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https://dev.mysql.com/doc/refman/8.4/en/data-directory-initialization.html
After MySQL is installed, the data directory must be initialized, including the tables in the mysql system schema: For some MySQL installation methods, data directory initialization is automatic, as described in Section 2.9, “Postinstallation ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-indexes.html
Without an index, MySQL must begin with the first row and then read through the entire table to find the relevant rows. If the table has an index for the columns in question, MySQL can quickly determine the position to seek to in the middle of the ... Indexes are used to find rows with specific column values ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning.html
Note Table partitioning differs from partitioning as used by window functions. MySQL 8.4 does not currently support partitioning of tables using any storage engine other than InnoDB or NDB, such as MyISAM. An attempt to create a partitioned tables ...In MySQL 8.4, partitioning support is provided by the InnoDB and NDB storage ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-status-variables.html
Performance Schema status variables have the following meanings: Performance_schema_accounts_lost The number of times a row could not be added to the accounts table because it was full. Performance_schema_digest_lost The number of digest instances ...This can be nonzero if the value of performance_schema_digests_size is too ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-flush.html
Some forms of the FLUSH statement are not logged because they could cause problems if replicated to a replica: FLUSH LOGS and FLUSH TABLES WITH READ LOCK. The FLUSH TABLES, ANALYZE TABLE, OPTIMIZE TABLE, and REPAIR TABLE statements are written to ...These statements are written to the binary log unless you specify NO_WRITE_TO_BINLOG or its alias ...
https://dev.mysql.com/doc/refman/8.4/en/silent-column-changes.html
In some cases, MySQL silently changes column specifications from those given in a CREATE TABLE or ALTER TABLE statement. See Section 10.4.7, “Limits on Table Column Count and Row Size”. Trailing spaces are automatically deleted from ENUM and ...
https://dev.mysql.com/doc/extending-mysql/8.4/en/plugin-types.html
The plugin API enables creation of plugins that implement several capabilities: Loadable functions (UDFs) Storage engines Full-text parsers Daemons INFORMATION_SCHEMA tables Semisynchronous replication Auditing Authentication Password validation ...
https://dev.mysql.com/doc/relnotes/mysql-cluster/8.4/en/news-8-1-0.html
Table IDs and fragment IDs are undefined and thus not relevant when an LCP has reached WAIT_END_LCP state, and are no longer printed at that point. (Bug #35306351) When deferred triggers remained pending for an uncommitted transaction, a subsequent ... IPv6 Support Functionality Added or Changed Bugs Fixed IPv6 Support NDB did not start if IPv6 support was not enabled on the host, even when no nodes in the cluster used any IPv6 ...
https://dev.mysql.com/doc/refman/8.4/en/constraint-foreign-key.html
Foreign keys let you cross-reference related data across tables, and foreign key constraints help keep this spread-out data consistent. MySQL supports ON UPDATE and ON DELETE foreign key references in CREATE TABLE and ALTER TABLE statements. MySQL ...The available referential actions are RESTRICT, CASCADE, SET NULL, and NO ACTION (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, ...