MySQL Workbench 歷史版本列表 Page1

更新時間：2023-07-19
更新細節：

What's new in this version:

Account Management Notes:
- A new password-validation system variable now permits the configuration and enforcement of a minimum number of characters that users must change when attempting to replace their own MySQL account passwords. This new verification setting is a percentage of the total characters in the current password. For example, if validate_password.changed_characters_percentage has a value of 50, at least half of the characters in the replacement account password must not be present in the current password, or the password is rejected.
- This new capability is one several that provide DBAs more complete control over password management. For more information, see Password Management. (WL #15751)

Audit Log Notes:
- In MySQL 8.0.33, the audit_log plugin added support for choosing which database to use to store JSON filter tables. It is now possible to specify an alternative to the default system database, mysql, when run the plugin installation script. Use the audit_log_database server system variable (or -D database_name) on the command line together with the alternative database name, for example:
- $> mysql -u root -D database_name -p < audit_log_filter_linux_install.sql
- For additional information about using audit_log plugin installation scripts, see Installing or Uninstalling MySQL Enterprise Audit.
- MySQL Enterprise Audit now supports using the scheduler component to configure and execute a recurring task to flush the in-memory cache. For setup instructions, see Enabling the Audit Log Flush Task. (WL #15567)

Binary Logging:
- Several functions now are added to the libmysqlclient.so shared library that enable developers to access a MySQL server binary log: mysql_binlog_open(), mysql_binlog_fetch(), and mysql_binlog_close().

C API Notes:
- In the calling function, len is initialized to 0 and never changed if net->vio is null. This fix adds a check of net before dereferencing vio.
- A variable in the async client was uninitialized in certain code paths. It is fixed by always initializing the variable.

Compilation Notes:
- Microsoft Windows: For Windows, improved MSVC_CPPCHECK support; and check for MSVC warnings similar to "maintainer" mode. For example, check after all third party configurations are complete.
- Microsoft Windows: For Windows builds, improved WIN_DEBUG_NO_INLINE=1 support; usage would exceed the library limit of 65535 objects.
- Upgraded the bundled robin-hood-hashing from v3.8.1 to v3.11.5.
- Removed the unused extra/libcbor/doc/ directory as extra/libcbor/doc/source/requirements.txt inspired bogus pull requests on GitHub.
- Updated the bundled ICU files from version 69.1 to version 73 for the icu-data-files package.
- ZSTD sources bundled in the source tree were upgraded to ZSTD 1.5.5 from 1.5.0.
- Initialize the internal MEM_ROOT class memory with garbage using the TRASH macro to make easier to reproduce bugs caused by reading initialized memory allocated from MEM_ROOT.
- We now determine stack direction at runtime rather than at configure time.
- Added the OPTIMIZE_SANITIZER_BUILDS CMake option that adds -O1 -fno-inline to sanitizer builds. It defaults to ON.
- Changed the minimum Bison version requirement from v2.1 to v3.0.4. For macOS, this may require installing Bison via a package manager such as Homebrew.
- MySQL now sets LANG=C in the environment when executing readelf to avoid problems with non-ASCII output.
- On macOS, MySQL would not compile if rapidjson was installed via Homebrew. The workaround was to brew unlink rapidjson.
- MySQL would not build with -DWITH_ZLIB=system; it'd complain about not finding the system zlib library despite finding it.
- Deprecation and Removal Notes:
- Important Change: Since MySQL provides other means of performing database dumps and backups with the same or additional functionality, including mysqldump and MySQL Shell Utilities, the mysqlpump client utility program has become redundant, and is now deprecated. Invocation of this program now produces a warning. You should keep in mind that mysqlpump is subject to removal in a future version of MySQL, and move applications depending on it to another solution, such as those mentioned previously. (WL #15652)
- Replication: The sync_relay_log_info server system variable is deprecated in this release, and getting or setting this variable or its equivalent startup option --sync-relay-log-info now raises a warning.
- Expect this variable to be removed in a future version of MySQL; applications which make use of it should be rewritten not to depend on it before this happens.
- Replication: The binlog_format server system variable is now deprecated, and subject to removal in a future version of MySQL. The functionality associated with this variable, that of changing the binary logging format, is also deprecated.
- The implication of this change is that, when binlog_format is removed, only row-based binary logging, already the default in MySQL 8.0, will be supported by the MySQL server. For this reason, new installations should use only row-based binary logging, and existing ones using the statement-based or mixed logging format should be migrated to the row-based format. See Replication Formats, for more information.
- The system variables log_bin_trust_function_creators and log_statements_unsafe_for_binlog, being useful only in the context of statement-based logging, are now also deprecated, and are thus also subject to removal in a future release of MySQL.
- Setting or selecting the values of any of the variables just mentioned now raises a warning. (WL #13966, WL #15669)
- Group Replication: The group_replication_recovery_complete_at server system variable is now deprecated, and setting it produces a warning. You should expect its removal in a future release of MySQL. (WL #15460)
- The mysql_native_password authentication plugin now is deprecated and subject to removal in a future version of MySQL. CREATE USER, ALTER USER, and SET PASSWORD operations now insert a deprecation warning into the server error log if an account attempts to authenticate using mysql_native_password as an authentication method.
- Previously, if the audit_log plugin was installed without the accompanying audit tables and functions needed for rule-based filtering, the plugin operated in legacy filtering mode. Now, legacy filtering mode is deprecated. New deprecation warnings are emitted for legacy audit log filtering system variables. These deprecated variables are either read-only or dynamic.
- (Read-only) audit_log_policy now writes a warning message to the MySQL server error log during server startup when the value is not ALL (default value).
- (Dynamic) audit_log_include_accounts, audit_log_exclude_accounts, audit_log_statement_policy, and audit_log_connection_policy. Dynamic variables print a warning message based on usage:
- Passing in a non-NULL value to audit_log_include_accounts or audit_log_exclude_accounts during MySQL server startup now writes a warning message to the server error log.
- Passing in a non-default value to audit_log_statement_policy or audit_log_connection_policy during MySQL server startup now writes a warning message to the server error log. ALL is the default value for both variables.
- Changing an existing value using SET syntax during a MySQL client session now writes a warning message to the client log.
- Persisting a variable using SET PERSIST syntax during a MySQL client session now writes a warning message to the client log.
- MySQL enables control of FIPS mode on the server side and the client side using a system variable and client option. Application programs can use the MYSQL_OPT_SSL_FIPS_MODE option to mysql_options() to enable FIPS mode on the client. Alternatively, it is possible to handle FIPS mode directly through OpenSSL configuration files rather than using the current server-side system variable and client-side options. When MySQL is compiled using OpenSSL 3.0, and an OpenSSL library and FIPS Object Module are available at runtime, the server reads the OpenSSL configuration 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.
- 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)

IPv6 Support:
- NDB Cluster: NDB did not start if IPv6 support was not enabled on the host, even when no nodes in the cluster used any IPv6 addresses

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

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
- 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.

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.
- Binary packages that include curl rather than linking to the system curl library have been upgraded to use curl 8.1.1.

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.
- 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.
- InnoDB: Possible congestion due to purging a large number of system threads has been fixed.
- InnoDB: ddl::Aligned_buffer now uses the standard memory allocator and not kernel memory management.
- 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.
- InnoDB: The rules for aggregating entries in the redo log have been fixed.
- InnoDB: Several errors due to tablespace deletion and the buffer pool have been fixed.
- 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.
- Replication: Changes in session_track_gtids were not always propagated correctly.
- 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.
- 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.
- Replication: Compressed binary log event handling was improved.
- 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.
- 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:
- 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.
- A view is created with Ticket 3, and must wait on transactions from Ticket 2.
- The view change (VC1) entered the GR applier channel applier and waited for the ticket to change to 3.
- 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.
- Group Replication: Removed a memory leak discovered in Network_provider_manager::open_xcom_connection().
- 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.
- 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.
- 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
- With this fix, the query just shown now returns (1, 0), as expected
- JSON: Some JSON schemas were not always processed correctly by JSON_SCHEMA_VALID()
- In rare cases, MySQL server could exit rather than emit an error message as expected
- The internal resource-group enhancement added in MySQL 8.0.31 and refactored in MySQL 8.0.32 is now reverted
- 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.
- 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.
- Changes in session_track_gtids were not always handled correctly
- Some pointers were not always released following statement execution
- Some instances of subqueries within stored routines were not always handled correctly
- Fortified parsing of the network packet data sent by the server to the client
- Encryption enhancements now strengthen compliance and remove the use of deprecated APIs.
- 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.
- Deprecated the lz4_decompress and zlib_decompress command-line utilities that exist to support the deprecated mysqlpump command-line utility.
- Queries using LIKE '%...%' ran more poorly than in previous versions of MySQL.
- 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
- 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.
- Some queries using common table expressions were not always processed correctly.
- The internal function compare_pair_for_nulls() did not always set an explicit return value.
- Removed the clang-tidy checks that clash with the MySQL coding style.
- Some subqueries using EXISTS in both the inner and outer parts of the query were not handled correctly.
- Rotated audit log files now always reset the ID value of the bookmark to zero, rather than continuing the value from the previous file.
- Errors were not always propagated correctly when evaluating items to be sorted by filesort.
- The fix for a previous issue with ROLLUP led to a premature server exit in debug builds.
- Simplified the implementation of Item_func_make_set::val_str() to make sure that we never try to reuse any of the input arguments, always using the local string buffer instead.
- When transforming subqueries to a join with derived tables, with the containing query being grouped, we created an extra derived table in which to do the grouping. This process moved the initial select list items from the containing query into the extra derived table, replacing all of the original select list items (other than subqueries, which get their own derived tables) with columns from the extra derived table.
- This logic did not handle DEFAULT correctly due to the manner in which default values were modelled internally. This fix adds support for DEFAULT(expression) in queries undergoing the transform previously mentioned. This fix also solves an issue with item names in metadata whereby two occurrences of the same column in the select list were given the same item name as a result of this same transform.
- A query of the form SELECT * FROM t1 WHERE (SELECT a FROM t2 WHERE t2.a=t1.a + ABS(t2.b)) > 0 should be rejected with Subquery returns more than 1 row, but when the subquery_to_derived optimization was enabled, the transform was erroneously applied and the query returned an incorrect result.
- Handling of certain potentially conflicting GRANT statements has been improved.
- A query using both MEMBER OF() and ORDER BY DESC returned only a partial result set following the creation of a multi-valued index on a JSON column. This is similar to an issue fixed in MySQL 8.0.30, but with the addition of the ORDER BY DESC clause to the prblematic query.
- For index skip scans, the first range read set an end-of-range value to indicate the end of the first range, but the next range read did not clear the stale end-of-range value and applies this stale value to the current range. Since the indicated end-of-range boundary had already been crossed in the previous range read, this caused the reads to stop, causing multiple rows to be missed in the result.
- We fix this by making sure in such cases that the old end-of-range value is cleared.
- The debug server asserted on certain operations involving DECIMAL values.
- All instances of adding and replacing expressions in the select list when transforming subqueries to use derived tables and joins have been changed so that their reference counts are maintained properly.
- Index Merge (see Index Merge Optimization) should favor ROR-union plans (that is, using RowID Ordered Retrieval) over sort-union plans if they have similar costs, since sort-union requires additionally sorting of the rows by row ID whereas ROR-union does not.
- For each part of a WHERE clause containing an OR condition, the range optimizer gets the best range scan possible and uses all these range scans to build an index merge scan (that is, a sort-union scan). If it finds that all the best range scans are also ROR-scans, the range optimizer always proposes a ROR-union scan because it is always cheaper than a sort-union scan. Problems arose when the best range scan for any one part of an OR condition is not a ROR-scan, in which case, the range optimizer always chose sort-union. This was true even in cases, where it might be advantageous to choose a ROR-scan (even though it might not be the best range scan to handle one part of the OR condition), since this would eleminate any need to sort the rows by row ID.
- Now, in such cases, when determining the best range scan, the range optimizer also detects whether there is any possible ROR-scan, and uses this information to see whether each part of the OR condition has at least one possible ROR-scan. If so, we rerun the range optimizer to obtain the best ROR-scan for handling each part of the OR condition, and to make a ROR-union path. We then compare this cost with the cost of a sort-union when proposing the final plan.
- Selecting from a view sometimes raised the error Illegal mix of collations ... for operation '=' when the collation used in the table or tables from which the view definition selected did not match the current session value of collation_connection.
- Valid MySQL commands (use and status) and C API functions (mysql_refresh, mysql_stat, mysql_dump_debug_info, mysql_ping, mysql_set_server_option, mysql_list_processes, and mysql_reset_connection) could write an error message to the audit log, even though running the command or calling the function emitted no such error.
- Increased the maximum fixed array size to 8192 instead of 512. This fixes an issue with mysqladmin extended status requests, which can exceed 512 entries.
- The mysqldump --column-statistics option attempted to select from information_schema.column_statistics against MySQL versions before 8.0.2, but this now generates the warning column statistics not supported by the server and sets the option to false.
- The function used by MySQL to get the length of a directory name was enhanced.
- Executing a query with an implicit aggregation should return exactly one row, unless the query has a HAVING clause that filters out the row, but a query with a HAVING clause which evaluated to FALSE sometimes ignored this, and returned a row regardless.
- For a query with a derived condition pushdown where a column in the condition needs to be replaced, a matching item could not found, even when known to be present, when the replacement item was wrapped in a ROLLUP while the matching item was not.
- The presence of an unused window function in a query, along with an ORDER BY that could have been eliminated, led to an unplanned server exit.
- ORDER BY RANDOM_BYTES() had no effect on query output
- Fixed an issue which could occur when loading user-defined functions
- Concurrent execution of FLUSH STATUS, COM_CHANGE_USER, and SELECT FROM I_S.PROCESSLIST could result in a deadlock. A similar issue was observed for concurrent execution of COM_STATISTICS, COM_CHANGE_USER, and SHOW PROCESSLIST.
- The mysqldump utility could generate invalid INSERT statements for generated columns.
- During optimization, range-select tree creation uses logic which differs based on the left-hand side of the IN() predicate. For a field item, each value on the right-hand side is added to an OR tree to create the necessary expression. In the case of a row item comparison (example: WHERE (a,b) IN ((n1,m1), (n2, m2), ...)), an expression in disjunctive normal form (DNF) is needed. A DNF expression is created by adding an AND tree with column values to an OR tree for each set of RHS values, but instead the OR tree was added to the AND tree causing the tree merge to require exponential time due to O(n2) runtime complexity.
- When using SELECT to create a table and the statement has an expression of type GEOMETRY, MySQL could generate an empty string as the column value by default. To resolve this issue, MySQL no longer generates default values for columns of type GEOMETRY under these circumstances.

更新時間：2023-07-19
更新細節：

更新時間：2023-06-06
更新細節：

更新時間：2023-05-24
更新細節：

更新時間：2023-04-19
更新細節：

更新時間：2023-04-19
更新細節：

What's new in this version:

Audit Log Notes:
- MySQL Enterprise Audit previously used tables in the mysql system database for persistent storage of filter and user account data. For enhanced flexibility, the new audit_log_database server system variable now permits specifying other databases in the global schema namespace at server startup. The mysql system database is the default setting for table storage. (WL #15500)

Compilation Notes:
- Microsoft Windows: Added MSVC Code Analysis support for Visual Studio 2017 and higher. This adds a new MSVC_CPPCHECK (defaults to OFF) CMake option that either enables or disables this analysis on the current directory and its subdirectories
- Downgraded curl deprecation warnings to -Wno-error for curl versions greater than 7.86 when MySQL is built with a GNU compiler or clang
- On macOS, added -framework CoreFoundation and -framework SystemConfiguration when linking the curl interface to link with shared system libraries as needed
- Replaced the MY_INCLUDE_SYSTEM_DIRECTORIES macro with library interfaces
- Improved CMake code to support alternative linkers
- Removed the deprecated Docs/mysql.info file from the build system
- Added a top-level .clang-tidy file and associated .clang.tidy files in the strings/ and mysys/ directories. Also enabled compdb support to enable clang-tidy usage on header files
- Removed several unmaintained or unused C++ source files for functionality such as uca-dump and uctypedump
- Added a CMake build option to enable colorized compiler output for GCC and Clang when compiling on the command line. To enable, pass -DFORCE_COLORED_OUTPUT=1 to CMake
- On Windows, also install .pdb files for associated .dll files if they are found for 3rd-party libraries
- Enterprise Linux 8 and Enterprise Linux 9 builds now use GCC 12 instead of GCC 11
- Building with -static-libgcc -static-libstdc++ now also builds the bundled protobuf with static libraries, as required.
- Thanks to Alex Xing for the contribution

Component Notes:
- INSTALL COMPONENT now includes the SET clause, which sets the values of component system variables while installing one or more components. The new clause reduces the inconvenience and limitations associated with the other ways of assigning variable values. For usage information, see INSTALL COMPONENT Statement. (WL #10916)

Deprecation and Removal Notes:
- User-defined collations (see Adding a Collation to a Character Set) are now deprecated. Either of the following now causes a warning to be written to the log:
- Any occurrence of COLLATE followed by the name of a user-defined collation in an SQL statement
- Use of the name of a user-defined collation as the value of collation_server, collation_database, or collation_connection
- You should expect support for user-defined collations to be removed in a future version of MySQL. (WL #14277)

MySQL Enterprise Notes:
- MySQL Enterprise Edition now provides data masking and de-identification capabilities based on components, rather than being based on a plugin library that was introduced in MySQL 8.0.13. The component implementation provides dedicated privileges to manage dictionaries and extends the list of specific types to include:
- Canada Social Insurance Number
- United Kingdom National Insurance Number
- International Bank Account Number
- Universally Unique Identifier (UUID)
- An improved table-based dictionary registry replaces the file-based dictionary used by the plugin. For a summary of the differences between the component and plugin implementations, see Data-Masking Components Versus the Data-Masking Plugin. Existing plugin users should uninstall the server-side plugin and drop its loadable functions before installing the new MySQL Enterprise Data Masking and De-Identification components
- Performance Schema Notes:
- The Performance Schema Server Telemetry Traces service is added in this release. An interface which provides plugins and components a way to retrieve notifications related to SQL statements' lifetime.
- For more information on this interface, see the Server telemetry traces service section in the MySQL Source Code documentation.
- The following were added:
- Status variable Telemetry_traces_supported. Whether server telemetry traces is supported. (Boolean)
- TELEMETRY_ACTIVE column was added to the threads table. Indicates whether the thread has an active telemetry session attached.
- (WL #15059)

Functionality Added or Changed:
- Important Change: For platforms on which OpenSSL libraries are bundled, the linked OpenSSL library for MySQL Server has been updated to version 1.1.1t. Issues fixed in OpenSSL version 1.1.1t are described at https://www.openssl.org/news/cl111.txt
- InnoDB: InnoDB now supports parallel index builds, which improves index build performance. In particular, loading sorted index entries into a B-tree is now multithreaded. Previously, this action was performed by a single thread. (WL #14772)
- Replication: As part of ongoing work to change old terminology used in MySQL products, the terms “master”, “slave”, and “MTS” have been replaced in error messages relating to MySQL Replication by “source”, “replica”, and “MTA”, respectively. This includes all error messages listed in messages_to_clients.txt and messages_to_error_log.txt relating to replication; the present task does not perform this replacement for messages used in other contexts.
- See the MySQL 8.0 Error Message Reference, for more information
- Replication: mysqlbinlog --start-position now accepts values up to 18446744073709551615, unless the --read-from-remote-server or --read-from-remote-source option is also used, in which case the maximum is 4294967295
- Binary packages that include curl rather than linking to the system curl library have been upgraded to use curl 7.88.1
- The use of a generated column with DEFAULT(col_name) to specify the default value for a named column is not permitted and now emits an error message

Fixed:
- NDB Cluster: Occasional temporary errors which could occur when opening a table from the NDB dictionary while repeatedly performing concurrent schema operations were not retried
- NDB Cluster: During iteration, ordered index scans retain a cursor position within each concurrently scanned ordered index fragment. Ordered index fragments are modified and balanced as a result of committing DML transactions, which can require scan cursors to be moved within the tree. When running with query threads configured (AutomaticThreadConfig set to 1), multiple threads can access the same index fragment tree structure, and the scans of multiple threads can have their cursors present in the same structure.
- The current issue arose due to an assumption in the logic for moving scan cursors when committing DML operations that all scan cursors belonged to the LDM thread owning the index fragment, which did not allow for the possibility that such fragments might belong to query threads
- Partitioning: Some IN() queries on partitioned tables were not always handled correctly
- Partitioning: Queries using the INDEX_MERGE optimizer hint was not handled correctly in all cases
- Replication: XA transactions whose XIDs contained null bytes could not be recovered
- Replication: When binlog_order_commits was set equal to 1, for any two transactions and for any sub-step of the commit phase, the transaction that was written to the binary log first did not always execute the sub-step first, as expected
- Replication: The binary log recovery process did not report all possible error states
- Replication: Following CHANGE REPLICATION SOURCE TO SOURCE_CONNECTION_AUTO_FAILOVER=1, failover generated a number of misleading warnings in the log that implied there were problems when in fact conditions were those expected for such a failover. These log messages have been updated accordingly
- Replication: When a transaction failed, as a side effect, extraneous error messages relating the replication data repositories were written to the log. Now in such cases, we suppress such error messages, which are not directly related to the issue of the failed transaction or its cause
- Replication: Setting binlog_order_commits to OFF could lead to a missed GTID in the next binary log file's Previous_gtids event.
- Our thanks to Yewei Xu and the Tencent team for the contribution
- Replication: Corrected the SQL statements suggested in the error message text for ER_RPL_REPLICA_ERROR_RUNNING_QUERY.
- Our thanks to Dan McCombs for the contribution
- Replication: A hash scan builds a hash of changes, scans the target table or index, and applies any matching change for the current entry. In the build phase, it uses only the before image, and skips any after image. Problems arose in some cases because generated columns were computed for the (skipped) after image, leading to replication errors. This is fixed by not computing generated columns any longer for seek-only calls such as hash scans.
- Our thanks to dc huang for the contribution
- Replication: In certain rare cases, it was possible to set gtid_mode=OFF for one session while another session, after WAIT_FOR_EXECUTED_GTID_SET() was issued by a user in this second session, was still waiting for the next GTID set from the first session. This could result in the second session waiting indefinitely for the function to return
- Group Replication: Accessing the Performance Schema replication_group_communication_information and replication_group_member_stats tables in parallel sometimes caused subsequent group replication operations to hang
- Group Replication: In certain cases, the group replication secondary node unexpectedly shut down while purging the relay log
- Group Replication: When shutting down the Group Replication plugin, the order in which the associated events were reported the error log sometimes led to confusion. To remove any doubts, we now make sure that Plugin group_replication reported: 'Plugin 'group_replication' has been stopped. is in fact the last log message relating to the shutdown, written only when all other events associated with shutting down the plugin have been logged
- Microsoft Windows: The authentication_fido_client plugin stopped responding during the authentication process if it was unable to find a FIDO device on the Windows client host
- In certain cases, CONVERT(utf8mb3_column USING UTF16) was rejected with the error Cannot convert string 'x--...' from binary to utf16
- When joining two tables on a string column, and the column from one of the tables has an additional predicate comparing it with a temporal literal, constant propagation in some cases incorrectly caused the join condition to be modified such that it used temporal rather than string semantics when comparing the strings. This caused incorrect results to be returned from the join
- Error messages returned after calling the mysql_reset_connection() C API function in a prepared statement did not identify the function name properly
- Fixed a regression in a previous fix for an issue with windowing functions.
- Our thanks to Dmitry Lenev for the contribution
- When replacing subqueries in transforms, the internal flag showing whether a given query block contains any subqueries (PROP_SUBQUERY) was not updated afterwards
- A client setting the character set to an impermissible client character set (ucs2, utf16, utf16le, or utf32) could cause unexpected behavior when the client used an authentication plugin
- EXPLAIN ANALYZE displayed 0 when the average number of rows was less than 1. To fix this, we now format numbers in the output of EXPLAIN ANALYZE and EXPLAIN FORMAT=TREE such that numbers in the range 0.001-999999.5 are printed as decimal numbers, and numbers outside this range are printed using engineering notation (for example: 1.23e+9, 934e-6). In addition, trailing zeroes are no longer printed, and numbers less than 1e-12 are printed as 0.
- This helps ensure consistent precision regardless of the number's value and improve readability, while producing minimal rounding errors
- The NTILE() function did not work correctly in all cases
- Some joins on views did not perform correctly
- Transforming a correlated scalar subquery to a derived table led to a wrong result for InnoDB tables when the subquery included duplicate predicates.
- Fixed an assert in sql/item_strfunc.cc that could potentially lead to issues with the SPACE() function
- Using ROW_COUNT() as the length argument to LPAD() or RPAD() did not perform as expected
- A query with a window function having an expression with a CASE function in its ORDER BY clause could lead to a server exit
- The fix for a previous issue introduced an assertion in debug builds when optimizing a HAVING clause
- When using mysqld_multi, the system that obscures "--password" usage as "--password=*****" would also match "--password-history" and "--password-require-current" definitions as "--password", but now explicitly checks for "--password=" instead
- In some cases, calling the mysql_bind_param() C API function could cause the server to become unresponsive
- The authentication_oci_client plugin was unable to open a valid configuration file if any of its entries contained an equals sign character separated by spaces (for example, key_file = /home/user/.oci/oci_api_key.pem). Now, both 'key=value' and 'key = value' entry formats are supported
- Incorrect results were returned when the result of an INTERSECT or EXCEPT operation was joined with another table. This issue affected these operations in such cases when used with either DISTINCT or ALL
- When preparing a view query, the operation used the system character set (instead of the character set stored in data dictionary) and then reported an invalid character-string error
- Prepared statements that operate on derived tables, including views, could stop unexpectedly due to problems with the code for reopening tables after an error
- Removed an assertion raised in certain cases by the RANDOM_BYTES() function in debug builds
- There was an issue in how persisted variables were set on startup, causing certain variables not to get properly set to their persisted value
- The MAKETIME() function did not perform correctly in all cases
- Some functions with multiple arguments did not produce the expected results
- A table reference in an ORDER BY outside the parenthesized query block in which the table was used, and which query block had no LIMIT or ORDER BY of its own, raised an error
- A left join with an impossible condition as part of an ON clause was not optimized as in MySQL 5.7, so that in MySQL 8.0, the query executed more quickly without the impossible condition than with it. An example of such a query, impossible condition included, is SELECT * FROM t1 JOIN t2 ON t1.c1=t2.c1 AND 1=2
- When a user defined function was part of a derived table that was merged into the outer query block, or was part of a subquery converted to a semi-join, knowledge of whether this UDF was deterministic (or not) was lost during processing
- With JSON logging enabled and an event subclass specified in the audit log filter definition, an empty item ("" : { }) was appended to the end of the logged event
- Some subqueries did not execute properly
- After the asymmetric_encrypt() component function in a SELECT query encountered a NULL field to decrypt, it could return NULL values for other non-NULL encrypted fields
- The server did not always shut down cleanly after uninstalling the audit log plugin
- Certain antijoins were not handled correctly by the server
- When the MySQL 5.7 Optimizer has 2 choices for an index to filter rows, one primary and one secondary, it picks a range scan on the secondary index because the range scan uses more key parts. MySQL 8.0 did not use this logic, instead choosing the primary index to filter rows with WHERE clause filtering. Primary key use is not suitable in such cases due to the presence of LIMIT, and due to the nature of data distribution. The secondary index was not considered while resolving order by due to constant elimination. This resulted in much different query plans in MySQL 5.7 and MySQL 8.0 for the same query.
- We solve this issue in MySQL 8.0 by skipping the constant key parts of the index during order-by evaluation only if the query is constant-optimized, which can be done at this time, but not during LIMIT analysis
- The MySQL data dictionary caches failed lookups of se_private_id values (IDs which are not found), which speeds up execution of code specific to InnoDB, relying on the fact that InnoDB does not reuse these IDs. This assumption does not necessarily hold for other storage engines, most notably NDB, where this problem was resolved previously by not using this cache.
- We extend the previous fix made for NDB so that the cache lookup is now employed only when the table uses the InnoDB storage engine
- Unexpected results were seen in some queries using DENSE_RANK(), possibly with the addition of WITH ROLLUP
- Fixed an assert raised in sql/sql_tmp_table.cc following work done previously to reimplement ROLLUP processing
- Some CTEs that did not use any tables were not always handled correctly
- Accessing rows from a window frame of a window function call present only in the query's ORDER BY list raised an error
- PERCENT_RANK() used with ORDER BY column did not return the correct result
- The --exclude-tables and --include-tables mysqlpump options did not handle views
- Changed the MySQL systemd service unit configuration from After=network-online.target to Wants=network-online.target to ensure that all configured network devices are available and have an IP address assigned before the service is started
- AVG(...) OVER (ROWS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING) did not return the correct result
- A query of the form SELECT 1 FROM t1 WHERE NOT EXISTS (VALUES ROW(1), ROW(2)) caused an assert in debug builds when the subquery_to_derived optimizer switch was enabled
- mysqlimport did not escape reserved word table names when used with the --delete option
- When cloning a condition to push down to a derived table, characters in strings representing conditions were converted to utfmb4 correctly only for values less than 128 (the ASCII subset), and code points outside the ASCII subset were converted to invalid characters, causing the resulting character strings to become invalid. For derived tables without UNION, this led to problems when a column name from the derived table used characters outside the ASCII subset, and was used in the WHERE condition. For derived tables with UNION, it created problems when a character outside the ASCII subset was present in a WHERE condition.
- We fix these issues by initializing the string used for representing the condition in such cases to the connection character set
- Using --single-transaction with mysqldump version 8.0.32 required either the RELOAD or FLUSH_TABLES privilege. This requirement now applies only when both gtid_mode=ON (default OFF) and with --set-gtid-purged = ON|AUTO (default AUTO)
- Many joins using eq_ref access did not perform as well as in previous versions. This issue was first reported in MySQL 8.0.29
- Fixed a number of issues present in the internal documentation for the scramble generator algorithm in sha256_scramble_generator.cc and sha2_password_common.cc.
- Our thanks to Niklas Keller for the contribution
- CREATE USER IF NOT EXISTS added a password history entry even when the user already existed and the password was not updated. This caused a subsequent ALTER USER statement to be rejected
- A hash outer join sometimes incorrectly matched NULL with a decimal zero or an empty string that used a non-padding collation, leading to erroneous results
- An object used internally by ALTER INSTANCE RELOAD TLS was not freed until the number of readers reached 0, under the assumption is that the number of readers should reach 0 fairly frequently. The read lock held during an SSL handshake is generally an expensive operation, with network calls, so when roundtrips between the client and the server took excessively long, the lock was held for a relatively long amount of time. This meant that, when changing the value of this object and there were a sufficient number of incoming SSL connections being made, the number of readers might not reach 0 in a reasonable length of time, leaving the thread holding the lock using 100% of the CPU until the lock was released.
- We fix this by adding a wait after setting the pointer to this object to a new value, but before releasing the old object.
- Our thanks to Sinisa Milivojevic for the contribution
- If mysqldump or mysqlpump could not convert a field's default value to UTF-8 (for instance, if the field was of type BINARY and the default value did not coincide with valid UTF-8), the operation produced results that were not valid to import. Further, using the --hex-blob option did not resolve the issue. We now convert the default value to the system character set. If this fails, the server sends the value as hexadecimal instead to make it more human-readable
- A connection using the C API (libmysqlclient) client library could fail with the FUTURE crypto policy
- While cloning a temporary table for a common table expression which used shared materialization, the cloned temp table was not marked as using hash deduplication, leading to wrong results. We now set the hash field for the cloned temporary table correctly, and update the hidden field count to take this into account
- CREATE EVENT and ALTER EVENT assumed that all values passed to them (other than in a DO clause) resolved as scalars without actually checking the values. This led to assertions when any such values actually rows.
- We now perform an explicit check for the number of columns when resolving such items, and report an error when one produces a row and not a scalar value
- A view reference whose underlying field is a constant is not marked as constant when the reference is part of an inner table of an outer join. It was found that, when pushing a condition down to a derived table, the reference was stripped off and only the underlying field was cloned, which made it a constant, and led to wrong results.
- To fix this problem, we ensure that we do not push such a condition down to the derived table by adding a check to see first whether the table used by the condition matches the derived table or is a constant expression; only when it is one or the other of these do we actually push the condition down

更新時間：2023-04-19
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更新時間：2023-04-19
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What's new in this version:

- New: added dark theme support. It will be used when the Windows has the dark theme enabled). There's an option under Settings/UI to enable/disable it.
- New: added option to specify the covers format (under Program Settings/Metadata)

更新時間：2023-04-19
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更新時間：2023-04-14
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