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https://dev.mysql.com/doc/refman/5.7/en/commit.html
To disable autocommit mode implicitly for a single series of statements, use the START TRANSACTION statement: START TRANSACTION; SELECT @A:=SUM(salary) FROM table1 WHERE type=1; UPDATE table2 SET summary=@A WHERE type=1; COMMIT; With START ...SET ...
https://dev.mysql.com/doc/refman/5.7/en/timestamp-initialization.html
For any TIMESTAMP or DATETIME column in a table, you can assign the current timestamp as the default value, the auto-update value, or both: An auto-initialized column is set to the current timestamp for inserted rows that specify no value for the ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-table-compression.html
Table compression is enabled using the ROW_FORMAT=COMPRESSED attribute with CREATE TABLE or ALTER TABLE. This section describes InnoDB table compression, which is supported with InnoDB tables that reside in file_per_table tablespaces or general ...
https://dev.mysql.com/doc/refman/5.7/en/getting-information.html
What if you forget the name of a database or table, or what the structure of a given table is (for example, what its columns are called)? MySQL addresses this problem through several statements that provide information about the databases and ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-best-practices.html
Specify a primary key for every table using the most frequently queried column or columns, or an auto-increment value if there is no obvious primary key. Use joins wherever data is pulled from multiple tables based on identical ID values from those ...Adding foreign keys ensures that referenced columns are indexed, which can improve ...
https://dev.mysql.com/doc/refman/5.7/en/optimizing-innodb-storage-layout.html
Once your data reaches a stable size, or a growing table has increased by tens or some hundreds of megabytes, consider using the OPTIMIZE TABLE statement to reorganize the table and compact any wasted space. The reorganized tables require less disk ...This is a straightforward technique that can improve performance when other techniques such as improving index usage or tuning application code are not ...
https://dev.mysql.com/doc/refman/5.7/en/replication-options-gtids.html
Only statements that can be logged using GTID safe statements can be logged when enforce_gtid_consistency is set to ON, so the operations listed here cannot be used with this option: CREATE TABLE ... SELECT statements CREATE TEMPORARY TABLE or DROP ... The MySQL Server system variables described in this section are used to monitor and control Global Transaction Identifiers ...
https://dev.mysql.com/doc/refman/5.7/en/creating-many-tables.html
If you have many MyISAM tables in the same database directory, open, close, and create operations are slow. If you execute SELECT statements on many different tables, there is a little overhead when the table cache is full, because for every table ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-engines-table.html
The ENGINES table has these columns: ENGINE The name of the storage engine. SUPPORT The server's level of support for the storage engine, as shown in the following table. This is particularly useful for checking whether a storage engine is ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-plugins-table.html
The PLUGINS table has these columns: PLUGIN_NAME The name used to refer to the plugin in statements such as INSTALL PLUGIN and UNINSTALL PLUGIN. For plugins installed with INSTALL PLUGIN, the PLUGIN_NAME and PLUGIN_LIBRARY values are also registered ...PLUGIN_STATUS The plugin status, one of ACTIVE, INACTIVE, DISABLED, or ...