MDEV-21810 MBR: Unexpected "Unsafe statement" warning for unsafe IODKU
MDEV-17614 fixes to replication unsafety for INSERT ON DUP KEY UPDATE
on two or more unique key table left a flaw. The fixes checked the
safety condition per each inserted record with the idea to catch a user-created
value to an autoincrement column and when that succeeds the autoincrement column
would become the source of unsafety too.
It was not expected that after a duplicate error the next record's
write_set may become different and the unsafe decision for that
specific record will be computed to screw the Query's binlogging
state and when @@binlog_format is MIXED nothing gets bin-logged.
This case has been already fixed in 10.5.2 by 91ab42a823 that
relocated/optimized THD::decide_logging_format_low() out of the record insert
loop. The safety decision is computed once and at the right time.
Pertinent parts of the commit are cherry-picked.
Also a spurious warning about unsafety is removed when MIXED
@@binlog_format; original MDEV-17614 test result corrected.
The original test of MDEV-17614 is extended and made more readable.
Problem:
========
If a primary is shutdown during an active semi-sync connection
during the period when the primary is awaiting an ACK, the primary
hard kills the active communication thread and does not ensure the
transaction was received by a replica. This can lead to an
inconsistent replication state.
Solution:
========
During shutdown, the primary should wait for an ACK or timeout
before hard killing a thread which is awaiting a communication. We
extend the `SHUTDOWN WAIT FOR SLAVES` logic to identify and ignore
any threads waiting for a semi-sync ACK in phase 1. Then, before
stopping the ack receiver thread, the shutdown is delayed until all
waiting semi-sync connections receive an ACK or time out. The
connections are then killed in phase 2.
Notes:
1) There remains an unresolved corner case that affects this
patch. MDEV-28141: Slave crashes with Packets out of order when
connecting to a shutting down master. Specifically, If a slave is
connecting to a master which is actively shutting down, the slave
can crash with a "Packets out of order" assertion error. To get
around this issue in the MTR tests, the primary will wait a small
amount of time before phase 1 killing threads to let the replicas
safely stop (if applicable).
2) This patch also fixes MDEV-28114: Semi-sync Master ACK Receiver
Thread Can Error on COM_QUIT
Reviewed By
============
Andrei Elkin <andrei.elkin@mariadb.com>
the bug was that in_vector array in Item_func_in was allocated in the
statement arena, not in the table->expr_arena.
revert part of the 5acd391e8b. Instead, change the arena correctly
in fix_all_session_vcol_exprs().
Remove TABLE_ARENA, that was introduced in 5acd391e8b to force
item tree changes to be rolled back (because they were allocated in the
wrong arena and didn't persist. now they do)
Problem: In regular replication, when master binlogged using statement format
slave might not have written an event to its binary log when the Query
event aimed at a temporary table.
Specifically this was observed with LOAD DATA INFILE.
This effect was possible because unlike master slave holds temporary
tables in its pool and the master side check of existence of a
temporary table at the format bin-logging decision did not apply.
Solution: replace THD::has_thd_temporary_tables() with
THD::has_temporary_tables which allows to identify temporary table
presence on either side.
--
Reviewed by Andrei Elkin.
Using parallel slave applying can cause deadlock between between DDL and
other events. GTID with lower seqno can be blocked in galera when node
entered TOI mode, but DDL GTID which has higher node can be blocked
before previous GTIDs are applied locally.
Fix is to check prior commits before entering TOI.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
Handling BF abort for prepared statement execution so that EXECUTE processing will continue
until parameter setup is complete, before BF abort bails out the statement execution.
THD class has new boolean member: wsrep_delayed_BF_abort, which is set if BF abort is observed
in do_command() right after reading client's packet, and if the client has sent PS execute command.
In such case, the deadlock error is not returned immediately back to client, but the PS execution
will be started. However, the PS execution loop, will now check if wsrep_delayed_BF_abort is set, and
stop the PS execution after the type information has been assigned for the PS.
With this, the PS protocol type information, which is present in the first PS EXECUTE command, is not lost
even if the first PS EXECUTE command was marked to abort.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
extra2_read_len resolved by keeping the implementation
in sql/table.cc by exposed it for use by ha_partition.cc
Remove identical implementation in unireg.h
(ref: bfed2c7d57)
Problem:
Parse-time conversion from binary to tricky character sets like utf32
produced ill-formed strings. So, later a chash happened in debug builds,
or a wrong SHOW CREATE TABLE was returned in release builds.
Fix:
1. Backporting a few methods from 10.3:
- THD::check_string_for_wellformedness()
- THD::convert_string() overloads
- THD::make_text_string_connection()
2. Adding a new method THD::reinterpret_string_from_binary(),
which makes sure to either returns a well-formed string
(optionally prepending with zero bytes), or returns an error.
close_connections() in mysqld.cc sends a signal to all threads.
But InnoDB is too busy purging, doesn't react immediately.
close_connections() waits 20 seconds, which isn't enough in this
particular case, and then unlinks all threads from
the list and forcibly closes their vio connection.
InnoDB background threads have no vio connection to close, but
they're unlinked all the same. So when later they finally notice
the shutdown request and try to unlink themselves, they fail to
assert that they're still linked.
Fix: don't assert_linked, as another thread can unlink this THD anytime
When transaction creates or drops temporary tables and afterward its statement
faces an error even the transactional table statement's cached ROW
format events get involved into binlog and are visible after the transaction's commit.
Fixed with proper analysis of whether the errored-out statement needs
to be rolled back in binlog.
For instance a fact of already cached CREATE or DROP for temporary
tables by previous statements alone
does not cause to retain the being errored-out statement events in the
cache.
Conversely, if the statement creates or drops a temporary table
itself it can't be rolled back - this rule remains.
Mutex order violation when wsrep bf thread kills a conflicting trx,
the stack is
wsrep_thd_LOCK()
wsrep_kill_victim()
lock_rec_other_has_conflicting()
lock_clust_rec_read_check_and_lock()
row_search_mvcc()
ha_innobase::index_read()
ha_innobase::rnd_pos()
handler::ha_rnd_pos()
handler::rnd_pos_by_record()
handler::ha_rnd_pos_by_record()
Rows_log_event::find_row()
Update_rows_log_event::do_exec_row()
Rows_log_event::do_apply_event()
Log_event::apply_event()
wsrep_apply_events()
and mutexes are taken in the order
lock_sys->mutex -> victim_trx->mutex -> victim_thread->LOCK_thd_data
When a normal KILL statement is executed, the stack is
innobase_kill_query()
kill_handlerton()
plugin_foreach_with_mask()
ha_kill_query()
THD::awake()
kill_one_thread()
and mutexes are
victim_thread->LOCK_thd_data -> lock_sys->mutex -> victim_trx->mutex
This patch is the plan D variant for fixing potetial mutex locking
order exercised by BF aborting and KILL command execution.
In this approach, KILL command is replicated as TOI operation.
This guarantees total isolation for the KILL command execution
in the first node: there is no concurrent replication applying
and no concurrent DDL executing. Therefore there is no risk of
BF aborting to happen in parallel with KILL command execution
either. Potential mutex deadlocks between the different mutex
access paths with KILL command execution and BF aborting cannot
therefore happen.
TOI replication is used, in this approach, purely as means
to provide isolated KILL command execution in the first node.
KILL command should not (and must not) be applied in secondary
nodes. In this patch, we make this sure by skipping KILL
execution in secondary nodes, in applying phase, where we
bail out if applier thread is trying to execute KILL command.
This is effective, but skipping the applying of KILL command
could happen much earlier as well.
This also fixed unprotected calls to wsrep_thd_abort
that will use wsrep_abort_transaction. This is fixed
by holding THD::LOCK_thd_data while we abort transaction.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
Mutex order violation when wsrep bf thread kills a conflicting trx,
the stack is
wsrep_thd_LOCK()
wsrep_kill_victim()
lock_rec_other_has_conflicting()
lock_clust_rec_read_check_and_lock()
row_search_mvcc()
ha_innobase::index_read()
ha_innobase::rnd_pos()
handler::ha_rnd_pos()
handler::rnd_pos_by_record()
handler::ha_rnd_pos_by_record()
Rows_log_event::find_row()
Update_rows_log_event::do_exec_row()
Rows_log_event::do_apply_event()
Log_event::apply_event()
wsrep_apply_events()
and mutexes are taken in the order
lock_sys->mutex -> victim_trx->mutex -> victim_thread->LOCK_thd_data
When a normal KILL statement is executed, the stack is
innobase_kill_query()
kill_handlerton()
plugin_foreach_with_mask()
ha_kill_query()
THD::awake()
kill_one_thread()
and mutexes are
victim_thread->LOCK_thd_data -> lock_sys->mutex -> victim_trx->mutex
This patch is the plan D variant for fixing potetial mutex locking
order exercised by BF aborting and KILL command execution.
In this approach, KILL command is replicated as TOI operation.
This guarantees total isolation for the KILL command execution
in the first node: there is no concurrent replication applying
and no concurrent DDL executing. Therefore there is no risk of
BF aborting to happen in parallel with KILL command execution
either. Potential mutex deadlocks between the different mutex
access paths with KILL command execution and BF aborting cannot
therefore happen.
TOI replication is used, in this approach, purely as means
to provide isolated KILL command execution in the first node.
KILL command should not (and must not) be applied in secondary
nodes. In this patch, we make this sure by skipping KILL
execution in secondary nodes, in applying phase, where we
bail out if applier thread is trying to execute KILL command.
This is effective, but skipping the applying of KILL command
could happen much earlier as well.
This also fixed unprotected calls to wsrep_thd_abort
that will use wsrep_abort_transaction. This is fixed
by holding THD::LOCK_thd_data while we abort transaction.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
When transaction creates or drops temporary tables and afterward its statement
faces an error even the transactional table statement's cached ROW
format events get involved into binlog and are visible after the transaction's commit.
Fixed with proper analysis of whether the errored-out statement needs
to be rolled back in binlog.
For instance a fact of already cached CREATE or DROP for temporary
tables by previous statements alone
does not cause to retain the being errored-out statement events in the
cache.
Conversely, if the statement creates or drops a temporary table
itself it can't be rolled back - this rule remains.
This patch is the plan D variant for fixing potetial mutex locking
order exercised by BF aborting and KILL command execution.
In this approach, KILL command is replicated as TOI operation.
This guarantees total isolation for the KILL command execution
in the first node: there is no concurrent replication applying
and no concurrent DDL executing. Therefore there is no risk of
BF aborting to happen in parallel with KILL command execution
either. Potential mutex deadlocks between the different mutex
access paths with KILL command execution and BF aborting cannot
therefore happen.
TOI replication is used, in this approach, purely as means
to provide isolated KILL command execution in the first node.
KILL command should not (and must not) be applied in secondary
nodes. In this patch, we make this sure by skipping KILL
execution in secondary nodes, in applying phase, where we
bail out if applier thread is trying to execute KILL command.
This is effective, but skipping the applying of KILL command
could happen much earlier as well.
This patch also fixes mutex locking order and unprotected
THD member accesses on bf aborting case. We try to hold
THD::LOCK_thd_data during bf aborting. Only case where it
is not possible is at wsrep_abort_transaction before
call wsrep_innobase_kill_one_trx where we take InnoDB
mutexes first and then THD::LOCK_thd_data.
This will also fix possible race condition during
close_connection and while wsrep is disconnecting
connections.
Added wsrep_bf_kill_debug test case
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
In commit 1bd681c8b3 (MDEV-25506 part 3)
we introduced a "fake instant timeout" when a transaction would wait
for a table or record lock while holding dict_sys.latch. This prevented
a deadlock of the server but could cause bogus errors for operations
on the InnoDB persistent statistics tables.
A better fix is to ensure that whenever a transaction is being
executed in the InnoDB internal SQL parser (which will for now
require dict_sys.latch to be held), it will already have acquired
all locks that could be required for the execution. So, we will
acquire the following locks upfront, before acquiring dict_sys.latch:
(1) MDL on the affected user table (acquired by the SQL layer)
(2) If applicable (not for RENAME TABLE): InnoDB table lock
(3) If persistent statistics are going to be modified:
(3.a) MDL_SHARED on mysql.innodb_table_stats, mysql.innodb_index_stats
(3.b) exclusive table locks on the statistics tables
(4) Exclusive table locks on the InnoDB data dictionary tables
(not needed in ANALYZE TABLE and the like)
Note: Acquiring exclusive locks on the statistics tables may cause
more locking conflicts between concurrent DDL operations.
Notably, RENAME TABLE will lock the statistics tables
even if no persistent statistics are enabled for the table.
DROP DATABASE will only acquire locks on statistics tables if
persistent statistics are enabled for the tables on which the
SQL layer is invoking ha_innobase::delete_table().
For any "garbage collection" in innodb_drop_database(), a timeout
while acquiring locks on the statistics tables will result in any
statistics not being deleted for any tables that the SQL layer
did not know about.
If innodb_defragment=ON, information may be written to the statistics
tables even for tables for which InnoDB persistent statistics are
disabled. But, DROP TABLE will no longer attempt to delete that
information if persistent statistics are not enabled for the table.
This change should also fix the hangs related to InnoDB persistent
statistics and STATS_AUTO_RECALC (MDEV-15020) as well as
a bug that running ALTER TABLE on the statistics tables
concurrently with running ALTER TABLE on InnoDB tables could
cause trouble.
lock_rec_enqueue_waiting(), lock_table_enqueue_waiting():
Do not issue a fake instant timeout error when the transaction
is holding dict_sys.latch. Instead, assert that the dict_sys.latch
is never being held here.
lock_sys_tables(): A new function to acquire exclusive locks on all
dictionary tables, in case DROP TABLE or similar operation is
being executed. Locking non-hard-coded tables is optional to avoid
a crash in row_merge_drop_temp_indexes(). The SYS_VIRTUAL table was
introduced in MySQL 5.7 and MariaDB Server 10.2. Normally, we require
all these dictionary tables to exist before executing any DDL, but
the function row_merge_drop_temp_indexes() is an exception.
When upgrading from MariaDB Server 10.1 or MySQL 5.6 or earlier,
the table SYS_VIRTUAL would not exist at this point.
ha_innobase::commit_inplace_alter_table(): Invoke
log_write_up_to() while not holding dict_sys.latch.
dict_sys_t::remove(), dict_table_close(): No longer try to
drop index stubs that were left behind by aborted online ADD INDEX.
Such indexes should be dropped from the InnoDB data dictionary by
row_merge_drop_indexes() as part of the failed DDL operation.
Stubs for aborted indexes may only be left behind in the
data dictionary cache.
dict_stats_fetch_from_ps(): Use a normal read-only transaction.
ha_innobase::delete_table(), ha_innobase::truncate(), fts_lock_table():
While waiting for purge to stop using the table,
do not hold dict_sys.latch.
ha_innobase::delete_table(): Implement a work-around for the rollback
of ALTER TABLE...ADD PARTITION. MDL_EXCLUSIVE would not be held if
ALTER TABLE hits lock_wait_timeout while trying to upgrade the MDL
due to a conflicting LOCK TABLES, such as in the first ALTER TABLE
in the test case of Bug#53676 in parts.partition_special_innodb.
Therefore, we must explicitly stop purge, because it would not be
stopped by MDL.
dict_stats_func(), btr_defragment_chunk(): Allocate a THD so that
we can acquire MDL on the InnoDB persistent statistics tables.
mysqltest_embedded: Invoke ha_pre_shutdown() before free_used_memory()
in order to avoid ASAN heap-use-after-free related to acquire_thd().
trx_t::dict_operation_lock_mode: Changed the type to bool.
row_mysql_lock_data_dictionary(), row_mysql_unlock_data_dictionary():
Implemented as macros.
rollback_inplace_alter_table(): Apply an infinite timeout to lock waits.
innodb_thd_increment_pending_ops(): Wrapper for
thd_increment_pending_ops(). Never attempt async operation for
InnoDB background threads, such as the trx_t::commit() in
dict_stats_process_entry_from_recalc_pool().
lock_sys_t::cancel(trx_t*): Make dictionary transactions immune to KILL.
lock_wait(): Make dictionary transactions immune to KILL, and to
lock wait timeout when waiting for locks on dictionary tables.
parts.partition_special_innodb: Use lock_wait_timeout=0 to instantly
get ER_LOCK_WAIT_TIMEOUT.
main.mdl: Filter out MDL on InnoDB persistent statistics tables
Reviewed by: Thirunarayanan Balathandayuthapani
