Chapter 1 General Information

Text in this style is used for SQL statements; database, table, and column names; program listings and source code; and environment variables. Example: “To reload the grant tables, use the FLUSH PRIVILEGES statement.”

Text in this style indicates input that you type in examples.

Text in this style indicates the names of executable programs and scripts, examples being mysql (the MySQL command-line client program) and mysqld (the MySQL server executable).

Text in this style is used for variable input for which you should substitute a value of your own choosing.

Text in this style is used for emphasis.

Text in this style is used in table headings and to convey especially strong emphasis.

Text in this style is used to indicate a program option that affects how the program is executed, or that supplies information that is needed for the program to function in a certain way. Example: “The --host option (short form -h) tells the mysql client program the hostname or IP address of the MySQL server that it should connect to”.

File names and directory names are written like this: “The global my.cnf file is located in the /etc directory.”

Character sequences are written like this: “To specify a wildcard, use the ‘%’ character.”

Data dictionary.  MySQL now incorporates a transactional data dictionary that stores information about database objects. In previous MySQL releases, dictionary data was stored in metadata files and nontransactional tables. For more information, see Chapter 14, MySQL Data Dictionary.

Atomic data definition statements (Atomic DDL).  An atomic DDL statement combines the data dictionary updates, storage engine operations, and binary log writes associated with a DDL operation into a single, atomic transaction. For more information, see Section 13.1.1, “Atomic Data Definition Statement Support”.

Upgrade procedure.  Previously, after installation of a new version of MySQL, the MySQL server automatically upgrades the data dictionary tables at the next startup, after which the DBA is expected to invoke mysql_upgrade manually to upgrade the system tables in the mysql schema, as well as objects in other schemas such as the sys schema and user schemas.

As of MySQL 8.0.16, the server performs the tasks previously handled by mysql_upgrade. After installation of a new MySQL version, the server now automatically performs all necessary upgrade tasks at the next startup and is not dependent on the DBA invoking mysql_upgrade. In addition, the server updates the contents of the help tables (something mysql_upgrade did not do). A new --upgrade server option provides control over how the server performs automatic data dictionary and server upgrade operations. For more information, see Section 2.11.3, “What the MySQL Upgrade Process Upgrades”.

Security and account management.  These enhancements were added to improve security and enable greater DBA flexibility in account management:

Resource management.  MySQL now supports creation and management of resource groups, and permits assigning threads running within the server to particular groups so that threads execute according to the resources available to the group. Group attributes enable control over its resources, to enable or restrict resource consumption by threads in the group. DBAs can modify these attributes as appropriate for different workloads. Currently, CPU time is a manageable resource, represented by the concept of “virtual CPU” as a term that includes CPU cores, hyperthreads, hardware threads, and so forth. The server determines at startup how many virtual CPUs are available, and database administrators with appropriate privileges can associate these CPUs with resource groups and assign threads to groups. For more information, see Section 5.1.16, “Resource Groups”.

Table encryption management.  Table encryption can now be managed globally by defining and enforcing encryption defaults. The default_table_encryption variable defines an encryption default for newly created schemas and general tablespace. The encryption default for a schema can also be defined using the DEFAULT ENCRYPTION clause when creating a schema. By default, a table inherits the encryption of the schema or general tablespace it is created in. Encryption defaults are enforced by enabling the table_encryption_privilege_check variable. The privilege check occurs when creating or altering a schema or general tablespace with an encryption setting that differs from the default_table_encryption setting, or when creating or altering a table with an encryption setting that differs from the default schema encryption. The TABLE_ENCRYPTION_ADMIN privilege permits overriding default encryption settings when table_encryption_privilege_check is enabled. For more information, see Defining an Encryption Default for Schemas and General Tablespaces.

InnoDB enhancements.  These InnoDB enhancements were added:

As of MySQL 8.0.21, table and table partition data files created outside of the data directory using the DATA DIRECTORY clause are restricted to directories known to InnoDB. This change permits database administrators to control where tablespace data files are created and ensures that the data files can be found during recovery.

General and file-per-table tablespaces data files (.ibd files) can no longer be created in the undo tablespace directory (innodb_undo_directory) unless that directly is known to InnoDB.

Known directories are those defined by the datadir, innodb_data_home_dir, and innodb_directories variables.

Truncating an InnoDB table that resides in a file-per-table tablespace drops the existing tablespace and creates a new one. As of MySQL 8.0.21, InnoDB creates the new tablespace in the default location and writes a warning to the error log if the current tablespace directory is unknown. To have TRUNCATE TABLE create the tablespace in its current location, add the directory to the innodb_directories setting before running TRUNCATE TABLE.

As of MySQL 8.0.21, redo logging can be enabled and disabled using ALTER INSTANCE {ENABLE|DISABLE} INNODB REDO_LOG syntax. This functionality is intended for loading data into a new MySQL instance. Disabling redo logging helps speed up data loading by avoiding redo log writes.

The new INNODB_REDO_LOG_ENABLE privilege permits enabling and disabling redo logging.

The new Innodb_redo_log_enabled status variable permits monitoring redo logging status.

See Disabling Redo Logging.

At startup, InnoDB validates the paths of known tablespace files against tablespace file paths stored in the data dictionary in case tablespace files have been moved to a different location. The new innodb_validate_tablespace_paths variable, introduced in MySQL 8.0.21, permits disabling tablespace path validation. This feature is intended for environments where tablespaces files are not moved. Disabling tablespace path validation improves startup time on systems with a large number of tablespace files.

For more information, see Section 15.6.3.7, “Disabling Tablespace Path Validation”.

As of MySQL 8.0.21, on storage engines that support atomic DDL, the CREATE TABLE ... SELECT statement is logged as one transaction in the binary log when row-based replication is in use. Previously, it was logged as two transactions, one to create the table, and the other to insert data. With this change, CREATE TABLE ... SELECT statements are now safe for row-based replication and permitted for use with GTID-based replication. For more information, see Section 13.1.1, “Atomic Data Definition Statement Support”.

Truncating an undo tablespace on a busy system could affect performance due to associated flushing operations that remove old undo tablespace pages from the buffer pool and flush the initial pages of the new undo tablespace to disk. To address this issue, the flushing operations are removed as of MySQL 8.0.21.

Old undo tablespace pages are released passively as they become least recently used, or are removed at the next full checkpoint. The initial pages of the new undo tablespace are now redo logged instead of flushed to disk during the truncate operation, which also improves durability of the undo tablespace truncate operation.

To prevent potential issues caused by an excessive number of undo tablespace truncate operations, truncate operations on the same undo tablespace between checkpoints are now limited to 64. If the limit is exceeded, an undo tablespace can still be made inactive, but it is not truncated until after the next checkpoint.

INNODB_METRICS counters associated with defunct undo truncate flushing operations were removed. Removed counters include: undo_truncate_sweep_count, undo_truncate_sweep_usec, undo_truncate_flush_count, and undo_truncate_flush_usec.

See Section 15.6.3.4, “Undo Tablespaces”.

As of MySQL 8.0.22, the new innodb_extend_and_initialize variable permits configuring how InnoDB allocates space to file-per-table and general tablespaces on Linux. By default, when an operation requires additional space in a tablespace, InnoDB allocates pages to the tablespace and physically writes NULLs to those pages. This behavior affects performance if new pages are allocated frequently. You can disable innodb_extend_and_initialize on Linux systems to avoid physically writing NULLs to newly allocated tablespace pages. When innodb_extend_and_initialize is disabled, space is allocated using posix_fallocate() calls, which reserve space without physically writing NULLs.

A posix_fallocate() operation is not atomic, which makes it possible for a failure to occur between allocating space to a tablespace file and updating the file metadata. Such a failure can leave newly allocated pages in an uninitialized state, resulting in a failure when InnoDB attempts to access those pages. To prevent this scenario, InnoDB writes a redo log record before allocating a new tablespace page. If a page allocation operation is interrupted, the operation is replayed from the redo log record during recovery.

As of MySQL 8.0.23, InnoDB supports encryption of doublewrite file pages belonging to encrypted tablespaces. The pages are encrypted using the encryption key of the associated tablespace. For more information, see Section 15.13, “InnoDB Data-at-Rest Encryption”.

The temptable_max_mmap variable, introduced in MySQL 8.0.23, defines the maximum amount of memory the TempTable storage engine is permitted to allocate from memory-mapped (MMAP) files before it starts storing internal temporary table data on disk. A setting of 0 disables allocation from MMAP files. For more information, see Section 8.4.4, “Internal Temporary Table Use in MySQL”.

Character set support.  The default character set has changed from latin1 to utf8mb4. The utf8mb4 character set has several new collations, including utf8mb4_ja_0900_as_cs, the first Japanese language-specific collation available for Unicode in MySQL. For more information, see Section 10.10.1, “Unicode Character Sets”.

JSON enhancements.  The following enhancements or additions were made to MySQL's JSON functionality:

Data type support.  MySQL now supports use of expressions as default values in data type specifications. This includes the use of expressions as default values for the BLOB, TEXT, GEOMETRY, and JSON data types, which previously could not be assigned default values at all. For details, see Section 11.6, “Data Type Default Values”.

Optimizer.  These optimizer enhancements were added:

Common table expressions.  MySQL now supports common table expressions, both nonrecursive and recursive. Common table expressions enable use of named temporary result sets, implemented by permitting a WITH clause preceding SELECT statements and certain other statements. For more information, see Section 13.2.15, “WITH (Common Table Expressions)”.

As of MySQL 8.0.19, the recursive SELECT part of a recursive common table expression (CTE) supports a LIMIT clause. LIMIT with OFFSET is also supported. See Recursive Common Table Expressions, for more information.

Window functions.  MySQL now supports window functions that, for each row from a query, perform a calculation using rows related to that row. These include functions such as RANK(), LAG(), and NTILE(). In addition, several existing aggregate functions now can be used as window functions (for example, SUM() and AVG()). For more information, see Section 12.21, “Window Functions”.

Lateral derived tables.  A derived table now may be preceded by the LATERAL keyword to specify that it is permitted to refer to (depend on) columns of preceding tables in the same FROM clause. Lateral derived tables make possible certain SQL operations that cannot be done with nonlateral derived tables or that require less-efficient workarounds. See Section 13.2.11.9, “Lateral Derived Tables”.

Aliases in single-table DELETE statements.  In MySQL 8.0.16 and later, single-table DELETE statements support the use of table aliases.

Regular expression support.  Previously, MySQL used the Henry Spencer regular expression library to support regular expression operators (REGEXP, RLIKE). Regular expression support has been reimplemented using International Components for Unicode (ICU), which provides full Unicode support and is multibyte safe. The REGEXP_LIKE() function performs regular expression matching in the manner of the REGEXP and RLIKE operators, which now are synonyms for that function. In addition, the REGEXP_INSTR(), REGEXP_REPLACE(), and REGEXP_SUBSTR() functions are available to find match positions and perform substring substitution and extraction, respectively. The regexp_stack_limit and regexp_time_limit system variables provide control over resource consumption by the match engine. For more information, see Section 12.8.2, “Regular Expressions”. For information about ways in which applications that use regular expressions may be affected by the implementation change, see Regular Expression Compatibility Considerations.

Internal temporary tables.  The TempTable storage engine replaces the MEMORY storage engine as the default engine for in-memory internal temporary tables. The TempTable storage engine provides efficient storage for VARCHAR and VARBINARY columns. The internal_tmp_mem_storage_engine session variable defines the storage engine for in-memory internal temporary tables. Permitted values are TempTable (the default) and MEMORY. The temptable_max_ram variable defines the maximum amount of memory that the TempTable storage engine can use before data is stored to disk.

Logging.  Error logging was rewritten to use the MySQL component architecture. Traditional error logging is implemented using built-in components, and logging using the system log is implemented as a loadable component. In addition, a loadable JSON log writer is available. To control which log components to enable, use the log_error_services system variable. For more information, see Section 5.4.2, “The Error Log”.

Backup lock.  A new type of backup lock permits DML during an online backup while preventing operations that could result in an inconsistent snapshot. The new backup lock is supported by LOCK INSTANCE FOR BACKUP and UNLOCK INSTANCE syntax. The BACKUP_ADMIN privilege is required to use these statements.

Replication.  The following enhancements have been made to MySQL Replication:

Connection management.  MySQL Server now permits a TCP/IP port to be configured specifically for administrative connections. This provides an alternative to the single administrative connection that is permitted on the network interfaces used for ordinary connections even when max_connections connections are already established. See Section 5.1.12.1, “Connection Interfaces”.

MySQL now provides more control over the use of compression to minimize the number of bytes sent over connections to the server. Previously, a given connection was either uncompressed or used the zlib compression algorithm. Now, it is also possible to use the zstd algorithm, and to select a compression level for zstd connections. The permitted compression algorithms can be configured on the server side, as well as on the connection-origination side for connections by client programs and by servers participating in source/replica replication or Group Replication. For more information, see Section 4.2.8, “Connection Compression Control”.

Configuration.  The maximum permitted length of host names throughout MySQL has been raised to 255 ASCII characters, up from the previous limit of 60 characters. This applies to, for example, host name-related columns in the data dictionary, mysql system schema, Performance Schema, INFORMATION_SCHEMA, and sys schema; the MASTER_HOST value for the CHANGE MASTER TO statement; the Host column in SHOW PROCESSLIST statement output; host names in account names (such as used in account-management statements and in DEFINER attributes); and host name-related command options and system variables.

Caveats:

Plugins.  Previously, MySQL plugins could be written in C or C++. MySQL header files used by plugins now contain C++ code, which means that plugins must be written in C++, not C.

C API.  The MySQL C API now supports asynchronous functions for nonblocking communication with the MySQL server. Each function is the asynchronous counterpart to an existing synchronous function. The synchronous functions block if reads from or writes to the server connection must wait. The asynchronous functions enable an application to check whether work on the server connection is ready to proceed. If not, the application can perform other work before checking again later. See C API Asynchronous Interface.

Additional target types for casts.  The functions CAST() and CONVERT() now support conversions to types DOUBLE, FLOAT, and REAL. Added in MySQL 8.0.17. See Section 12.11, “Cast Functions and Operators”.

JSON schema validation.  MySQL 8.0.17 adds two functions JSON_SCHEMA_VALID() and JSON_SCHEMA_VALIDATION_REPORT() for validating JSON documents again JSON schemas. JSON_SCHEMA_VALID() returns TRUE (1) if the document validates against the schema and FALSE (0) if it does not. JSON_SCHEMA_VALIDATION_REPORT() returns a JSON document containing detailed information about the results of the validation. The following statements apply to both of these functions:

See Section 12.18.7, “JSON Schema Validation Functions”, for more information and examples.

Multi-valued indexes.  Beginning with MySQL 8.0.17, InnoDB supports the creation of a multi-valued index, which is a secondary index defined on a JSON column that stores an array of values and which can have multiple index records for a single data record. Such an index uses a key part definition such as CAST(data->'$.zipcode' AS UNSIGNED ARRAY). A multi-valued index is used automatically by the MySQL optimizer for suitable queries, as can be viewed in the output of EXPLAIN.

As part of this work, MySQL adds a new function JSON_OVERLAPS() and a new MEMBER OF() operator for working with JSON documents, additionally extending the CAST() function with a new ARRAY keyword, as described in the following list:

For detailed information about multi-valued indexes, including examples, see Multi-Valued Indexes. Section 12.18.3, “Functions That Search JSON Values”, provides information about JSON_OVERLAPS() and MEMBER OF(), along with examples of use.

Hintable time_zone.  As of MySQL 8.0.17, the time_zone session variable is hintable using SET_VAR.

Redo Log Archiving.  As of MySQL 8.0.17, InnoDB supports redo log archiving. Backup utilities that copy redo log records may sometimes fail to keep pace with redo log generation while a backup operation is in progress, resulting in lost redo log records due to those records being overwritten. The redo log archiving feature addresses this issue by sequentially writing redo log records to an archive file. Backup utilities can copy redo log records from the archive file as necessary, thereby avoiding the potential loss of data. For more information, see Redo Log Archiving.

The Clone Plugin.  As of MySQL 8.0.17, MySQL provides a clone plugin that permits cloning InnoDB data locally or from a remote MySQL server instance. A local cloning operation stores cloned data on the same server or node where the MySQL instance runs. A remote cloning operation transfers cloned data over the network from a donor MySQL server instance to the recipient server or node where the cloning operation was initiated.

The clone plugin supports replication. In addition to cloning data, a cloning operation extracts and transfers replication coordinates from the donor and applies them on the recipient, which enables using the clone plugin for provisioning Group Replication members and replicas. Using the clone plugin for provisioning is considerably faster and more efficient than replicating a large number of transactions. Group Replication members can also be configured to use the clone plugin as an alternative method of recovery, so that members automatically choose the most efficient way to retrieve group data from seed members.

For more information, see Section 5.6.7, “The Clone Plugin”, and Section 18.4.3.2, “Cloning for Distributed Recovery”.

Hash Join Optimization.  Beginning with MySQL 8.0.18, a hash join is used whenever each pair of tables in a join includes at least one equi-join condition, and no indexes apply to any join condition. A hash join does not require indexes, although it can be used with indexes applying to single-table predicates only. A hash join is more efficient in most cases than the block-nested loop algorithm. Joins such as those shown here can be optimized in this manner:

SELECT *
    FROM t1
    JOIN t2
        ON t1.c1=t2.c1;

SELECT *
    FROM t1
    JOIN t2
        ON (t1.c1 = t2.c1 AND t1.c2 < t2.c2)
    JOIN t3
        ON (t2.c1 = t3.c1)

Hash joins can also be used for Cartesian products—that is, when no join condition is specified.

You can see when the hash join optimization is being used for a particular query using EXPLAIN FORMAT=TREE or EXPLAIN ANALYZE. (In MySQL 8.0.20 and later, you can also use EXPLAIN, omitting FORMAT=TREE.)

The amount of memory available to a hash join is limited by the value of join_buffer_size. A hash join that requires more than this much memory is executed on disk; the number of disk files that can be used by an on-disk hash join is limited by open_files_limit.

As of MySQL 8.0.19, the hash_join optimizer switch which was introduced in MySQL 8.0.18 no longer supported (hash_join=on still appears as part of the value of optimizer_switch, but setting it no longer has any effect). The HASH_JOIN and NO_HASH_JOIN optimizer hints are also no longer supported. The switch and the hint are both now deprecated; expect them to be removed in a future MySQL release. In MySQL 8.0.18 and later, hash joins can be disabled using the NO_BNL optimizer switch.

In MySQL 8.0.20 and later, block nested loop is no longer used in the MySQL server, and a hash join is employed any time a block nested loop would have been used previously, even when the query contains no equi-join conditions. This applies to inner non-equijoins, semijoins, antijoins, left outer joins, and right outer joins. TThe block_nested_loop flag for the optimizer_switch system variable as well as the BNL and NO_BNL optimizer hints are still supported, but henceforth control use of hash joins only. In addition, both inner and outer joins (including semijoins and antijoins) can now employ batched key access (BKA), which allocates join buffer memory incrementally so that individual queries need not use up large amounts of resources that they do not actually require for resolution. BKA for inner joins only is supported starting with MySQL 8.0.18.

MySQL 8.0.20 also replaces the executor used in previous versions of MySQL with the iterator executor. This work includes replacement of the old index subquery engines that governed queries of the form WHERE value IN (SELECT column FROM table WHERE ...) for those IN queries which have not been optimized as semijoins, as well as queries materialized in the same form, which formerly depended on the old executor.

For more information and examples, see Section 8.2.1.4, “Hash Join Optimization”. See also Batched Key Access Joins.

EXPLAIN ANALYZE Statement.  A new form of the EXPLAIN statement, EXPLAIN ANALYZE, is implemented in MySQL 8.0.18, providing expanded information about the execution of SELECT statements in TREE format for each iterator used in processing the query, and making it possible to compare estimated cost with the actual cost of the query. This information includes startup cost, total cost, number of rows returned by this iterator, and the number of loops executed.

In MySQL 8.0.21 and later, this statement also supports a FORMAT=TREE specifier. TREE is the only supported format.

See Obtaining Information with EXPLAIN ANALYZE, for more information.

Query cast injection.  In version 8.0.18 and later, MySQL injects cast operations into the query item tree inside expressions and conditions in which the data type of the argument and the expected data type do not match. This has no effect on query results or speed of execution, but makes the query as executed equivalent to one which is compliant with the SQL standard while maintaining backwards compatibility with previous releases of MySQL.

Such implicit casts are now performed between temporal types (DATE, DATETIME, TIMESTAMP, TIME) and numeric types (SMALLINT, TINYINT, MEDIUMINT, INT/INTEGER, BIGINT; DECIMAL/NUMERIC; FLOAT, DOUBLE, REAL; BIT) whenever they are compared using any of the standard numeric comparison operators (=, >=, >, <, <=, <>/!=, or <=>). In this case, any value that is not already a DOUBLE is cast as one. Cast injection is also now performed for comparisons between DATE or TIME values and DATETIME values, where the arguments are cast whenever necessary as DATETIME.

Beginning with MySQL 8.0.21, such casts are also performed when comparing string types with other types. String types that are cast include CHAR, VARCHAR, BINARY, VARBINARY, BLOB, TEXT, ENUM, and SET. When comparing a value of a string type with a numeric type or YEAR, the string cast is to DOUBLE; if the type of the other argument is not FLOAT, DOUBLE, or REAL, it is also cast to DOUBLE. When comparing a string type to a DATETIME or TIMESTAMP value, the string is cast is to DATETIME; when comparing a string type with DATE, the string is cast to DATE.

It is possible to see when casts are injected into a given query by viewing the output of EXPLAIN ANALYZE, EXPLAIN FORMAT=JSON, or, as shown here, EXPLAIN FORMAT=TREE:

mysql> CREATE TABLE d (dt DATETIME, d DATE, t TIME);
Query OK, 0 rows affected (0.62 sec)

mysql> CREATE TABLE n (i INT, d DECIMAL, f FLOAT, dc DECIMAL);
Query OK, 0 rows affected (0.51 sec)

mysql> CREATE TABLE s (c CHAR(25), vc VARCHAR(25),
    ->     bn BINARY(50), vb VARBINARY(50), b BLOB, t TEXT,
    ->     e ENUM('a', 'b', 'c'), se SET('x' ,'y', 'z'));
Query OK, 0 rows affected (0.50 sec)

mysql> EXPLAIN FORMAT=TREE SELECT * from d JOIN n ON d.dt = n.i\G
*************************** 1. row ***************************
EXPLAIN: -> Inner hash join (cast(d.dt as double) = cast(n.i as double))
(cost=0.70 rows=1)
    -> Table scan on n  (cost=0.35 rows=1)
    -> Hash
        -> Table scan on d  (cost=0.35 rows=1)

mysql> EXPLAIN FORMAT=TREE SELECT * from s JOIN d ON d.dt = s.c\G
*************************** 1. row ***************************
EXPLAIN: -> Inner hash join (d.dt = cast(s.c as datetime(6)))  (cost=0.72 rows=1)
    -> Table scan on d  (cost=0.37 rows=1)
    -> Hash
        -> Table scan on s  (cost=0.35 rows=1)

1 row in set (0.01 sec)

mysql> EXPLAIN FORMAT=TREE SELECT * from n JOIN s ON n.d = s.c\G
*************************** 1. row ***************************
EXPLAIN: -> Inner hash join (cast(n.d as double) = cast(s.c as double))  (cost=0.70 rows=1)
    -> Table scan on s  (cost=0.35 rows=1)
    -> Hash
        -> Table scan on n  (cost=0.35 rows=1)

1 row in set (0.00 sec)

Such casts can also be seen by executing EXPLAIN [FORMAT=TRADITIONAL], in which case it is also necessary to issue SHOW WARNINGS after executing the EXPLAIN statement.

Time zone support for TIMESTAMP and DATETIME.  As of MySQL 8.0.19, the server accepts a time zone offset with inserted datetime (TIMESTAMP and DATETIME) values. This offset uses the same format as that employed when setting the time_zone system variable, except that a leading zero is required when the hours portion of the offset is less than 10, and '-00:00' is not allowed. Examples of datetime literals that include time zone offsets are '2019-12-11 10:40:30-05:00', '2003-04-14 03:30:00+10:00', and '2020-01-01 15:35:45+05:30'.

Time zone offsets are not displayed when selecting datetime values.

Datetime literals incorporating time zone offsets can be used as prepared statement parameter values.

As part of this work, the value used to set the time_zone system variable is now also restricted to the range -14:00 to +14:00, inclusive. (It remains possible to assign name values to time_zone such as 'EST', 'Posix/Australia/Brisbane', and 'Europe/Stockholm' to this variable, provided that the MySQL time zone tables are loaded; see Populating the Time Zone Tables).

For more information and examples, see Section 5.1.15, “MySQL Server Time Zone Support”, as well as Section 11.2.2, “The DATE, DATETIME, and TIMESTAMP Types”.

Precise information for JSON schema CHECK constraint failures.  When using JSON_SCHEMA_VALID() to specify a CHECK constraint, MySQL 8.0.19 and later provides precise information about the reasons for failures of such constraints.

For examples and more information, see JSON_SCHEMA_VALID() and CHECK constraints. See also Section 13.1.20.6, “CHECK Constraints”.

Row and column aliases with ON DUPLICATE KEY UPDATE.  Beginning with MySQL 8.0.19, it is possible to reference the row to be inserted, and, optionally, its columns, using aliases. Consider the following INSERT statement on a table t having columns a and b:

INSERT INTO t SET a=9,b=5
    ON DUPLICATE KEY UPDATE a=VALUES(a)+VALUES(b);

Using the alias new for the new row, and, in some cases, the aliases m and n for this row's columns, the INSERT statement can be rewritten in many different ways, some examples of which are shown here:

INSERT INTO t SET a=9,b=5 AS new
    ON DUPLICATE KEY UPDATE a=new.a+new.b;

INSERT INTO t VALUES(9,5) AS new
    ON DUPLICATE KEY UPDATE a=new.a+new.b;

INSERT INTO t SET a=9,b=5 AS new(m,n)
    ON DUPLICATE KEY UPDATE a=m+n;

INSERT INTO t VALUES(9,5) AS new(m,n)
    ON DUPLICATE KEY UPDATE a=m+n;

For more information and examples, see Section 13.2.6.2, “INSERT ... ON DUPLICATE KEY UPDATE Statement”.

SQL standard explicit table clause and table value constructor.  Added table value constructors and explicit table clauses according to the SQL standard. These are implemented in MySQL 8.0.19, respectively, as the TABLE statement and the VALUES statement.

The TABLE statement has the format TABLE table_name, and is equivalent to SELECT * FROM table_name. It supports ORDER BY and LIMIT clauses ( the latter with optional OFFSET), but does not allow for the selection of individual table columns. TABLE can be used anywhere that you would employ the equivalent SELECT statement; this includes joins, unions, INSERT ... SELECT, REPLACE, CREATE TABLE ... SELECT statements, and subqueries. For example:

VALUES can be used to supply a table value to an INSERT, REPLACE, or SELECT statement, and consists of the VALUES keyword followed by a series of row constructors (ROW()) separated by commas. For example, the statement INSERT INTO t1 VALUES ROW(1,2,3), ROW(4,5,6), ROW(7,8,9) provides an SQL-compliant equivalent to the MySQL-specific INSERT INTO t1 VALUES (1,2,3), (4,5,6), (7,8,9). You can also select from a VALUES table value constructor just as you would a table, bearing in mind that you must supply a table alias when doing so, and use this SELECT just as you would any other; this includes joins, unions, and subqueries.

For more information about TABLE and VALUES, and for examples of their use, see the following sections of this documentation:

Optimizer hints for FORCE INDEX, IGNORE INDEX.  MySQL 8.0 introduces index-level optimizer hints which serve as analogs to the traditional index hints as described in Section 8.9.4, “Index Hints”. The new hints are listed here, along with their FORCE INDEX or IGNORE INDEX equivalents:

For example, the following two queries are equivalent:

SELECT a FROM t1 FORCE INDEX (i_a) FOR JOIN WHERE a=1 AND b=2;

SELECT /*+ JOIN_INDEX(t1 i_a) */ a FROM t1 WHERE a=1 AND b=2;

The optimizer hints listed previously follow the same basic rules for syntax and usage as existing index-level optimizer hints.

These optimizer hints are intended to replace FORCE INDEX and IGNORE INDEX, which we plan to deprecate in a future MySQL release, and subsequently to remove from MySQL. They do not implement a single exact equivalent for USE INDEX; instead, you can employ one or more of NO_INDEX, NO_JOIN_INDEX, NO_GROUP_INDEX, or NO_ORDER_INDEX to achieve the same effect.

For further information and examples of use, see Index-Level Optimizer Hints.

JSON_VALUE() function.  MySQL 8.0.21 implements a new function JSON_VALUE() intended to simplify indexing of JSON columns. In its most basic form, it takes as arguments a JSON document and a JSON path pointing to a single value in that document, as well as (optionally) allowing you to specify a return type with the RETURNING keyword. JSON_VALUE(json_doc, path RETURNING type) is equivalent to this:

CAST(
    JSON_UNQUOTE( JSON_EXTRACT(json_doc, path) )
    AS type
);

You can also specify ON EMPTY, ON ERROR, or both clauses, similar to those employed with JSON_TABLE().

You can use JSON_VALUE() to create an index on an expression on a JSON column like this:

CREATE TABLE t1(
    j JSON,
    INDEX i1 ( (JSON_VALUE(j, '$.id' RETURNING UNSIGNED)) )
);

INSERT INTO t1 VALUES ROW('{"id": "123", "name": "shoes", "price": "49.95"}');

A query using this expression, such as that shown here, can make use of the index:

SELECT name, price FROM t1
    WHERE JSON_VALUE(j, '$.id' RETURNING UNSIGNED) = 123;

In many cases, this is simpler than creating a generated column from the JSON column and then creating an index on the generated column.

For more information and examples, see the description of JSON_VALUE().

User comments and user attributes.  MySQL 8.0.21 introduces the ability to set user comments and user attributes when creating or updating user accounts. A user comment consists of arbitrary text passed as the argument to a COMMENT clause used with a CREATE USER or ALTER USER statement. A user attribute consists of data in the form of a JSON object passed as the argument to an ATTRIBUTE clause used with either of these two statements. The attribute can contain any valid key-value pairs in JSON object notation. Only one of COMMENT or ATTRIBUTE can be used in a single CREATE USER or ALTER USER statement.

User comments and user attributes are stored together internally as a JSON object, the comment text as the value of an element having comment as its key. This information can be retrieved from the ATTRIBUTE column of the INFORMATION_SCHEMA.USER_ATTRIBUTES table; since it is in JSON format, you can use MySQL's JSON function and operators to parse its contents (see Section 12.18, “JSON Functions”). Successive changes to the user attribute are merged with its current value as when using the JSON_MERGE_PATCH() function.

Example:

mysql> CREATE USER 'mary'@'localhost' COMMENT 'This is Mary Smith\'s account';
Query OK, 0 rows affected (0.33 sec)

mysql> ALTER USER 'mary'@'localhost'
    -≫     ATTRIBUTE '{"fname":"Mary", "lname":"Smith"}';
Query OK, 0 rows affected (0.14 sec)

mysql> ALTER USER 'mary'@'localhost'
    -≫     ATTRIBUTE '{"email":"mary.smith@example.com"}';
Query OK, 0 rows affected (0.12 sec)

mysql> SELECT
    ->    USER,
    ->    HOST,
    ->    ATTRIBUTE->>"$.fname" AS 'First Name',
    ->    ATTRIBUTE->>"$.lname" AS 'Last Name',
    ->    ATTRIBUTE->>"$.email" AS 'Email',
    ->    ATTRIBUTE->>"$.comment" AS 'Comment'
    -> FROM INFORMATION_SCHEMA.USER_ATTRIBUTES
    -> WHERE USER='mary' AND HOST='localhost'\G
*************************** 1. row ***************************
      USER: mary
      HOST: localhost
First Name: Mary
 Last Name: Smith
     Email: mary.smith@example.com
   Comment: This is Mary Smith's account
1 row in set (0.00 sec)

For more information and examples, see Section 13.7.1.3, “CREATE USER Statement”, Section 13.7.1.1, “ALTER USER Statement”, and Section 26.46, “The INFORMATION_SCHEMA USER_ATTRIBUTES Table”.

New optimizer_switch flags.  MySQL 8.0.21 adds two new flags for the optimizer_switch system variable, as described in the following list:

For more information, see Section 8.9.2, “Switchable Optimizations”. See also Section 8.2.1.19, “LIMIT Query Optimization”, Section 8.2.2.1, “Optimizing IN and EXISTS Subquery Predicates with Semijoin Transformations”, and Section 8.2.2.4, “Optimizing Derived Tables, View References, and Common Table Expressions with Merging or Materialization”.

XML enhancements.  As of MySQL 8.0.21, the LOAD XML statement now supports CDATA sections in the XML to be imported.

Casting to the YEAR type now supported.  Beginning with MySQL 8.0.22, the server allows casting to YEAR. Both the CAST() and CONVERT() functions support single-digit, two-digit, and four-digit YEAR values. For one-digit and two-digit values, the allowed range is 0-99. Four-digit values must be in the range 1901-2155. YEAR can also be used as the return type for the JSON_VALUE() function; this function supports four-digit years only.

String, time-and-date, and floating-point values can all be cast to YEAR. Casting of GEOMETRY values to YEAR is not supported.

For more information, including conversion rules, see the description of the CONVERT() function.

Retrieval of TIMESTAMP values as UTC.  MySQL 8.0.22 and later supports conversion of a TIMESTAMP column value from the system time zone to a UTC DATETIME on retrieval, using CAST(value AT TIME ZONE specifier AS DATETIME), where the specifier is one of [INTERVAL] '+00:00' or 'UTC'. The precision of the DATETIME value returned by the cast can be specified up to 6 decimal places, if desired. The ARRAY keyword is not supported with this construct.

TIMESTAMP values inserted into a table using a timezone offset are also supported. Use of AT TIME ZONE is not supported for CONVERT() or any other MySQL function or construct.

For further information and examples, see the description of the CAST() function.

Dump file output synchronization.  MySQL 8.0.22 and later supports periodic synchronization when writing to files by SELECT INTO DUMPFILE and SELECT INTO OUTFILE statements. This can be enabled by setting the select_into_disk_sync system variable to ON; the size of the write buffer is determined by the value set for select_into_buffer_size; the default is 131072 (2¹⁷) bytes.

In addition, an optional delay following synchronization to disk can be set using select_into_disk_sync_delay; the default is no delay (0 milliseconds).

For more information, see the descriptions of the variables referenced previously in this item.

Single preparation of statements.  As of MySQL 8.0.22, a prepared statement is prepared a single time, rather than once each time it is executed. This is done when executing PREPARE. This is also true for any statement inside a stored procedure; the statement is prepared once, when the stored procedure is first executed.

One result of this change is that the fashion in which dynamic parameters used in prepared statements are resolved is also changed in the ways listed here:

Preparing a statement used as a prepared statement or within a stored procedure only once enhances the performance of the statement, since it negates the added cost of repeated preparation. Doing so also avoids possible multiple rollbacks of preparation structures, which has been the source of numerous issues in MySQL.

For more information, see Section 13.5.1, “PREPARE Statement”.

RIGHT JOIN as LEFT JOIN handling.  As of MySQL 8.0.22, the server handles all instances of RIGHT JOIN internally as LEFT JOIN, eliminating a number of special cases in which a complete conversion was not performed at parse time.

Derived condition pushdown optimization.  MySQL 8.0.22 (and later) implements derived condition pushdown for queries having materialized derived tables. For a query such as SELECT * FROM (SELECT i, j FROM t1) AS dt WHERE i > constant, it is now possible in many cases to push the the outer WHERE condition down to the derived table, in this case resulting in SELECT * FROM (SELECT i, j FROM t1 WHERE i > constant) AS dt.

Previously, if the derived table was materialized and not merged, MySQL materialized the entire table, then qualified the rows with the WHERE condition. Moving the WHERE condition into the subquery using the derived condition pushdown optimization can often reduce the number of rows must be be processed, which can decrease the time needed to execute the query.

An outer WHERE condition can be pushed down directly to a materialized derived table when the derived table does not use any aggregate or window functions. When the derived table has a GROUP BY and does not use any window functions, the outer WHERE condition can be pushed down to the derived table as a HAVING condition. The WHERE condition can also be pushed down when the derived table uses a window function and the outer WHERE references columns used in the window function's PARTITION clause.

Derived condition pushdown is enabled by default, as indicated by the optimizer_switch system variable's derived_condition_pushdown flag. The flag, added in MySQL 8.0.22, is set to on by default; to disable the optimization for a specific query, you can use the NO_DERIVED_CONDITION_PUSHDOWN optimizer hint (also added in MySQL 8.0.22). If the optimization is disabled due to derived_condition_pushdown being set to off, you can enable it for a given query using DERIVED_CONDITION_PUSHDOWN.

The derived condition pushdown optimization cannot be employed for a derived table that contains a UNION or LIMIT clause. In addition, a condition that itself uses a subquery cannot be pushed down, and a WHERE condition cannot be pushed down to a derived table that is also an inner table of an outer join. For additional information and examples, see Section 8.2.2.5, “Derived Condition Pushdown Optimization”.

Non-locking reads on MySQL grant tables.  As of MySQL 8.0.22, to permit concurrent DML and DDL operations on MySQL grant tables, read operations that previously acquired row locks on MySQL grant tables are executed as non-locking reads.

The operations that are now performed as non-locking reads on MySQL grant tables include:

For additional information, see Grant Table Concurrency.

The utf8mb3 character set is deprecated. Please use utf8mb4 instead.

Because caching_sha2_password is the default authentication plugin in MySQL 8.0 and provides a superset of the capabilities of the sha256_password authentication plugin, sha256_password is deprecated; expect it to be removed in a future version of MySQL. MySQL accounts that authenticate using sha256_password should be migrated to use caching_sha2_password instead.

The validate_password plugin has been reimplemented to use the component infrastructure. The plugin form of validate_password is still available but is now deprecated; expect it to be removed in a future version of MySQL. MySQL installations that use the plugin should make the transition to using the component instead. See Section 6.4.3.3, “Transitioning to the Password Validation Component”.

The ENGINE clause for the ALTER TABLESPACE and DROP TABLESPACE statements is deprecated.

The PAD_CHAR_TO_FULL_LENGTH SQL mode is deprecated.

AUTO_INCREMENT support is deprecated for columns of type FLOAT and DOUBLE (and any synonyms). Consider removing the AUTO_INCREMENT attribute from such columns, or convert them to an integer type.

The UNSIGNED attribute is deprecated for columns of type FLOAT, DOUBLE, and DECIMAL (and any synonyms). Consider using a simple CHECK constraint instead for such columns.

FLOAT(M,D) and DOUBLE(M,D) syntax to specify the number of digits for columns of type FLOAT and DOUBLE (and any synonyms) is a nonstandard MySQL extension. This syntax is deprecated.

The ZEROFILL attribute is deprecated for numeric data types, as is the display width attribute for integer data types. Consider using an alternative means of producing the effect of these attributes. For example, applications could use the LPAD() function to zero-pad numbers up to the desired width, or they could store the formatted numbers in CHAR columns.

For string data types, the BINARY attribute is a nonstandard MySQL extension that is shorthand for specifying the binary (_bin) collation of the column character set (or of the table default character set if no column character set is specified). In MySQL 8.0, this nonstandard use of BINARY is ambiguous because the utf8mb4 character set has multiple _bin collations, so the BINARY attribute is deprecated; expect support for it to be removed in a future version of MySQL. Applications should be adjusted to use an explicit _bin collation instead.

The use of BINARY to specify a data type or character set remains unchanged.

The nonstandard C-style &&, ||, and ! operators that are synonyms for the standard SQL AND, OR, and NOT operators, respectively, are deprecated. Applications that use the nonstandard operators should be adjusted to use the standard operators.

The JSON_MERGE() function is deprecated. Use JSON_MERGE_PRESERVE() instead.

The SQL_CALC_FOUND_ROWS query modifier and accompanying FOUND_ROWS() function are deprecated. See the FOUND_ROWS() description for information about an alternative strategy.

Support for TABLESPACE = innodb_file_per_table and TABLESPACE = innodb_temporary clauses with CREATE TEMPORARY TABLE is deprecated as of MySQL 8.0.13.

For SELECT statements, use of an INTO clause after FROM but not at the end of the SELECT is deprecated as of MySQL 8.0.20. It is preferred to place the INTO at the end of the statement.

For UNION statements, these two variants containing INTO are deprecated as of MySQL 8.0.20:

See Section 13.2.10.1, “SELECT ... INTO Statement”, and Section 13.2.10.3, “UNION Clause”.

FLUSH HOSTS is deprecated as of MySQL 8.0.23. Instead, truncate the Performance Schema host_cache table:

TRUNCATE TABLE performance_schema.host_cache;

The TRUNCATE TABLE operation requires the DROP privilege for the table.

The mysql_upgrade client is deprecated because its capabilities for upgrading the system tables in the mysql system schema and objects in other schemas have been moved into the MySQL server. See Section 2.11.3, “What the MySQL Upgrade Process Upgrades”.

The --no-dd-upgrade server option is deprecated. It is superseded by the --upgrade option, which provides finer control over data dictionary and server upgrade behavior.

The mysql_upgrade_info file, which is created data directory and used to store the MySQL version number, is deprecated; expect it to be removed in a future version of MySQL.

The relay_log_info_file system variable and --master-info-file option are deprecated. Previously, these were used to specify the name of the relay log info log and source info log when relay_log_info_repository=FILE and master_info_repository=FILE were set, but those settings have been deprecated. The use of files for the relay log info log and source info log has been superseded by crash-safe replica tables, which are the default in MySQL 8.0.

The max_length_for_sort_data system variable is now deprecated due to optimizer changes that make it obsolete and of no effect.

These legacy parameters for compression of connections to the server are deprecated: The --compress client command-line option; the MYSQL_OPT_COMPRESS option for the mysql_options() C API function; the slave_compressed_protocol system variable. For information about parameters to use instead, see Section 4.2.8, “Connection Compression Control”.

Use of the MYSQL_PWD environment variable to specify a MySQL password is deprecated.

Use of VALUES() to access new row values in INSERT ... ON DUPLICATE KEY UPDATE is deprecated as of MySQL 8.0.20. Use aliases for the new row and columns, instead.

Because specifying ON ERROR before ON EMPTY when invoking JSON_TABLE() is counter to the SQL standard, this syntax is now deprecated in MySQL. Beginning with MySQL 8.0.20, the server prints a warning whenever you attempt to do so. When specifying both of these clauses in a single JSON_TABLE() invocation, make sure that ON EMPTY is used first.

Columns with index prefixes have never been supported as part of a table's partitioning key; previously, these were allowed when creating, altering, or upgrading partitioned tables but were excluded by the table's partitioning function, and no warning that this had occurred was issued by the server. This permissive behavior is now deprecated, and subject to removal in a future version of MySQL in which using any such columns in the partitioning key causes the CREATE TABLE or ALTER TABLE statement in they occur to be rejected.

As of MySQL 8.0.21, whenever columns using index prefixes are specified as part of the partitioning key, a warning is generated for each such column. Whenever a CREATE TABLE or ALTER TABLE statement is rejected because all columns in the proposed partitioning key would have index prefixes, the resulting error now provides the exact reason for the rejection. In either instance, this includes cases in which the columns used in the partitioning function are defined implicitly as those in the table's primary key by employing an empty PARTITION BY KEY() clause.

For more information and examples, see Column index prefixes not supported for key partitioning.

The InnoDB memcached plugin is deprecated as of MySQL 8.0.22; expect support for it to be removed in a future version of MySQL.

The innodb_locks_unsafe_for_binlog system variable was removed. The READ COMMITTED isolation level provides similar functionality.

The information_schema_stats variable, introduced in MySQL 8.0.0, was removed and replaced by information_schema_stats_expiry in MySQL 8.0.3.

information_schema_stats_expiry defines an expiration setting for cached INFORMATION_SCHEMA table statistics. For more information, see Section 8.2.3, “Optimizing INFORMATION_SCHEMA Queries”.

Code related to obsoleted InnoDB system tables was removed in MySQL 8.0.3. INFORMATION_SCHEMA views based on InnoDB system tables were replaced by internal system views on data dictionary tables. Affected InnoDB INFORMATION_SCHEMA views were renamed:

After upgrading to MySQL 8.0.3 or later, update any scripts that reference previous InnoDB INFORMATION_SCHEMA view names.

The following features related to account management are removed:

The query cache was removed. Removal includes these items:

These deprecated query cache items remain deprecated, but have no effect; expect them to be removed in a future MySQL release:

The have_query_cache system variable remains deprecated, and always has a value of NO; expect it to be removed in a future MySQL release.

The data dictionary provides information about database objects, so the server no longer checks directory names in the data directory to find databases. Consequently, the --ignore-db-dir option and ignore_db_dirs system variables are extraneous and are removed.

The DDL log, also known as the metadata log, has been removed. Beginning with MySQL 8.0.3, this functionality is handled by the data dictionary innodb_ddl_log table. See Viewing DDL Logs.

The tx_isolation and tx_read_only system variables have been removed. Use transaction_isolation and transaction_read_only instead.

The sync_frm system variable has been removed because .frm files have become obsolete.

The secure_auth system variable and --secure-auth client option have been removed. The MYSQL_SECURE_AUTH option for the mysql_options() C API function was removed.

The multi_range_count system variable is removed.

The log_warnings system variable and --log-warnings server option have been removed. Use the log_error_verbosity system variable instead.

The global scope for the sql_log_bin system variable was removed. sql_log_bin has session scope only, and applications that rely on accessing @@GLOBAL.sql_log_bin should be adjusted.

The metadata_locks_cache_size and metadata_locks_hash_instances system variables are removed.

The unused date_format, datetime_format, time_format, and max_tmp_tables system variables are removed.

These deprecated compatibility SQL modes are removed: DB2, MAXDB, MSSQL, MYSQL323, MYSQL40, ORACLE, POSTGRESQL, NO_FIELD_OPTIONS, NO_KEY_OPTIONS, NO_TABLE_OPTIONS. They can no longer be assigned to the sql_mode system variable or used as permitted values for the mysqldump --compatible option.

Removal of MAXDB means that the TIMESTAMP data type for CREATE TABLE or ALTER TABLE is treated as TIMESTAMP, and is no longer treated as DATETIME.

The deprecated ASC or DESC qualifiers for GROUP BY clauses are removed. Queries that previously relied on GROUP BY sorting may produce results that differ from previous MySQL versions. To produce a given sort order, provide an ORDER BY clause.

The EXTENDED and PARTITIONS keywords for the EXPLAIN statement have been removed. These keywords are unnecessary because their effect is always enabled.

These encryption-related items are removed:

In place of the removed encryption functions: For ENCRYPT(), consider using SHA2() instead for one-way hashing. For the others, consider using AES_ENCRYPT() and AES_DECRYPT() instead.

In MySQL 5.7, several spatial functions available under multiple names were deprecated to move in the direction of making the spatial function namespace more consistent, the goal being that each spatial function name begin with ST_ if it performs an exact operation, or with MBR if it performs an operation based on minimum bounding rectangles. In MySQL 8.0, the deprecated functions are removed to leave only the corresponding ST_ and MBR functions:

The functions described in Section 12.17.4, “Functions That Create Geometry Values from WKB Values” previously accepted either WKB strings or geometry arguments. Geometry arguments are no longer permitted and produce an error. See that section for guidelines for migrating queries away from using geometry arguments.

The parser no longer treats \N as a synonym for NULL in SQL statements. Use NULL instead.

This change does not affect text file import or export operations performed with LOAD DATA or SELECT ... INTO OUTFILE, for which NULL continues to be represented by \N. See Section 13.2.7, “LOAD DATA Statement”.

PROCEDURE ANALYSE() syntax is removed.

The client-side --ssl and --ssl-verify-server-cert options have been removed. Use --ssl-mode=REQUIRED instead of --ssl=1 or --enable-ssl. Use --ssl-mode=DISABLED instead of --ssl=0, --skip-ssl, or --disable-ssl. Use --ssl-mode=VERIFY_IDENTITY instead of --ssl-verify-server-cert options. (The server-side --ssl option remains unchanged.)

For the C API, MYSQL_OPT_SSL_ENFORCE and MYSQL_OPT_SSL_VERIFY_SERVER_CERT options for mysql_options() correspond to the client-side --ssl and --ssl-verify-server-cert options and are removed. Use MYSQL_OPT_SSL_MODE with an option value of SSL_MODE_REQUIRED or SSL_MODE_VERIFY_IDENTITY instead.

The --temp-pool server option was removed.

The ignore_builtin_innodb system variable is removed.

The server no longer performs conversion of pre-MySQL 5.1 database names containing special characters to 5.1 format with the addition of a #mysql50# prefix. Because these conversions are no longer performed, the --fix-db-names and --fix-table-names options for mysqlcheck, the UPGRADE DATA DIRECTORY NAME clause for the ALTER DATABASE statement, and the Com_alter_db_upgrade status variable are removed.

Upgrades are supported only from one major version to another (for example, 5.0 to 5.1, or 5.1 to 5.5), so there should be little remaining need for conversion of older 5.0 database names to current versions of MySQL. As a workaround, upgrade a MySQL 5.0 installation to MySQL 5.1 before upgrading to a more recent release.

The mysql_install_db program has been removed from MySQL distributions. Data directory initialization should be performed by invoking mysqld with the --initialize or --initialize-insecure option instead. In addition, the --bootstrap option for mysqld that was used by mysql_install_db was removed, and the INSTALL_SCRIPTDIR CMake option that controlled the installation location for mysql_install_db was removed.

The generic partitioning handler was removed from the MySQL server. In order to support partitioning of a given table, the storage engine used for the table must now provide its own (“native”) partitioning handler. The --partition and --skip-partition options are removed from the MySQL Server, and partitioning-related entries are no longer shown in the output of SHOW PLUGINS or in the INFORMATION_SCHEMA.PLUGINS table.

Two MySQL storage engines currently provide native partitioning support: InnoDB and NDB. Of these, only InnoDB is supported in MySQL 8.0. Any attempt to create partitioned tables in MySQL 8.0 using any other storage engine fails.

Ramifications for upgrades.  The direct upgrade of a partitioned table using a storage engine other than InnoDB (such as MyISAM) from MySQL 5.7 (or earlier) to MySQL 8.0 is not supported. There are two options for handling such a table:

At least one of the two operations just listed must be performed for each partitioned non-InnoDB table prior to upgrading the server to MySQL 8.0. Otherwise, such a table cannot be used following the upgrade.

Due to the fact that table creation statements that would result in a partitioned table using a storage engine without partitioning support now fail with an error (ER_CHECK_NOT_IMPLEMENTED), you must make sure that any statements in a dump file (such as that written by mysqldump) from an older version of MySQL that you wish to import into a MySQL 8.0 server that create partitioned tables do not also specify a storage engine such as MyISAM that has no native partitioning handler. You can do this by performing either of the following:

For more information, see Section 24.6.2, “Partitioning Limitations Relating to Storage Engines”.

System and status variable information is no longer maintained in the INFORMATION_SCHEMA. These tables are removed: GLOBAL_VARIABLES, SESSION_VARIABLES, GLOBAL_STATUS, SESSION_STATUS. Use the corresponding Performance Schema tables instead. See Section 27.12.14, “Performance Schema System Variable Tables”, and Section 27.12.15, “Performance Schema Status Variable Tables”. In addition, the show_compatibility_56 system variable was removed. It was used in the transition period during which system and status variable information in INFORMATION_SCHEMA tables was moved to Performance Schema tables, and is no longer needed. These status variables are removed: Slave_heartbeat_period, Slave_last_heartbeat, Slave_received_heartbeats, Slave_retried_transactions, Slave_running. The information they provided is available in Performance Schema tables; see Migrating to Performance Schema System and Status Variable Tables.

The Performance Schema setup_timers table was removed, as was the TICK row in the performance_timers table.

The libmysqld embedded server library is removed, along with:

The mysql_plugin utility was removed. Alternatives include loading plugins at server startup using the --plugin-load or --plugin-load-add option, or at runtime using the INSTALL PLUGIN statement.

The resolveip utility is removed. nslookup, host, or dig can be used instead.

The resolve_stack_dump utility is removed. Stack traces from official MySQL builds are always symbolized, so there is no need to use resolve_stack_dump.

The following server error codes are not used and have been removed. Applications that test specifically for any of these errors should be updated.

ER_BINLOG_READ_EVENT_CHECKSUM_FAILURE
ER_BINLOG_ROW_RBR_TO_SBR
ER_BINLOG_ROW_WRONG_TABLE_DEF
ER_CANT_ACTIVATE_LOG
ER_CANT_CHANGE_GTID_NEXT_IN_TRANSACTION
ER_CANT_CREATE_FEDERATED_TABLE
ER_CANT_CREATE_SROUTINE
ER_CANT_DELETE_FILE
ER_CANT_GET_WD
ER_CANT_SET_GTID_PURGED_WHEN_GTID_MODE_IS_OFF
ER_CANT_SET_WD
ER_CANT_WRITE_LOCK_LOG_TABLE
ER_CREATE_DB_WITH_READ_LOCK
ER_CYCLIC_REFERENCE
ER_DB_DROP_DELETE
ER_DELAYED_NOT_SUPPORTED
ER_DIFF_GROUPS_PROC
ER_DISK_FULL
ER_DROP_DB_WITH_READ_LOCK
ER_DROP_USER
ER_DUMP_NOT_IMPLEMENTED
ER_ERROR_DURING_CHECKPOINT
ER_ERROR_ON_CLOSE
ER_EVENTS_DB_ERROR
ER_EVENT_CANNOT_DELETE
ER_EVENT_CANT_ALTER
ER_EVENT_COMPILE_ERROR
ER_EVENT_DATA_TOO_LONG
ER_EVENT_DROP_FAILED
ER_EVENT_MODIFY_QUEUE_ERROR
ER_EVENT_NEITHER_M_EXPR_NOR_M_AT
ER_EVENT_OPEN_TABLE_FAILED
ER_EVENT_STORE_FAILED
ER_EXEC_STMT_WITH_OPEN_CURSOR
ER_FAILED_ROUTINE_BREAK_BINLOG
ER_FLUSH_MASTER_BINLOG_CLOSED
ER_FORM_NOT_FOUND
ER_FOUND_GTID_EVENT_WHEN_GTID_MODE_IS_OFF__UNUSED
ER_FRM_UNKNOWN_TYPE
ER_GOT_SIGNAL
ER_GRANT_PLUGIN_USER_EXISTS
ER_GTID_MODE_REQUIRES_BINLOG
ER_GTID_NEXT_IS_NOT_IN_GTID_NEXT_LIST
ER_HASHCHK
ER_INDEX_REBUILD
ER_INNODB_NO_FT_USES_PARSER
ER_LIST_OF_FIELDS_ONLY_IN_HASH_ERROR
ER_LOAD_DATA_INVALID_COLUMN_UNUSED
ER_LOGGING_PROHIBIT_CHANGING_OF
ER_MALFORMED_DEFINER
ER_MASTER_KEY_ROTATION_ERROR_BY_SE
ER_NDB_CANT_SWITCH_BINLOG_FORMAT
ER_NEVER_USED
ER_NISAMCHK
ER_NO_CONST_EXPR_IN_RANGE_OR_LIST_ERROR
ER_NO_FILE_MAPPING
ER_NO_GROUP_FOR_PROC
ER_NO_RAID_COMPILED
ER_NO_SUCH_KEY_VALUE
ER_NO_SUCH_PARTITION__UNUSED
ER_OBSOLETE_CANNOT_LOAD_FROM_TABLE
ER_OBSOLETE_COL_COUNT_DOESNT_MATCH_CORRUPTED
ER_ORDER_WITH_PROC
ER_PARTITION_SUBPARTITION_ERROR
ER_PARTITION_SUBPART_MIX_ERROR
ER_PART_STATE_ERROR
ER_PASSWD_LENGTH
ER_QUERY_ON_MASTER
ER_RBR_NOT_AVAILABLE
ER_SKIPPING_LOGGED_TRANSACTION
ER_SLAVE_CHANNEL_DELETE
ER_SLAVE_MULTIPLE_CHANNELS_HOST_PORT
ER_SLAVE_MUST_STOP
ER_SLAVE_WAS_NOT_RUNNING
ER_SLAVE_WAS_RUNNING
ER_SP_GOTO_IN_HNDLR
ER_SP_PROC_TABLE_CORRUPT
ER_SQL_MODE_NO_EFFECT
ER_SR_INVALID_CREATION_CTX
ER_TABLE_NEEDS_UPG_PART
ER_TOO_MUCH_AUTO_TIMESTAMP_COLS
ER_UNEXPECTED_EOF
ER_UNION_TABLES_IN_DIFFERENT_DIR
ER_UNSUPPORTED_BY_REPLICATION_THREAD
ER_UNUSED1
ER_UNUSED2
ER_UNUSED3
ER_UNUSED4
ER_UNUSED5
ER_UNUSED6
ER_VIEW_SELECT_DERIVED_UNUSED
ER_WRONG_MAGIC
ER_WSAS_FAILED

The deprecated INFORMATION_SCHEMA INNODB_LOCKS and INNODB_LOCK_WAITS tables are removed. Use the Performance Schema data_locks and data_lock_waits tables instead.

InnoDB no longer supports compressed temporary tables. When innodb_strict_mode is enabled (the default), CREATE TEMPORARY TABLE returns an error if ROW_FORMAT=COMPRESSED or KEY_BLOCK_SIZE is specified. If innodb_strict_mode is disabled, warnings are issued and the temporary table is created using a non-compressed row format.

InnoDB no longer creates .isl files (InnoDB Symbolic Link files) when creating tablespace data files outside of the MySQL data directory. The innodb_directories option now supports locating tablespace files created outside of the data directory.

With this change, moving a remote tablespace while the server is offline by manually modifying an .isl file is no longer supported. Moving remote tablespace files is now supported by the innodb_directories option. See Section 15.6.3.6, “Moving Tablespace Files While the Server is Offline”.

The following InnoDB file format variables were removed:

File format variables were necessary for creating tables compatible with earlier versions of InnoDB in MySQL 5.1. Now that MySQL 5.1 has reached the end of its product lifecycle, these options are no longer required.

The FILE_FORMAT column was removed from the INNODB_TABLES and INNODB_TABLESPACES Information Schema tables.

The innodb_support_xa system variable, which enables support for two-phase commit in XA transactions, was removed. InnoDB support for two-phase commit in XA transactions is always enabled.

Support for DTrace was removed.

The JSON_APPEND() function was removed. Use JSON_ARRAY_APPEND() instead.

Support for placing table partitions in shared InnoDB tablespaces was removed in MySQL 8.0.13. Shared tablespaces include the InnoDB system tablespace and general tablespaces. For information about identifying partitions in shared tablespaces and moving them to file-per-table tablespaces, see Section 2.11.5, “Preparing Your Installation for Upgrade”.

Support for setting user variables in statements other than SET was deprecated in MySQL 8.0.13. This functionality is subject to removal in MySQL 9.0.

The --ndb perror option was removed. Use the ndb_perror utility instead.

The innodb_undo_logs variable was removed. The innodb_rollback_segments variables performs the same function and should be used instead.

The Innodb_available_undo_logs status variable was removed. The number of available rollback segments per tablespace may be retrieved using SHOW VARIABLES LIKE 'innodb_rollback_segments';

As of MySQL 8.0.14, the previously deprecated innodb_undo_tablespaces variable is no longer configurable. For more information, see Section 15.6.3.4, “Undo Tablespaces”.

Support for the ALTER TABLE ... UPGRADE PARTITIONING statement has been removed.

As of MySQL 8.0.16, support for the internal_tmp_disk_storage_engine system variable has been removed; internal temporary tables on disk now always use the InnoDB storage engine. See Storage Engine for On-Disk Internal Temporary Tables,for more information.

The DISABLE_SHARED CMake option was unused and has been removed.

Acl_cache_items_count: Number of cached privilege objects. Added in MySQL 8.0.0.

Audit_log_current_size: Audit log file current size. Added in MySQL 8.0.11.

Audit_log_event_max_drop_size: Size of largest dropped audited event. Added in MySQL 8.0.11.

Audit_log_events: Number of handled audited events. Added in MySQL 8.0.11.

Audit_log_events_filtered: Number of filtered audited events. Added in MySQL 8.0.11.

Audit_log_events_lost: Number of dropped audited events. Added in MySQL 8.0.11.

Audit_log_events_written: Number of written audited events. Added in MySQL 8.0.11.

Audit_log_total_size: Combined size of written audited events. Added in MySQL 8.0.11.

Audit_log_write_waits: Number of write-delayed audited events. Added in MySQL 8.0.11.

Authentication_ldap_sasl_supported_methods: Supported authentication methods for SASL LDAP authentication. Added in MySQL 8.0.21.

Caching_sha2_password_rsa_public_key: caching_sha2_password authentication plugin RSA public key value. Added in MySQL 8.0.4.

Com_alter_resource_group: Count of ALTER RESOURCE GROUP statements. Added in MySQL 8.0.3.

Com_alter_user_default_role: Count of ALTER USER ... DEFAULT ROLE statements. Added in MySQL 8.0.0.

Com_clone: Count of CLONE statements. Added in MySQL 8.0.2.

Com_create_resource_group: Count of CREATE RESOURCE GROUP statements. Added in MySQL 8.0.3.

Com_create_role: Count of CREATE ROLE statements. Added in MySQL 8.0.0.

Com_drop_resource_group: Count of DROP RESOURCE GROUP statements. Added in MySQL 8.0.3.

Com_drop_role: Count of DROP ROLE statements. Added in MySQL 8.0.0.

Com_grant_roles: Count of GRANT ROLE statements. Added in MySQL 8.0.0.

Com_install_component: Count of INSTALL COMPONENT statements. Added in MySQL 8.0.0.

Com_replica_start: Count of START REPLICA and START SLAVE statements. Added in MySQL 8.0.22.

Com_replica_stop: Count of STOP REPLICA and STOP SLAVE statements. Added in MySQL 8.0.22.

Com_restart: Count of RESTART statements. Added in MySQL 8.0.4.

Com_revoke_roles: Count of REVOKE ROLES statements. Added in MySQL 8.0.0.

Com_set_resource_group: Count of SET RESOURCE GROUP statements. Added in MySQL 8.0.3.

Com_set_role: Count of SET ROLE statements. Added in MySQL 8.0.0.

Com_show_replica_status: Count of SHOW REPLICA STATUS and SHOW SLAVE STATUS statements. Added in MySQL 8.0.22.

Com_show_replicas: Count of SHOW REPLICAS and SHOW SLAVE HOSTS statements. Added in MySQL 8.0.22.

Com_uninstall_component: Count of UINSTALL COMPONENT statements. Added in MySQL 8.0.0.

Compression_algorithm: Compression algorithm for current connection. Added in MySQL 8.0.18.

Compression_level: Compression level for current connection. Added in MySQL 8.0.18.

Connection_control_delay_generated: How many times server delayed connection request. Added in MySQL 8.0.1.

Current_tls_ca: Current value of ssl_ca system variable. Added in MySQL 8.0.16.

Current_tls_capath: Current value of ssl_capath system variable. Added in MySQL 8.0.16.

Current_tls_cert: Current value of ssl_cert system variable. Added in MySQL 8.0.16.

Current_tls_cipher: Current value of ssl_cipher system variable. Added in MySQL 8.0.16.

Current_tls_ciphersuites: Current value of tsl_ciphersuites system variable. Added in MySQL 8.0.16.

Current_tls_crl: Current value of ssl_crl system variable. Added in MySQL 8.0.16.

Current_tls_crlpath: Current value of ssl_crlpath system variable. Added in MySQL 8.0.16.

Current_tls_key: Current value of ssl_key system variable. Added in MySQL 8.0.16.

Current_tls_version: Current value of tls_version system variable. Added in MySQL 8.0.16.

Error_log_buffered_bytes: Number of bytes used in error_log table. Added in MySQL 8.0.22.

Error_log_buffered_events: Number of events in error_log table. Added in MySQL 8.0.22.

Error_log_expired_events: Number of events discarded from error_log table. Added in MySQL 8.0.22.

Error_log_latest_write: Time of last write to error_log table. Added in MySQL 8.0.22.

Firewall_access_denied: Number of statements rejected by MySQL Enterprise Firewall. Added in MySQL 8.0.11.

Firewall_access_granted: Number of statements accepted by MySQL Enterprise Firewall. Added in MySQL 8.0.11.

Firewall_cached_entries: Number of statements recorded by MySQL Enterprise Firewall. Added in MySQL 8.0.11.

Innodb_redo_log_enabled: InnoDB redo log status. Added in MySQL 8.0.21.

Innodb_system_rows_deleted: Number of rows deleted from system schema tables. Added in MySQL 8.0.19.

Innodb_system_rows_inserted: Number of rows inserted into system schema tables. Added in MySQL 8.0.19.

Innodb_system_rows_read: Number of rows read from system schema tables. Added in MySQL 8.0.19.

Innodb_undo_tablespaces_active: Number of active undo tablespaces. Added in MySQL 8.0.14.

Innodb_undo_tablespaces_explicit: Number of user-created undo tablespaces. Added in MySQL 8.0.14.

Innodb_undo_tablespaces_implicit: Number of undo tablespaces created by InnoDB. Added in MySQL 8.0.14.

Innodb_undo_tablespaces_total: Total number of undo tablespaces. Added in MySQL 8.0.14.

Mysqlx_bytes_received_compressed_payload: Number of bytes received as compressed message payloads, measured before decompression. Added in MySQL 8.0.19.

Mysqlx_bytes_received_uncompressed_frame: Number of bytes received as compressed message payloads, measured after decompression. Added in MySQL 8.0.19.

Mysqlx_bytes_sent_compressed_payload: Number of bytes sent as compressed message payloads, measured after compression. Added in MySQL 8.0.19.

Mysqlx_bytes_sent_uncompressed_frame: Number of bytes sent as compressed message payloads, measured before compression. Added in MySQL 8.0.19.

Mysqlx_compression_algorithm: Compression algorithm in use for X Protocol connection for this session. Added in MySQL 8.0.20.

Mysqlx_compression_level: Compression level in use for X Protocol connection for this session. Added in MySQL 8.0.20.

Secondary_engine_execution_count: Number of queries offloaded to a secondary engine.. Added in MySQL 8.0.13.

activate_all_roles_on_login: Whether to activate all user roles at connect time. Added in MySQL 8.0.2.

admin-ssl: Enable connection encryption. Added in MySQL 8.0.21.

admin_address: IP address to bind to for connections on administrative interface. Added in MySQL 8.0.14.

admin_port: TCP/IP number to use for connections on administrative interface. Added in MySQL 8.0.14.

admin_ssl_ca: File that contains list of trusted SSL Certificate Authorities. Added in MySQL 8.0.21.

admin_ssl_capath: Directory that contains trusted SSL Certificate Authority certificate files. Added in MySQL 8.0.21.

admin_ssl_cert: File that contains X.509 certificate. Added in MySQL 8.0.21.

admin_ssl_cipher: Permissible ciphers for connection encryption. Added in MySQL 8.0.21.

admin_ssl_crl: File that contains certificate revocation lists. Added in MySQL 8.0.21.

admin_ssl_crlpath: Directory that contains certificate revocation list files. Added in MySQL 8.0.21.

admin_ssl_key: File that contains X.509 key. Added in MySQL 8.0.21.

admin_tls_ciphersuites: Permissible TLSv1.3 ciphersuites for encrypted connections. Added in MySQL 8.0.21.

admin_tls_version: Permissible TLS protocols for encrypted connections. Added in MySQL 8.0.21.

audit-log: Whether to activate audit log plugin. Added in MySQL 8.0.11.

audit_log_buffer_size: Size of audit log buffer. Added in MySQL 8.0.11.

audit_log_compression: Audit log file compression method. Added in MySQL 8.0.11.

audit_log_connection_policy: Audit logging policy for connection-related events. Added in MySQL 8.0.11.

audit_log_current_session: Whether to audit current session. Added in MySQL 8.0.11.

audit_log_encryption: Audit log file encryption method. Added in MySQL 8.0.11.

audit_log_exclude_accounts: Accounts not to audit. Added in MySQL 8.0.11.

audit_log_file: Name of audit log file. Added in MySQL 8.0.11.

audit_log_filter_id: ID of current audit log filter. Added in MySQL 8.0.11.

audit_log_flush: Close and reopen audit log file. Added in MySQL 8.0.11.

audit_log_format: Audit log file format. Added in MySQL 8.0.11.

audit_log_include_accounts: Accounts to audit. Added in MySQL 8.0.11.

audit_log_password_history_keep_days: Number of days to keep archived audit log encryption passwords. Added in MySQL 8.0.17.

audit_log_policy: Audit logging policy. Added in MySQL 8.0.11.

audit_log_prune_seconds: The number of seconds after which audit log files become subject to pruning. Added in MySQL 8.0.24.

audit_log_read_buffer_size: Audit log file read buffer size. Added in MySQL 8.0.11.

audit_log_rotate_on_size: Close and reopen audit log file at this size. Added in MySQL 8.0.11.

audit_log_statement_policy: Audit logging policy for statement-related events. Added in MySQL 8.0.11.

audit_log_strategy: Audit logging strategy. Added in MySQL 8.0.11.

authentication_ldap_sasl_auth_method_name: Authentication method name. Added in MySQL 8.0.11.

authentication_ldap_sasl_bind_base_dn: LDAP server base distinguished name. Added in MySQL 8.0.11.

authentication_ldap_sasl_bind_root_dn: LDAP server root distinguished name. Added in MySQL 8.0.11.

authentication_ldap_sasl_bind_root_pwd: LDAP server root bind password. Added in MySQL 8.0.11.

authentication_ldap_sasl_ca_path: LDAP server certificate authority file name. Added in MySQL 8.0.11.

authentication_ldap_sasl_group_search_attr: LDAP server group search attribute. Added in MySQL 8.0.11.

authentication_ldap_sasl_group_search_filter: LDAP custom group search filter. Added in MySQL 8.0.11.

authentication_ldap_sasl_init_pool_size: LDAP server initial connection pool size. Added in MySQL 8.0.11.

authentication_ldap_sasl_log_status: LDAP server log level. Added in MySQL 8.0.11.

authentication_ldap_sasl_max_pool_size: LDAP server maximum connection pool size. Added in MySQL 8.0.11.

authentication_ldap_sasl_referral: Whether to enable LDAP search referral. Added in MySQL 8.0.20.

authentication_ldap_sasl_server_host: LDAP server host name or IP address. Added in MySQL 8.0.11.

authentication_ldap_sasl_server_port: LDAP server port number. Added in MySQL 8.0.11.

authentication_ldap_sasl_tls: Whether to use encrypted connections to LDAP server. Added in MySQL 8.0.11.

authentication_ldap_sasl_user_search_attr: LDAP server user search attribute. Added in MySQL 8.0.11.

authentication_ldap_simple_auth_method_name: Authentication method name. Added in MySQL 8.0.11.

authentication_ldap_simple_bind_base_dn: LDAP server base distinguished name. Added in MySQL 8.0.11.

authentication_ldap_simple_bind_root_dn: LDAP server root distinguished name. Added in MySQL 8.0.11.

authentication_ldap_simple_bind_root_pwd: LDAP server root bind password. Added in MySQL 8.0.11.

authentication_ldap_simple_ca_path: LDAP server certificate authority file name. Added in MySQL 8.0.11.

authentication_ldap_simple_group_search_attr: LDAP server group search attribute. Added in MySQL 8.0.11.

authentication_ldap_simple_group_search_filter: LDAP custom group search filter. Added in MySQL 8.0.11.

authentication_ldap_simple_init_pool_size: LDAP server initial connection pool size. Added in MySQL 8.0.11.

authentication_ldap_simple_log_status: LDAP server log level. Added in MySQL 8.0.11.

authentication_ldap_simple_max_pool_size: LDAP server maximum connection pool size. Added in MySQL 8.0.11.

authentication_ldap_simple_referral: Whether to enable LDAP search referral. Added in MySQL 8.0.20.

authentication_ldap_simple_server_host: LDAP server host name or IP address. Added in MySQL 8.0.11.

authentication_ldap_simple_server_port: LDAP server port number. Added in MySQL 8.0.11.

authentication_ldap_simple_tls: Whether to use encrypted connections to LDAP server. Added in MySQL 8.0.11.

authentication_ldap_simple_user_search_attr: LDAP server user search attribute. Added in MySQL 8.0.11.

authentication_windows_log_level: Windows authentication plugin logging level. Added in MySQL 8.0.11.

authentication_windows_use_principal_name: Whether to use Windows authentication plugin principal name. Added in MySQL 8.0.11.

binlog_encryption: Enable encryption for binary log files and relay log files on this server. Added in MySQL 8.0.14.

binlog_expire_logs_seconds: Purge binary logs after this many seconds. Added in MySQL 8.0.1.

binlog_rotate_encryption_master_key_at_startup: Rotate binary log master key at server startup. Added in MySQL 8.0.14.

binlog_row_metadata: Whether to record all or only minimal table related metadata to binary log when using row-based logging. Added in MySQL 8.0.1.

binlog_row_value_options: Enables binary logging of partial JSON updates for row-based replication. Added in MySQL 8.0.3.

binlog_transaction_compression: Enable compression for transaction payloads in binary log files. Added in MySQL 8.0.20.

binlog_transaction_compression_level_zstd: Compression level for transaction payloads in binary log files. Added in MySQL 8.0.20.

binlog_transaction_dependency_history_size: Number of row hashes kept for looking up transaction that last updated some row. Added in MySQL 8.0.1.

binlog_transaction_dependency_tracking: Source of dependency information (commit timestamps or transaction write sets) from which to assess which transactions can be executed in parallel by replica's multithreaded applier. Added in MySQL 8.0.1.

caching_sha2_password_auto_generate_rsa_keys: Whether to autogenerate RSA key-pair files. Added in MySQL 8.0.4.

caching_sha2_password_digest_rounds: Number of hash rounds for caching_sha2_password authentication plugin. Added in MySQL 8.0.24.

caching_sha2_password_private_key_path: SHA2 authentication plugin private key path name. Added in MySQL 8.0.3.

caching_sha2_password_public_key_path: SHA2 authentication plugin public key path name. Added in MySQL 8.0.3.

clone_autotune_concurrency: Enables dynamic spawning of threads for remote cloning operations. Added in MySQL 8.0.17.

clone_buffer_size: Defines size of intermediate buffer on donor MySQL server instance. Added in MySQL 8.0.17.

clone_ddl_timeout: Number of seconds cloning operation waits for backup lock. Added in MySQL 8.0.17.

clone_enable_compression: Enables compression of data at network layer during cloning. Added in MySQL 8.0.17.

clone_max_concurrency: Maximum number of concurrent threads used to perform cloning operation. Added in MySQL 8.0.17.

clone_max_data_bandwidth: Maximum data transfer rate in MiB per second for remote cloning operation. Added in MySQL 8.0.17.

clone_max_network_bandwidth: Maximum network transfer rate in MiB per second for remote cloning operation. Added in MySQL 8.0.17.

clone_ssl_ca: Specifies path to certificate authority (CA) file. Added in MySQL 8.0.14.

clone_ssl_cert: Specifies path to public key certificate file. Added in MySQL 8.0.14.

clone_ssl_key: Specifies path to private key file. Added in MySQL 8.0.14.

clone_valid_donor_list: Defines donor host addresses for remote cloning operations. Added in MySQL 8.0.17.

connection_control_failed_connections_threshold: Consecutive failed connection attempts before delays occur. Added in MySQL 8.0.1.

connection_control_max_connection_delay: Maximum delay (milliseconds) for server response to failed connection attempts. Added in MySQL 8.0.1.

connection_control_min_connection_delay: Minimum delay (milliseconds) for server response to failed connection attempts. Added in MySQL 8.0.1.

create_admin_listener_thread: Whether to use dedicated listening thread for connections on administrative interface. Added in MySQL 8.0.14.

cte_max_recursion_depth: Common table expression maximum recursion depth. Added in MySQL 8.0.3.

ddl-rewriter: Whether to activate ddl_rewriter plugin. Added in MySQL 8.0.16.

default_collation_for_utf8mb4: Default collation for utf8mb4 character set. Added in MySQL 8.0.11.

default_table_encryption: Default schema and tablespace encryption setting. Added in MySQL 8.0.16.

dragnet.Status: Result of most recent assignment to dragnet.log_error_filter_rules. Added in MySQL 8.0.12.

dragnet.log_error_filter_rules: Filter rules for error logging. Added in MySQL 8.0.4.

early-plugin-load: Specify plugins to load before loading mandatory built-in plugins and before storage engine initialization. Added in MySQL 8.0.0.

generated_random_password_length: Maximum length of generated passwords. Added in MySQL 8.0.18.

group_replication_advertise_recovery_endpoints: Connections offered for distributed recovery. Added in MySQL 8.0.21.

group_replication_autorejoin_tries: Number of tries that member makes to rejoin group automatically. Added in MySQL 8.0.16.

group_replication_clone_threshold: Transaction number gap between donor and recipient above which remote cloning operation is used for state transfer. Added in MySQL 8.0.17.

group_replication_communication_debug_options: Level of debugging messages for Group Replication components. Added in MySQL 8.0.3.

group_replication_communication_max_message_size: Maximum message size for Group Replication communications, larger messages are fragmented. Added in MySQL 8.0.16.

group_replication_consistency: Type of transaction consistency guarantee which group provides. Added in MySQL 8.0.14.

group_replication_exit_state_action: How instance behaves when it leaves group involuntarily. Added in MySQL 8.0.12.

group_replication_flow_control_hold_percent: Percentage of group quota to remain unused. Added in MySQL 8.0.2.

group_replication_flow_control_max_commit_quota: Maximum flow control quota for group. Added in MySQL 8.0.2.

group_replication_flow_control_member_quota_percent: Percentage of quota which member should assume is available for itself when calculating quotas. Added in MySQL 8.0.2.

group_replication_flow_control_min_quota: Lowest flow control quota which can be assigned per member. Added in MySQL 8.0.2.

group_replication_flow_control_min_recovery_quota: Lowest quota which can be assigned per member because another group member is recovering. Added in MySQL 8.0.2.

group_replication_flow_control_period: Defines how many seconds to wait between flow control iterations. Added in MySQL 8.0.2.

group_replication_flow_control_release_percent: How group quota should be released when flow control no longer needs to throttle writer members. Added in MySQL 8.0.2.

group_replication_ip_allowlist: List of hosts permitted to connect to group (MySQL 8.0.22 and later). Added in MySQL 8.0.22.

group_replication_member_expel_timeout: Time between suspected failure of group member and expelling it from group, causing group membership reconfiguration. Added in MySQL 8.0.13.

group_replication_member_weight: Chance of this member being elected as primary. Added in MySQL 8.0.2.

group_replication_message_cache_size: Maximum memory for group communication engine message cache (XCom). Added in MySQL 8.0.16.

group_replication_recovery_compression_algorithm: Permitted compression algorithms for outgoing recovery connections. Added in MySQL 8.0.18.

group_replication_recovery_get_public_key: Whether to accept preference about fetching public key from donor. Added in MySQL 8.0.4.

group_replication_recovery_public_key_path: To accept public key information. Added in MySQL 8.0.4.

group_replication_recovery_tls_ciphersuites: Permitted cipher suites when TLSv1.3 is used for connection encryption with this instance as client (joining member). Added in MySQL 8.0.19.

group_replication_recovery_tls_version: Permitted TLS protocols for connection encryption as client (joining member). Added in MySQL 8.0.19.

group_replication_recovery_zstd_compression_level: Compression level for recovery connections that use zstd compression. Added in MySQL 8.0.18.

group_replication_tls_source: Source of TLS material for Group Replication. Added in MySQL 8.0.21.

group_replication_unreachable_majority_timeout: How long to wait for network partitions that result in minority to leave group. Added in MySQL 8.0.2.

histogram_generation_max_mem_size: Maximum memory for creating histogram statistics. Added in MySQL 8.0.2.

immediate_server_version: MySQL Server release number of server which is immediate replication source. Added in MySQL 8.0.14.

information_schema_stats_expiry: Expiration setting for cached table statistics. Added in MySQL 8.0.3.

innodb_buffer_pool_debug: Permits multiple buffer pool instances when buffer pool is less than 1GB in size. Added in MySQL 8.0.0.

innodb_buffer_pool_in_core_file: Controls writing of buffer pool pages to core files. Added in MySQL 8.0.14.

innodb_checkpoint_disabled: Disables checkpoints so that deliberate server exit always initiates recovery. Added in MySQL 8.0.2.

innodb_ddl_log_crash_reset_debug: Debug option that resets DDL log crash injection counters. Added in MySQL 8.0.3.

innodb_deadlock_detect: Enables or disables deadlock detection. Added in MySQL 8.0.0.

innodb_dedicated_server: Enables automatic configuration of buffer pool size, log file size, and flush method. Added in MySQL 8.0.3.

innodb_directories: Defines directories to scan at startup for tablespace data files. Added in MySQL 8.0.4.

innodb_doublewrite_batch_size: Number of doublewrite pages to write per batch. Added in MySQL 8.0.20.

innodb_doublewrite_dir: Doublewrite buffer file directory. Added in MySQL 8.0.20.

innodb_doublewrite_files: Number of doublewrite files. Added in MySQL 8.0.20.

innodb_doublewrite_pages: Number of doublewrite pages per thread. Added in MySQL 8.0.20.

innodb_extend_and_initialize: Controls how new tablespace pages are allocated on Linux. Added in MySQL 8.0.22.

innodb_fsync_threshold: Controls how often InnoDB calls fsync when creating new file. Added in MySQL 8.0.13.

innodb_idle_flush_pct: Limits I/0 operations when InnoDB is idle. Added in MySQL 8.0.18.

innodb_log_checkpoint_fuzzy_now: Debug option that forces InnoDB to write fuzzy checkpoint. Added in MySQL 8.0.13.

innodb_log_spin_cpu_abs_lwm: Minimum amount of CPU usage below which user threads no longer spin while waiting for flushed redo. Added in MySQL 8.0.11.

innodb_log_spin_cpu_pct_hwm: Maximum amount of CPU usage above which user threads no longer spin while waiting for flushed redo. Added in MySQL 8.0.11.

innodb_log_wait_for_flush_spin_hwm: Maximum average log flush time beyond which user threads no longer spin while waiting for flushed redo. Added in MySQL 8.0.11.

innodb_log_writer_threads: Enables dedicated log writer threads for writing and flushing redo logs. Added in MySQL 8.0.22.

innodb_parallel_read_threads: Number of threads for parallel index reads. Added in MySQL 8.0.14.

innodb_print_ddl_logs: Whether or not to print DDL logs to error log. Added in MySQL 8.0.3.

innodb_redo_log_archive_dirs: Labeled redo log archive directories. Added in MySQL 8.0.17.

innodb_redo_log_encrypt: Controls encryption of redo log data for encrypted tablespaces. Added in MySQL 8.0.1.

innodb_scan_directories: Defines directories to scan for tablespace files during InnoDB recovery. Added in MySQL 8.0.2.

innodb_spin_wait_pause_multiplier: Multiplier value used to determine number of PAUSE instructions in spin-wait loops. Added in MySQL 8.0.16.

innodb_stats_include_delete_marked: Include delete-marked records when calculating persistent InnoDB statistics. Added in MySQL 8.0.1.

innodb_temp_tablespaces_dir: Session temporary tablespaces path. Added in MySQL 8.0.13.

innodb_tmpdir: Directory location for temporary table files created during online ALTER TABLE operations. Added in MySQL 8.0.0.

innodb_undo_log_encrypt: Controls encryption of undo log data for encrypted tablespaces. Added in MySQL 8.0.1.

innodb_validate_tablespace_paths: Enables tablespace path validation at startup. Added in MySQL 8.0.21.

internal_tmp_mem_storage_engine: Storage engine to use for internal in-memory temporary tables. Added in MySQL 8.0.2.

keyring-migration-destination: Key migration destination keyring plugin. Added in MySQL 8.0.4.

keyring-migration-host: Host name for connecting to running server for key migration. Added in MySQL 8.0.4.

keyring-migration-password: Password for connecting to running server for key migration. Added in MySQL 8.0.4.

keyring-migration-port: TCP/IP port number for connecting to running server for key migration. Added in MySQL 8.0.4.

keyring-migration-socket: Unix socket file or Windows named pipe for connecting to running server for key migration. Added in MySQL 8.0.4.

keyring-migration-source: Key migration source keyring plugin. Added in MySQL 8.0.4.

keyring-migration-user: User name for connecting to running server for key migration. Added in MySQL 8.0.4.

keyring_aws_cmk_id: AWS keyring plugin customer master key ID value. Added in MySQL 8.0.11.

keyring_aws_conf_file: AWS keyring plugin configuration file location. Added in MySQL 8.0.11.

keyring_aws_data_file: AWS keyring plugin storage file location. Added in MySQL 8.0.11.

keyring_aws_region: AWS keyring plugin region. Added in MySQL 8.0.11.

keyring_encrypted_file_data: keyring_encrypted_file plugin data file. Added in MySQL 8.0.11.

keyring_encrypted_file_password: keyring_encrypted_file plugin password. Added in MySQL 8.0.11.

keyring_hashicorp_auth_path: HashiCorp Vault AppRole authentication path. Added in MySQL 8.0.18.

keyring_hashicorp_ca_path: Path to keyring_hashicorp CA file. Added in MySQL 8.0.18.

keyring_hashicorp_caching: Whether to enable keyring_hashicorp caching. Added in MySQL 8.0.18.

keyring_hashicorp_commit_auth_path: keyring_hashicorp_auth_path value in use. Added in MySQL 8.0.18.

keyring_hashicorp_commit_ca_path: keyring_hashicorp_ca_path value in use. Added in MySQL 8.0.18.

keyring_hashicorp_commit_caching: keyring_hashicorp_caching value in use. Added in MySQL 8.0.18.

keyring_hashicorp_commit_role_id: keyring_hashicorp_role_id value in use. Added in MySQL 8.0.18.

keyring_hashicorp_commit_server_url: keyring_hashicorp_server_url value in use. Added in MySQL 8.0.18.

keyring_hashicorp_commit_store_path: keyring_hashicorp_store_path value in use. Added in MySQL 8.0.18.

keyring_hashicorp_role_id: HashiCorp Vault AppRole authentication role ID. Added in MySQL 8.0.18.

keyring_hashicorp_secret_id: HashiCorp Vault AppRole authentication secret ID. Added in MySQL 8.0.18.

keyring_hashicorp_server_url: HashiCorp Vault server URL. Added in MySQL 8.0.18.

keyring_hashicorp_store_path: HashiCorp Vault store path. Added in MySQL 8.0.18.

keyring_oci_ca_certificate: CA certificate file for peer authentication. Added in MySQL 8.0.22.

keyring_oci_compartment: OCI compartment OCID. Added in MySQL 8.0.22.

keyring_oci_encryption_endpoint: OCI encryption server endpoint. Added in MySQL 8.0.22.

keyring_oci_key_file: OCI RSA private key file. Added in MySQL 8.0.22.

keyring_oci_key_fingerprint: OCI RSA private key file fingerprint. Added in MySQL 8.0.22.

keyring_oci_management_endpoint: OCI management server endpoint. Added in MySQL 8.0.22.

keyring_oci_master_key: OCI master key OCID. Added in MySQL 8.0.22.

keyring_oci_secrets_endpoint: OCI secrets server endpoint. Added in MySQL 8.0.22.

keyring_oci_tenancy: OCI tenancy OCID. Added in MySQL 8.0.22.

keyring_oci_user: OCI user OCID. Added in MySQL 8.0.22.

keyring_oci_vaults_endpoint: OCI vaults server endpoint. Added in MySQL 8.0.22.

keyring_oci_virtual_vault: OCI vault OCID. Added in MySQL 8.0.22.

keyring_okv_conf_dir: Oracle Key Vault keyring plugin configuration directory. Added in MySQL 8.0.11.

keyring_operations: Whether keyring operations are enabled. Added in MySQL 8.0.4.

lock_order: Whether to enable LOCK_ORDER tool at runtime. Added in MySQL 8.0.17.

lock_order_debug_loop: Whether to cause debug assert when LOCK_ORDER tool encounters dependency flagged as loop. Added in MySQL 8.0.17.

lock_order_debug_missing_arc: Whether to cause debug assert when LOCK_ORDER tool encounters undeclared dependency. Added in MySQL 8.0.17.

lock_order_debug_missing_key: Whether to cause debug assert when LOCK_ORDER tool encounters object not properly instrumented with Performance Schema. Added in MySQL 8.0.17.

lock_order_debug_missing_unlock: Whether to cause debug assert when LOCK_ORDER tool encounters lock that is destroyed while still held. Added in MySQL 8.0.17.

lock_order_dependencies: Path to lock_order_dependencies.txt file. Added in MySQL 8.0.17.

lock_order_extra_dependencies: Path to second dependency file. Added in MySQL 8.0.17.

lock_order_output_directory: Directory where LOCK_ORDER tool writes logs. Added in MySQL 8.0.17.

lock_order_print_txt: Whether to perform lock-order graph analysis and print textual report. Added in MySQL 8.0.17.

lock_order_trace_loop: Whether to print log file trace when LOCK_ORDER tool encounters dependency flagged as loop. Added in MySQL 8.0.17.

lock_order_trace_missing_arc: Whether to print log file trace when LOCK_ORDER tool encounters undeclared dependency. Added in MySQL 8.0.17.

lock_order_trace_missing_key: Whether to print log file trace when LOCK_ORDER tool encounters object not properly instrumented with Performance Schema. Added in MySQL 8.0.17.

lock_order_trace_missing_unlock: Whether to print log file trace when LOCK_ORDER tool encounters lock that is destroyed while still held. Added in MySQL 8.0.17.

log_error_filter_rules: Filter rules for error logging. Added in MySQL 8.0.2.

log_error_services: Components to use for error logging. Added in MySQL 8.0.2.

log_error_suppression_list: Warning/information error log messages to suppress. Added in MySQL 8.0.13.

log_slow_extra: Whether to write extra information to slow query log file. Added in MySQL 8.0.14.

mandatory_roles: Automatically granted roles for all users. Added in MySQL 8.0.2.

mysql_firewall_mode: Whether MySQL Enterprise Firewall is operational. Added in MySQL 8.0.11.

mysql_firewall_trace: Whether to enable firewall trace. Added in MySQL 8.0.11.

mysqlx: Whether X Plugin is initialized. Added in MySQL 8.0.11.

mysqlx_compression_algorithms: Compression algorithms permitted for X Protocol connections. Added in MySQL 8.0.19.

mysqlx_deflate_default_compression_level: Default compression level for Deflate algorithm on X Protocol connections. Added in MySQL 8.0.20.

mysqlx_deflate_max_client_compression_level: Maximum permitted compression level for Deflate algorithm on X Protocol connections. Added in MySQL 8.0.20.

mysqlx_interactive_timeout: Number of seconds to wait for interactive clients to timeout. Added in MySQL 8.0.4.

mysqlx_lz4_default_compression_level: Default compression level for LZ4 algorithm on X Protocol connections. Added in MySQL 8.0.20.

mysqlx_lz4_max_client_compression_level: Maximum permitted compression level for LZ4 algorithm on X Protocol connections. Added in MySQL 8.0.20.

mysqlx_read_timeout: Number of seconds to wait for blocking read operations to complete. Added in MySQL 8.0.4.

mysqlx_wait_timeout: Number of seconds to wait for activity from connection. Added in MySQL 8.0.4.

mysqlx_write_timeout: Number of seconds to wait for blocking write operations to complete. Added in MySQL 8.0.4.

mysqlx_zstd_default_compression_level: Default compression level for zstd algorithm on X Protocol connections. Added in MySQL 8.0.20.

mysqlx_zstd_max_client_compression_level: Maximum permitted compression level for zstd algorithm on X Protocol connections. Added in MySQL 8.0.20.

named_pipe_full_access_group: Name of Windows group granted full access to named pipe. Added in MySQL 8.0.14.

no-dd-upgrade: Prevent automatic upgrade of data dictionary tables at startup. Added in MySQL 8.0.4.

no-monitor: Do not fork monitor process required for RESTART. Added in MySQL 8.0.12.

original_commit_timestamp: Time when transaction was committed on original source. Added in MySQL 8.0.1.

original_server_version: MySQL Server release number of server on which transaction was originally committed. Added in MySQL 8.0.14.

partial_revokes: Whether partial revocation is enabled. Added in MySQL 8.0.16.

password_history: Number of password changes required before password reuse. Added in MySQL 8.0.3.

password_require_current: Whether password changes require current password verification. Added in MySQL 8.0.13.

password_reuse_interval: Number of days elapsed required before password reuse. Added in MySQL 8.0.3.

performance_schema_max_digest_sample_age: Query resample age in seconds. Added in MySQL 8.0.3.

performance_schema_show_processlist: Select SHOW PROCESSLIST implementation. Added in MySQL 8.0.22.

persist_only_admin_x509_subject: SSL certificate X.509 Subject that enables persisting persist-restricted system variables. Added in MySQL 8.0.14.

persisted_globals_load: Whether to load persisted configuration settings. Added in MySQL 8.0.0.

print_identified_with_as_hex: For SHOW CREATE USER, print hash values containing unprintable characters in hex. Added in MySQL 8.0.17.

protocol_compression_algorithms: Permitted compression algorithms for incoming connections. Added in MySQL 8.0.18.

regexp_stack_limit: Regular expression match stack size limit. Added in MySQL 8.0.4.

regexp_time_limit: Regular expression match timeout. Added in MySQL 8.0.4.

require_row_format: For internal server use. Added in MySQL 8.0.19.

resultset_metadata: Whether server returns result set metadata. Added in MySQL 8.0.3.

rpl_read_size: Set minimum amount of data in bytes which is read from binary log files and relay log files. Added in MySQL 8.0.11.

secondary_engine_cost_threshold: Optimizer cost threshold for query offload to a secondary engine.. Added in MySQL 8.0.16.

select_into_buffer_size: Size of buffer used for OUTFILE or DUMPFILE export file; overrides read_buffer_size. Added in MySQL 8.0.22.

select_into_disk_sync: Synchronize data with storage device after flushing buffer for OUTFILE or DUMPFILE export file; OFF disables synchronization and is default value. Added in MySQL 8.0.22.

select_into_disk_sync_delay: When select_into_sync_disk = ON, sets delay in milliseconds after each synchronization of OUTFILE or DUMPFILE export file buffer, no effect otherwise. Added in MySQL 8.0.22.

show_create_table_skip_secondary_engine: Whether to exclude the SECONDARY ENGINE clause from SHOW CREATE TABLE output. Added in MySQL 8.0.18.

show_create_table_verbosity: Whether to display ROW_FORMAT in SHOW CREATE TABLE even if it has default value. Added in MySQL 8.0.11.

sql_require_primary_key: Whether tables must have primary key. Added in MySQL 8.0.13.

ssl_fips_mode: Whether to enable FIPS mode on server side. Added in MySQL 8.0.11.

syseventlog.facility: Facility for syslog messages. Added in MySQL 8.0.13.

syseventlog.include_pid: Whether to include server PID in syslog messages. Added in MySQL 8.0.13.

syseventlog.tag: Tag for server identifier in syslog messages. Added in MySQL 8.0.13.

table_encryption_privilege_check: Enables TABLE_ENCRYPTION_ADMIN privilege check. Added in MySQL 8.0.16.

temptable_max_mmap: The maximum amount of memory the TempTable storage engine can allocate from memory-mapped temporary files. Added in MySQL 8.0.23.

temptable_max_ram: Defines maximum amount of memory that can occupied by TempTable storage engine before data is stored on disk. Added in MySQL 8.0.2.

temptable_use_mmap: Defines whether TempTable storage engine allocates memory-mapped files when the temptable_max_ram threshold is reached. Added in MySQL 8.0.16.

thread_pool_algorithm: Thread pool algorithm. Added in MySQL 8.0.11.

thread_pool_high_priority_connection: Whether current session is high priority. Added in MySQL 8.0.11.

thread_pool_max_active_query_threads: Maximum permissible number of active query threads per group. Added in MySQL 8.0.19.

thread_pool_max_unused_threads: Maximum permissible number of unused threads. Added in MySQL 8.0.11.

thread_pool_prio_kickup_timer: How long before statement is moved to high-priority execution. Added in MySQL 8.0.11.

thread_pool_size: Number of thread groups in thread pool. Added in MySQL 8.0.11.

thread_pool_stall_limit: How long before statement is defined as stalled. Added in MySQL 8.0.11.

tls_ciphersuites: Permissible TLSv1.3 ciphersuites for encrypted connections. Added in MySQL 8.0.16.

upgrade: Control automatic upgrade at startup. Added in MySQL 8.0.16.

use_secondary_engine: Whether to execute queries using a secondary engine. Added in MySQL 8.0.13.

validate-config: Validate server configuration. Added in MySQL 8.0.16.

validate_password.check_user_name: Whether to check passwords against user name. Added in MySQL 8.0.4.

validate_password.dictionary_file: validate_password dictionary file. Added in MySQL 8.0.4.

validate_password.dictionary_file_last_parsed: When dictionary file was last parsed. Added in MySQL 8.0.4.

validate_password.dictionary_file_words_count: Number of words in dictionary file. Added in MySQL 8.0.4.

validate_password.length: validate_password required password length. Added in MySQL 8.0.4.

validate_password.mixed_case_count: validate_password required number of uppercase/lowercase characters. Added in MySQL 8.0.4.

validate_password.number_count: validate_password required number of digit characters. Added in MySQL 8.0.4.

validate_password.policy: validate_password password policy. Added in MySQL 8.0.4.

validate_password.special_char_count: validate_password required number of special characters. Added in MySQL 8.0.4.

version_compile_zlib: Version of compiled-in zlib library. Added in MySQL 8.0.11.

windowing_use_high_precision: Whether to compute window functions to high precision. Added in MySQL 8.0.2.

Compression: Whether client connection uses compression in client/server protocol. Deprecated as of MySQL 8.0.18.

expire_logs_days: Purge binary logs after this many days. Deprecated as of MySQL 8.0.3.

group_replication_ip_whitelist: List of hosts permitted to connect to group. Deprecated as of MySQL 8.0.22.

innodb_undo_tablespaces: Number of tablespace files that rollback segments are divided between. Deprecated as of MySQL 8.0.4.

log_bin_use_v1_row_events: Whether server is using version 1 binary log row events. Deprecated as of MySQL 8.0.18.

log_syslog: Whether to write error log to syslog. Deprecated as of MySQL 8.0.2.

master-info-file: Location and name of file that remembers source and where I/O replication thread is in source's binary log. Deprecated as of MySQL 8.0.18.

master_info_repository: Whether to write connection metadata repository, containing source information and replication I/O thread location in source's binary log, to file or table. Deprecated as of MySQL 8.0.23.

max_length_for_sort_data: Max number of bytes in sorted records. Deprecated as of MySQL 8.0.20.

no-dd-upgrade: Prevent automatic upgrade of data dictionary tables at startup. Deprecated as of MySQL 8.0.16.

relay_log_info_file: File name for applier metadata repository in which replica records information about relay logs. Deprecated as of MySQL 8.0.18.

relay_log_info_repository: Whether to write location of replication SQL thread in relay logs to file or table. Deprecated as of MySQL 8.0.23.

slave_compressed_protocol: Use compression of source/replica protocol. Deprecated as of MySQL 8.0.18.

slave_rows_search_algorithms: Determines search algorithms used for replica update batching. Any 2 or 3 from this list: INDEX_SEARCH, TABLE_SCAN, HASH_SCAN. Deprecated as of MySQL 8.0.18.

symbolic-links: Permit symbolic links for MyISAM tables. Deprecated as of MySQL 8.0.2.

Com_alter_db_upgrade: Count of ALTER DATABASE ... UPGRADE DATA DIRECTORY NAME statements. Removed in MySQL 8.0.0.

Innodb_available_undo_logs: Total number of InnoDB rollback segments; different from innodb_rollback_segments, which displays number of active rollback segments. Removed in MySQL 8.0.2.

Qcache_free_blocks: Number of free memory blocks in query cache. Removed in MySQL 8.0.3.

Qcache_free_memory: Amount of free memory for query cache. Removed in MySQL 8.0.3.

Qcache_hits: Number of query cache hits. Removed in MySQL 8.0.3.

Qcache_inserts: Number of query cache inserts. Removed in MySQL 8.0.3.

Qcache_lowmem_prunes: Number of queries which were deleted from query cache due to lack of free memory in cache. Removed in MySQL 8.0.3.

Qcache_not_cached: Number of noncached queries (not cacheable, or not cached due to query_cache_type setting). Removed in MySQL 8.0.3.

Qcache_queries_in_cache: Number of queries registered in query cache. Removed in MySQL 8.0.3.

Qcache_total_blocks: Total number of blocks in query cache. Removed in MySQL 8.0.3.

Slave_heartbeat_period: Replica's replication heartbeat interval, in seconds. Removed in MySQL 8.0.1.

Slave_last_heartbeat: Shows when latest heartbeat signal was received, in TIMESTAMP format. Removed in MySQL 8.0.1.

Slave_received_heartbeats: Number of heartbeats received by replica since previous reset. Removed in MySQL 8.0.1.

Slave_retried_transactions: Total number of times since startup that replication SQL thread has retried transactions. Removed in MySQL 8.0.1.

Slave_running: State of this server as replica (replication I/O thread status). Removed in MySQL 8.0.1.

bootstrap: Used by mysql installation scripts. Removed in MySQL 8.0.0.

date_format: DATE format (unused). Removed in MySQL 8.0.3.

datetime_format: DATETIME/TIMESTAMP format (unused). Removed in MySQL 8.0.3.

des-key-file: Load keys for des_encrypt() and des_encrypt from given file. Removed in MySQL 8.0.3.

group_replication_allow_local_disjoint_gtids_join: Allow current server to join group even if it has transactions not present in group. Removed in MySQL 8.0.4.

have_crypt: Availability of crypt() system call. Removed in MySQL 8.0.3.

ignore-db-dir: Treat directory as nondatabase directory. Removed in MySQL 8.0.0.

ignore_builtin_innodb: Ignore built-in InnoDB. Removed in MySQL 8.0.3.

ignore_db_dirs: Directories treated as nondatabase directories. Removed in MySQL 8.0.0.

innodb_checksums: Enable InnoDB checksums validation. Removed in MySQL 8.0.0.

innodb_disable_resize_buffer_pool_debug: Disables resizing of InnoDB buffer pool. Removed in MySQL 8.0.0.

innodb_file_format: Format for new InnoDB tables. Removed in MySQL 8.0.0.

innodb_file_format_check: Whether InnoDB performs file format compatibility checking. Removed in MySQL 8.0.0.

innodb_file_format_max: File format tag in shared tablespace. Removed in MySQL 8.0.0.

innodb_large_prefix: Enables longer keys for column prefix indexes. Removed in MySQL 8.0.0.

innodb_locks_unsafe_for_binlog: Force InnoDB not to use next-key locking. Instead use only row-level locking. Removed in MySQL 8.0.0.

innodb_scan_directories: Defines directories to scan for tablespace files during InnoDB recovery. Removed in MySQL 8.0.4.

innodb_stats_sample_pages: Number of index pages to sample for index distribution statistics. Removed in MySQL 8.0.0.

innodb_support_xa: Enable InnoDB support for XA two-phase commit. Removed in MySQL 8.0.0.

innodb_undo_logs: Number of undo logs (rollback segments) used by InnoDB; alias for innodb_rollback_segments. Removed in MySQL 8.0.2.

internal_tmp_disk_storage_engine: Storage engine for internal temporary tables. Removed in MySQL 8.0.16.

log-warnings: Write some noncritical warnings to log file. Removed in MySQL 8.0.3.

log_builtin_as_identified_by_password: Whether to log CREATE/ALTER USER, GRANT in backward-compatible fashion. Removed in MySQL 8.0.11.

log_error_filter_rules: Filter rules for error logging. Removed in MySQL 8.0.4.

log_syslog: Whether to write error log to syslog. Removed in MySQL 8.0.13.

log_syslog_facility: Facility for syslog messages. Removed in MySQL 8.0.13.

log_syslog_include_pid: Whether to include server PID in syslog messages. Removed in MySQL 8.0.13.

log_syslog_tag: Tag for server identifier in syslog messages. Removed in MySQL 8.0.13.

max_tmp_tables: Unused. Removed in MySQL 8.0.3.

metadata_locks_cache_size: Size of metadata locks cache. Removed in MySQL 8.0.13.

metadata_locks_hash_instances: Number of metadata lock hashes. Removed in MySQL 8.0.13.

multi_range_count: Maximum number of ranges to send to table handler at once during range selects. Removed in MySQL 8.0.3.

old_passwords: Selects password hashing method for PASSWORD(). Removed in MySQL 8.0.11.

partition: Enable (or disable) partitioning support. Removed in MySQL 8.0.0.

query_cache_limit: Do not cache results that are bigger than this. Removed in MySQL 8.0.3.

query_cache_min_res_unit: Minimal size of unit in which space for results is allocated (last unit is trimmed after writing all result data). Removed in MySQL 8.0.3.

query_cache_size: Memory allocated to store results from old queries. Removed in MySQL 8.0.3.

query_cache_type: Query cache type. Removed in MySQL 8.0.3.

query_cache_wlock_invalidate: Invalidate queries in query cache on LOCK for write. Removed in MySQL 8.0.3.

secure_auth: Disallow authentication for accounts that have old (pre-4.1) passwords. Removed in MySQL 8.0.3.

show_compatibility_56: Compatibility for SHOW STATUS/VARIABLES. Removed in MySQL 8.0.1.

skip-partition: Do not enable user-defined partitioning. Removed in MySQL 8.0.0.

sync_frm: Sync .frm to disk on create. Enabled by default. Removed in MySQL 8.0.0.

temp-pool: Using this option causes most temporary files created to use small set of names, rather than unique name for each new file. Removed in MySQL 8.0.1.

time_format: TIME format (unused). Removed in MySQL 8.0.3.

tx_isolation: Default transaction isolation level. Removed in MySQL 8.0.3.

tx_read_only: Default transaction access mode. Removed in MySQL 8.0.3.

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