When high priority replication slave applier encounters lock conflict in innodb,
it will force the conflicting lock holder transaction (victim) to rollback.
This is a must in multi-master sychronous replication model to avoid cluster lock-up.
This high priority victim abort (aka "brute force" (BF) abort), is started
from innodb lock manager while holding the victim's transaction's (trx) mutex.
Depending on the execution state of the victim transaction, it may happen that the
BF abort will call for THD::awake() to wake up the victim transaction for the rollback.
Now, if BF abort requires THD::awake() to be called, then the applier thread executed
locking protocol of: victim trx mutex -> victim THD::LOCK_thd_data
If, at the same time another DBMS super user issues KILL command to abort the same victim,
it will execute locking protocol of: victim THD::LOCK_thd_data -> victim trx mutex.
These two locking protocol acquire mutexes in opposite order, hence unresolvable mutex locking
deadlock may occur.
The fix in this commit adds THD::wsrep_aborter flag to synchronize who can kill the victim
This flag is set both when BF is called for from innodb and by KILL command.
Either path of victim killing will bail out if victim's wsrep_killed is already
set to avoid mutex conflicts with the other aborter execution. THD::wsrep_aborter
records the aborter THD's ID. This is needed to preserve the right to kill
the victim from different locations for the same aborter thread.
It is also good error logging, to see who is reponsible for the abort.
A new test case was added in galera.galera_bf_kill_debug.test for scenario where
wsrep applier thread and manual KILL command try to kill same idle victim
Analysis:
========
When "Profiling" is enabled, server collects the resource usage of each
statement that gets executed in current session. Profiling doesn't support
nested statements. In order to ensure this behavior when profiling is enabled
for a statement, there should not be any other active query which is being
profiled. This active query information is stored in 'current' variable. When
a nested query arrives it finds 'current' being not NULL and server aborts.
When 'init_connect' and 'init_slave' system variables are set they contain a
set of statements to be executed. "execute_init_command" is the function call
which invokes "dispatch_command" for each statement provided in
'init_connect', 'init_slave' system variables. "execute_init_command" invokes
"start_new_query" and it passes the statement list to "dispatch_command". This
"dispatch_command" intern invokes "start_new_query" which leads to nesting of
queries. Hence '!current' assert is triggered.
Fix:
===
Remove profiling from "execute_init_command" as it will be done within
"dispatch_command" execution.
MDEV-21398 Deadlock (server hang) or assertion failure in
Diagnostics_area::set_error_status upon ALTER under lock
This failure could only happen if one locked the same table
multiple times and then did an ALTER TABLE on the table.
Major change is to change all instances of
table->m_needs_reopen= true;
to
table->mark_table_for_reopen();
The main fix for the problem was to ensure that we mark all
instances of the table in the locked_table_list and when we
reopen the tables, we first close all tables before reopening
and locking them.
Other things:
- Don't call thd->locked_tables_list.reopen_tables if there
are no tables marked for reopen. (performance)
in fact, in MariaDB it cannot, but it can show spurious slaves
in SHOW SLAVE HOSTS.
slave was registered in COM_REGISTER_SLAVE and un-registered after
COM_BINLOG_DUMP. If there was no COM_BINLOG_DUMP, it would never
unregister.
sig_return: Solaris/OSX returns different function ptr
Move defination to my_alarm.h as its the only use.
prevents compile warnings (copied from 10.3 branch)
mysys/my_sync.c:136:19: error: 'cur_dir_name' defined but not used [-Werror=unused-const-variable=]
136 | static const char cur_dir_name[]= {FN_CURLIB, 0};
| ^~~~~~~~~~~~
fix compile error (DEPRECATED) leaked from ssl headers.
In file included from /export/home/dan/mariadb-server-10.4/sql/sys_vars.cc:37:
/export/home/dan/mariadb-server-10.4/sql/sys_vars.ic:69: error: "DEPRECATED" redefined [-Werror]
69 | #define DEPRECATED(X) X
|
In file included from /export/home/dan/mariadb-server-10.4/include/violite.h:150,
from /export/home/dan/mariadb-server-10.4/sql/sql_class.h:38,
from /export/home/dan/mariadb-server-10.4/sql/sys_vars.cc:36:
/usr/include/openssl/ssl.h:2356: note: this is the location of the previous definition
2356 | # define DEPRECATED __attribute__((deprecated))
|
Avoid Werror condition on non-Linux:
plugin/server_audit/server_audit.c:2267:7: error: variable 'db_len_off' set but not used [-Werror=unused-but-set-variable]
2267 | int db_len_off;
| ^~~~~~~~~~
plugin/server_audit/server_audit.c:2266:7: error: variable 'db_off' set but not used [-Werror=unused-but-set-variable]
2266 | int db_off;
| ^~~~~~
auth_gssapi fix include path for Solaris
Consistent with the upstream packaged patch:
https://github.com/OpenIndiana/oi-userland/blob/oi/hipster/components/database/mariadb-103/patches/06-gssapi.h.patch
compile warnings on Solaris
[ 91%] Building C object plugin/server_audit/CMakeFiles/server_audit.dir/server_audit.c.o
/plugin/server_audit/server_audit.c: In function 'auditing_v8':
/plugin/server_audit/server_audit.c:2194:20: error: unused variable 'db_len_off' [-Werror=unused-variable]
2194 | static const int db_len_off= 128;
| ^~~~~~~~~~
/plugin/server_audit/server_audit.c:2193:20: error: unused variable 'db_off' [-Werror=unused-variable]
2193 | static const int db_off= 120;
| ^~~~~~
/plugin/server_audit/server_audit.c:2192:20: error: unused variable 'cmd_off' [-Werror=unused-variable]
2192 | static const int cmd_off= 4432;
| ^~~~~~~
At top level:
/plugin/server_audit/server_audit.c:2192:20: error: 'cmd_off' defined but not used [-Werror=unused-const-variable=]
/plugin/server_audit/server_audit.c:2193:20: error: 'db_off' defined but not used [-Werror=unused-const-variable=]
2193 | static const int db_off= 120;
| ^~~~~~
/plugin/server_audit/server_audit.c:2194:20: error: 'db_len_off' defined but not used [-Werror=unused-const-variable=]
2194 | static const int db_len_off= 128;
| ^~~~~~~~~~
cc1: all warnings being treated as errors
tested on:
$ uname -a
SunOS openindiana 5.11 illumos-b97b1727bc i86pc i386 i86pc
This is a backport of the applicable part of
commit 93475aff8d and
commit 2c39f69d34
from 10.4.
Before 10.4 and Galera 4, WSREP_ON is a macro that points to
a global Boolean variable, so it is not that expensive to
evaluate, but we will add an unlikely() hint around it.
WSREP_ON_NEW: Remove. This macro was introduced in
commit c863159c32
when reverting WSREP_ON to its previous definition.
We replace some use of WSREP_ON with WSREP(thd), like it was done
in 93475aff8d. Note: the macro
WSREP() in 10.1 is equivalent to WSREP_NNULL() in 10.4.
Item_func_rand::seed_random(): Avoid invoking current_thd
when WSREP is not enabled.
One may access freed THD members after LOCK_thd_kill is released.
With original code it can happen when killing wsrep-disabled thread on a
wsrep-enabled server. With 91ab42a8 it is happening on a wsrep-disabled
server.
If async slave thread (slave SQL handler), becomes a BF victim, it may occasionally happen that rollbacker thread is used to carry out the rollback instead of the async slave thread.
This can happen, if async slave thread has flagged "idle" state when BF thread tries to figure out how to kill the victim.
The issue was possible to test by using a galera cluster as slave for external master, and issuing high load of conflicting writes through async replication and directly against galera cluster nodes.
However, a deterministic mtr test for the "conflict window" has not yet been worked on.
The fix, in this patch makes sure that async slave thread state is never set to IDLE. This prevents the rollbacker thread to intervene.
The wsrep_query_state change was refactored to happen by dedicated function to make controlling the idle state change in one place.
Context involves semicolon batching, and the error starts 10.2
No reproducible examples were made yet, but TCP trace suggests
multiple packets that are "squeezed" together (e.g overlong OK packet
that has a trailer which is belongs to another packet)
Remove thd->get_stmt_da()->set_skip_flush() when processing a batch.
skip_flush stems from the COM_MULTI code, which was checked in during
10.2 (and is never used)
The fix is confirmed to work, when evaluated by bug reporter (one of them)
We never reproduced it locally, with multiple tries
thus the root cause analysis is still missing.
(Variant #2 of the patch, which keeps the sp_head object inside the
MEM_ROOT that sp_head object owns)
(10.3 requires extra work due to sp_package, will commit a separate
patch for it)
sp_head::operator new() and operator delete() were dereferencing sp_head*
pointers to memory that didn't hold a valid sp_head object (it was
not created/already destroyed).
This caused UBSan to crash when looking up type information.
Fixed by providing static sp_head::create() and sp_head::destroy() methods.
(Variant #2 of the patch, which keeps the sp_head object inside the
MEM_ROOT that sp_head object owns)
(10.3 version of the fix, with handling for class sp_package)
sp_head::operator new() and operator delete() were dereferencing sp_head*
pointers to memory that didn't hold a valid sp_head object (it was
not created/already destroyed).
This caused UBSan to crash when looking up type information.
Fixed by providing static sp_head::create() and sp_head::destroy() methods.
MDEV-18957 UPDATE with LIMIT clause is wrong for versioned partitioned tables
UPDATE, DELETE: replace linear search of current/historical records
with vers_setup_conds().
Additional DML cases in view.test
- Use local variables table and share to simplify code
- Use sql_command_flags to detect what kind of command was used
- Added CF_DELETES_DATA to simplify detecton of delete commands
- Removed duplicate error in create_table_from_items().
For release builds, do not declare unused variables.
unpack_row(): Omit a debug-only variable from WSREP diagnostic message.
create_wsrep_THD(): Fix -Wmaybe-uninitialized for the PSI_thread_key.
- Fixes a situation in which a thread gets BF aborted and does not send the reply back to
the client, even though the connection is still alive. That caused
both sides to hang waiting for the next message. Now we explicitly
check that the connection is still alive.
- MTR test for the above
- Replaced thd->killed assignments to thd->reset_kill_query where applicable.
Command COM_SHUTDOWN was rejected in non-Primary because
server_command_flags[COM_SHUTDOWN] had value CF_NO_COM_MULTI
instead of CF_SKIP_WSREP_CHECK.
As a fix removed assignment
server_command_flags[CF_NO_COM_MULTI]= CF_NO_COM_MULTI
which overwrote server_command_flags[COM_SHUTDOWN].
Command COM_SHUTDOWN was rejected in non-Primary because
server_command_flags[COM_SHUTDOWN] had value CF_NO_COM_MULTI
instead of CF_SKIP_WSREP_CHECK.
As a fix removed assignment
server_command_flags[CF_NO_COM_MULTI]= CF_NO_COM_MULTI
which overwrote server_command_flags[COM_SHUTDOWN].
This patch corrects the fix of the patch for mdev-19421 that resolved
the problem of parsing some embedded join expressions such as
t1 join t2 left join t3 on t2.a=t3.a on t1.a=t2.a.
Yet the patch contained a bug that prevented proper context analysis
of the queries where such expressions were used together with comma
separated table references in from clauses.
With --skip-debug-assert, DBUG_ASSERT(false) will allow execution to
continue. Hence, we will need /* fall through */ after them.
Some DBUG_ASSERT(0) were replaced by break; when the switch () statement
was followed by DBUG_ASSERT(0).
For MDEV-15955, the fix in create_tmp_field_from_item() would cause a
compilation error. After a discussion with Alexander Barkov, the fix
was omitted and only the test case was kept.
In 10.3 and later, MDEV-15955 is fixed properly by overriding
create_tmp_field() in Item_func_user_var.
This patch corrects the fix of the patch for mdev-19421 that resolved
the problem of parsing some embedded join expressions such as
t1 join t2 left join t3 on t2.a=t3.a on t1.a=t2.a.
Yet the patch contained a bug that prevented proper context analysis
of the queries where such expressions were used together with comma
separated table references in from clauses.
