Search Results
https://dev.mysql.com/doc/refman/8.4/en/index-extensions.html
Consider this table definition: CREATE TABLE t1 ( i1 INT NOT NULL DEFAULT 0, i2 INT NOT NULL DEFAULT 0, d DATE DEFAULT NULL, PRIMARY KEY (i1, i2), INDEX k_d (d) ) ENGINE = InnoDB; This table defines the primary key on columns (i1, i2). InnoDB ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-buffer-page-table.html
The column is NULL if the server has not yet accessed the table. The INNODB_BUFFER_PAGE table provides information about each page in the InnoDB buffer pool. For related usage information and examples, see Section 17.15.5, “InnoDB ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-key-column-usage-table.html
This table provides no information about functional key parts because they are expressions and the table provides information only about columns. The KEY_COLUMN_USAGE table has these columns: CONSTRAINT_CATALOG The name of the catalog to which the ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-optimization.html
row *************************** id: 1 select_type: SIMPLE table: cs partitions: NULL type: const possible_keys: PRIMARY,name key: name key_len: 194 ref: const rows: 1 filtered: 100.00 Extra: Using index *************************** 2. row ...
https://dev.mysql.com/doc/refman/8.4/en/multiple-column-indexes.html
MySQL can create composite indexes (that is, indexes on multiple columns). For certain data types, you can index a prefix of the column (see Section 10.3.5, “Column Indexes”). MySQL can use multiple-column indexes for queries that test all the ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-logging.html
Then use either of the following techniques to prevent it from being created again: Set the MYSQL_HISTFILE environment variable to /dev/null. Create .mysql_history as a symbolic link to /dev/null; this need be done only once: ln -s /dev/null ... The ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-shell-tutorial-javascript-documents-in-tables.html
In MySQL, a table may contain traditional relational data, JSON values, or both. You can combine traditional data with JSON documents by storing the documents in columns having a native JSON data type. Examples in this section use the city table in ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-shell-tutorial-python-documents-in-tables.html
In MySQL, a table may contain traditional relational data, JSON values, or both. You can combine traditional data with JSON documents by storing the documents in columns having a native JSON data type. Examples in this section use the city table in ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-queries.html
If an indexed column cannot contain any NULL values, declare it as NOT NULL when you create the table. The optimizer can better determine which index is most effective to use for a query, when it knows whether each column contains NULL values. To ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-linear-hash.html
MySQL also supports linear hashing, which differs from regular hashing in that linear hashing utilizes a linear powers-of-two algorithm whereas regular hashing employs the modulus of the hashing function's value. We call this value V; it can be ...