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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.
17 lines
706 B
Text
17 lines
706 B
Text
SET @save_fpt=@@GLOBAL.innodb_file_per_table;
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SET GLOBAL innodb_file_per_table=OFF;
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Warnings:
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Warning 1287 '@@innodb_file_per_table' is deprecated and will be removed in a future release
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create table bug56947(a int not null) engine = innodb;
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SET @saved_dbug = @@SESSION.debug_dbug;
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SET DEBUG_DBUG='+d,ib_rebuild_cannot_rename';
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alter table bug56947 add unique index (a);
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ERROR HY000: Got error 11 "xxx" from storage engine InnoDB
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check table bug56947;
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Table Op Msg_type Msg_text
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test.bug56947 check status OK
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drop table bug56947;
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SET GLOBAL innodb_file_per_table=@save_fpt;
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Warnings:
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Warning 1287 '@@innodb_file_per_table' is deprecated and will be removed in a future release
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SET debug_dbug= @saved_dbug;
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