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https://github.com/MariaDB/server.git
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e581396b7a
Before commit6112853cdain MySQL 4.1.1 introduced the parameter innodb_file_per_table, all InnoDB data was written to the InnoDB system tablespace (often named ibdata1). A serious design problem is that once the system tablespace has grown to some size, it cannot shrink even if the data inside it has been deleted. There are also other design problems, such as the server hang MDEV-29930 that should only be possible when using innodb_file_per_table=0 and innodb_undo_tablespaces=0 (storing both tables and undo logs in the InnoDB system tablespace). The parameter innodb_change_buffering was deprecated in commitb5852ffbee. Starting with commitbaf276e6d4(MDEV-19229) the number of innodb_undo_tablespaces can be increased, so that the undo logs can be moved out of the system tablespace of an existing installation. If all these things (tables, undo logs, and the change buffer) are removed from the InnoDB system tablespace, the only variable-size data structure inside it is the InnoDB data dictionary. DDL operations on .ibd files was optimized in commit86dc7b4d4c(MDEV-24626). That should have removed any thinkable performance advantage of using innodb_file_per_table=0. Since there should be no benefit of setting innodb_file_per_table=0, the parameter should be deprecated. Starting with MySQL 5.6 and MariaDB Server 10.0, the default value is innodb_file_per_table=1.
124 lines
2.6 KiB
Plaintext
124 lines
2.6 KiB
Plaintext
SET GLOBAL tx_isolation='REPEATABLE-READ';
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CREATE TABLE bug56680(
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a INT AUTO_INCREMENT PRIMARY KEY,
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b CHAR(1),
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c INT,
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INDEX(b))
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ENGINE=InnoDB STATS_PERSISTENT=0;
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INSERT INTO bug56680 VALUES(0,'x',1);
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BEGIN;
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SELECT b FROM bug56680;
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b
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x
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connect con1,localhost,root,,;
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connection con1;
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BEGIN;
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UPDATE bug56680 SET b='X';
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connection default;
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SELECT b FROM bug56680;
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b
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x
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SELECT * FROM bug56680;
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a b c
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1 x 1
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connection con1;
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ROLLBACK;
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disconnect con1;
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connection default;
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SELECT b FROM bug56680;
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b
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x
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SET GLOBAL tx_isolation='READ-UNCOMMITTED';
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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INSERT INTO bug56680 SELECT 0,b,c FROM bug56680;
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BEGIN;
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SELECT b FROM bug56680 LIMIT 2;
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b
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x
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x
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connect con1,localhost,root,,;
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connection con1;
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BEGIN;
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DELETE FROM bug56680 WHERE a=1;
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INSERT INTO bug56680 VALUES(1,'X',1);
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SELECT b FROM bug56680 LIMIT 3;
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b
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X
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x
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x
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connection default;
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SELECT b FROM bug56680 LIMIT 2;
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b
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x
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x
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CHECK TABLE bug56680;
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Table Op Msg_type Msg_text
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test.bug56680 check status OK
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connection con1;
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ROLLBACK;
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SELECT b FROM bug56680 LIMIT 2;
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b
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x
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x
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CHECK TABLE bug56680;
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Table Op Msg_type Msg_text
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test.bug56680 check status OK
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connection default;
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disconnect con1;
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SELECT b FROM bug56680 LIMIT 2;
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b
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x
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x
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CREATE TABLE bug56680_2(
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a INT AUTO_INCREMENT PRIMARY KEY,
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b VARCHAR(2) CHARSET latin1 COLLATE latin1_german2_ci,
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c INT,
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INDEX(b))
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ENGINE=InnoDB STATS_PERSISTENT=0;
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INSERT INTO bug56680_2 SELECT 0,_latin1 0xdf,c FROM bug56680;
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BEGIN;
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SELECT HEX(b) FROM bug56680_2 LIMIT 2;
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HEX(b)
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DF
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DF
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DELETE FROM bug56680_2 WHERE a=1;
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INSERT INTO bug56680_2 VALUES(1,'SS',1);
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SELECT HEX(b) FROM bug56680_2 LIMIT 3;
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HEX(b)
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5353
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DF
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DF
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CHECK TABLE bug56680_2;
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Table Op Msg_type Msg_text
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test.bug56680_2 check status OK
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ALTER TABLE bug56680_2 ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=1;
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SELECT HEX(b) FROM bug56680_2 LIMIT 2;
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HEX(b)
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5353
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DF
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DELETE FROM bug56680_2 WHERE a=1;
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INSERT INTO bug56680_2 VALUES(1,_latin1 0xdf,1);
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SELECT HEX(b) FROM bug56680_2 LIMIT 3;
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HEX(b)
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DF
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DF
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DF
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CHECK TABLE bug56680_2;
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Table Op Msg_type Msg_text
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test.bug56680_2 check status OK
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# restart
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CHECK TABLE bug56680_2;
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Table Op Msg_type Msg_text
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test.bug56680_2 check status OK
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DROP TABLE bug56680_2;
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DROP TABLE bug56680;
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