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https://dev.mysql.com/doc/refman/8.4/en/data-dictionary-file-removal.html
Unless otherwise noted, data previously stored in metadata files is now stored in data dictionary tables. With the removal of .frm files: The 64KB table definition size limit imposed by the .frm file structure is removed. The Information Schema ...
https://dev.mysql.com/doc/refman/8.4/en/fulltext-restrictions.html
Full-text searches are supported for InnoDB and MyISAM tables only. A character-based ngram full-text parser that supports Chinese, Japanese, and Korean (CJK), and a word-based MeCab parser plugin that supports Japanese are provided for use with ...
https://dev.mysql.com/doc/refman/8.4/en/fulltext-search-ngram.html
Creating a FULLTEXT Index that Uses the ngram Parser To create a FULLTEXT index that uses the ngram parser, specify WITH PARSER ngram with CREATE TABLE, ALTER TABLE, or CREATE INDEX. The following example demonstrates creating a table with an ngram ... The built-in MySQL full-text parser uses the white space between words as a delimiter to determine where words begin and end, which is a limitation when working with ideographic languages that do not use word ...
https://dev.mysql.com/doc/refman/8.4/en/function-loading.html
It registers the function in the mysql.func system table to make it persistent across server restarts. It adds the function to the Performance Schema user_defined_functions table that provides runtime information about installed loadable functions.
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 ...