- Adding optional qualifiers to data types:
CREATE TABLE t1 (a schema.DATE);
Qualifiers now work only for three pre-defined schemas:
mariadb_schema
oracle_schema
maxdb_schema
These schemas are virtual (hard-coded) for now, but may turn into real
databases on disk in the future.
- mariadb_schema.TYPE now always resolves to a true MariaDB data
type TYPE without sql_mode specific translations.
- oracle_schema.DATE translates to MariaDB DATETIME.
- maxdb_schema.TIMESTAMP translates to MariaDB DATETIME.
- Fixing SHOW CREATE TABLE to use a qualifier for a data type TYPE
if the current sql_mode translates TYPE to something else.
The above changes fix the reported problem, so this script:
SET sql_mode=ORACLE;
CREATE TABLE t2 AS SELECT mariadb_date_column FROM t1;
is now replicated as:
SET sql_mode=ORACLE;
CREATE TABLE t2 (mariadb_date_column mariadb_schema.DATE);
and the slave can unambiguously treat DATE as the true MariaDB DATE
without ORACLE specific translation to DATETIME.
Similar,
SET sql_mode=MAXDB;
CREATE TABLE t2 AS SELECT mariadb_timestamp_column FROM t1;
is now replicated as:
SET sql_mode=MAXDB;
CREATE TABLE t2 (mariadb_timestamp_column mariadb_schema.TIMESTAMP);
so the slave treats TIMESTAMP as the true MariaDB TIMESTAMP
without MAXDB specific translation to DATETIME.
* Allocate items on thd->mem_root while refixing vcol exprs
* Make vcol tree changes register and roll them back after the statement is executed.
Explanation:
Due to collation implementation specifics an Item tree could change while fixing.
The tricky thing here is to make it on a proper arena.
It's usually not a problem when a field is deterministic, however, makes a pain vice-versa, during allocation allocating.
A non-deterministic field should be refixed on each statement, since it depends on the environment state.
Changing the tree will be temporary and therefore it should be reverted after the statement execution.
For low sort_buffer_size, in the cost calculation of using the Unique object the elements in the tree were evaluated to 0, make sure to have atleast 1 element in the Unique tree.
Also for the function Unique::get allocate memory for atleast MERGEBUFF2+1 keys.
cannot use the current THD::mem_root, because it can be temporarily
reassigned to something with a very different life time
(e.g. to TABLE::mem_root or range optimizer mem_root).
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)
* size represents the size of an element in the Unique class
* full_size is used when the Unique class counts the number of
duplicates stored per element. This requires additional space per Unique
element.
mysql_insert() first opens all affected tables (which implicitly
starts a transaction in InnoDB), then stat tables.
A failure to open a stat table caused open_tables() to abort
the current stmt transaction (trans_rollback_stmt()). So, from the
server point of view the following ha_write_row()-s happened outside
of a transactions, and the server didn't bother to commit them.
The server has a mechanism to prevent a transaction being
unexpectedly committed or rolled back in the middle of a statement -
if an operation takes place _in a sub-statement_ it cannot change
the transaction state. Operations on stat tables are exactly that -
they are not allowed to change a transaction state. Put them in
a sub-statement to make sure they don't.
- 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().
read_statistics_for_tables_if_needed
Regression after 279a907, read_statistics_for_tables_if_needed() was
called after open_normal_and_derived_tables() failure.
Fixed by moving read_statistics_for_tables() call to a branch of
get_schema_stat_record() where result of open_normal_and_derived_tables()
is checked.
Removed THD::force_read_stats, added read_statistics_for_tables() instead.
Simplified away statistics_for_command_is_needed().
Always initialize ScopedStatementReplication::saved_binlog_format,
so that GCC cannot emit a bogus warning about
ScopedStatementReplication::~ScopedStatementReplication() using the
variable.
The code was originally introduced in
commit d998da03069dca1aae83ec6af7eb407bbdc9fc58.
(Backported to 10.3, addressed review input)
Sj_materialization_picker::check_qep(): fix error in cost/fanout
calculations:
- for each join prefix, add #prefix_rows / TIME_FOR_COMPARE to the cost,
like best_extension_by_limited_search does
- Remove the fanout produced by the subquery tables.
- Also take into account join condition selectivity
optimize_wo_join_buffering() (used by LooseScan and FirstMatch)
- also add #prefix_rows / TIME_FOR_COMPARE to the cost of each prefix.
- Also take into account join condition selectivity
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
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
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.
