MySQL 8.0 发布详情：8.0.37版本更新概述

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MySQL 8.0 Release Notes是一份详尽的文档，记录了MySQL 8.0数据库系统自初始发布以来各版本的主要更新和改进，直至MySQL 8.0.37版本。这份文档对于跟踪MySQL 8.0系列的变更历史至关重要，无论是新功能的介绍、升级注意事项，还是向下兼容性问题的处理，都提供了全面的信息。在MySQL 8.0的更新中，最值得关注的是其新增的功能和特性。比如，"What Is New in MySQL 8.0"章节概述了这一版本引入的重要创新，包括但不限于性能优化、安全性增强、存储引擎的改进、对JSON和列存表的支持，以及对SQL标准的遵循程度提升等。这些新特性的目标是提高数据库的效率和易用性，使得开发人员能够更好地利用MySQL进行现代应用的构建。在升级方面，MySQL 8.0.37建议用户在实际生产环境进行升级前，先在测试环境中进行验证，确保新版本的稳定性和兼容性。由于不支持从MySQL 8.0向下回滚至MySQL 5.7或其他较早版本，因此在升级前备份数据是至关重要的步骤。只有当升级过程在测试系统上顺利后，才能放心地在生产环境中执行。平台支持随着时间的推移而变化，用户应该参考MySQL官方文档，了解最新的平台支持情况以及可能遇到的技术限制。这包括但不限于操作系统、硬件配置、并发性能等方面的要求。 MySQL 8.0 Release Notes是开发人员、运维人员和数据库管理员在迁移和优化数据库系统时不可或缺的参考资料，它提供了一个全面的视图，帮助用户了解并适应MySQL 8.0的革新特性，同时指导他们在升级过程中做出明智的决策。

MySQL 8.0 Release Notes

file and respects the preference to use a FIPS provider, if one is set. OpenSSL 3.0 is certified for use

with FIPS.

To favor the OpenSSL alternative, the ssl_fips_mode server system variable, --ssl-fips-

mode client option, and the MYSQL_OPT_SSL_FIPS_MODE option now are deprecated and subject

to removal in a future version of MySQL. A deprecation warning prints to standard error output when

an application uses the MYSQL_OPT_SSL_FIPS_MODE option or when a client user specifies the --

ssl-fips-mode option on the command line, through option files, or both.

Prior to being deprecated, the ssl_fips_mode server-side system variable was dynamically

settable. It is now a read-only variable (accepts SET PERSIST_ONLY, but not SET PERSIST or SET

GLOBAL). When specified on the command line or in the mysqld-auto.cnf option file (with SET

PERSIST_ONLY) a deprecation warning prints to the server error log. (WL #15631)

• The mysql_ssl_rsa_setup program originally provided a simple way for community

users to generate certificates manually, if OpenSSL was installed on the system. Now,

mysql_ssl_rsa_setup is deprecated because MySQL Community Edition no longer supports

using yaSSL as the SSL library, and source distributions no longer include yaSSL. Instead, use

MySQL server to generate missing SSL and RSA files automatically at startup (see Automatic SSL

and RSA File Generation). (WL #15668)

• The keyring_file and keyring_encrypted_file plugins now are deprecated.

These keyring plugins are superseded by the component_keyring_file and

component_keyring_encrypted_file components. For a concise comparison of keyring

components and plugins, see Keyring Components Versus Keyring Plugins. (WL #15659)

• Previously, the MySQL server processed a version-specific comment without regard as to whether

any whitespace followed the MySQL version number contained within it. For example, the comments

/*!80034KEY_BLOCK_SIZE=1024*/ and /*!80034 KEY_BLOCK_SIZE=1024*/ were handled

identically. Beginning with this release, when the next character following the version number in

such a comment is neither a whitespace character nor the end of the comment, the server issues a

warning: Immediately starting the version comment after the version number

is deprecated and may change behavior in a future release. Please insert a

whitespace character after the version number.

You should expect the whitespace requirement for version-specific comments to become strictly

enforced in a future version of MySQL.

See Comments, for more information. (WL #15686)

• The MySQL client library currently supports performing an automatic reconnection to the server if it

finds that the connection is down and an application attempts to send a statement to the server to be

executed. Now, this feature is deprecated and subject to removal in a future release of MySQL.

The related MYSQL_OPT_RECONNECT option is still available but it is also deprecated. C API

functions mysql_get_option() and mysql_options() now write a deprecation warning to the

standard error output when an application specifies MYSQL_OPT_RECONNECT. (WL #15766)

Performance Schema Notes

• The type used for the Performance Schema clone_status table's gtid_executed column has

been changed from VARCHAR(4096) to LONGTEXT. (Bug #109171, Bug #34828542)

SQL Syntax Notes

• CURRENT_USER() can now be used as a default value for VARCHAR and TEXT columns in CREATE

TABLE and ALTER TABLE ... ADD COLUMN statements.

The functions SESSION_USER(), USER(), and SYSTEM_USER() are also supported in all of the

cases just mentioned. By way of example, the following sequence of statements now works similarly

to what is shown here, with the precise output dependent on your environment:

MySQL 8.0 Release Notes

mysql> SELECT CURRENT_USER();

+-------------------+

| CURRENT_USER() |

+-------------------+

| sakila@localhost |

+-------------------+

1 row in set (0.00 sec)

mysql> CREATE TABLE t (

> c1 VARCHAR(288) DEFAULT (USER()),

> c2 VARCHAR(288) DEFAULT (CURRENT_USER()),

> c3 VARCHAR(288) DEFAULT (SESSION_USER()),

> c4 VARCHAR(288) DEFAULT (SYSTEM_USER())

> );

Query OK, 0 rows affected (0.04 sec)

mysql> INSERT INTO t VALUES ROW();

Query OK, 1 row affected (0.01 sec)

mysql> TABLE t;

+-------------------+-------------------+-------------------+-------------------+

| c1 | c2 | c3 | c4 |

+-------------------+-------------------+-------------------+-------------------+

+-------------------+-------------------+-------------------+-------------------+

1 row in set (0.00 sec)

When used in this way, these functions are also included in the output of SHOW CREATE TABLE

and SHOW COLUMNS, and referenced in the COLUMN_DEFAULT column of the Information Schema

COLUMNS table where applicable.

If you need to insure that values having the maximum possible length can be stored in such a

column, you should make sure that the column can accommodate at least 288 characters (255 for

the user name and 32 for the host name, plus 1 for the separator @). For this reason—while it is

possible to use one of these functions as the default for a CHAR column, it is not recommended due

to the risk of errors or truncation of values. (Bug #17809, Bug #11745618)

Functionality Added or Changed

• Important Change: For platforms on which OpenSSL libraries are bundled, the linked OpenSSL

library for MySQL Server has been updated from OpenSSL 1.1.1 to OpenSSL 3.0. The exact

version is now 3.0.9. More information on changes from 1.1.1 to 3.0 can be found at https://

www.openssl.org/docs/man3.0/man7/migration_guide.html. (Bug #35475140, WL #15614)

• Packaging: Beginning with this release, binary archive packages previously named using -

el7-x86_64.tar and -el7-x86_64.tar.gz are now named using -linux-glibc2.17-

x86_64.tar and -linux-glibc2.17-x86_64.tar.gz, respectively. For example, if you

used mysql-8.0.33-el7-x86_64.tar to install or upgrade to MySQL 8.0.33, you should use

mysql-8.0.34-linux-glibc2.17-x86_64.tar for installing or upgrading to MySQL 8.0.34.

The naming change reflects the fact that these binaries are intended to be compatible with any Linux

system using glibc2.17 or newer; this includes Enterprise Linux 7, EL8, and EL9.

• Binary packages that include curl rather than linking to the system curl library have been upgraded to

use curl 8.1.2. (Bug #35329529)

Bugs Fixed

• Important Change: The default value of the connection_memory_chunk_size server system

variable, when introduced in MySQL 8.0.28, was mistakenly set at 8912. This fix changes the default

to 8192, which is the value originally intended. (Bug #35218020)

MySQL 8.0 Release Notes

• NDB Cluster: The fix for a previous issue introduced a slight possibility of unequal string values

comparing as equal, if any Unicode 9.0 collations were in use, and the collation hash methods

calculated identical hash keys for two unequal strings. (Bug #35168702)

References: See also: Bug #27522732. This issue is a regression of: Bug #30884622.

• InnoDB: Possible congestion due to purging a large number of system threads has been fixed. (Bug

#35289390, Bug #110685)

• InnoDB: ddl::Aligned_buffer now uses the standard memory allocator and not kernel memory

management. (Bug #35194732, Bug #110411)

• InnoDB: An upgrade from MySQL 5.7 to MySQL 8.0.32 might fail due to deprecated configuration

parameters innodb_log_file_size or innodb_log_files_in_group. The workaround is to

start MySQL 8.0.32 with --innodb-redo-log-capacity=206158430208. (Bug #35155280)

• InnoDB: Performance regression due to hash function changes in MySQL 8.0.30 have been fixed.

(Bug #34870256)

• InnoDB: The rules for aggregating entries in the redo log have been fixed. (Bug #34752625, Bug

#108944)

• InnoDB: Several errors due to tablespace deletion and the buffer pool have been fixed. (Bug

#34330475, Bug #107689)

• Packaging; Group Replication: The group replication plugin from the Generic Linux packages did

not load on some platforms that lacked a compatible version of tirpc. (Bug #35323208)

• Replication: Changes in session_track_gtids were not always propagated correctly. (Bug

#35401212)

• Replication: By design, all DDL operations (including binary log operations such as purging the

binary log) acquire a shared lock on the BACKUP_LOCK object, which helps to prevent simultaneous

backup and DDL operations. For binary log operations, we checked whether any locks existed

on BACKUP_LOCK but did not check the types of any such locks. This caused problems due to

the fact that binary log operations should be prevented only when an exclusive lock is held on the

BACKUP_LOCK object, that is, only when a backup is actually in progress, and backups should be

prevented when purging the binary log.

Now in such cases, instead of checking for locks held on the BACKUP_LOCK object, we acquire a

shared lock on BACKUP_LOCK while purging the binary log. (Bug #35342521)

• Replication: In all cases except one, when mysqlbinlog encountered an error while reading

an event, it wrote an error message and returned a nonzero exit code, the exception being for

the active binary log file (or any binary log where the format_description_log_event had the

LOG_EVENT_BINLOG_IN_USE_F flag set), in which case it did not write a message, and returned

exit code 0, thus hiding the error.

Now mysqlbinlog suppresses only those errors which are related to truncated events, and when

doing so, prints a comment rather than an error message. This fix also improves the help text for the

--force-if-open option. (Bug #35083373)

• Replication: Compressed binary log event handling was improved. (Bug #33666652)

• Replication: A transaction consisting of events each smaller than 1 GiB, but whose total size was

larger than 1 GiB, and where compression did not make it smaller than 1 GiB, was still written to

the binary log as one event bigger than 1 GiB. This made the binary log unusable; in effect, it was

corrupted since neither the server nor other tools such as mysqlbinlog could read it.

Now, when the compressed data grows larger than 1 GiB, we fall back to processing the transaction

without any compression. (Bug #33588473)

MySQL 8.0 Release Notes

• Group Replication: In a group replication setup, when there was a source of transactions other than

the applier channel, the following sequence of events was possible:

1. Several transactions being applied locally were already certified, and so were associated with

a ticket, which we refer to as Ticket 2, but had not yet been committed. These could be local or

nonlocal transactions.

2. A view is created with Ticket 3, and must wait on transactions from Ticket 2.

3. The view change (VC1) entered the GR applier channel applier and waited for the ticket to

change to 3.

4. Another group change, and another view change (VC2), occurred while the transactions from

Ticket 2 were still completing.

This gave rise to the following issue: There was a window wherein the last transaction from Ticket

2 had already marked itself as being executed but had not yet popped the ticket; VC2 popped

the ticket instead but never notified any of the participants. This meant that VC1 continued to wait

indefinitely for the ticket to change, and with the additional effect that the worker could not be killed.

We fix this by checking for the need to break each second so that this loop is responsive to changes

in the loop condition; we also register a new stage, so that the loop is more responsive to kill signals.

(Bug #35392640)

References: See also: Bug #35206392, Bug #35374425.

• Group Replication: Removed a memory leak discovered in

Network_provider_manager::open_xcom_connection(). (Bug #34991101)

• Group Replication: When a group action was sent to the group and the connection was killed

on the coordinator, group members were in different states, with members which received the

coordinated action waiting for the member that executed it, and the member which started execution

having nothing to process, which caused problems with coordination of the group.

Now in such cases, we prevent this issue from occurring by causing group actions to wait until all

members have completed the action. (Bug #34815537)

• Group Replication: Cleanup of resources used by OpenSSL connections created indirectly

by group replication was not carried out as expected at all times. We fix this by adding cleanup

functionality that can be called at any time such connections are created by group replication. (Bug

#34727136)

• JSON: When the result of JSON_VALUE() was an empty string and was assigned to a user variable,

the user variable could in some cases be set to NULL instead, as shown here:

mysql> SELECT JSON_VALUE('{"fname": "Joe", "lname": ""}', '$.lname') INTO @myvar;

Query OK, 1 row affected (0.01 sec)

mysql> SELECT @myvar = '', @myvar IS NULL;

+-------------+----------------+

| @myvar = '' | @myvar IS NULL |

+-------------+----------------+

| NULL | 1 |

+-------------+----------------+

1 row in set (0.00 sec)

With this fix, the query just shown now returns (1, 0), as expected. (Bug #35206138)

• JSON: Some JSON schemas were not always processed correctly by JSON_SCHEMA_VALID().

(Bug #109296, Bug #34867398)

• In rare cases, MySQL server could exit rather than emit an error message as expected. (Bug

#35442407)

MySQL 8.0 Release Notes

• The internal resource-group enhancement added in MySQL 8.0.31 and refactored in MySQL 8.0.32

is now reverted. (Bug #35434219)

References: Reverted patches: Bug #34702833.

• An in-place upgrade from MySQL 5.7 to MySQL 8.0, without a server restart, could result in

unexpected errors when executing queries on tables. This fix eliminates the need to restart the

server between the upgrade and queries. (Bug #35410528)

• A fix in MySQL 8.0.33 made a change for ORDER BY items already resolved so as not to resolve

them again (as is usually the case when a derived table is merged), but this did not handle the case

in which an ORDER BY item was itself a reference. (Bug #35410465)

References: This issue is a regression of: Bug #34890862.

• Changes in session_track_gtids were not always handled correctly. (Bug #35401212)

• Some pointers were not always released following statement execution. (Bug #35395965)

• Some instances of subqueries within stored routines were not always handled correctly. (Bug

#35377192)

• Fortified parsing of the network packet data sent by the server to the client. (Bug #35374491)

• Encryption enhancements now strengthen compliance and remove the use of deprecated APIs. (Bug

#35339886)

• When a column reference given by table name and column name was looked up in the function

find_item_in_list(), we ignored that the item searched for might not have a table name, as it

was not yet resolved. We fix this by making an explicit check for a null table name in the sought-after

item. (Bug #35338776)

• Deprecated the lz4_decompress and zlib_decompress command-line utilities that exist to

support the deprecated mysqlpump command-line utility. (Bug #35328235)

• Queries using LIKE '%...%' ran more poorly than in previous versions of MySQL. (Bug

#35296563)

• In Bounded_queue::push(), when Key_generator::make_sortkey() returns UINT_MAX

(error), then no key has been produced; now when this occurs, we no longer update the internal

queue.

As part of this fix, push() now returns true on error. (Bug #35237721)

• The authentication_oci plugin is fixed to allow federated and provisioned users to connect to a

DB System as a mapped Proxy User using an ephemeral key-pair generated through the OCI CLI.

(Bug #35232697)

• Some queries using common table expressions were not always processed correctly. (Bug

#35231475)

• The internal function compare_pair_for_nulls() did not always set an explicit return value.

(Bug #35217471)

• Removed the clang-tidy checks that clash with the MySQL coding style. (Bug #35208735)

• Some subqueries using EXISTS in both the inner and outer parts of the query were not handled

correctly. (Bug #35201901)

• Rotated audit log files now always reset the ID value of the bookmark to zero, rather than continuing

the value from the previous file. (Bug #35200070)

• Errors were not always propagated correctly when evaluating items to be sorted by filesort. (Bug

#35195181)

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MySQL 8.0 发布详情：8.0.37版本更新概述

数据库MySQL 8.0.37版本

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MySQL 8.0手册

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MySQL 8.0 Reference Manual 参考手册原版

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