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https://dev.mysql.com/doc/refman/8.4/en/alter-table.html
An index must be dropped and added back with the desired change, which can be performed in a single ALTER TABLE statement. For details about permissible index_option values, see Section 15.1.15, “CREATE INDEX Statement”. old_index_name must be ... ALTER TABLE tbl_name [alter_option [, alter_option] ...] [partition_options] alter_option: { table_options | ADD [COLUMN] col_name column_definition [FIRST | AFTER col_name] | ADD [COLUMN] (col_name column_definition,...) | ADD {INDEX | KEY} [index_name] [index_type] (key_part,...) [index_option] ...
https://dev.mysql.com/doc/refman/8.4/en/show-columns.html
A UNIQUE index may display as MUL if several columns form a composite UNIQUE index; although the combination of the columns is unique, each column can still hold multiple occurrences of a given value. The SHOW CREATE TABLE, SHOW TABLE STATUS, and ...
https://dev.mysql.com/doc/refman/8.4/en/alter-user.html
Statements that modify secondary passwords require these privileges: The APPLICATION_PASSWORD_ADMIN privilege is required to use the RETAIN CURRENT PASSWORD or DISCARD OLD PASSWORD clause for ALTER USER statements that apply to your own account.
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-events-statements-current-table.html
NO_INDEX_USED 1 if the statement performed a table scan without using an index, 0 otherwise. NO_GOOD_INDEX_USED 1 if the server found no good index to use for the statement, 0 otherwise. The events_statements_current table has these indexes: Primary ...The table stores one row per thread showing the current status of the thread's most recent monitored statement event, so there is no system variable for configuring the table ...
https://dev.mysql.com/doc/refman/8.4/en/explain.html
The SHOW CREATE TABLE, SHOW TABLE STATUS, and SHOW INDEX statements also provide information about tables. row *************************** EXPLAIN: -> Filter: (t.c2 > 50) (cost=0.35 rows=1) -> Covering index scan on t using i1 (cost=0.35 rows=1) 1 ...In this case, the statement displays information only for the named ...In practice, the DESCRIBE keyword is more often used to obtain information about table structure, whereas EXPLAIN is used to obtain a query ...
https://dev.mysql.com/doc/refman/8.4/en/create-user.html
These additional privilege considerations also apply: The authentication_policy system variable places certain constraints on how the authentication-related clauses of CREATE USER statements may be used; for details, see the description of that ...
https://dev.mysql.com/doc/refman/8.4/en/grant.html
These syntax restrictions apply: GRANT cannot mix granting both privileges and roles in the same statement. The ON clause distinguishes whether the statement grants privileges or roles: With ON, the statement grants privileges. It is permitted to ...
https://dev.mysql.com/doc/mysql-em-plugin/en/myoem-metric-mysqlserver-dmlstatementactivity-category.html
Lists the DML Statement Activity metrics and provides a brief description of each. Table 6.6 DML Statement Activity Metrics NameDescriptionCall Procedure (Delta) The total number of CALL statements executed. Dealloc SQL (Delta) The total number of ...Stmt Send Long Data (Delta) The total number of mysql_stmt_send_long_data calls ...
https://dev.mysql.com/doc/refman/8.4/en/replication-sbr-rbr.html
UPDATE statements that require a table scan (because no index is used in the WHERE clause) must lock a greater number of rows than with row-based replication. If, however, you want to take advantage of the features specific to the statement-based or ...For most users, the mixed replication format should provide the best combination of data integrity and ...
https://dev.mysql.com/doc/mysql-em-plugin/en/myoem-metric-mysqlserver-showstatementactivity-category.html
Show Keys (Delta) The total number of SHOW KEYS | INDEX | INDEXES statements executed. Lists the Show Statement Activity metrics and provides a brief description of each. Table 6.29 Show Statement Activity Metrics NameDescriptionShow Authors ...