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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-summary-tables.html
Generally, the effect is to reset the summary columns to 0 or NULL, not to remove rows. Summary tables provide aggregated information for terminated events over time. The tables in this group summarize event data in different ways. Each summary ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-table-characteristics.html
Generally, the effect is to reset the summary columns to 0 or NULL, not to remove rows. The name of the performance_schema database is lowercase, as are the names of tables within it. Many tables in the performance_schema database are read only and ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-users-table.html
This is NULL for an internal thread, or for a user session that failed to authenticate. The users table contains a row for each user who has connected to the MySQL server. For each user name, the table counts the current and total number of ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-wait-summary-tables.html
This value is calculated only for timed events because nontimed events have a wait time of NULL. The Performance Schema maintains tables for collecting current and recent wait events, and aggregates that information in summary tables. Section ...
https://dev.mysql.com/doc/refman/8.4/en/plugin-loading.html
These can be identified as those that have a library name of NULL in the output from the Information Schema PLUGINS table or SHOW PLUGINS. Server plugins must be loaded into the server before they can be used. It is also possible to control the ...
https://dev.mysql.com/doc/refman/8.4/en/point-in-time-recovery-binlog.html
If your binary log contains \0 (null) characters, that output cannot be parsed by mysql unless you invoke it with the --binary-mode option. This section explains the general idea of using the binary log to perform a point-in-time-recovery. The next ...
https://dev.mysql.com/doc/refman/8.4/en/precision-math.html
Similarly, you can treat division by zero as an error rather than as an operation that produces a result of NULL. MySQL provides support for precision math: numeric value handling that results in extremely accurate results and a high degree control ...
https://dev.mysql.com/doc/refman/8.4/en/rebuilding-tables.html
This section describes how to rebuild or repair tables or indexes, which may be necessitated by: Changes to how MySQL handles data types or character sets. For example, an error in a collation might have been corrected, necessitating a table ...
https://dev.mysql.com/doc/refman/8.4/en/replication-privilege-checks-gr.html
Group Replication requires every table that is to be replicated by the group to have a defined primary key, or primary key equivalent where the equivalent is a non-null unique key. You can also use a PRIVILEGE_CHECKS_USER account to secure the two ...
https://dev.mysql.com/doc/refman/8.4/en/se-csv-limitations.html
All tables that you create using the CSV storage engine must have the NOT NULL attribute on all columns.