Details
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Bug
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Status: Closed (View Workflow)
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Minor
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Resolution: Fixed
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N/A
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None
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bb-10.6-midenok-
MDEV-17554
Description
If partitioning structure is not specified, by default a versioned table is created with one history partition (and one current partition):
MariaDB [test]> create or replace table t1 (a int) with system versioning partition by system_time limit 10000 auto; |
Query OK, 0 rows affected (0.400 sec) |
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MariaDB [test]> show create table t1; |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| Table | Create Table | |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| t1 | CREATE TABLE `t1` ( |
`a` int(11) DEFAULT NULL |
) ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING |
PARTITION BY SYSTEM_TIME LIMIT 10000 AUTO_INCREMENT |
PARTITIONS 2 |
|
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
1 row in set (0.009 sec) |
Given that the hardcoded VERS_MIN_EMPTY for auto-partitioning is 1, it means that any DML on the table will trigger creation of a new partition, even a no-op DML:
MariaDB [test]> delete from t1; |
Query OK, 0 rows affected (0.380 sec) |
|
|
MariaDB [test]> show create table t1; |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| Table | Create Table | |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
| t1 | CREATE TABLE `t1` ( |
`a` int(11) DEFAULT NULL |
) ENGINE=InnoDB DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING |
PARTITION BY SYSTEM_TIME LIMIT 10000 AUTO_INCREMENT |
PARTITIONS 3 |
|
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |
1 row in set (0.012 sec) |
It doesn't seem to be reasonable. Maybe it makes sense to initially create 3 partitions by default, if partitioning structure is not specified? Or, limiting it to tables with auto-creation only, make sure that when auto-creation is added to a table (be it creating a new table or altering an existing one), this same DDL ensures that there are VERS_MIN_EMPTY+1 empty partitions at the end, so the next DML doesn't automatically cause creating of a new one?
Attachments
Issue Links
- relates to
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MDEV-17554 Auto-create history partitions for system-versioned tables
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- Closed
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