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https://dev.mysql.com/doc/refman/8.4/en/information-schema-processlist-table.html
This is the same value displayed in the Id column of the SHOW PROCESSLIST statement, displayed in the PROCESSLIST_ID column of the Performance Schema threads table, and returned by the CONNECTION_ID() function within the thread. For system user, ...
https://dev.mysql.com/doc/refman/8.4/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. For fast join performance, define foreign keys on the join columns, and declare those columns ...Use joins wherever data is pulled from multiple tables based on identical ID values from those ...
https://dev.mysql.com/doc/refman/8.4/en/local-variable-scope.html
A local variable should not have the same name as a table column. INTO statement, contains a reference to a column and a declared local variable with the same name, MySQL currently interprets the reference as the name of a variable. Consequently, ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-disk-data-storage-requirements.html
The following items apply to Disk Data storage requirements: Variable-length columns of Disk Data tables take up a fixed amount of space. For each row, this is equal to the space required to store the largest possible value for that column. In a ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-dictionary-tables.html
dictionary_tables contains the columns listed here: table_id The table' unique ID database_name Name of the database containing the table table_name Name of the table status The table status; one of New, Changed, Retrieved, Invalid, or Altered.
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-transporter-details.html
See the Notes for the transporters table for more information about each of the columns in this table. The sendbuffer_used_bytes, sendbuffer_max_used_bytes, sendbuffer_alloc_bytes, and sendbuffer_max_alloc_bytes columns were added in NDB 8.4.0.
https://dev.mysql.com/doc/refman/8.4/en/optimizing-spatial-analysis.html
For MyISAM and InnoDB tables, search operations in columns containing spatial data can be optimized using SPATIAL indexes. The most typical operations are: Point queries that search for all objects that contain a given point Region queries that ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-replication-applier-configuration-table.html
The replication_applier_configuration table has these columns: CHANNEL_NAME The replication channel which this row is displaying. The following table shows the correspondence between replication_applier_configuration columns and SHOW REPLICA STATUS ... This table shows the configuration parameters that affect transactions applied by the ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-replication-applier-status-table.html
The replication_applier_status table has these columns: CHANNEL_NAME The replication channel which this row is displaying. The following table shows the correspondence between replication_applier_status columns and SHOW REPLICA STATUS columns. This ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-setup-actors-table.html
If a row from that table matches, its ENABLED and HISTORY column values are used to set the INSTRUMENTED and HISTORY columns, respectively, of the threads table row for the thread. If there is no match, the INSTRUMENTED and HISTORY columns for the ... The setup_actors table contains information that determines whether to enable monitoring and historical event logging for new foreground server threads (threads associated with client ...