added item_empty_name and item_used_name to be able to distingush between
items that was given an empty name and items that was not given a name
This is used in sql_yacc.yy to know when to give an item a name.
- select table_name."*' is not anymore same as table_name.*
- removed not used function Item::rename()
- Added comparision of item->name_length before some calls to
my_strcasecmp() to speed up comparison
- Moved Item_sp_variable::make_field() from item.h to item.cc
- Some minimal code changes to avoid copying to const char *
- Fixed wrong error message in wsrep_mysql_parse()
- Fixed wrong code in find_field_in_natural_join() where real_item() was
set when it shouldn't
- ER_ERROR_ON_RENAME was used with extra arguments.
- Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already
give the error.
TODO:
- Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c
- Change code to not modify LEX_CSTRING for database name
(as part of lower_case_table_names)
Intermediate commit.
Move the discovery of mysql.gtid_slave_pos* tables into the SQL thread.
This avoids doing things like opening tables and scanning the mysql
schema for tables inside of the START SLAVE statement, which might
interact badly with existing transaction or table locks.
(Even though START SLAVE is documented to implicitly commit any active
transactions, this appears not to be the case in current code).
Table discovery fits naturally in the SQL thread init code, next to
the loading of mysql.gtid_slave_pos state.
Intermediate commit.
Implement auto-creation of mysql.gtid_slave_pos* tables with needed engines,
if listed in --gtid-pos-auto-engines.
Uses an asynchronous approach to minimise locking overhead.
The list of available tables is extended with a flag. Extra entries are
added for --gtid-pos-auto-engines tables that do not exist yet, marked as
not existing but ready for auto-creation.
If record_gtid() needs a table marked for auto-creation, it sends a request
to the slave background thread to create the table, and continues to use an
existing table for the current and immediately coming transactions.
As soon as the slave background thread has made the new table available, it
will be used for all subsequent relevant transactions in record_gtid().
This asynchronous approach also avoids a lot of complex issues around trying
to do DDL in the middle of an on-going transaction.
When master_use_gtid=no, the IO thread loads the slave GTID state from
the master during connect. This races with the SQL thread when
gtid_ignore_duplicates=1. If an event is in the relay log from before
the new connect and has not been applied yet, moving the slave
position causes the SQL thread to think that event should be skipped
due to gtid_ignore_duplicates=1.
This patch simply disables gtid_ignore_duplicates when not using GTID,
which seems to be what one would expect.
- Before this patch during startup all slave threads was started without
any check that they had started properly.
- If one did a START SLAVE, STOP SLAVE or CHANGE MASTER as first command to the server
there was a chance that server could access structures that where not
properly initialized which could lead to crashes in
Log_event::read_log_event
- Fixed by waiting for slave threads to start up properly also during
server startup, like we do with START SLAVE.
Protection added to reopen_file() and new_file_impl().
Without this we could get an assert in fn_format() as name == 0,
because the file was closed and name reset, atthe same time
new_file_impl() was called.
is starting.
This is needed as if we kill the START SLAVE thread too early during
shutdown then the IO_THREAD or SQL_THREAD will not have time to properly
initlize it's replication or THD structures and clean_up() will try to
delete master_info structures that are still in use.
The reason for this is that stop slave takes LOCK_active_mi over the
whole operation while some slave operations will also need LOCK_active_mi
which causes deadlocks.
Fixed by introducing object counting for Master_info and not taking
LOCK_active_mi over stop slave or even stop_all_slaves()
Another benefit of this approach is that it allows:
- Multiple threads can run SHOW SLAVE STATUS at the same time
- START/STOP/RESET/SLAVE STATUS on a slave will not block other slaves
- Simpler interface for handling get_master_info()
- Added some missing unlock of 'log_lock' in error condtions
- Moved rpl_parallel_inactivate_pool(&global_rpl_thread_pool) to end
of stop_slave() to not have to use LOCK_active_mi inside
terminate_slave_threads()
- Changed argument for remove_master_info() to Master_info, as we always
have this available
- Fixed core dump when doing FLUSH TABLES WITH READ LOCK and parallel
replication. Problem was that waiting for pause_for_ftwrl was not done
when deleting rpt->current_owner after a force_abort.
Description:
============
If you have a relay log index file that has ended up with
some relay log files that do not exists, then RESET SLAVE
ALL is not enough to get back to a clean state.
Analysis:
=========
In the bug scenario slave server is in stopped state and
some of the relay logs got deleted but the relay log index
file is not updated.
During slave server restart replication initialization fails
as some of the required relay logs are missing. User
executes RESET SLAVE/RESET SLAVE ALL command to start a
clean slave. As per the documentation RESET SLAVE command
clears the master info and relay log info repositories,
deletes all the relay log files, and starts a new relay log
file. But in a scenario where the slave server's
Relay_log_info object is not initialized slave will not
purge the existing relay logs. Hence the index file still
remains in a bad state. Users will not be able to start
the slave unless these files are cleared.
Fix:
===
RESET SLAVE/RESET SLAVE ALL commands should do the cleanup
even in a scenario where Relay_log_info object
initialization failed.
Backported a flag named 'error_on_rli_init_info' which is
required to identify slave's Relay_log_info object
initialization failure. This flag exists in MySQL-5.6
onwards as part of BUG#14021292 fix.
During RESET SLAVE/RESET SLAVE ALL execution this flag
indicates the Relay_log_info initialization failure.
In such a case open the relay log index/relay log files
and do the required clean up.
Make the slave SQL thread always output to the error log the message "Slave
SQL thread exiting, replication stopped in ..." whenever it previously
outputted "Slave SQL thread initialized, starting replication ...".
Before this patch, it was somewhat inconsistent in which cases the message
would be output and in which not, depending on the exact time and cause of
the condition that caused the SQL thread to stop.
The SQL thread keeps track of the position in the current relay log from
which to read the next event. This position is not normally used, but a
certain interaction with the IO thread can cause the SQL thread to re-open
the relay log and seek to the stored position.
In parallel replication, there were a couple of places where the position
was not updated. This created a race where a re-open of the relay log could
seek to the wrong position and start re-reading and processing events
already handled once, causing various kinds of problems.
Fix this by moving the position update into a single place in
apply_event_and_update_pos(), which should ensure that the position is
always updated in the parallel replication case.
This problem was found from the testcase of MDEV-10863, but it is logically
a separate problem.
This has no functional changes, but it helps avoid merge problems from 10.0
to 10.1. In 10.0, code that checks for parallel replication uses
opt_slave_parallel_threads > 0, but this check needs to be
mi->using_parallel() in 10.1. By using the same check in 10.0 (with
unchanged semantics), merge problems to 10.1 are avoided.
This occured when the SQL thread (but not the IO thread) stops while
GTID and parallel replication are used with multiple domain ids in the
GTID position, and is restarted.
In this case, the SQL needs to start some way back in the relay log,
applying or skipping events within each replication domain as
appropriate.
The SQL threads starts at the beginning of an old relay log file, and
this position may be in the middle of an event group. The bug was that
such partial event group could be re-applied, causing replication
corruption.
This patch fixes the issue, by making sure to skip any initial events
that were part of an earlier (already applied) event group.
cherry-pick from 5.7:
commit 6b24763
Author: Manish Kumar <manish.4.kumar@oracle.com>
Date: Tue Mar 27 13:10:42 2012 +0530
BUG#12977988 - ON STOP SLAVE: ERROR READING PACKET FROM SERVER: LOST CONNECTION
TO MYSQL SERVER
BUG#11761457 - ERROR 2013 + "ERROR READING RELAY LOG EVENT" ON STOP SLAVEBUG#12977988 - ON STOP SLAVE: ERROR READING PACKET FROM SERVER: LOST CONNECTION
TO MYSQL SERVER
Minor review comments/changes:
- A bunch of style-fixes.
- Change macros to static inline functions.
- Update check_event_type() with compressed event types.
- Small .result file update.
Add some event types for the compressed event, there are:
QUERY_COMPRESSED_EVENT,
WRITE_ROWS_COMPRESSED_EVENT_V1,
UPDATE_ROWS_COMPRESSED_EVENT_V1,
DELETE_POWS_COMPRESSED_EVENT_V1,
WRITE_ROWS_COMPRESSED_EVENT,
UPDATE_ROWS_COMPRESSED_EVENT,
DELETE_POWS_COMPRESSED_EVENT.
These events inheritance the uncompressed editor events. One of their constructor functions and write
function have been overridden for uncompressing and compressing. Anything but this is totally the same.
On slave, The IO thread will uncompress and convert them When it receiving the events from the master.
So the SQL and worker threads can be stay unchanged.
Now we use zlib as compress algorithm. It maybe support other algorithm in the future.
Merge feature into 10.2 from feature branch.
Delayed replication adds an option
CHANGE MASTER TO master_delay=<seconds>
Replication will then delay applying events with that many
seconds. This creates a replication slave that reflects the state of
the master some time in the past.
Feature is ported from MySQL source tree.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
Problem:
When using the delayed slave feature, and the SQL thread is delaying,
and the user issues STOP SLAVE, the event we wait for was executed.
It should not be executed.
Fix:
Check the return value from the delay function,
slave.cc:slave_sleep(). If the return value is 1, it means the thread
has been stopped, in this case we don't execute the statement.
Also, refactored the test case for delayed slave a little: added the
test script include/rpl_assert.inc, which asserts that a condition holds
and prints a message if not. Made rpl_delayed_slave.test use this. The
advantage is that the test file is much easier to read and maintain,
because it is clear what is an assertion and what is not, and also the
expected result can be found in the test file, you don't have to compare
it to the result file.
Manually merged into MariaDB from MySQL commit
fd2b210383358fe7697f201e19ac9779879ba72a
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
The original MySQL patch left some refactoring todo's, possibly
because of known conflicts with other parallel development (like
info-repository feature perhaps).
This patch fixes those todos/refactorings.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
Initial merge of delayed replication from MySQL git.
The code from the initial push into MySQL is merged, and the
associated test case passes. A number of tasks are still pending:
1. Check full test suite run for any regressions or .result file updates.
2. Extend the feature to also work for parallel replication.
3. There are some todo-comments about future refactoring left from
MySQL, these should be located and merged on top.
4. There are some later related MySQL commits, these should be checked
and merged. These include:
e134b9362ba0b750d6ac1b444780019622d14aa5
b38f0f7857c073edfcc0a64675b7f7ede04be00f
fd2b210383358fe7697f201e19ac9779879ba72a
afc397376ec50e96b2918ee64e48baf4dda0d37d
5. The testcase from MySQL relies heavily on sleep and timing for
testing, and seems likely to sporadically fail on heavily loaded test
servers in buildbot or distro build farms.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
The function apply_event_and_update_pos() is called with the
rli->data_lock mutex held. However, there seems to be nothing in the
function actually needing the mutex to be held. Certainly not in the
parallel replication case, where sql_slave_skip_counter is always 0
since the non-zero case is handled by the SQL driver thread.
So this patch makes parallel replication use a variant of
apply_event_and_update_pos() without the need to take the
rli->data_lock mutex. This avoids one contended global mutex for each
event executed, which might improve performance on CPU-bound workloads
somewhat.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
When a deadlock kill is detected inside the storage engine, the kill
is not done immediately, to avoid calling back into the storage engine
kill_query method with various lock subsystem mutexes held. Instead the
kill is queued and done later by a slave background thread.
This patch in preparation for fixing TokuDB optimistic parallel
replication, as well as for removing locking hacks in InnoDB/XtraDB in
10.2.
Signed-off-by: Kristian Nielsen <knielsen at knielsen-hq.org>
- When waiting for events, start time is now counted from start of wait
- Instead of having "Connect" as "Command" for all replication threads we
now have:
- Slave_IO for Slave thread reading relay log
- Slave_SQL for slave executing SQL commands or distribution queries to
Slave workers
- Slave_worker for slave threads executin SQL commands in parallel replication
In well defined C code, the "this" pointer is never NULL. Currently, we
were potentially dereferencing a NULL pointer (master_info_index). GCC v6
removes any "if (!this)" conditions as it assumes this is always a
non-null pointer. In order to prevent undefined behaviour, check the
pointer before dereferencing and remove the check within member
functions.
- Fixed typos
- Added --core-on-failure to mysql-test-run
- More DBUG_PRINT in viosocket.c
- Don't forget CLIENT_REMEMBER_OPTIONS for compressed slave protocol
- Removed not used stage variables
Make the slave SQL thread always output to the error log the message "Slave
SQL thread exiting, replication stopped in ..." whenever it previously
outputted "Slave SQL thread initialized, starting replication ...".
Before this patch, it was somewhat inconsistent in which cases the message
would be output and in which not, depending on the exact time and cause of
the condition that caused the SQL thread to stop.
1. remove unnecessary rpl-tokudb combination file.
2. fix rpl_ignore_table to cleanup properly (not leave test
grants in memory)
3. check_temp_dir() is supposed to set the error in stmt_da - do
it even when called multiple times, this fixes a crash when
rpl.rpl_slave_load_tmpdir_not_exist is run twice.
Chery-picked commits from codership/mysql-wsrep.
MW-284: Slave I/O retry on ER_COM_UNKNOWN_ERROR
Slave would treat ER_COM_UNKNOWN_ERROR as fatal error and stop.
The fix here is to treat it as a network error and rely on the
built-in mechanism to retry.
MW-284: Add an MTR test
mysqld maintains a list of TABLE objects for all temporary
tables created within a session in THD. Here each table is
represented by a TABLE object.
A query referencing a particular temporary table for more
than once, however, failed with ER_CANT_REOPEN_TABLE error
because a TABLE_SHARE was allocate together with the TABLE,
so temporary tables always had only one TABLE per TABLE_SHARE.
This patch lift this restriction by separating TABLE and
TABLE_SHARE objects and storing TABLE_SHAREs for temporary
tables in a list in THD, and TABLEs in a list within their
respective TABLE_SHAREs.
- To ensure that mallocs are marked for the correct THD, even if it's
allocated in another thread, I added the thread_id to the THD constructor
- Added st_my_thread_var to thr_lock_info_init() to avoid a call to my_thread_var
- Moved things from THD::THD() to THD::init()
- Moved some things to THD::cleanup()
- Added THD::free_connection() and THD::reset_for_reuse()
- Added THD to CONNECT::create_thd()
- Added THD::thread_dbug_id and st_my_thread_var->dbug_id. These are needed
to ensure that we have a constant thread_id used for debugging with a THD,
even if it changes thread_id (=connection_id)
- Set variables.pseudo_thread_id in constructor. Removed not needed sets.
Revert following bug fix:
Bug#20685029: SLAVE IO THREAD SHOULD STOP WHEN DISK IS
FULL
Bug#21753696: MAKE SHOW SLAVE STATUS NON BLOCKING IF IO
THREAD WAITS FOR DISK SPACE
This fix results in a deadlock between slave IO thread
and SQL thread.
(cherry picked from commit e3fea6c6dbb36c6ab21c4ab777224560e9608b53)
Revert following bug fix:
Bug#20685029: SLAVE IO THREAD SHOULD STOP WHEN DISK IS
FULL
Bug#21753696: MAKE SHOW SLAVE STATUS NON BLOCKING IF IO
THREAD WAITS FOR DISK SPACE
This fix results in a deadlock between slave IO thread
and SQL thread.
There was a race between end_slave() and cleanup code at the end of
handle_slave_sql(). This could cause access to master_info_index and
global_rpl_thread_pool after they had been freed.
Fix by skipping that cleanup if server shutdown is in progress, as is done
in other parts of the code as well (the cleanup, which stops worker threads
that are not needed anymore, is redundant anyway when the server is shutting
down).
FULL
Bug#21753696: MAKE SHOW SLAVE STATUS NON BLOCKING IF IO
THREAD WAITS FOR DISK SPACE
Problem:
========
Currently SHOW SLAVE STATUS blocks if IO thread waits for
disk space. This makes automation tools verifying
server health block on taking relevant action. Finally this
will create SHOW SLAVE STATUS piles.
Analysis:
=========
SHOW SLAVE STATUS hangs on mi->data_lock if relay log write
is waiting for free disk space while holding mi->data_lock.
mi->data_lock is needed to protect the format description
event (mi->format_description_event) which is accessed by
the clients running FLUSH LOGS and slave IO thread. Note
relay log writes don't need to be protected by
mi->data_lock, LOCK_log is used to protect relay log between
IO and SQL thread (see MYSQL_BIN_LOG::append_event). The
code takes mi->data_lock to protect
mi->format_description_event during relay log rotate which
might get triggered right after relay log write.
Fix:
====
Release the data_lock just for the duration of writing into
relay log.
Made change to ensure the following lock order is maintained
to avoid deadlocks.
data_lock, LOCK_log
data_lock is held during relay log rotations to protect
the description event.
Creating a CONNECT object on client connect and pass this to the working thread which creates the THD.
Split LOCK_thread_count to different mutexes
Added LOCK_thread_start to syncronize threads
Moved most usage of LOCK_thread_count to dedicated functions
Use next_thread_id() instead of thread_id++
Other things:
- Thread id now starts from 1 instead of 2
- Added cast for thread_id as thread id is now of type my_thread_id
- Made THD->host const (To ensure it's not changed)
- Removed some DBUG_PRINT() about entering/exiting mutex as these was already logged by mutex code
- Fixed that aborted_connects and connection_errors_internal are counted in all cases
- Don't take locks for current_linfo when we set it (not needed as it was 0 before)
This occurs when replication stops with an error, domain-based parallel
replication is used, and the GTID position contains more than one domain.
Furthermore, it relates to the case where the SQL thread is restarted
without first stopping the IO thread.
In this case, the file/offset relay-log position does not correctly
represent the slave's multi-dimensional position, because other domains may
be far ahead of, or behind, the domain with the failing event. So the code
reverts the relay log position back to the start of a relay log file that is
known to be before all active domains.
There was a bug that when the SQL thread was restarted, the
rli->relay_log_state was incorrectly initialised from @@gtid_slave_pos. This
position will likely be too far ahead, due to reverting the relay log
position. Thus, if the replication fails again after the SQL thread restart,
the rli->restart_gtid_pos might be updated incorrectly. This in turn would
cause a second SQL thread restart to replicate from the wrong position, if
the IO thread was still left running.
The fix is to initialise rli->relay_log_state from @@gtid_slave_pos only
when we actually purge and re-fetch relay logs from the master, not at every
SQL thread start.
A related problem is the use of sql_slave_skip_counter to resolve
replication failures in this kind of scenario. Since the slave position is
multi-dimensional, sql_slave_skip_counter can not work properly - it is
indeterminate exactly which event is to be skipped, and is unlikely to work
as expected for the user. So make this an error in the case where
domain-based parallel replication is used with multiple domains, suggesting
instead the user to set @@gtid_slave_pos to reliably skip the desired event.
The problem was that wait_for_slave_io_to_start reported that the io thread
was ready, when it was still initializing. This caused test suite to
continue too early, for example before the semi sync plugin was properly
enabled.
Fixed by introducing a new internal stage: "Preparing". Slave_IO_Running is
now set to "Yes" only when all initializing is done and the IO thread is
ready to read things from the master.
The only test affected by this change is rpl_flsh_tbls, which got stuck in
the preparing phase while trying to read the GTID position from a table.
Fixed by having this test waiting for Preparing instead of Yes.
- Added testing if connection is killed to shortcut reading of connection data
This will allow us later in 10.2 to do a cleaner shutdown of slaves (less errors in the log)
- Add new status variables: Slaves_connected, Slaves_running and Slave_connections.
- Use MYSQL_SLAVE_NOT_RUN instead of 0 with slave_running.
- Don't print obvious extra warnings to the error log when slave is shut down normally.
This includes fixing all utilities to not have any memory leaks,
as safemalloc warnings stopped tests from passing on MacOSX.
- Ensure that all clients takes character-set-dir, as the
libmysqlclient library will use it.
- mysql-test-run now passes character-set-dir to all external clients.
- Changed dynstr_free() so that it can be called twice (made freeing code easier)
- Changed rpl_global_gtid_slave_state to be allocated dynamicly as it
includes a mutex that needs to be initizlied/destroyed before my_end() is called.
- Removed rpl_slave_state::init() and rpl_slave_stage::deinit() as
their job are better handling by constructor and delete.
- Print alias instead of table_name in check_duplicate_key as
table_name may have been converted to lower case.
Other things:
- Fixed a case in time_to_datetime_with_warn() where we where
using && instead of & in tests
In domain ID based filtering, a flag is used to filter-out
the events that belong to a particular domain. This flag gets
set when IO thread receives a GTID_EVENT for the domain on
filter list and its reset at the last event in the GTID group.
The resetting, however, was wrongly done before the decision to
write/filter the event from relay log is made. As a result, the
last event in the group will always pass through the filter.
Fixed by deferring the reset logic. Also added a test case.
Before, the Seconds_behind_master was updated already when an event
was queued for a worker thread to execute later. This might lead users
to interpret a low value as the slave being almost up to date with the
master, while in reality there might still be lots and lots of events
still queued up waiting to be applied by the slave.
See https://lists.launchpad.net/maria-developers/msg08958.html for
more detailed discussions.
Patch backported from MariaDB 10.1
- Ensure that we wait with cleanup() until slave thread has stopped.
- Added signal_thd_deleted() to signal close_connections() that all THD's has been freed.
Other things
- Removed not needed calls to THD_CHECK_SENTRY() when we are calling 'delete thd'.
MDEV-8685 MariaDB fails to decode Anonymous_GTID entries
MDEV-5705 Replication testing: 5.6->10.0
- Ignoring GTID events from MySQL 5.6+ (Allows replication from MySQL 5.6+ with GTID enabled)
- Added ignorable events from MySQL 5.6
- mysqlbinlog now writes information about GTID and ignorable events.
- Added more information in error message when replication stops because of wrong information in binary log.
- Fixed wrong test when write_on_release() should flush cache.
Introduce Log_event_writer() that encapsulates
writing data to an IO_CACHE with automatic checksum calculation.
Now all events properly checksum themselves as needed.
Use Log_event_writer in MYSQL_BIN_LOG::write_cache() instead
of copy-pasting its logic all over.
Later Log_event_writer will also do encryption.
commit f1abd015dc
Author: Andrei Elkin <aelkin@mysql.com>
Date: Thu Nov 12 17:10:19 2009 +0200
Bug #47210 first execution of "start slave until" stops too early
- If run with valgrind, mysqltest will now wait longer when syncronizing slave with master
- Ensure that we wait with cleanup() until slave thread has stopped.
- Added signal_thd_deleted() to signal close_connections() that all THD's has been freed.
- Check in handle_fatal_signal() that we don't use variables that has been freed.
- Increased some timeouts when run with --valgrind
Other things:
- Fixed wrong test in one_thread_per_connection_end() if galera is used.
- Removed not needed calls to THD_CHECK_SENTRY() when we are calling 'delete thd'.
- Part 3: Adding mem_root to push_back() and push_front()
Other things:
- Added THD as an argument to some partition functions.
- Added memory overflow checking for XML tag's in read_xml()
- Added mem_root to all calls to new Item
- Added private method operator new(size_t size) to Item to ensure that
we always use a mem_root when creating an item.
This saves use once call to current_thd per Item creation
Added mandatory thd parameter to Item (and all derivative classes) constructor.
Added thd parameter to all routines that may create items.
Also removed "current_thd" from Item::Item. This reduced number of
pthread_getspecific() calls from 290 to 177 per OLTP RO transaction.
Fix was to add a test in Query_log_event::Query_log_event() if we are using
CREATE ... SELECT and in this case use trans cache, like we do on the master.
This avoid using (with doesn't have checksum)
Other things:
- Removed dummy call my_checksum(0L, NULL, 0)
- More DBUG_PRINT
- Cleaned up Log_event::need_checksum() to make it more readable (similar as in MySQL 5.6)
- Renamed variable that was hiding another one in create_table_imp()
field.cc
- Fixed warning about overlapping memory copy (backport from 10.0)
Item_subselect.cc
- Fixed core dump in main.view
- Problem was that thd->lex->current_select->master_unit()->item was not set, which caused crash in maxr_as_dependent
sql/mysqld.cc
- Got error on shutdown as we where freeing mutex before all THD objects was freed
(~THD uses some mutex). Fixed by during shutdown freeing THD inside mutex.
sql/log.cc
- log_space_lock and LOCK_log where locked in inconsistenly. Fixed by not having a log_space_lock around purge_logs.
sql/slave.cc
- Remove unnecessary log_space_lock
- Move cond_broadcast inside lock to ensure we don't miss the signal
Other things:
- Avoid calling init_and_set_log_file_name() when opening binary log.
- Remove newlines early when reading from index file.
- Ensure that reset_logs() will work even if thd is 0 (Can happen on startup)
- Added thd to sart_slave_threads() for better error handling.
- Changed ER(ER_...) to ER_THD(thd, ER_...) when thd was known or if there was many calls to current_thd in the same function.
- Changed ER(ER_..) to ER_THD_OR_DEFAULT(current_thd, ER...) in some places where current_thd is not necessary defined.
- Removing calls to current_thd when we have access to thd
Part of this is optimization (not calling current_thd when not needed),
but part is bug fixing for error condition when current_thd is not defined
(For example on startup and end of mysqld)
Notable renames done as otherwise a lot of functions would have to be changed:
- In JOIN structure renamed:
examined_rows -> join_examined_rows
record_count -> join_record_count
- In Field, renamed new_field() to make_new_field()
Other things:
- Added DBUG_ASSERT(thd == tmp_thd) in Item_singlerow_subselect() just to be safe.
- Removed old 'tab' prefix in JOIN_TAB::save_explain_data() and use members directly
- Added 'thd' as argument to a few functions to avoid calling current_thd.
Add log_bin_index, log_bin_basename and relay_log_basename system
variables. Also, convert relay_log_index system variable to
NO_CMD_LINE and implement --relay-log-index as a command line
option.
1. After a period of wait (where last_master_timestamp=0)
do NOT restore the last_master_timestamp to the timestamp
of the last executed event (which would mean we've just
executed it, and we're that much behind the master).
2. Update last_master_timestamp before executing the event,
not after.
Take the approach from the this commit (but with a different test
case that actually makes sense):
commit 0c75ab453fb8c5439576af8fe5add7a1b89f1569
Author: Luis Soares <luis.soares@sun.com>
Date: Thu Apr 15 17:39:31 2010 +0100
BUG#52166: Seconds_Behind_Master spikes after long idle period
The slave SQL thread was clearing serial_rgi->thd before deleting
serial_rgi, which could cause access to NULL THD.
The clearing was introduced in commit
2e100cc5a4 and is just plain wrong. So revert
that part (single line) of that commit.
Thanks to Daniel Black for bug analysis and test case.
Add some suppressions that were missing. They are for if a STOP SLAVE is
executed early during IO thread startup, when it is negotiating with the
master. The master connection may be killed in the middle of a
mysql_real_query(), which is not a test failure if it is a network error.
This also caught one real code error, fixed with this commit: The I/O thread
would fail to automatically reconnect if a network error happened while
fetching the value of @@GLOBAL.gtid_domain_id.
Delay spawning parallel replication worker threads until a slave SQL
thread is running, and de-spawn them when the last SQL thread stops.
This is especially useful to avoid needless threads on a master in a
setup where same my.cnf is used on masters and slaves.
The problem occurs in parallel replication in GTID mode, when we are using
multiple replication domains. In this case, if the SQL thread stops, the
slave GTID position may refer to a different point in the relay log for each
domain.
The bug was that when the SQL thread was stopped and restarted (but the IO
thread was kept running), the SQL thread would resume applying the relay log
from the point of the most advanced replication domain, silently skipping all
earlier events within other domains. This caused replication corruption.
This patch solves the problem by storing, when the SQL thread stops with
multiple parallel replication domains active, the current GTID
position. Additionally, the current position in the relay logs is moved back
to a point known to be earlier than the current position of any replication
domain. Then when the SQL thread restarts from the earlier position, GTIDs
encountered are compared against the stored GTID position. Any GTID that was
already applied before the stop is skipped to avoid duplicate apply.
This patch should have no effect if multi-domain GTID parallel replication is
not used. Similarly, if both SQL and IO thread are stopped and restarted, the
patch has no effect, as in this case the existing relay logs are removed and
re-fetched from the master at the current global @@gtid_slave_pos.
If somehow the COMMIT or XID event in an event group was missing, the code in
parallel replication to handle this was not sufficient, leading to server
deadlock.
The order of initialisation during server startup was incorrect. The slave
threads were started before the parallel replication worker thread pool was
initialised, allowing a race where uninitialised data could be accessed.
Adjust the configuration options, as discussed on the
maria-developers@ mailing list.
The option to hint a transaction to not be replicated in parallel is
now called @@skip_parallel_replication, consistent with
@@skip_replication.
And the --slave-parallel-mode is now simplified to have just one of
the following values:
none
minimal
conservative
optimistic
aggressive
This reflects successively harder efforts to find opportunities to run
things in parallel on the slave. It allows to extend the server with
more automatic heuristics in the future without having to introduce a
new configuration option for each and every one.
special character sets like utf16, utf32, ucs2.
Analysis: MySQL server does not support few special character sets like
utf16,utf32 and ucs2 as "client's character set"(eg: utf16,utf32, ucs2).
It is known limitation listed in the documentation
http://dev.mysql.com/doc/refman/5.5/en/charset-connection.html.
The default value for default-character-set parameter is 'auto'
which means that if the server's character set is not supported,
then server automatically changes client's character set to
predefined character-set which is 'latin1' in the current code.
Eg:
$ ./mysql -uroot -S$SOCKET_FILE --default-character-set=utf16
ERROR 1231 (42000): Variable 'character_set_client' can't be set to the value of 'utf16'
$ ./mysql -uroot -S$SOCKET_FILE will be successfully connected to
server with 'latin1' as default client side character set.
When IO thread is trying to connect to Master, it sets server's character
set as client's character set. When Slave server is started with these
special character sets, IO thread (which is like a connection to Master)
fails because of the above said limitation.
Fix: Now even IO thread also behaves the same as a regular client behaves.
i.e., If server's character set is not supported as client's character set,
then set default's client character set(latin1) as client's character set.
Implement a new mode for parallel replication. In this mode, all transactions
are optimistically attempted applied in parallel. In case of conflicts, the
offending transaction is rolled back and retried later non-parallel.
This is an early-release patch to facilitate testing, more changes to user
interface / options will be expected. The new mode is not enabled by default.
The reason for the failure was a bug in an include file on debian that causes 'struct stat'
to have different sized depending on the environment.
This patch fixes so that we always include my_global.h or my_config.h before we include any other files.
Other things:
- Removed #include <my_global.h> in some include files; Better to always do this at the top level to have as few
"always-include-this-file-first' files as possible.
- Removed usage of some include files that where already included by my_global.h or by other files.
client/mysql_plugin.c:
Use my_global.h first
client/mysqlslap.c:
Remove duplicated include files
extra/comp_err.c:
Remove duplicated include files
include/m_string.h:
Remove duplicated include files
include/maria.h:
Remove duplicated include files
libmysqld/emb_qcache.cc:
Use my_global.h first
plugin/semisync/semisync.h:
Use my_pthread.h first
sql/datadict.cc:
Use my_global.h first
sql/debug_sync.cc:
Use my_global.h first
sql/derror.cc:
Use my_global.h first
sql/des_key_file.cc:
Use my_global.h first
sql/discover.cc:
Use my_global.h first
sql/event_data_objects.cc:
Use my_global.h first
sql/event_db_repository.cc:
Use my_global.h first
sql/event_parse_data.cc:
Use my_global.h first
sql/event_queue.cc:
Use my_global.h first
sql/event_scheduler.cc:
Use my_global.h first
sql/events.cc:
Use my_global.h first
sql/field.cc:
Use my_global.h first
Remove duplicated include files
sql/field_conv.cc:
Use my_global.h first
sql/filesort.cc:
Use my_global.h first
Remove duplicated include files
sql/gstream.cc:
Use my_global.h first
sql/ha_ndbcluster.cc:
Use my_global.h first
sql/ha_ndbcluster_binlog.cc:
Use my_global.h first
sql/ha_ndbcluster_cond.cc:
Use my_global.h first
sql/ha_partition.cc:
Use my_global.h first
sql/handler.cc:
Use my_global.h first
sql/hash_filo.cc:
Use my_global.h first
sql/hostname.cc:
Use my_global.h first
sql/init.cc:
Use my_global.h first
sql/item.cc:
Use my_global.h first
sql/item_buff.cc:
Use my_global.h first
sql/item_cmpfunc.cc:
Use my_global.h first
sql/item_create.cc:
Use my_global.h first
sql/item_geofunc.cc:
Use my_global.h first
sql/item_inetfunc.cc:
Use my_global.h first
sql/item_row.cc:
Use my_global.h first
sql/item_strfunc.cc:
Use my_global.h first
sql/item_subselect.cc:
Use my_global.h first
sql/item_sum.cc:
Use my_global.h first
sql/item_timefunc.cc:
Use my_global.h first
sql/item_xmlfunc.cc:
Use my_global.h first
sql/key.cc:
Use my_global.h first
sql/lock.cc:
Use my_global.h first
sql/log.cc:
Use my_global.h first
sql/log_event.cc:
Use my_global.h first
sql/log_event_old.cc:
Use my_global.h first
sql/mf_iocache.cc:
Use my_global.h first
sql/mysql_install_db.cc:
Remove duplicated include files
sql/mysqld.cc:
Remove duplicated include files
sql/net_serv.cc:
Remove duplicated include files
sql/opt_range.cc:
Use my_global.h first
sql/opt_subselect.cc:
Use my_global.h first
sql/opt_sum.cc:
Use my_global.h first
sql/parse_file.cc:
Use my_global.h first
sql/partition_info.cc:
Use my_global.h first
sql/procedure.cc:
Use my_global.h first
sql/protocol.cc:
Use my_global.h first
sql/records.cc:
Use my_global.h first
sql/records.h:
Don't include my_global.h
Better to do this at the upper level
sql/repl_failsafe.cc:
Use my_global.h first
sql/rpl_filter.cc:
Use my_global.h first
sql/rpl_gtid.cc:
Use my_global.h first
sql/rpl_handler.cc:
Use my_global.h first
sql/rpl_injector.cc:
Use my_global.h first
sql/rpl_record.cc:
Use my_global.h first
sql/rpl_record_old.cc:
Use my_global.h first
sql/rpl_reporting.cc:
Use my_global.h first
sql/rpl_rli.cc:
Use my_global.h first
sql/rpl_tblmap.cc:
Use my_global.h first
sql/rpl_utility.cc:
Use my_global.h first
sql/set_var.cc:
Added comment
sql/slave.cc:
Use my_global.h first
sql/sp.cc:
Use my_global.h first
sql/sp_cache.cc:
Use my_global.h first
sql/sp_head.cc:
Use my_global.h first
sql/sp_pcontext.cc:
Use my_global.h first
sql/sp_rcontext.cc:
Use my_global.h first
sql/spatial.cc:
Use my_global.h first
sql/sql_acl.cc:
Use my_global.h first
sql/sql_admin.cc:
Use my_global.h first
sql/sql_analyse.cc:
Use my_global.h first
sql/sql_audit.cc:
Use my_global.h first
sql/sql_base.cc:
Use my_global.h first
sql/sql_binlog.cc:
Use my_global.h first
sql/sql_bootstrap.cc:
Use my_global.h first
Use my_global.h first
sql/sql_cache.cc:
Use my_global.h first
sql/sql_class.cc:
Use my_global.h first
sql/sql_client.cc:
Use my_global.h first
sql/sql_connect.cc:
Use my_global.h first
sql/sql_crypt.cc:
Use my_global.h first
sql/sql_cursor.cc:
Use my_global.h first
sql/sql_db.cc:
Use my_global.h first
sql/sql_delete.cc:
Use my_global.h first
sql/sql_derived.cc:
Use my_global.h first
sql/sql_do.cc:
Use my_global.h first
sql/sql_error.cc:
Use my_global.h first
sql/sql_explain.cc:
Use my_global.h first
sql/sql_expression_cache.cc:
Use my_global.h first
sql/sql_handler.cc:
Use my_global.h first
sql/sql_help.cc:
Use my_global.h first
sql/sql_insert.cc:
Use my_global.h first
sql/sql_lex.cc:
Use my_global.h first
sql/sql_load.cc:
Use my_global.h first
sql/sql_locale.cc:
Use my_global.h first
sql/sql_manager.cc:
Use my_global.h first
sql/sql_parse.cc:
Use my_global.h first
sql/sql_partition.cc:
Use my_global.h first
sql/sql_plugin.cc:
Added comment
sql/sql_prepare.cc:
Use my_global.h first
sql/sql_priv.h:
Added error if we use this before including my_global.h
This check is here becasue so many files includes sql_priv.h first.
sql/sql_profile.cc:
Use my_global.h first
sql/sql_reload.cc:
Use my_global.h first
sql/sql_rename.cc:
Use my_global.h first
sql/sql_repl.cc:
Use my_global.h first
sql/sql_select.cc:
Use my_global.h first
sql/sql_servers.cc:
Use my_global.h first
sql/sql_show.cc:
Added comment
sql/sql_signal.cc:
Use my_global.h first
sql/sql_statistics.cc:
Use my_global.h first
sql/sql_table.cc:
Use my_global.h first
sql/sql_tablespace.cc:
Use my_global.h first
sql/sql_test.cc:
Use my_global.h first
sql/sql_time.cc:
Use my_global.h first
sql/sql_trigger.cc:
Use my_global.h first
sql/sql_udf.cc:
Use my_global.h first
sql/sql_union.cc:
Use my_global.h first
sql/sql_update.cc:
Use my_global.h first
sql/sql_view.cc:
Use my_global.h first
sql/sys_vars.cc:
Added comment
sql/table.cc:
Use my_global.h first
sql/thr_malloc.cc:
Use my_global.h first
sql/transaction.cc:
Use my_global.h first
sql/uniques.cc:
Use my_global.h first
sql/unireg.cc:
Use my_global.h first
sql/unireg.h:
Removed inclusion of my_global.h
storage/archive/ha_archive.cc:
Added comment
storage/blackhole/ha_blackhole.cc:
Use my_global.h first
storage/csv/ha_tina.cc:
Use my_global.h first
storage/csv/transparent_file.cc:
Use my_global.h first
storage/federated/ha_federated.cc:
Use my_global.h first
storage/federatedx/federatedx_io.cc:
Use my_global.h first
storage/federatedx/federatedx_io_mysql.cc:
Use my_global.h first
storage/federatedx/federatedx_io_null.cc:
Use my_global.h first
storage/federatedx/federatedx_txn.cc:
Use my_global.h first
storage/heap/ha_heap.cc:
Use my_global.h first
storage/innobase/handler/handler0alter.cc:
Use my_global.h first
storage/maria/ha_maria.cc:
Use my_global.h first
storage/maria/unittest/ma_maria_log_cleanup.c:
Remove duplicated include files
storage/maria/unittest/test_file.c:
Added comment
storage/myisam/ha_myisam.cc:
Move sql_plugin.h first as this includes my_global.h
storage/myisammrg/ha_myisammrg.cc:
Use my_global.h first
storage/oqgraph/oqgraph_thunk.cc:
Use my_config.h and my_global.h first
One could not include my_global.h before oqgraph_thunk.h (don't know why)
storage/spider/ha_spider.cc:
Use my_global.h first
storage/spider/hs_client/config.cpp:
Use my_global.h first
storage/spider/hs_client/escape.cpp:
Use my_global.h first
storage/spider/hs_client/fatal.cpp:
Use my_global.h first
storage/spider/hs_client/hstcpcli.cpp:
Use my_global.h first
storage/spider/hs_client/socket.cpp:
Use my_global.h first
storage/spider/hs_client/string_util.cpp:
Use my_global.h first
storage/spider/spd_conn.cc:
Use my_global.h first
storage/spider/spd_copy_tables.cc:
Use my_global.h first
storage/spider/spd_db_conn.cc:
Use my_global.h first
storage/spider/spd_db_handlersocket.cc:
Use my_global.h first
storage/spider/spd_db_mysql.cc:
Use my_global.h first
storage/spider/spd_db_oracle.cc:
Use my_global.h first
storage/spider/spd_direct_sql.cc:
Use my_global.h first
storage/spider/spd_i_s.cc:
Use my_global.h first
storage/spider/spd_malloc.cc:
Use my_global.h first
storage/spider/spd_param.cc:
Use my_global.h first
storage/spider/spd_ping_table.cc:
Use my_global.h first
storage/spider/spd_sys_table.cc:
Use my_global.h first
storage/spider/spd_table.cc:
Use my_global.h first
storage/spider/spd_trx.cc:
Use my_global.h first
storage/xtradb/handler/handler0alter.cc:
Use my_global.h first
storage/xtradb/handler/i_s.cc:
Use my_global.h first
Moved freeing of mutex earlier, as we don't need to have log_space_cond locked for doing rotate_relay_log()
sql/slave.cc:
Moved freeing of mutex earlier, as we don't need to have log_space_cond locked for doing rotate_relay_log()
If the slave gets a reconnect in the middle of a GTID event group, normally
it will re-fetch that event group, skipping the first part that was already
queued for the SQL thread.
However, if the master crashed while writing the event group, the group is
incomplete. This patch detects this case and makes sure that the
transaction is rolled back and nothing is skipped from any following
event groups.
Similarly, a network proxy might cause the reconnect to end up on a
different master server. Detect this by noticing a different server_id,
and similarly in this case roll back the partially received group.
Merged lp:maria/maria-10.0-galera up to revision 3880.
Added a new functions to handler API to forcefully abort_transaction,
producing fake_trx_id, get_checkpoint and set_checkpoint for XA. These
were added for future possiblity to add more storage engines that
could use galera replication.
Merged lp:maria/maria-10.0-galera up to revision 3879.
Added a new functions to handler API to forcefully abort_transaction,
producing fake_trx_id, get_checkpoint and set_checkpoint for XA. These
were added for future possiblity to add more storage engines that
could use galera replication.
mysqldump:
- Added --log-queries to allow one to disable logging for the dump
sql/log_event.cc:
- Removed setting of enable_slow_log as it's not required anymore.
sql/sql_parse.cc:
- Set enable_slow_log to value of thd->variables.sql_log_slow as this will speed up tests if slow log is disabled.
- opt_log_slow_admin_statements can now only disable slow log, not enable it.
sql/sql_explain.cc:
- Minor cleanup
Other things:
- Added sql_log_slow to system variables.
- Changed opt_slow_log to global_system_variables.sql_log_slow in all files
- Updated tests to reflect changes
config.h.cmake:
define NOMINMAX, otherwise Windows system headers define min() and max() macros
sql/slave.cc:
mi->report() has one more argument in MariaDB
storage/xtradb/buf/buf0flu.cc:
xtradb fixes for windows, again
bzr merge -r4264 maria/5.5
Text conflict in sql/mysqld.cc
Text conflict in storage/xtradb/btr/btr0cur.c
Text conflict in storage/xtradb/buf/buf0buf.c
Text conflict in storage/xtradb/buf/buf0lru.c
Text conflict in storage/xtradb/handler/ha_innodb.cc
5 conflicts encountered.
Fix the bug properly (plugin cannot be unloaded as long as it's locked).
Enable and fix the test case.
Significantly reduce number of LOCK_plugin locks for semisync
(practically all locks were removed)
Merge the patches into MariaDB 10.0 main.
With this patch, parallel replication will now automatically retry a
transaction that fails due to deadlock or other temporary error, same as
single-threaded replication.
We catch deadlocks with InnoDB transactions due to enforced commit order. If
T1 must commit before T2 in parallel replication and T1 ends up waiting for T2
inside InnoDB, we kill T2 and retry it later to resolve the deadlock
automatically.
Fix a bug discovered in Buildbot valgrind. The logic in checking for slave
init thread completion was reversed, so depending on thread scheduling server
startup could hang.
Also add another variant of SSL valgrind suppression, needed for different
library version.
After-review changes.
For this patch in 10.0, we do not introduce a new public storage engine API,
we just fix the InnoDB/XtraDB issues. In 10.1, we will make a better public
API that can be used for all storage engines (MDEV-6429).
Eliminate the background thread that did deadlock kills asynchroneously.
Instead, we ensure that the InnoDB/XtraDB code can handle doing the kill from
inside the deadlock detection code (when thd_report_wait_for() needs to kill a
later thread to resolve a deadlock).
(We preserve the part of the original patch that introduces dedicated mutex
and condition for the slave init thread, to remove the abuse of
LOCK_thread_count for start/stop synchronisation of the slave init thread).
The sql_slave_skip_counter is important to be able to recover replication from
certain errors. Often, an appropriate solution is to set
sql_slave_skip_counter to skip over a problem event. But setting
sql_slave_skip_counter produced an error in GTID mode, with a suggestion to
instead set @@gtid_slave_pos to point past the problem event. This however is
not always possible; for example, in case of an INCIDENT event, that event
does not have any GTID to assign to @@gtid_slave_pos.
With this patch, sql_slave_skip_counter now works in GTID mode the same was as
in non-GTID mode. When set, that many initial events are skipped when the SQL
thread starts, plus as many extra events are needed to completely skip any
partially skipped event group. The GTID position is updated to point past the
skipped event(s).
If replication breaks in GTID mode, it is not trivial to determine the GTID of
the failing event group. This is a problem, as such GTID is needed eg. to
explicitly set @@gtid_slave_pos to skip to after that event group, or to
compare errors on different servers, etc.
Fix by ensuring that relevant slave errors logged to the error log include the
GTID of the event group containing the problem event.
Preserve CLIENT_REMEMBER_OPTIONS flag for compressed connections
Code cleanup: removed reference to CLIENT_REMEMBER_OPTIONS from server
code. This flag is ignored in MariaDB.
That particular part of slave connect to master was missing code to handle
retry in case of network errors. The same problem is present in MySQL 5.5, but
fixed in MySQL 5.6.
Fixed with this patch, by adding the code (mostly identical to MySQL 5.6), and
also adding a test case.
I checked other queries done towards master during slave connect, and they now
all seem to handle reconnect in case of network failures.
replication causing replication to fail.
Remove the temporary fix for MDEV-5914, which used READ COMMITTED for parallel
replication worker threads. Replace it with a better, more selective solution.
The issue is with certain edge cases of InnoDB gap locks, for example between
INSERT and ranged DELETE. It is possible for the gap lock set by the DELETE to
block the INSERT, if the DELETE runs first, while the record lock set by
INSERT does not block the DELETE, if the INSERT runs first. This can cause a
conflict between the two in parallel replication on the slave even though they
ran without conflicts on the master.
With this patch, InnoDB will ask the server layer about the two involved
transactions before blocking on a gap lock. If the server layer tells InnoDB
that the transactions are already fixed wrt. commit order, as they are in
parallel replication, InnoDB will ignore the gap lock and allow the two
transactions to proceed in parallel, avoiding the conflict.
Improve the fix for MDEV-6020. When InnoDB itself detects a deadlock, it now
asks the server layer for any preferences about which transaction to roll
back. In case of parallel replication with two transactions T1 and T2 fixed to
commit T1 before T2, the server layer will ask InnoDB to roll back T2 as the
deadlock victim, not T1. This helps in some cases to avoid excessive deadlock
rollback, as T2 will in any case need to wait for T1 to complete before it can
itself commit.
Also some misc. fixes found during development and testing:
- Remove thd_rpl_is_parallel(), it is not used or needed.
- Use KILL_CONNECTION instead of KILL_QUERY when a parallel replication
worker thread is killed to resolve a deadlock with fixed commit
ordering. There are some cases, eg. in sql/sql_parse.cc, where a KILL_QUERY
can be ignored if the query otherwise completed successfully, and this
could cause the deadlock kill to be lost, so that the deadlock was not
correctly resolved.
- Fix random test failure due to missing wait_for_binlog_checkpoint.inc.
- Make sure that deadlock or other temporary errors during parallel
replication are not printed to the the error log; there were some places
around the replication code with extra error logging. These conditions can
occur occasionally and are handled automatically without breaking
replication, so they should not pollute the error log.
- Fix handling of rgi->gtid_sub_id. We need to be able to access this also at
the end of a transaction, to be able to detect and resolve deadlocks due to
commit ordering. But this value was also used as a flag to mark whether
record_gtid() had been called, by being set to zero, losing the value. Now,
introduce a separate flag rgi->gtid_pending, so rgi->gtid_sub_id remains
valid for the entire duration of the transaction.
- Fix one place where the code to handle ignored errors called reset_killed()
unconditionally, even if no error was caught that should be ignored. This
could cause loss of a deadlock kill signal, breaking deadlock detection and
resolution.
- Fix a couple of missing mysql_reset_thd_for_next_command(). This could
cause a prior error condition to remain for the next event executed,
causing assertions about errors already being set and possibly giving
incorrect error handling for following event executions.
- Fix code that cleared thd->rgi_slave in the parallel replication worker
threads after each event execution; this caused the deadlock detection and
handling code to not be able to correctly process the associated
transactions as belonging to replication worker threads.
- Remove useless error code in slave_background_kill_request().
- Fix bug where wfc->wakeup_error was not cleared at
wait_for_commit::unregister_wait_for_prior_commit(). This could cause the
error condition to wrongly propagate to a later wait_for_prior_commit(),
causing spurious ER_PRIOR_COMMIT_FAILED errors.
- Do not put the binlog background thread into the processlist. It causes
too many result differences in mtr, but also it probably is not useful
for users to pollute the process list with a system thread that does not
really perform any user-visible tasks...
replication causing replication to fail.
In parallel replication, we run transactions from the master in parallel, but
force them to commit in the same order they did on the master. If we force T1
to commit before T2, but T2 holds eg. a row lock that is needed by T1, we get
a deadlock when T2 waits until T1 has committed.
Usually, we do not run T1 and T2 in parallel if there is a chance that they
can have conflicting locks like this, but there are certain edge cases where
it can occasionally happen (eg. MDEV-5914, MDEV-5941, MDEV-6020). The bug was
that this would cause replication to hang, eventually getting a lock timeout
and causing the slave to stop with error.
With this patch, InnoDB will report back to the upper layer whenever a
transactions T1 is about to do a lock wait on T2. If T1 and T2 are parallel
replication transactions, and T2 needs to commit later than T1, we can thus
detect the deadlock; we then kill T2, setting a flag that causes it to catch
the kill and convert it to a deadlock error; this error will then cause T2 to
roll back and release its locks (so that T1 can commit), and later T2 will be
re-tried and eventually also committed.
The kill happens asynchroneously in a slave background thread; this is
necessary, as the reporting from InnoDB about lock waits happen deep inside
the locking code, at a point where it is not possible to directly call
THD::awake() due to mutexes held.
Deadlock is assumed to be (very) rarely occuring, so this patch tries to
minimise the performance impact on the normal case where no deadlocks occur,
rather than optimise the handling of the occasional deadlock.
Also fix transaction retry due to deadlock when it happens after a transaction
already signalled to later transactions that it started to commit. In this
case we need to undo this signalling (and later redo it when we commit again
during retry), so following transactions will not start too early.
Also add a missing thd->send_kill_message() that got triggered during testing
(this corrects an incorrect fix for MySQL Bug#58933).
Handle retry of event groups that span multiple relay log files.
- If retry reaches the end of one relay log file, move on to the next.
- Handle refcounting of relay log files, and avoid purging relay log
files until all event groups have completed that might have needed
them for transaction retry.
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
