Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Won't Fix
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10.2.26, 10.3.20
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None
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CentOS 7
Description
TRANSACTIONAL flag is not well managed in ALTER TABLE.
When an Aria table is created without specifying TRANSACTIONAL, it can be converted to MyISAM with 'ALTER TABLE ENGINE_MyISAM'.
When an Aria table is created and subsequently altered with 'ALTER TABLE X TRANSACTIONAL=1; ALTER TABLE X TRANSACTIONAL=0' it can no longer be converted to MyISAM at all because of the orphaned TRANSACTIONAL attribute. Instead, the server produces this (incorrect) message:
ERROR 1478 (HY000): Table storage engine 'MyISAM' does not support the create option 'TRANSACTIONAL=1'
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To be clear - once the TRANSACTIONAL flag is explicitly started and set back to 0, this message failing the ALTER TABLE and incorrectly claiming TRANSACTIONAL=1 is the result.
What this means to users is that altering tables from MyISAM to Aria not only carries a 40% performance penalty, but is irreversible after using the TRANSACTIONAL flag.
The flag is harmless for other storage engines, producing the warning mentioned in MDEV-8733, but they make going back to MyISAM impossible without a full table migration in this case. 10.4 shows a warning instead of an error and completes the operation.
MariaDB [t34628]> create table taria3( id int(10) unsigned NOT NULL AUTO_INCREMENT,
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-> `modified` timestamp NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
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-> `val` int(10) unsigned DEFAULT NULL,
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-> `blah` varchar(511) DEFAULT NULL,
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-> PRIMARY KEY (`id`) ) Engine=MyISAM;
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Query OK, 0 rows affected (0.03 sec)
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MariaDB [t34628]> alter table taria3 engine=aria, transactional=0;
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Query OK, 0 rows affected (0.07 sec)
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Records: 0 Duplicates: 0 Warnings: 0
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MariaDB [t34628]> alter table taria3 engine=myisam;
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ERROR 1478 (HY000): Table storage engine 'MyISAM' does not support the create option 'TRANSACTIONAL=1'
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MariaDB [t34628]> show warnings;
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+-------+------+------------------------------------------------------------------------------------+
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| Level | Code | Message |
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+-------+------+------------------------------------------------------------------------------------+
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| Error | 1478 | Table storage engine 'MyISAM' does not support the create option 'TRANSACTIONAL=1' |
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+-------+------+------------------------------------------------------------------------------------+
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1 row in set (0.00 sec)
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MariaDB [t34628]> show create table taria3\G
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*************************** 1. row ***************************
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Table: taria3
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Create Table: CREATE TABLE `taria3` (
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`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
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`modified` timestamp NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
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`val` int(10) unsigned DEFAULT NULL,
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`blah` varchar(511) DEFAULT NULL,
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PRIMARY KEY (`id`)
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) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1 TRANSACTIONAL=0
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1 row in set (0.00 sec)
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Attachments
Issue Links
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- Closed
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- relates to
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- Closed
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