Instead of updating global counter, calculate Threads_running on the fly.
All threads having command != COM_SLEEP are included.
Behaviour changes:
Previously SHOW STATUS and SHOW GLOBAL STATUS returned the same values
representing global status. Now SHOW STATUS always returns 1 indicating that
current session has 1 thread running.
Previously only threads that were executing dispatch_command() or running events
were accounted by Threads_running. Now it is rough equivalent of
SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST WHERE state!='Sleep'
The problem was that multi_range_read_info_const() called
multi_range_key_create_key() which changed m_part_spec.start_part,
while there was an activ table scan ongoing.
Fixed by copying and restoring m_part_spec around
multi_range_key_create_calls()
first, and we do not not care whether client has received all data.
This is a TCP optimization to avoid TIME_WAIT in TCP connection teardown.
This patch would abort connection on timeout, which usually happens when
client reads a large result set, at slower pace then the server can
write.
The patch also cleans up socket timeout handling, so that Windows
is consistent with another platforms (using nonblocking socket IO
+ waiting in poll/select on single socket, rather than setsockopt).
This makes identifying timeouts easier.
Also removed the superficial shutdown() before closesocket() in a few
places where it was used, because it was never needed , and
reportedly breaks SO_LINGER on Windows.
When the transaction isolation level is SERIALIZABLE, or when
a locking read is performed in the REPEATABLE READ isolation level,
InnoDB must lock delete-marked records in order to prevent another
transaction from inserting something.
However, at READ UNCOMMITTED or READ COMMITTED isolation level or
when the parameter innodb_locks_unsafe_for_binlog is set, the
repeatability of the reads does not matter, and there is no need
to lock any records.
row_search_mvcc(): Skip locks on delete-marked committed records upfront,
instead of invoking row_unlock_for_mysql() afterwards. The unlocking
never worked for secondary index records.
dict_stats_rename_table(): After DB_LOCK_WAIT_TIMEOUT
or DB_DUPLICATE_KEY, reset the trx->error_state before retrying.
Also, properly treat DB_DEADLOCK as a hard error.
Part2: make MyRocks add its directory into @@ignore_db_dirs when starting.
This is necessary because apparently not everybody are using plugin's my.cnf
So load ha_rocksdb.{so,dll} manually and then hit MDEV-12451, MDEV-14461
etc.
The assertion failure was caused by
MDEV-14511 Use fewer transactions for updating InnoDB persistent statistics
We are reusing a transaction object after commit, and sometimes,
even after a successful operation, the trx_t::error_state may be
something else than DB_SUCCESS. Reset the field when needed.
* Note: breaking change; since this commit, a plugin that has
worked so far might get rejected due to plugin maturity
* mariabackup is not affected (allows all plugins)
* VERSION file defines SERVER_MATURITY, which defines the
corresponding numeric value as SERVER_MATURITY_LEVEL in
include/mysql_version.h
* The default value for 'plugin_maturity' is SERVER_MATURITY_LEVEL - 1
* Logs a warning if a plugin has maturity lower than
SERVER_MATURITY_LEVEL
* Tests suppress the plugin maturity warning
* Tests use --plugin-maturity=unknown by default so as not to fail
due to the stricter plugin maturity handling
Starting with MySQL 5.7 (or MariaDB 10.2.2) InnoDB no longer contains
the "table monitor" or "tablespace monitor". The conditions on
srv_print_innodb_tablespace_monitor, srv_print_innodb_table_monitor
never hold. So, the code was dead.
Also, remove a bogus reference to dict_print(), which used to implement
the InnoDB table monitor.
Relax memory barrier for lock_word.
rw_lock_lock_word_decr() - used to acquire rw-lock, thus we only need to issue
ACQUIRE when we succeed locking.
rw_lock_x_lock_func_nowait() - same as above, but used to attempt to acquire
X-lock.
rw_lock_s_unlock_func() - used to release S-lock, RELEASE is what we need here.
rw_lock_x_unlock_func() - used to release X-lock. Ideally we'd need only RELEASE
here, but due to mess with waiters (they must be loaded after lock_word is
stored) we have to issue both ACQUIRE and RELEASE.
rw_lock_sx_unlock_func() - same as above, but used to release SX-lock.
rw_lock_s_lock_spin(), rw_lock_x_lock_func(), rw_lock_sx_lock_func() -
fetch-and-store to waiters has to issue only ACQUIRE memory barrier, so that
waiters are stored before lock_word is loaded.
Note that there is violation of RELEASE-ACQUIRE protocol here, because we do
on lock:
my_atomic_fas32_explicit((int32*) &lock->waiters, 1, MY_MEMORY_ORDER_ACQUIRE);
my_atomic_load32_explicit(&lock->lock_word, MY_MEMORY_ORDER_RELAXED);
on unlock
my_atomic_add32_explicit(&lock->lock_word, X_LOCK_DECR, MY_MEMORY_ORDER_ACQ_REL);
my_atomic_load32_explicit((int32*) &lock->waiters, MY_MEMORY_ORDER_RELAXED);
That is we kind of synchronize ACQUIRE on lock_word with ACQUIRE on waiters.
It was there before this patch. Simple fix may have negative performance impact.
Proper fix requires refactoring of lock_word.
Relax memory barrier for waiters: these 2 stores must be completed before
os_event_set() finishes. This is guaranteed by RELEASE barrier issued by
mutex.exit() of os_event_set().
Remove volatile modifier from waiters: it's not supposed for inter-thread
communication, use appropriate atomic operations instead.
Changed waiters to int32_t, my_atomic friendly type.
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
This will allow show processlist to continue, without blocking
all new connections, if some threads gets stuck while holding
LOCK_thd_data or mysys_var->mutex
Connections that has mutex 'stuck' are marked as 'Busy' in 'Command'
Todo:
Make F_BACKOFF to do 'pause' instead of just (1)
- 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
Allow DROP TABLE `#mysql50##sql-...._.` to drop tables that were
being rebuilt by ALGORITHM=INPLACE
NOTE: If the server is killed after the table-rebuilding ALGORITHM=INPLACE
commits inside InnoDB but before the .frm file has been replaced, then
the recovery will involve something else than DROP TABLE.
NOTE: If the server is killed in a true inplace ALTER TABLE commits
inside InnoDB but before the .frm file has been replaced, then we
are really out of luck. To properly handle that situation, we would
need a transactional mysql.ddl_fixup table that directs recovery to
rename or remove files.
prepare_inplace_alter_table_dict(): Use the altered_table->s->table_name
for generating the new_table_name.
table_name_t::part_suffix: The start of the partition name suffix.
table_name_t::dbend(): Return the end of the schema name.
table_name_t::dblen(): Return the length of the schema name, in bytes.
table_name_t::basename(): Return the name without the schema name.
table_name_t::part(): Return the partition name, or NULL if none.
row_drop_table_for_mysql(): Assert for #sql, not #sql-ib.
