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This article focuses on "what are the new features of MySQL 8.0.3". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn what are the new features of MySQL 8.0.3.

Some important new features and changes in version 8.0.3:

Directly abolish query cache (should just close the entry and compile the source code by yourself, it can be enabled again)

The query optimizer supports modifying some session-level options directly in SQL using the HINT syntax of SET_VAR, such as-SELECT / * + SET_VAR (sort_buffer_size = 16m) * / name FROM people ORDER BY name;- INSERT / * + SET_VAR (foreign_key_checks=OFF) * / INTO T2 VALUES (2); (this function is super practical, it can be modified directly in SQL, you don't have to write a SQL, and you're worried about affecting others.)

The query optimizer now supports storing individual column statistical result histograms in column_statistics data dictionaries to construct execution plans. With this histogram, it can be used to compare the column with the constant.

A new tag bit use_invisible_indexes is added to the query optimizer to control whether the invisible index (invisible indexes) factor is taken into account when constructing the execution plan

A special backup lock has been added to InnoDB. In the past, if DML was performed at the same time during the online hot backup of InnoDB table, it may lead to inconsistent snapshots of InnoDB files. With this backup lock, you don't have to worry about it. The usage of backup lock is LOCK INSTANCE FOR BACKUP and UNLOCK INSTANCE, and BACKUP_ADMIN permission is required

InnoDB now supports the atomicity of the table DDL, that is, the DDL on the InnoDB table can also achieve transaction integrity, either failed rollback or successfully committed, avoiding the partial success of DDL. In addition, it also supports the crash-safe feature (this feature is awesome)

If you delay initializing group replication (GR,Group Replication), that is, in single-primary mode, data can be written to the secondary node through the asynchronous replication channel, which is not allowed when initializing the group replication plug-in normally (Bug # 26314756, this is an internal BUG ID, we can't see it, don't bother. However, there is also * github, ah, you can also see the relevant description, see: https://github.com/mysql/mysql-server/commit/acbf1d13ecd1d89557f8ca62116f06e8633dc90d)

Several views such as FILES, PARTITIONS and REFERENTIAL_CONSTRAINTS in the system library INFORMATION_SCHEMA have been reimplemented (this is not too specific, it may have something to do with putting all DDL into InnoDB, and no longer using FRM files to store DDL information)

Due to the modification of the foreign key constraint lock function, the column renaming function on the parent table involving foreign key constraints will be temporarily disabled for a period of time (it is estimated that a few small versions will be able to be used normally)

New renaming syntax for InnoDB common tablespaces: ALTER TABLESPACE. RENAME TO (as a MySQL DBA, few people seem to play with universal tablespaces, so they may be more accustomed to using them from Oracle DBA)

On the slave node replicated by MySQL, the default value of the log_slave_updates option is changed to ON (this is also more practical, so it is convenient to use the slave directly as a relay node)

The global scope of the option sql_log_bin is changed to the callback-level scope, that is, modifying this option affects only the session, not the global (this option is generally also used at the session level)

The default value of the option max_allowed_packet has been increased from 4m to 64m (which seems more realistic)

The default value of the option event_scheduler is changed from OFF to ON, so that the event scheduler feature is enabled by default (I think the event function is quite good, but it seems that few people use event)

The default value of the option max_error_count has been increased from 64 to 1024.

* one. Add Russian check set to utf8mb4 character set (add utf8mb4_ru_0900_ai_ci and utf8mb4_ru_0900_as_cs collations set)

At this point, I believe you have a deeper understanding of "what are the new features of MySQL 8.0.3?" you might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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