Problem:-
When mysql executes INSERT ON DUPLICATE KEY INSERT, the storage engine checks
if the inserted row would generate a duplicate key error. If yes, it returns
the existing row to mysql, mysql updates it and sends it back to the storage
engine.When the table has more than one unique or primary key, this statement
is sensitive to the order in which the storage engines checks the keys.
Depending on this order, the storage engine may determine different rows
to mysql, and hence mysql can update different rows.The order that the
storage engine checks keys is not deterministic. For example, InnoDB checks
keys in an order that depends on the order in which indexes were added to
the table. The first added index is checked first. So if master and slave
have added indexes in different orders, then slave may go out of sync.
Solution:-
Make INSERT...ON DUPLICATE KEY UPDATE unsafe while using stmt or mixed format
When there is more then one unique key.
Although there is two exception.
1. Auto Increment key is not counted because Innodb will get gap lock for
failed Insert and concurrent insert will get a next increment value. But if
user supplies auto inc value it can be unsafe.
2. Count only unique keys for which insertion is performed.
So this patch also addresses the bug id #72921
Sources did not compile in some builds because of undeclared
ER_BLOB_KEY_WITHOUT_LENGTH. Moving the implementations of
Key_part_spec::check_key_length_for_blob() from sql_class.h to sql_class.cc
cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Debug
Maintainer mode makes all warnings errors. This patch fix warnings. Mostly about
deprecated `register` keyword.
Too much warnings came from Mroonga and I gave up on it.
Plugin fixed to not lock the LOCK_operations when not active.
Server fixed to lock the LOCK_plugin less - do it once per
thread and then only if a plugin was installed/uninstalled.
truncating a temporary table
TRUNCATE expects only one TABLE instance (which is used by TRUNCATE
itself) to be open. However this requirement wasn't enforced after
"MDEV-5535: Cannot reopen temporary table".
Fixed by closing unused table instances before performing TRUNCATE.
Originally introduced by e972125f1 to avoid harmless wait for
LOCK_global_system_variables in a newly created thread, which creation was
initiated by system variable update.
At the same time it opens dangerous hole, when system variable update
thread already released LOCK_global_system_variables and ack_receiver
thread haven't yet completed new THD construction. In this case THD
constructor goes completely unprotected.
Since ack_receiver.stop() waits for the thread to go down, we have to
temporarily release LOCK_global_system_variables so that it doesn't
deadlock with ack_receiver.run(). Unfortunately it breaks atomicity
of rpl_semi_sync_master_enabled updates and makes them not serialized.
LOCK_rpl_semi_sync_master_enabled was introduced to workaround the above.
TODO: move ack_receiver start/stop into repl_semisync_master
enable_master/disable_master under LOCK_binlog protection?
Part of MDEV-14984 - regression in connect performance
XID_STATE::rm_error is never used by internal 2PC, it is intended to be
used by explicit XA only.
Also removed redundant xid reset from THD::init_for_queries(). Must've
been done already either by THD::transaction constructor or by
THD::cleanup().
Part of MDEV-7974 - backport fix for mysql bug#12161 (XA and binlog)
The command SHOW INDEXES ignored setting of the system variable
use_stat_tables to the value of 'preferably' and and showed statistical
data received from the engine. Similarly queries over the table
STATISTICS from INFORMATION_SCHEMA ignored this setting. It happened
because the function fill_schema_table_by_open() did not read any data
from statistical tables.
This bug is caused by pushdown from HAVING into WHERE.
It appears because condition that is pushed wasn't fixed.
It is also discovered that condition pushdown from HAVING into
WHERE is done wrong. There is no need to build clones for some
conditions that can be pushed. They can be simply moved from HAVING
into WHERE without cloning.
build_pushable_cond_for_having_pushdown(),
remove_pushed_top_conjuncts_for_having() methods are changed.
It is found that there is no transformation made for fields of
pushed condition.
field_transformer_for_having_pushdown transformer is added.
New tests are added. Some comments are changed.
Do not register intermediate tables created by inplace ALTER TABLE in
THD::temporary_tables.
Regular ALTER TABLE doesn't create .frm for temporary and discoverable
tables anymore. For inplace ALTER TABLE moved .frm creation to
create_table_for_inplace_alter().
Removed open_in_engine argument of create_and_open_tmp_table() and
open_temporary_table(): it became unused after this patch.
Part of MDEV-17805 - Remove InnoDB cache for temporary tables.
CREATE TEMPORARY TABLE locks SE plugin 6 times. 5 of these locks are
released by the end of the statement. And only 1 acquired by
init_from_binary_frm_image() / plugin_lock() remains.
The lock removed in this patch was clearly redundant.
Part of MDEV-17805 - Remove InnoDB cache for temporary tables.
