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https://dev.mysql.com/doc/refman/8.4/en/identifier-mapping.html
There is a correspondence between database and table identifiers and names in the file system. For the basic structure, MySQL represents each database as a directory in the data directory, and depending upon the storage engine, each table may be ...
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/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 ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndb-size-pl.html
Options that can be used with ndb_size.pl are shown in the following table. Similarly, you can cause specific tables to be skipped by listing their names, separated by commas, following the optional --excludetables option. Memory requirements for ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-atom-molecule-events.html
For a table I/O event, there are usually two rows in events_waits_current, not one. For example, a row fetch might result in rows like this: Row# EVENT_NAME TIMER_START TIMER_END ---- ---------- ----------- --------- 1 wait/io/file/myisam/dfile ...