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:: Syntax change ::
Keyword AUTO enables history partition auto-creation.
Examples:
CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO;
CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
PARTITION BY SYSTEM_TIME INTERVAL 1 MONTH
STARTS '2021-01-01 00:00:00' AUTO PARTITIONS 12;
CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
PARTITION BY SYSTEM_TIME LIMIT 1000 AUTO;
Or with explicit partitions:
CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO
(PARTITION p0 HISTORY, PARTITION pn CURRENT);
To disable or enable auto-creation one can use ALTER TABLE by adding
or removing AUTO from partitioning specification:
CREATE TABLE t1 (x int) WITH SYSTEM VERSIONING
PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO;
# Disables auto-creation:
ALTER TABLE t1 PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR;
# Enables auto-creation:
ALTER TABLE t1 PARTITION BY SYSTEM_TIME INTERVAL 1 HOUR AUTO;
If the rest of partitioning specification is identical to CREATE TABLE
no repartitioning will be done (for details see MDEV-27328).
:: Description ::
Before executing history-generating DML command (see the list of commands below)
add N history partitions, so that N would be sufficient for potentially
generated history. N > 1 may be required when history partitions are switched
by INTERVAL and current_timestamp is N times further than the interval
boundary of the last history partition.
If the last history partition equals or exceeds LIMIT records then new history
partition is created and selected as the working partition. According to
MDEV-28411 partitions cannot be switched (or created) while the command is
running. Thus LIMIT does not carry strict limitation and the history partition
size must be planned as LIMIT value plus average number of history one DML
command can generate.
Auto-creation is implemented by synchronous fast_alter_partition_table() call
from the thread of the executed DML command before the command itself is run
(by the fallback and retry mechanism similar to Discovery feature,
see Open_table_context).
The name for newly added partitions are generated like default partition names
with extension of MDEV-22155 (which avoids name clashes by extending assignment
counter to next free-enough gap).
These DML commands can trigger auto-creation:
DELETE (including multitable DELETE, excluding DELETE HISTORY)
UPDATE (including multitable UPDATE)
REPLACE (including REPLACE .. SELECT)
INSERT .. ON DUPLICATE KEY UPDATE (including INSERT .. SELECT .. ODKU)
LOAD DATA .. REPLACE
:: Bug fixes ::
MDEV-23642 Locking timeout caused by auto-creation affects original DML
The reasons for this are:
- Do not disrupt main business process (the history is auxiliary service);
- Consequences are non-fatal (history is not lost, but comes into wrong
partition; fixed by partitioning rebuild);
- There is more freedom for application to fail in this case or not: it may
read warning info and find corresponding error number.
- While non-failing command is easy to handle by an application and fail it,
the opposite is hard to handle: there is no automatic actions to fix
failed command and retry, DBA intervention is required and until then
application is non-functioning.
MDEV-23639 Auto-create does not work under LOCK TABLES or inside triggers
Don't do tdc_remove_table() for OT_ADD_HISTORY_PARTITION because it is
not possible in locked tables mode.
LTM_LOCK_TABLES mode (and LTM_PRELOCKED_UNDER_LOCK_TABLES) works out
of the box as fast_alter_partition_table() can reopen tables via
locked_tables_list.
In LTM_PRELOCKED we reopen and relock table manually.
:: More fixes ::
* some_table_marked_for_reopen flag fix
some_table_marked_for_reopen affets only reopen of
m_locked_tables. I.e. Locked_tables_list::reopen_tables() reopens only
tables from m_locked_tables.
* Unused can_recover_from_failed_open() condition
Is recover_from_failed_open() can be really used after
open_and_process_routine()?
:: Reviewed by ::
Sergei Golubchik <serg@mariadb.org>
54 lines
2.2 KiB
C++
54 lines
2.2 KiB
C++
/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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#ifndef LOCK_INCLUDED
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#define LOCK_INCLUDED
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#include "thr_lock.h" /* thr_lock_type */
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#include "mdl.h"
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// Forward declarations
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struct TABLE;
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struct TABLE_LIST;
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class THD;
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typedef struct st_mysql_lock MYSQL_LOCK;
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MYSQL_LOCK *mysql_lock_tables(THD *thd, TABLE **table, uint count, uint flags);
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bool mysql_lock_tables(THD *thd, MYSQL_LOCK *sql_lock, uint flags);
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int mysql_unlock_tables(THD *thd, MYSQL_LOCK *sql_lock, bool free_lock);
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int mysql_unlock_tables(THD *thd, MYSQL_LOCK *sql_lock);
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int mysql_unlock_read_tables(THD *thd, MYSQL_LOCK *sql_lock);
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int mysql_unlock_some_tables(THD *thd, TABLE **table,uint count, uint flag);
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int mysql_lock_remove(THD *thd, MYSQL_LOCK *locked,TABLE *table);
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bool mysql_lock_abort_for_thread(THD *thd, TABLE *table);
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MYSQL_LOCK *mysql_lock_merge(MYSQL_LOCK *a, MYSQL_LOCK *b, THD *thd= NULL);
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/* Lock based on name */
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bool lock_schema_name(THD *thd, const char *db);
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/* Lock based on stored routine name */
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bool lock_object_name(THD *thd, MDL_key::enum_mdl_namespace mdl_type,
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const char *db, const char *name);
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/* flags for get_lock_data */
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#define GET_LOCK_UNLOCK 0
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#define GET_LOCK_STORE_LOCKS 1
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#define GET_LOCK_ACTION_MASK 1
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#define GET_LOCK_ON_THD (1 << 1)
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#define GET_LOCK_SKIP_SEQUENCES (1 << 2)
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MYSQL_LOCK *get_lock_data(THD *thd, TABLE **table_ptr, uint count, uint flags);
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void reset_lock_data(MYSQL_LOCK *sql_lock, bool unlock);
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#endif /* LOCK_INCLUDED */
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