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https://dev.mysql.com/doc/refman/8.4/en/information-schema-user-attributes-table.html
The USER_ATTRIBUTES table has these columns: USER The user name portion of the account to which the ATTRIBUTE column value applies. HOST The host name portion of the account to which the ATTRIBUTE column value applies. ATTRIBUTE The user comment, ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-views-table.html
The VIEWS table has these columns: TABLE_CATALOG The name of the catalog to which the view belongs. This column has most of what you see in the Create Table column that SHOW CREATE VIEW produces. The IS_UPDATABLE column in the VIEWS table displays ...You must have the SHOW VIEW privilege to access this ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-online-ddl-performance.html
Session 2: mysql> ALTER TABLE t1 ADD COLUMN x INT, ALGORITHM=INPLACE, LOCK=NONE; The online DDL operation in session 2, which requires an exclusive metadata lock on table t1 to commit table definition changes, must wait for the session 1 transaction ... Online DDL improves several aspects of MySQL operation: Applications that access the table are more responsive because queries and DML operations on the table can proceed while the DDL operation is in ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-transaction-isolation-levels.html
The second UPDATE blocks when it tries to acquire x-locks on the same records, as it also uses the index defined on column b. Transaction isolation is one of the foundations of database processing. Isolation is the I in the acronym ACID; the ...
https://dev.mysql.com/doc/refman/8.4/en/json-modification-functions.html
The optimizer can perform a partial, in-place update of a JSON column instead of removing the old document and writing the new document in its entirety to the column. The optimizer can perform a partial, in-place update of a JSON column instead of ... The functions in this section modify JSON values and return the ...
https://dev.mysql.com/doc/refman/8.4/en/loading-tables.html
You could create a text file pet.txt containing one record per line, with values separated by tabs, and given in the order in which the columns were listed in the CREATE TABLE statement. In its simplest form, you supply values for each column, in ...
https://dev.mysql.com/doc/refman/8.4/en/memory-storage-engine.html
MEMORY tables can have up to 64 indexes per table, 16 columns per index and a maximum key length of 3072 bytes. (This is an uncommon feature for implementations of hash indexes.) Columns that are indexed can contain NULL values. The MEMORY storage ...
https://dev.mysql.com/doc/refman/8.4/en/merge-table-problems.html
The checks ensure that the definitions of the tables and the parent MERGE table definition match by comparing column order, types, sizes and associated indexes. Because these checks take place when the tables are opened, any changes to the ... The ...
https://dev.mysql.com/doc/refman/8.4/en/monitor-mysql-memory-use.html
Instruments can be enabled by updating the ENABLED column of the Performance Schema setup_instruments table. After restarting the server, the ENABLED column of the Performance Schema setup_instruments table should report YES for memory instruments ... The following example demonstrates how to use Performance Schema and sys schema to monitor MySQL memory ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-cluster-operations.html
(Currently, the MySQL Server does not expose the NDB API transaction ID of an ongoing transaction.) The operation_type column can take any one of the values READ, READ-SH, READ-EX, INSERT, UPDATE, DELETE, WRITE, UNLOCK, REFRESH, SCAN, SCAN-SH, ...