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https://dev.mysql.com/doc/refman/8.4/en/identifiers.html
Certain objects within MySQL, including database, table, index, column, alias, view, stored procedure, partition, tablespace, resource group and other object names are known as identifiers. Use of the dollar sign as the first character in the ...
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). row ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-backup.html
Hot Backups The mysqlbackup command, part of the MySQL Enterprise Backup component, lets you back up a running MySQL instance, including InnoDB tables, with minimal disruption to operations while producing a consistent snapshot of the database. When ... The key to safe database management is making regular ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-read-only-instance.html
You can query InnoDB tables where the MySQL data directory is on read-only media by enabling the --innodb-read-only configuration option at server startup. This option specifies the path, file name, and file size for InnoDB temporary tablespace ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-system-tablespace.html
The system tablespace is the storage area for the change buffer. It may also contain table and index data if tables are created in the system tablespace rather than file-per-table or general tablespaces. By default, a single system tablespace data ...To do so, specify the autoextend attribute for the last data file in the innodb_data_file_path setting, and restart the ...
https://dev.mysql.com/doc/refman/8.4/en/keywords.html
Certain keywords, such as SELECT, DELETE, or BIGINT, are reserved and require special treatment for use as identifiers such as table and column names. Reserved words are permitted as identifiers if you quote them as described in Section 11.2, ...
https://dev.mysql.com/doc/refman/8.4/en/limit-optimization.html
MySQL sometimes optimizes a query that has a LIMIT row_count clause and no HAVING clause: If you select only a few rows with LIMIT, MySQL uses indexes in some cases when normally it would prefer to do a full table scan. If the server uses temporary ... If you need only a specified number of rows from a result set, use a LIMIT clause in the query, rather than fetching the whole result set and throwing away the extra ...
https://dev.mysql.com/doc/refman/8.4/en/myisam-key-cache.html
It employs a cache mechanism to keep the most frequently accessed table blocks in memory: For index blocks, a special structure called the key cache (or key buffer) is maintained. You can set up multiple key caches and assign table indexes to ... To ...
https://dev.mysql.com/doc/refman/8.4/en/myisamchk-other-options.html
myisamchk supports the following options for actions other than table checks and repairs: --analyze, -a Command-Line Format --analyze Analyze the distribution of key values. This improves join performance by enabling the join optimizer to better ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-disk-data-storage-requirements.html
The following items apply to Disk Data storage requirements: Variable-length columns of Disk Data tables take up a fixed amount of space. You can obtain an estimate the amount of space available in data files and undo log files by querying the ...