https://dev.mysql.com/performance-schema-statement-digests.html
If the table becomes full, the Performance Schema groups statements that have SCHEMA_NAME and DIGEST values not matching existing values in the table in a special row with SCHEMA_NAME and DIGEST set to NULL. The MySQL server is capable of ...
https://dev.mysql.com/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. Tables that ...
https://dev.mysql.com/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/performance-timers-table.html
For an explanation of how event timing occurs, see Section 26.4.1, “Performance Schema Event Timing”. For a cycle timer, the frequency is generally related to the CPU speed. For example, on a system with a 2.4GHz processor, the CYCLE may be ...
https://dev.mysql.com/plugin-loading.html
These can be identified as those that have a library name of NULL in the output from INFORMATION_SCHEMA.PLUGINS or SHOW PLUGINS. Server plugins must be loaded into the server before they can be used. It is also possible to control the activation ...
https://dev.mysql.com/plugins-table.html
If the library name is NULL, the plugin is compiled in and cannot be uninstalled with UNINSTALL PLUGIN. 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.
https://dev.mysql.com/point-in-time-recovery.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. Point-in-time recovery refers to recovery of data changes made since a given point in time. Typically, this ...
https://dev.mysql.com/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/query-results.html
mysql_info() returns a NULL pointer if there is no additional information. In addition to the result set returned by a query, you can also get the following information: mysql_affected_rows() returns the number of rows affected by the last query ...
https://dev.mysql.com/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 ...
