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https://dev.mysql.com/doc/refman/8.4/en/monitor-alter-table-performance-schema.html
Enable the stage/innodb/alter% instruments: mysql> UPDATE performance_schema.setup_instruments SET ENABLED = 'YES' WHERE NAME LIKE 'stage/innodb/alter%'; Query OK, 7 rows affected (0.00 sec) Rows matched: 7 Changed: 7 Warnings: 0 Enable the stage ...
https://dev.mysql.com/doc/refman/8.4/en/option-modifiers.html
For example, the mysql client supports a --column-names option that determines whether or not to display a row of column names at the beginning of query results. However, you may want to disable it in some instances, such as when sending the output ... Some options are “boolean” and control behavior that can be turned on or ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-info.html
The partition information is displayed if you specify the -v or --verbose option when viewing the binary log using mysqlbinlog. However, when a limiting condition making use of the partitioning key is added to the query, you can see that only those ... This section discusses obtaining information about existing partitions, which can be done in a number of ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-limitations-storage-engines.html
In MySQL 8.4, partitioning support is not actually provided by the MySQL Server, but rather by a table storage engine's own or native partitioning handler. In MySQL 8.4, only the InnoDB and NDB storage engines provide native partitioning handlers.
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-table-characteristics.html
Many tables in the performance_schema database are read only and cannot be modified: mysql> TRUNCATE TABLE performance_schema.setup_instruments; ERROR 1683 (HY000): Invalid performance_schema usage. That might be useful, for example, after you have ... The name of the performance_schema database is lowercase, as are the names of tables within ...
https://dev.mysql.com/doc/refman/8.4/en/perl-support.html
Although earlier versions are available, they do not support the full functionality of MySQL 8.4. The Perl DBI module provides a generic interface for database access. You can write a DBI script that works with many different database engines ...
https://dev.mysql.com/doc/refman/8.4/en/precision-math-rounding.html
This section discusses precision math rounding for the ROUND() function and for inserts into columns with exact-value types (DECIMAL and integer). The ROUND() function rounds differently depending on whether its argument is exact or approximate: ...
https://dev.mysql.com/doc/refman/8.4/en/rename-table.html
MySQL interprets CHECK constraint names that begin with the string “tbl_name_chk_” as internally generated names. RENAME TABLE tbl_name TO new_tbl_name [, tbl_name2 TO new_tbl_name2] ... You must have ALTER and DROP privileges for the original ...
https://dev.mysql.com/doc/refman/8.4/en/replication-howto-masterstatus.html
In a different session on the source, use the SHOW BINARY LOG STATUS statement to determine the current binary log file name and position: mysql> SHOW BINARY LOG STATUS\G *************************** 1. row *************************** File: ... To ...
https://dev.mysql.com/doc/refman/8.4/en/replication-multi-source-start-replica.html
For example, to start the two channels separately, use the mysql client to issue the following statements: mysql> START REPLICA FOR CHANNEL "source_1"; mysql> START REPLICA FOR CHANNEL "source_2"; For the full syntax of the START REPLICA statement ... Once you have added channels for all of the replication sources, issue a START REPLICA statement to start ...