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https://dev.mysql.com/doc/refman/8.4/en/innodb-optimize-tablespace-page-allocation.html
By default, when additional space is required, InnoDB allocates pages to the tablespace and physically writes NULLs to those pages. You can disable innodb_extend_and_initialize on Linux systems to avoid physically writing NULLs to newly allocated ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-dict-obj-tree.html
The dict_obj_tree table provides a tree-based view of table information from the dict_obj_info table. This is intended primarily for use in testing, but can be useful in visualizing hierarchies of NDB database objects. This means that you must know ...
https://dev.mysql.com/doc/refman/8.4/en/optimizer-hints.html
row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 256 filtered: 100.00 Extra: Using filesort The USE INDEX, FORCE INDEX, and IGNORE INDEX index ... One means of control over optimizer strategies is to set the optimizer_switch system variable (see Section 10.9.2, “Switchable ...
https://dev.mysql.com/doc/refman/8.4/en/other-vendor-data-types.html
To facilitate the use of code written for SQL implementations from other vendors, MySQL maps data types as shown in the following table. These mappings make it easier to import table definitions from other database systems into MySQL. If you create ...
https://dev.mysql.com/doc/refman/8.4/en/outer-join-optimization.html
If there is a row in A that matches the WHERE clause, but there is no row in B that matches the ON condition, an extra B row is generated with all columns set to NULL. For a LEFT JOIN, if the WHERE condition is always false for the generated NULL ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-ndb-sync-excluded-objects-table.html
row *************************** SCHEMA_NAME: NULL NAME: lg1 TYPE: LOGFILE GROUP REASON: Injected failure *************************** 2. row *************************** SCHEMA_NAME: NULL NAME: ts1 TYPE: TABLESPACE REASON: Injected failure ... This ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-ndb-sync-pending-objects-table.html
This table provides information about NDB database objects for which mismatches have been detected and which are waiting to be synchronized between the NDB dictionary and the MySQL data dictionary.
https://dev.mysql.com/doc/refman/8.4/en/show-create-table.html
row *************************** Table: t Create Table: CREATE TABLE `t` ( `id` int NOT NULL AUTO_INCREMENT, `s` char(60) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci SHOW CREATE TABLE displays ... SHOW CREATE TABLE tbl_name Shows the CREATE TABLE statement that creates the named ...
https://dev.mysql.com/doc/refman/8.4/en/show-plugins.html
row *************************** Name: binlog Status: ACTIVE Type: STORAGE ENGINE Library: NULL License: GPL *************************** 2. row *************************** Name: CSV Status: ACTIVE Type: STORAGE ENGINE Library: NULL License: GPL ...
https://dev.mysql.com/doc/refman/8.4/en/show-table-status.html
Not all storage engines update this time, in which case, the value is always NULL. For views, most columns displayed by SHOW TABLE STATUS are 0 or NULL except that Name indicates the view name, Create_time indicates the creation time, and Comment ...