MySQL 8.0.22 Release Highlights and New Features

The MySQL development team announced that MySQL 8.0.22 is now available for download, featuring bug fixes and a set of new capabilities detailed in the release notes.

Prepared Statements

Each DML statement is prepared only once (WL#9384), reducing execution overhead and simplifying code.

SHOW PROCESSLIST

SHOW PROCESSLIST is now implemented as a view on the processlist table in performance_schema , avoiding global mutex contention and allowing the use of the system variable -performance-schema-show-processlist=ON|OFF to select the implementation.

TIMESTAMP

A new AT TIME ZONE operator enables retrieval of UTC timestamps stored in tables; for example, a session in CET at 2020-04-29 16:43:19 returns 2020-04-29 14:43:19 UTC.

SELECT cast(a AT TIME ZONE 'UTC' AS DATETIME) FROM t1;

Read‑Only Schema

A new READ ONLY schema option can be set with ALTER SCHEMA to prohibit write operations; it requires ALTER privileges on the schema.

ALTER {DATABASE | SCHEMA} [db_name]
    alter_option ...
alter_option: {
    [DEFAULT] CHARACTER SET [=] charset_name
  | [DEFAULT] COLLATE [=] collation_name
  | [DEFAULT] ENCRYPTION [=] {'Y'|'N'}
  | READ ONLY [=] {DEFAULT|0|1}
}

Error Log

The error log can now be queried via the error_log table in Performance Schema, providing access without OS‑level permissions.

User Management

Locking on ACL tables has been relaxed (WL#14087) to avoid blocking non‑admin users, and DDL on ACL tables now improves when other connections hold locks (WL#14084). Dependencies between database objects and user definitions have been tightened (WL#14073).

Optimizer

WHERE‑condition push‑down to derived tables reduces row processing (WL#8084). The CAST function now accepts a YEAR argument, allowing conversion of various types to YEAR (WL#14015).

SELECT * FROM (SELECT i,j FROM t1) AS dt WHERE i > 10;

SELECT * FROM (SELECT i,j FROM t1 WHERE i > 10) AS dt;

Replication

Automatic reconnection to alternative asynchronous replication channels (WL#12649) adds fault tolerance. Slave commands have been renamed to replica commands (WL#14171). Variable group_replication_ip_whitelist is deprecated in favor of group_replication_ip_allowlist (WL#14175).

Router

Router now supports a higher maximum number of connections (WL#10703) by using one OS thread per CPU core instead of per connection. A REST API can be enabled during bootstrap (WL#13906), and systemd notifications reduce test suite runtime (WL#13707, WL#13708).

Other

Periodic data storage options allow output or dump to files (WL#13926) with three new GLOBAL variables: select_into_disk_sync , select_into_buffer_size , and select_into_disk_sync_delay . InnoDB adds innodb_extend_and_initialize to use fallocate() for faster inserts (WL#13782). The client library now supports DNS SRV records (WL#13905) for easier high‑availability configurations.

Deprecation and Removal

INFORMATION_SCHEMA.TABLESPACES is deprecated and will be removed in a future major release (WL#14064). The memcache plugin is deprecated with warnings on INSTALL PLUGIN (WL#14131).

These are the main updates in MySQL 8.0.22.

For the full release notes, see MySQL 8.0.22 Release Notes .