PolarDB:Engine versions

A complete engine version of PolarDB for MySQL consists of three parts: major version, minor version, and revision version. The following figure shows the relationship among the three parts. In the following example, the major version of PolarDB for MySQL is 8.0.

Alibaba Cloud provides release notes for each version, in which new features, modified features, and fixed issues are listed. For more information, see the following topics:

• PolarDB for MySQL 8.0.2
• PolarDB for MySQL 8.0.1
• PolarDB for MySQL 5.7
• PolarDB for MySQL 5.6

The compatibility of engine versions of PolarDB for MySQL:

• Complies with ANSI and ISO SQL standards. PolarDB for MySQL allows you to enable the ANSI session mode by setting the sql_mode parameter of your cluster to ANSI. For more information about how to modify the cluster parameters, see Specify cluster and node parameters.
• Supports Open Database Connectivity (ODBC) versions 0 to 3.51.
• Supports XML features that comply with W3C and XPath standards.
• PolarDB for MySQL 5.7 and 8.0 support the native JSON data types that comply with RFC 7159 and ECMA-262 standards.

The following table lists the correspondence between different versions of PolarDB for MySQL and MySQL Community Edition:

Engine version	Fully compatible MySQL minor version
8.0.2	8.0.18 and earlier
8.0.1	8.0.13 and earlier
5.7	5.7.28 and earlier
5.6	5.6.16 and earlier

To make PolarDB for MySQL 8.0.2.2.0 or later compatible with the CREATE TABLE statement, you can use the SHOW CREATE TABLE statement, mysqldump tool, and binary log synchronization to automatically add the CREATE TABLE statement.

• Method 1: Execute the SHOW CREATE TABLE statement. Example:

  CREATE TABLE `t1` (c1 int) ENGINE=InnoDB UNIQUE CHECK IGNORE=1
  PARTITION BY HASH (`c1`) PARTITIONS 4;
  
  -- result
  SHOW CREATE TABLE t1;
  Table Create Table
  t1  CREATE TABLE `t1` (
    `c1` int(11) DEFAULT NULL
  ) /*!99990 800020200 UNIQUE CHECK IGNORE=1 */ ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
  /*!50100 PARTITION BY HASH (`c1`)
  PARTITIONS 4 */

• Method 2: Use the mysqldump tool. Example:

  CREATE TABLE `t1` (c1 int) UNIQUE CHECK IGNORE=1 ENGINE=InnoDB
  DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci PARTITION BY HASH (`c1`);
  --result
  mysqldump --compact test t1
  
  include/mysqlbinlog.inc
  /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
  /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
  DELIMITER /*!*/;
  ROLLBACK/*!*/;
  # [empty]
  # original_commit_timestamp= MICROSECONDS-FROM-EPOCH (YYYY-MM-DD HOURS:MINUTES:SECONDS TZ)
  # immediate_commit_timestamp= MICROSECONDS-FROM-EPOCH (YYYY-MM-DD HOURS:MINUTES:SECONDS TZ)
  /*!80001 SET @@session.original_commit_timestamp= MICROSECONDS-FROM-EPOCH*//*!*/;
  /*!80014 SET @@session.original_server_version= ORIGINAL_SERVER_VERSION*//*!*/;
  /*!80014 SET @@session.immediate_server_version= IMMEDIATE_SERVER_VERSION*//*!*/;
  SET @@SESSION.GTID_NEXT= '#'/*!*/;
  use `test`/*!*/;
  SET TIMESTAMP=#/*!*/;
  SET @@session.pseudo_thread_id=#/*!*/;
  SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
  SET @@session.sql_mode=1168113696/*!*/;
  SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
  /*!\C utf8mb4 *//*!*/;
  SET @@session.character_set_client=255,@@session.collation_connection=255,@@session.collation_server=255/*!*/;
  SET @@session.lc_time_names=0/*!*/;
  SET @@session.collation_database=DEFAULT/*!*/;
  /*!80011 SET @@session.default_collation_for_utf8mb4=255*//*!*/;
  /*!80013 SET @@session.sql_require_primary_key=0*//*!*/;
  CREATE TABLE `t1` (
    `c1` int(11) DEFAULT NULL
  ) /*!99990 800020200 UNIQUE CHECK IGNORE=1 */ ENGINE=InnoDB
  /*!50100 PARTITION BY HASH (`c1`)
  PARTITIONS 4 */
  /*!*/;
  ......

• Method 3: Use binary log synchronization.
  In the following example, binary logs are synchronized from PolarDB for MySQL 8.0.2.2.0 to MySQL 8.0.27.

  1. Use DTS to synchronize PolarDB for MySQL binary logs to another MySQL database. For more information, see Synchronize data from a PolarDB for MySQL cluster to an ApsaraDB RDS for MySQL instance.
  2. View the binary log synchronization result on PolarDB for MySQL 8.0.2.2.0 and on the destination MySQL database.
     Sample result on PolarDB for MySQL:
     Sample result on the destination MySQL database:As shown in the preceding figures, the features provided by PolarDB for MySQL are not displayed in the result on the destination MySQL database.

     Note After PolarDB for MySQL data is synchronized to other MySQL databases, the features provided by PolarDB for MySQL are no longer available.

For DDL statements other than CREATE TABLE, you must manually add comments in PolarDB for MySQL statements to ensure compatibility. Syntax:

/*!99990 800020200 Special new PolarDB Syntax SQL supported >= version 2.2.0 */

Example:

CREATE TABLE `t1` (c1 int)
/*!99990 900020200 UNIQUE CHECK IGNORE=1 */
ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
/*!50100 PARTITION BY HASH (`c1`) */;
SHOW CREATE TABLE t1;
DROP TABLE `t1`;