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This article mainly explains "what are the new features of MySQL 5.7.9 GA stable Edition". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what are the new features of MySQL 5.7.9 GA stable Edition".

1. Security

The plugin field of the user table mysql.user is not allowed to be empty, the default value is mysql_native_password, not mysql_old_password, and the old password format is no longer supported

Add password expiration mechanism. You need to change the password after expiration, otherwise it may be disabled or enter sandbox mode.

When initializing with mysql_install_db, random passwords are automatically generated by default and saved to / var/log/mysqld.log (grep 'temporary password' / var/log/mysqld.log). No accounts other than root@localhost are created, and no test library is created.

Mysqld-- initialize is recommended to initialize the database. If-initial-insecure is added during initialization, an root@localhost account with an empty password will be created, otherwise a root@localhost account with a password will be created, and the password will be written directly in the log-error log file (placed in ~ / .mysql_secret in 5.6)

Unlock and lock operations can be performed on ordinary users in 5. 7.

2. Some functions of InnoDB engine are enhanced.

Optimized DDL operations to significantly improve performance when it comes to InnoDB temporary tables

The metadata of InnoDB temporary tables is stored in InnoDB system tables before 5.6. in 5.7.The information and metadata of temporary tables are stored in the newly added table INNODB_TEMP_TABLE_INFO.

The InnoDB temporary table is stored in an uncompressed, separate table space, which is automatically created each time the MySQL service is started, stored under DATADIR by default, and its path specified by the parameter innodb_temp_data_file_path

Support online (INPLACE) to increase the length of VARCHAR columns. However, the length of 0255is an interval, and more than 256is another interval, which cannot be crossed, for example, expanding the length from 100to 1000 (because the length is represented by an extra byte, and if the length is greater than 255, you need an additional 2 bytes).

Online reducing the length of VARCHAR is not supported.

Support innodb_page_cleaners option to set multiple page cleaner threads to improve the efficiency of dirty page refresh

Unused undo log can be deleted automatically by setting options such as innodb_undo_log_truncate.

Enhance the performance of InnoDB read-only mode

In 5.7, you can create a normal tablespace:

CREATE TABLESPACE `tablespace_ name`

ADD DATAFILE 'file_name.ibd'

[FILE_BLOCK_SIZE = n]

3 、 SQL_MODE

STRICT_TRANS_TABLES mode is enabled by default

More complex feature support for ONLY_FULL_GROUP_BY mode is implemented and is enabled by default

Other sql mode enabled by default is NO_ENGINE_SUBSTITUTION.

Writing 15 characters to a 10-character VARCHAR column in 5.6will automatically truncate and give an alarm, while at 5.7an error will be thrown directly.

4. Optimize online operations, such as modifying buffer pool, modifying index names (non-primary keys), modifying REPLICATION FILTER, modifying MASTER without shutting down SLAVE threads, and many other features.

5.7.You can view the system parameters of MySQL in the table in INFORMATION_SCHEMA

6. Support multiple triggers on a table, so that existing trigger tables can also support the use of pt-osc

7. Support directly viewing the execution plan for an online connection, such as EXPLAIN FOR CONNECTION 1024

8. Add log_syslog option to print MySQL log to Syslog file

9. Before MySQL 5.6. after the client CTRL+C, the client will directly exit, ah, the MySQL client, which is disgusting. It will not exit the client but the current operation of the terminal after 5.7,

10. Add a better feature, that is, when CREATE | ALTER TABLE, you can calculate the new columns on the basis of the existing columns in a table:

CREATE TABLE triangle (

Sidea DOUBLE

Sideb DOUBLE

Sidec DOUBLE AS (SQRT (sidea * sidea + sideb * sideb))

);

INSERT INTO triangle (sidea, sideb) VALUES (1), (3) 4), (6) 8)

Mysql > SELECT * FROM triangle

+-+

| | sidea | sideb | sidec | |

+-+

| | 1 | 1 | 1.4142135623730951 | |

| | 3 | 4 | 5 |

| | 6 | 8 | 10 | |

+-+

11. Multi-source replication is supported. Data from multiple MASTER can be merged into one instance. If it is the same table, there is a risk of conflict between primary key and unique index, which needs to be planned in advance.

12. Support multithreaded replication.

Thank you for reading, the above is the content of "what are the new features of MySQL 5.7.9 GA stable Edition". After the study of this article, I believe you have a deeper understanding of what the new features of MySQL 5.7.9 GA stable Edition have, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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