What features are deprecated in MySQL 8.0?

Some deprecated features may be removed in upcoming MySQL versions. If an application uses functionality that is deprecated in that particular version, it should modify the functionality and use an alternative if possible.

Let's take a brief look at the deprecated features in MySQL 8.0:

• The "utf8mb3" character set is deprecated, please use "utf8mb4" instead.
• The "sha256_password" password authentication is deprecated and may be removed in a future update. Please use "caching_sha2_password" instead.
• Some implementation changes were made to the "validate_password" plugin and may be removed in a future release. When using this plugin, make sure that component infrastructure is also used in it.
• Support for "AUTO_INCRMENT" has been deprecated for column types "FLOAT" and "DOUBLE". Support for "UNSIGNED" has been deprecated for column types "FLOAT", "DOUBLE" and "DECIMAL".
• The "ZEROFILL" attribute for numeric data has been deprecated, use the "LPAD" method instead.
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• The use of "||" is deprecated unless SQL mode "PIPES AS CONCAT" is enabled.
• "JSON_MERGE" has been deprecated, please use "JSON_MERGE_PRESERVE()" instead.
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• When using the "SELECT" statement, you can use the INTO clause after the FROM, but using it at the end of the "SELECT" is deprecated.
• The "FLUSH HOSTS" feature is deprecated. Truncate the performance schema host_cache table instead. As shown below-

TRUNCATE TABLE performance_schema.host_cache;

Note: TRUNCATE TABLE operation requires "DROP" permission on the corresponding table.

• The "mysql_upgrade" client has been deprecated because of its ability to upgrade system tables in the mysql system schema and other objects in the schema have been moved to the MySQL server.
• The InnoDB memcached plugin is deprecated and may be removed in an upcoming MySQL version.
• The "mysql_upgrade_info" file created in the data directory is used to store the MySQL version number and has been deprecated. It may be removed in a future version of MySQL.
• The "relay_log_info_file" system variable and the "--master-info-file" option have been deprecated.

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