MySQL 8.0 Release Notes  /  Changes in MySQL 8.0.1 (Not yet released, Development Milestone)

Changes in MySQL 8.0.1 (Not yet released, Development Milestone)

Note

This is a milestone release, for use at your own risk. Significant development changes take place in milestone releases and you may encounter compatibility issues, such as data format changes that require attention in addition to the usual procedure of running mysql_upgrade. For example, you may find it necessary to dump your data with mysqldump before the upgrade and reload it afterward.

Note

This release makes several important changes in Unicode character set support. In particular, the default character set has changed from latin1 to utf8mb4.

C API Notes

  • The C API implemented by libmysqlclient now includes a client interface for reading a stream of replication events from a MySQL server binary log. For more information, see C API Binary Log Interface

Character Set Support

  • Incompatible Change: Performance of UCA 9.0.0-based collations (for example, utf8mb4_0900_ai_ci) was improved. These collations are now faster than any other UCA collations. One consequence of this work is an exception to the normal DUCET sorting rules: For performance reasons, collations based on UCA 9.0.0 sort space characters lower than any other character. The main impact is that space now sorts before some whitespace characters that per DUCET it sorts after.

    Tables that used UCA 9.0.0 collations in MySQL 8.0.0 must be reindexed after an upgrade. Either drop and re-add affected indexes, or dump and reload affected tables. (Bug #24823885, Bug #83319)

  • Important Change: The default character set has changed from latin1 to utf8mb4.

  • The default collation for the utf8mb4 character set has changed from utf8mb4_general_ci to utf8mb4_0900_ai_ci. (utf8mb4_general_ci does not handle characters outside the Basic Multilingual Plane (BMP) correctly.) (Bug #24742157)

  • Complementing earlier work in MySQL 8.0.0 to add case-insensitive and accent-insensitive collations for the utf8mb4 Unicode character set, new case-sensitive and accent-sensitive collations have been added. The general collation is named utf8mb4_0900_as_cs, and there are language-specific collations with characteristics similar to utf8mb4_0900_as_cs except that language-specific rules take precedence where applicable. The language-specific collations are indicated by ISO 639-1 language codes in the collation name, as shown in the following table. In two cases the language code has an additional item that denotes a variant (German phone book order, Traditional Spanish).

    Note

    utf8mb4_ja_0900_as_cs is the first Japanese language-specific collation available for Unicode in MySQL.

    Table 1 utf8mb4 UCA 9.0.0 Language-Specific Collations

    Language Collation
    Croatian utf8mb4_hr_0900_as_cs
    Czech utf8mb4_cs_0900_as_cs
    Danish utf8mb4_da_0900_as_cs
    Esperanto utf8mb4_eo_0900_as_cs
    Estonian utf8mb4_et_0900_as_cs
    German phone book order utf8mb4_de_pb_0900_as_cs
    Hungarian utf8mb4_hu_0900_as_cs
    Icelandic utf8mb4_is_0900_as_cs
    Japanese utf8mb4_ja_0900_as_cs
    Latvian utf8mb4_lv_0900_as_cs
    Lithuanian utf8mb4_lt_0900_as_cs
    Polish utf8mb4_pl_0900_as_cs
    Classical Latin utf8mb4_la_0900_as_cs
    Romanian utf8mb4_ro_0900_as_cs
    Slovak utf8mb4_sk_0900_as_cs
    Slovenian utf8mb4_sl_0900_as_cs
    Modern Spanish utf8mb4_es_0900_as_cs
    Traditional Spanish utf8mb4_es_trad_0900_as_cs
    Swedish utf8mb4_sv_0900_as_cs
    Turkish utf8mb4_tr_0900_as_cs
    Vietnamese utf8mb4_vi_0900_as_cs

    utf8mb4_0900_as_cs also works as an accent-sensitive, case-sensitive collation for the languages in the following table.

    Table 2 Languages for Which utf8mb4_0900_as_cs is Suitable

    Language Name Language Code
    German (dictionary order) de
    English en
    French (locale fr_FR) fr
    Irish Gaelic ga
    Indonesian id
    Italian it
    Luxembourgian lb
    Malay ms
    Dutch nl
    Portuguese pt
    Swahili sw
    Zulu zu

    utf8mb4_0900_as_cs is suitable for French French (locale fr_FR) but not for Canadian French (locale fr_CA). For Canadian French, utf8mb4_0900_ai_ci is suitable. The reason for the difference between ai_ci and as_cs collations is that Canadian French has a different order of accented characters than French French.

    utf8mb4_da_0900_as_cs also works as an accent-sensitive, case-sensitive collation for the languages in the following table.

    Table 3 Languages for Which utf8mb4_da_0900_as_cs is Suitable

    Language Name Language Code
    Norwegian no
    Norwegian Bokmål nb
    Norwegian Nynorsk nn

    The nonlanguage-specific utf8mb4_0900_as_cs and language-specific utf8mb4_LANG_0900_as_cs Unicode collations each have these characteristics:

    • The collation is based on Unicode Collation Algorithm (UCA) 9.0.0 and Common Locale Data Repository (CLDR) v30, is accent sensitive, and case sensitive. These characteristics are indicated by _0900, _as, and _cs in the collation name. Exception: utf8mb4_la_0900_as_cs is not based on CLDR because Classical Latin is not defined in CLDR.

    • The collation works for all characters in the range [U+0, U+10FFFF].

    • If the collation is not language specific, it sorts all characters, including supplemental characters, in default order (described following). If the collation is language specific, it sorts characters of the language correctly according to language-specific rules, and characters not in the language in default order.

    • By default, the collation sorts characters having a code point listed in the DUCET table (Default Unicode Collation Element Table) according to the weight value assigned in the table. The collation sorts characters not having a code point listed in the DUCET table using their implicit weight value, which is constructed according to the UCA.

      The collation sorts on all three DUCET weight levels, including the tertiary level. This compares with accent-insensitive, case-insensitive collations, which sort only on the primary and secondary levels.

    • For non-language-specific collations, characters in contraction sequences are treated as separate characters. For language-specific collations, contractions might change character sorting order.

Compilation Notes

  • Incompatible Change: The mysql.h header file now requires a C++ or C99 compiler to compile.

    The my_bool type is no longer used in MySQL source code. Any third-party code that used this type to represent C boolean variables should use the bool or int C type instead. (Bug #25597667)

  • InnoDB: A LOB page deletion function failed to delete LOB pages. (Bug #24480254)

  • Windows builds now use the default runtime libraries (builds use the /MD flag). (Bug #25611609)

  • CMake support was added for compiling with Developer Studio 12.6. (Bug #25384295)

  • The rapidjson library included in MySQL distributions was upgraded to version 1.1.0. (Bug #24947436)

  • The required version of the Boost library for server builds has been raised to 1.63.0. (Bug #24579061, Bug #82834, Bug #25126144, Bug #83905)

  • For GCC versions higher than 4.4, -fno-expensive-optimizations was replaced with -ffp-contract=off, which has the effect of enabling more optimizations. Thanks to Alexey Kopytov for the patch. (Bug #24571672, Bug #82760)

  • For building MySQL 8.0, the minimum required version of CMake is now 3.2.3 on Windows, 3.4.0 on Solaris, and 2.8.12 otherwise. (Bug #24481181, Bug #82628)

    References: See also: Bug #24687701.

Configuration Notes

  • In source distributions, several utilities previously in the extra directory have been moved to the new utilities directory. (Bug #25416084)

  • Two new CMake options are available for debugging. LINK_RANDOMIZE indicates whether to randomize the order of symbols in the mysqld binary (default OFF), and LINK_RANDOMIZE_SEED specifies a seed value for LINK_RANDOMIZE. (Bug #25336715)

  • MySQL failed to compile if -DENABLE_DEBUG_SYNC=OFF AND -DWITH_DEBUG=ON were both given. The ENABLE_DEBUG_SYNC option has been removed and enabling WITH_DEBUG enables Debug Sync. (Bug #18374703)

  • These changes were made with respect to persisted system variables:

    • A new statement, RESET PERSIST, enables removal of variable settings that were persisted with SET PERSIST to the mysqld-auto.cnf file that stores persisted global system variable settings.

    • Using SET PERSIST (or @@persist.) to set a global variable to DEFAULT or to the variable literal default value previously also added a setting for the variable to the mysqld-auto.cnf file if was is not present, or removed it from mysqld-auto.cnf if it was present. Now the assignment always adds a setting for the variable to the mysqld-auto.cnf file; to remove the setting from the file, use RESET PERSIST.

    • A new Performance Schema table, persisted_variables, provides an SQL interface to the mysqld-auto.cnf file, enabling the file contents to be inspected at runtime using SELECT statements.

    • The Performance Schema variables_info table has new columns showing when and by which user each system variable was most recently set.

    For more information, see Using System Variables, and RESET PERSIST Syntax.

    If you upgrade to this MySQL release from an earlier version, you must run mysql_upgrade (and restart the server) to incorporate these changes into the Performance Schema.

    References: See also: Bug #24522064.

  • The default value of the query_cache_size system variable has been reduced from 1M to 0. Consequently no query cache buffer is allocated by default.

  • The --temp-pool server option has been removed.

Data Dictionary Notes

  • These INFORMATION_SCHEMA tables have been reimplemented as views on data dictionary tables:

    EVENTS
    PARAMETERS
    ROUTINES
    TRIGGERS
    

    Queries on those tables are now more efficient because they obtain information from data dictionary tables rather than by other, slower means. For example, the server no longer must create a temporary table for each query of the INFORMATION_SCHEMA table.

    Improvements for those tables also apply to SHOW statements that display information corresponding to the INFORMATION_SCHEMA tables. For example, SHOW TRIGGERS displays the same information as the TRIGGERS table.

    If you upgrade to this MySQL release from an earlier version, you must run mysql_upgrade (and restart the server) to incorporate these changes.

DTrace Support

  • Support for DTrace has been removed.

Optimizer Notes

  • InnoDB: MySQL now supports descending indexes: DESC in an index definition is no longer ignored but causes storage of key values in descending order. Previously, indexes could be scanned in reverse order but at a performance penalty. A descending index can be scanned in forward order, which is more efficient. Descending indexes also make it possible for the optimizer to use multiple-column indexes when the most efficient scan order mixes ascending order for some columns and descending order for others. For more information, see Descending Indexes.

    Note

    Previously, relying on implicit GROUP BY sorting was deprecated but GROUP BY did sort. GROUP BY no longer sorts by default, so query results may differ from previous MySQL versions. To produce a given sort order, use explicit ASC or DESC designators for GROUP BY columns or provide an ORDER BY clause.

  • Optimizer trace output now includes more information about filesort operations, such as key and payload size and why addon fields are not packed. (Bug #25246184, Bug #84180)

  • Previously, invisible indexes were supported only for the InnoDB storage engine. Invisible indexes are now storage engine neutral (supported for any engine). (Bug #23541244)

  • A GROUPING() function has been introduced for use in GROUP BY queries that include a WITH ROLLUP modifier. This function enables you to distinguish NULL values for super-aggregate rows in the query result from NULL values in regular grouped rows. For more information, see Miscellaneous Functions, and GROUP BY Modifiers. Thanks to Zhe Dong for a patch that was partially used to implement this feature.

    Note

    GROUPING is now a reserved word and cannot be used as an identifier without identifier quoting.

    (Bug #11754449, Bug #46053)

  • The optimizer now supports INDEX_MERGE and NO_INDEX_MERGE hints to affect use of the Index Merge access method. Examples:

    SELECT /*+ INDEX_MERGE(t1 f3, PRIMARY) */ f2 FROM t1
      WHERE f1 = 'o' AND f2 = f3 AND f3 <= 4;
    SELECT /*+ NO_INDEX_MERGE(t1 f2, f3) */ f1 FROM t1
      WHERE (f2 = 5 OR f3 = 'c') AND (f1 = 4 OR f4 = 'f');
    

    For more information, see Index Merge Optimization, and Optimizer Hints.

  • The server_cost and engine_cost optimizer cost model tables in the mysql system database now include a default_value column that contains the default value for each cost table estimate. This column is a read-only generated column that retains its value even if the associated cost estimate is changed. For more information, see The Optimizer Cost Model.

    If you upgrade to this MySQL release from an earlier version, you must run mysql_upgrade (and restart the server) to incorporate these changes into the mysql system database.

  • In the optimizer cost model engine_cost table, the cost for memory access was decreased relative to the cost for disk access. An implication of this change is that the execution plan may change between two runs of the same query. For example, at server startup before data has been read into the buffer pool, you may get a different plan than after the query has been run because then the data will be in memory.

  • MySQL now supports common table expressions, both nonrecursive and recursive. Common table expressions enable use of named temporary result sets, implemented by permitting a WITH clause preceding SELECT statements and certain other statements. For more information, see WITH Syntax (Common Table Expressions).

    Note

    RECURSIVE is now a reserved word and cannot be used as an identifier without identifier quoting.

  • The optimizer now supports hints that enable specifying the order in which to join tables. For more information, see Optimizer Hints.

Packaging Notes

  • Changes in RPM package structure require a larger set of packages to be removed to install MySQL Server cleanly. (Bug #25603087)

  • To avoid potential race conditions, Debian packages now use the GNU install utility rather than a combination of mkdir, touch, and chown. (Bug #25258829)

  • scripts/mysql_security_commands.sql and support-files/mysql.server-sys5.sh are no longer used and have been removed from MySQL distributions. (Bug #24756400, Bug #24756442)

  • RPM packages now are built with -DWITH_NUMA=ON for platforms with NUMA support: OEL higher than EL5, Fedora, SLES, Docker. (Bug #24689078)

  • The my-default.cnf.sh file (used to produce a default my-default.cnf or my-default.ini file) is no longer included in source distributions and my-default.cnf and my-default.ini are no longer included in or installed by distribution packages. (Bug #22525354)

  • The unused and undocumented archive_reader and archive_test utilities have been removed from MySQL source distributions. (Bug #12818207, Bug #62014)

  • Reminder: MySQL 8.0 requires the Microsoft Visual C++ 2015 Redistributable Package to run on Windows platforms. Users should make sure the package has been installed on the system before starting the server. The package is available at the Microsoft Download Center.

Parser Notes

  • The deprecated PROCEDURE ANALYSE() syntax has been removed.

  • The parser no longer considers \N as a synonym for NULL in SQL statements. Use NULL instead.

    This change does not affect text file import or export operations performed with LOAD DATA INFILE or SELECT ... INTO OUTFILE, for which NULL continues to be represented by \N. See LOAD DATA INFILE Syntax.

Performance Schema Notes

  • The Performance Schema maintains statement event summary tables that contain information about minimum, maximum, and average statement latency. Those tables permit high-level assessment of system performance. To permit assessment at a more fine-grained level, the Performance Schema now also collects histogram data for statement latencies. These histograms provide additional insight into latency distributions and are available in these tables:

    For more information, see Statement Histogram Summary Tables.

    In addition, the events_statements_summary_by_digest table now has columns that provide percentile information about statement latencies. For more information, see Statement Summary Tables.

    If you upgrade to this MySQL release from an earlier version, you must run mysql_upgrade (and restart the server) to incorporate these changes into the Performance Schema.

  • System and status variable information is no longer maintained in the INFORMATION_SCHEMA. These tables have been removed: GLOBAL_VARIABLES, SESSION_VARIABLES, GLOBAL_STATUS, SESSION_STATUS. Use the corresponding Performance Schema tables instead. See Performance Schema System Variable Tables, and Performance Schema Status Variable Tables. In addition, the show_compatibility_56 system variable has been removed. It was used in the transition period during which system and status variable information in INFORMATION_SCHEMA tables was moved to Performance Schema tables, and is no longer needed. These status variables have been removed: Slave_heartbeat_period, Slave_last_heartbeat, Slave_received_heartbeats, Slave_retried_transactions, Slave_running. The information they provided is available in Performance Schema tables; see Migrating to Performance Schema System and Status Variable Tables.

  • The deprecated INFORMATION_SCHEMA INNODB_LOCKS and INNODB_LOCK_WAITS tables have been removed. To obtain InnoDB data lock information, use the Performance Schema data_locks and data_lock_waits tables instead. Alternatively, use the sys schema innodb_lock_waits and x$innodb_lock_waits views, which have been reimplemented to use the new Performance Schema tables rather than the removed INFORMATION_SCHEMA tables.

    The Performance Schema tables expose what data locks exist, which transaction holds each lock, and which transaction lock requests are blocked by other locks. For InnoDB, the data_locks table reports all data locks, in contrast to the INNODB_LOCKS table, which reported only waited-for data locks, For more information, see The data_locks Table, and The data_lock_waits Table. For information about mapping old table columns to new table columns, see The INFORMATION_SCHEMA INNODB_LOCKS Table, and The INFORMATION_SCHEMA INNODB_LOCK_WAITS Table.

    The tables differ in the privileges required: The INFORMATION_SCHEMA tables require the global PROCESS privilege. The Performance Schema tables require the usual Performance Schema privilege of SELECT on the table to be selected from.

    The sys schema innodb_lock_waits and x$innodb_lock_waits views can be used without change, with the exception that the locked_table column containing combined schema/table name values has been removed and replaced with locked_table_schema and locked_table_name columns that contain separate schema and table name values. In addition, these views now contain locked_table_partition and locked_table_subpartition columns. For more information, see The innodb_lock_waits and x$innodb_lock_waits Views,

    If you upgrade to this MySQL release from an earlier version, you must run mysql_upgrade (and restart the server) to incorporate these changes into the Performance Schema and the sys schema.

Plugin Service Notes

  • MySQL Server 8.0 includes a component-based infrastructure for improving server extensibility; see Server Components. However, MySQL plugins use an interface that predates the component interface. A new plugin service, plugin_registry_service, enables plugins to access the component registry and its services.

Security Notes

  • Incompatible Change: For STANDALONE and WIN builds, the default secure_file_priv value has changed from the empty string to NULL. This is a secure-by-default setting because it disables import and export operations. To permit those operations, set secure_file_priv to the path name of the directory to use for those operations. (Bug #24679907, Bug #24695274, Bug #24707666)

  • Incompatible Change: These changes were made to mysqld_safe:

    • Unsafe use of rm and chown in mysqld_safe could result in privilege escalation. chown now can be used only when the target directory is /var/log. An incompatible change is that if the directory for the Unix socket file is missing, it is no longer created; instead, an error occurs. Due to these changes, /bin/bash is required to run mysqld_safe on Solaris. /bin/sh is still used on other Unix/Linux platforms.

    • The --ledir option now is accepted only on the command line, not in option files.

    • mysqld_safe ignores the current working directory.

    Other related changes:

    • Initialization scripts that invoke mysqld_safe pass --basedir explicitly.

    • Initialization scripts create the error log file only if the base directory is /var/log or /var/lib.

    • Unused systemd files for SLES were removed.

    (Bug #24483092, Bug #25088048, Bug #25378439, Bug #25378565)

    References: See also: Bug #24464380, Bug #24388753, Bug #24619033, Bug #82920.

  • yaSSL was upgraded to version 2.4.2. This upgrade corrects issues with: Potential AES side channel leaks; DSA padding for unusual sizes; the SSL_CTX_load_verify_locations() OpenSSL compatibility function failing to handle long path directory names. (Bug #24512715, Bug #24740291)

  • MySQL Server now includes a plugin library that enables administrators to introduce an increasing delay in server response to clients after a certain number of consecutive failed connection attempts. This capability provides a deterrent that slows down brute force attacks that attempt to access MySQL user accounts. For more information, see The Connection-Control Plugin.

  • OpenSSL is ending support for version 1.0.1 in December 2016; see https://www.openssl.org/policies/releasestrat.html. Consequently, MySQL Commercial Server builds now use version 1.0.2 rather than version 1.0.1, and the linked OpenSSL library for the MySQL Commercial Server has been updated from version 1.0.1 to version 1.0.2j. For a description of issues fixed in this version, see https://www.openssl.org/news/vulnerabilities.html.

    This change does not affect the Oracle-produced MySQL Community build of MySQL Server, which uses the yaSSL library instead.

Spatial Data Support

SQL Syntax Notes

  • Derived table syntax now permits a list of explicit column names following the table name, to override the default column names taken from the select list. For example, the column names for this derived table come from its select list:

    mysql> SELECT * FROM (SELECT 1, 2, 3, 4) AS dt;
    +---+---+---+---+
    | 1 | 2 | 3 | 4 |
    +---+---+---+---+
    | 1 | 2 | 3 | 4 |
    +---+---+---+---+
    

    To provide column names, follow the derived table name with a parenthesized list of column names:

    mysql> SELECT * FROM (SELECT 1, 2, 3, 4) AS dt (a, b, c, d);
    +---+---+---+---+
    | a | b | c | d |
    +---+---+---+---+
    | 1 | 2 | 3 | 4 |
    +---+---+---+---+
    

Test Suite Notes

  • mysql-test-run.pl now has a --charset-for-testdb=charset_name option for specifying the default character set for the test database. The default value is latin1. (Bug #25494068)

  • mysql-test-run.pl now has an --only-big-tests option, which causes only big tests to run. Normal (non-big) tests are skipped. If both --big-test and --only-big-tests are given, --only-big-tests is ignored. (Bug #25182306)

  • mysql-test-run.pl has a new --discover option. When given, mysql-test-run.pl attempts to preload discover, the Developer Studio Memory Error Discovery Tool when starting mysqld. Reports from discover may be found in log/mysqld.%p.txt under the directory given by --vardir. This option is supported only on SPARC-M7 systems. (Bug #25048971)

  • mysqltest now supports an expr command that enables an expression to be evaluated and assigned to a variable. For details, see the command description in mysqltest Commands. (Bug #24806741)

  • mysqltest now supports a force-cpdir command that copies a source directory to a destination directory recursively (that is, it copies subdirectories). (Bug #24806681)

  • mysql-test-run.pl has a new --summary-report option. When given, mysql-test-run.pl generates a plain text version of the test summary only and writes it to the file named as the option argument. The file is suitable for sending by email. (Bug #24512357, Bug #82708)

  • mysql-test-run.pl could not be run with --valgrind-option=--tool=custom_tool, for values of custom_tool such as massif or helgrind, because it added the options for memcheck that might not be understood by other tools. Also, the mysql-test-run.pl --callgrind option did not work because it supplied an invalid --base option to callgrind. Thanks to Daniel Black for the patch on which the fixes were based. (Bug #23713613, Bug #82039)

  • The mysqltest connect() function now permits SOCKET and TCP values for the options argument, to specify using the socket-file and TCP/IP connection protocols.

    In addition, connection protocols now must match the current system. Previously, passing PIPE or SHM on non-Windows systems caused the default (socket-file) connection protocol to be used. Now this causes an error, and, similarly, passing SOCKET on Windows systems causes an error. (Bug #21046241)

  • mysql-test-run.pl now supports a --bootstrap option that enables mysqld options to be designated as bootstrap options. When mysql-test-run.pl finds --bootstrap options in a master.opt file, it removes and reinitializes the data directory and restarts the server with the new option settings. (Bug #18184868)

X Plugin Notes

  • Connections were released which were not initialized when validation occurred. (Bug #25392280)

  • The manual definition of the MYSQL_DYNAMIC_PLUGIN macro was redundant. (Bug #25162590, Bug #83988)

  • IPv6 connectivity support defined a new system variable Mysqlx-bind-address with the default value of '0.0.0.0', but the default value should have been '*' so that connections to X Plugin may be made using an IPv6 address, an IPv4 address, or a hostname. (Bug #25047909, Bug #83688)

  • The stmt field was marked as required in the message:

            
    message Mysqlx.Crud.ModifyView {
       required Collection collection = 1;
    
       optional string definer = 2;
       optional ViewAlgorithm algorithm = 3;
       optional ViewSqlSecurity security = 4;
       optional ViewCheckOption check = 5;
    
       repeated string column = 6;
       required Mysqlx.Crud.Find stmt = 7;
    }
    

    (Bug #24968735, Bug #83595)

  • For a table created with CREATE TABLE foo (doc JSON), the statement list_objects incorrectly reported the table as a collection. (Bug #24963952)

  • Sending Expect.Open to a connected socket before authentication led to the following error messages:

            
    ... Plugin mysqlx reported: '10: Invalid message 24 received during client initialization'
    ... Plugin mysqlx reported: '10: ERROR reading from socket Bad file descriptor (9) 2'
    

    (Bug #24940144, Bug #83494)

  • Boost classes with corresponding functionality in C++ 11 were moved or wrapped. (Bug #24680856)

  • When two X Plugin instances were started on the same port, the resulting error message was split over two lines and contained duplicate information. (Bug #24679018, Bug #83008)

  • The performance_schema.threads table did not show processlist statistics for the X Plugin. (Bug #24638038)

  • If the client sent an unknown message type to the server, the server would send back an error message and then disconnect the client. (Bug #24611754, Bug #82868)

  • When the client sent a zero length message, the X Plugin did not send a response. For a subsequent message the client received an error E_X_BAD_MESSAGE and was disconnected, depending on the header content. (Bug #24595459, Bug #82862)

  • X Plugin displayed its version to any connected user, including those not authenticated. (Bug #24562707, Bug #82784)

  • X Plugin generated an incorrect query when a duplicate field name existed in an Update statement. (Bug #24510083)

  • The statement list_objects returned incorrect information for some views in sys database. (Bug #24472325)

  • X Plugin was trying to send result sets to a client, even where the connection had been closed. The plugin now stops execution of a stored procedure if the connection is reset. (Bug #24440344)

  • Attempting to list objects using the list_objects statement without explicitly setting the database name resulted in the collection being incorrectly classified as a table. (Bug #23205895, Bug #81248)

Functionality Added or Changed

  • InnoDB: By default, InnoDB reads uncommitted data when calculating statistics. In the case of an uncommitted transaction that deletes rows from a table, InnoDB excludes records that are delete-marked when calculating row estimates and index statistics, which can lead to non-optimal execution plans for other transactions that are operating on the table concurrently using a transaction isolation level other than READ UNCOMMITTED. To avoid this scenario, a new configuration option, innodb_stats_include_delete_marked, can be enabled to ensure that InnoDB includes delete-marked records when calculating persistent optimizer statistics. (Bug #23333990)

  • InnoDB: Geometry parsing and bounding box computational code for r-trees was moved from InnoDB to the server.

  • InnoDB: InnoDB now supports NOWAIT and SKIP LOCKED options with SELECT ... FOR SHARE and SELECT ... FOR UPDATE locking read statements. NOWAIT causes the statement to return immediately if a requested row is locked by another transaction. SKIP LOCKED removes locked rows from the result set. See Locking Read Concurrency with NOWAIT and SKIP LOCKED.

    SELECT ... FOR SHARE replaces SELECT ... LOCK IN SHARE MODE, but LOCK IN SHARE MODE remains available for backward compatibility. The statements are equivalent. However, FOR SHARE supports NOWAIT, SKIP LOCKED, and OF tbl_name options. See SELECT Syntax.

    OF tbl_name applies locking queries to named tables.

    Note

    OF is now a reserved word and cannot be used as an identifier without identifier quoting.

  • InnoDB: The InnoDB tablespace encryption feature now supports encryption of redo log and undo log data, controlled by the innodb_redo_log_encrypt and innodb_undo_log_encrypt configuration options. See Redo Log Data Encryption, and Undo Log Data Encryption.

  • InnoDB: InnoDB internal temporary tables that are stored on disk now support multiple cursor positions, permitting single writer and multiple reader access within the same thread. The purpose of this enhancement is to provide support for recursive and non-recursive common table expressions (CTEs).

    Additionally, consistent-read access to InnoDB on-disk internal temporary tables is replaced by a dirty-read scheme, and row counts for InnoDB on-disk internal temporary tables now use row count statistics instead of slower table scans.

  • InnoDB: InnoDB now compresses large objects into a sequence of smaller zlib streams for tables that use ROW_FORMAT=COMPRESSED. Previously, large object data was compressed into a single zlib stream.

  • JSON: Added the JSON utility function JSON_PRETTY(), which prints an existing JSON value, or any string that can successfully be parsed as a JSON document, in a format that can be easily read by humans. Each JSON object member or array value is displayed on a separate line of the output; each child object or array is intended 2 spaces with respect to its parent.

    Examples:

    mysql> SELECT JSON_PRETTY('123');
    +--------------------+
    | JSON_PRETTY('123') |
    +--------------------+
    | 123                |
    +--------------------+
    
    mysql> SELECT JSON_PRETTY("[1,3,5]");
    +------------------------+
    | JSON_PRETTY("[1,3,5]") |
    +------------------------+
    | [
      1,
      3,
      5
    ]      |
    +------------------------+
    
    mysql> SELECT JSON_PRETTY('{"a":"10","b":"15","x":"25"}');
    +---------------------------------------------+
    | JSON_PRETTY('{"a":"10","b":"15","x":"25"}') |
    +---------------------------------------------+
    | {
      "a": "10",
      "b": "15",
      "x": "25"
    }   |
    +---------------------------------------------+
    
  • JSON: Previously, when sorting JSON values in a query using ORDER BY, each value was represented by a part having a fixed length in the sort key, each such part requiring 1K of memory. In many cases this usage was excessive—for example, an integer scalar value requires only a relatively very few bytes, so that the remainder of the 1K (90% or more) was taken up by padding.

    Variable length parts for JSON sort keys have been introduced to address this issue, with each key part now taking up only the space that is needed to store the value. This has the following benefits for performance:

    • Because sort buffer space is used more effectively, filesorts need not flush to disk as early or often, which means that more data can be sorted in memory.

    • Shorter keys can be compared more quickly than longer ones, providing a noticeable improvement in performance for in-memory sorts as well as sorts requiring disk usage.

  • The WEIGHT_STRING() debugging function no longer supports the LEVEL clause. (Bug #25469683)

  • For Developer Studio 12.5, 32-bit builds are now disabled unless the FORCE_UNSUPPORTED_COMPILER option is given. (Bug #25267157, Bug #84230)

  • Several foreign key constraint checks that were storage engine agnostic were being done inside InnoDB. These are now done at the SQL layer. (Bug #25252847)

  • Some GIS out-of-bounds checking was simplified. Thanks to Daniel Black for the contribution. (Bug #25202470, Bug #84062)

  • The set of compiler flags used for Developer Studio 12.5 was improved. (Bug #25148549, Bug #83955)

  • CMake now uses CMAKE_POLICY of CMP0022 NEW rather than CMP0022 OLD. (Bug #25090147, Bug #83804)

  • If MySQL was configured to build with the -Wno-error option, mysql_config produced incorrect output for its --cflags option.

    The set of compiler options that mysql_config and pkg-config produce now is determined by whitelisting rather than blacklisting. (Bug #25040566, Bug #22898475, Bug #80662)

  • The performance of UTF-8 binary collations was improved. (Bug #24788778, Bug #83247, Bug #25076862)

  • The systemd service file for mysqld now includes a Documentation value in the [Unit] section to provide a link to the systemd documentation in the MySQL Reference Manual. (Bug #24735762)

  • Unit testing now uses Google Mock 1.8. (Bug #24572381, Bug #82823)

  • The unimplemented and nonstandard WITH CUBE clause for GROUP BY is no longer supported.

    Note

    CUBE is now a reserved word and cannot be used as an identifier without identifier quoting.

    (Bug #24572048, Bug #82821)

  • These outdated build scripts were removed from MySQL source distributions: BUILD/SETUP.sh, BUILD/autorun.sh, BUILD/cmake_configure.sh, BUILD/compile-dist, and cmake/configure.pl. (Bug #24512933)

  • Consistency and maintainability of Debian/Ubuntu packaging maintainer scripts was improved. (Bug #23588977)

  • In-place ALTER TABLE operations are now possible for column modifications of tables containing generated columns that depend on columns with a DEFAULT value if the modified columns are not involved in the generated column expressions. For example, changing the NULL property of a separate column can be done in place without a table rebuild. (Bug #22987899, Bug #80832)

  • For dumps of the mysql system database, mysqldump no longer generates DDL statements for the innodb_index_stats and innodb_table_stats tables. Such statements fail at dump reload time because those tables are not user accessible. (Bug #22655287)

  • If mysqld is invoked with --daemonize, stdout and stderr are redirected to /dev/null if connected to a terminal type device, so that mysqld can behave as a true daemon. (Bug #21627629)

  • mysql_secure_installation is more strict about what it considers valid yes and no responses. (Bug #13344753, Bug #62925)

  • MySQL client and utility programs reported their own program-specific version number when invoked with the --version option, and the version strings did not follow a consistent format. Now these programs print the MySQL version number (same as mysqld) in a consistent format. (Bug #11763201, Bug #55885)

  • A new mysqldump option, --network-timeout, enables large tables to be dumped by setting max_allowed_packet to its maximum value and network read and write timeouts to a large value. This option is enabled by default. To disable it, use --skip-network-timeout. (Bug #11754493, Bug #46103)

  • Added two JSON aggregation functions JSON_ARRAYAGG() and JSON_OBJECTAGG(). The JSON_ARRAYAGG() function takes a column or column expression as an argument, and aggregates the result set as a single JSON array, as shown here:

    mysql> SELECT col FROM t1;
    +--------------------------------------+
    | col                                  |
    +--------------------------------------+
    | {"key1": "value1", "key2": "value2"} |
    | {"keyA": "valueA", "keyB": "valueB"} |
    +--------------------------------------+
    2 rows in set (0.00 sec)
    
    mysql> SELECT JSON_ARRAYAGG(col) FROM t1;
    +------------------------------------------------------------------------------+
    | JSON_ARRAYAGG(col)                                                           |
    +------------------------------------------------------------------------------+
    | [{"key1": "value1", "key2": "value2"}, {"keyA": "valueA", "keyB": "valueB"}] |
    +------------------------------------------------------------------------------+
    1 row in set (0.00 sec)
    

    The order of the array elements is unspecified.

    JSON_OBJECTAGG() takes two columns or expressions which it interprets as a key and a value, respectively; it returns the result as a single JSON object, as shown here:

    mysql> SELECT id, col FROM t1;
    +------+--------------------------------------+
    | id   | col                                  |
    +------+--------------------------------------+
    |    1 | {"key1": "value1", "key2": "value2"} |
    |    2 | {"keyA": "valueA", "keyB": "valueB"} |
    +------+--------------------------------------+
    2 rows in set (0.00 sec)
    
    mysql> SELECT JSON_OBJECTAGG(id, col) FROM t1;
    +----------------------------------------------------------------------------------------+
    | JSON_OBJECTAGG(id, col)                                                                |
    +----------------------------------------------------------------------------------------+
    | {"1": {"key1": "value1", "key2": "value2"}, "2": {"keyA": "valueA", "keyB": "valueB"}} |
    +----------------------------------------------------------------------------------------+
    1 row in set (0.00 sec)
    

    A NULL key causes an error; duplicate keys are ignored.

    For more information, see Aggregate (GROUP BY) Functions. (Bug #78117, Bug #21647417)

  • The deprecated libmysqld embedded server library has been removed, along with:

    • The mysql_config --libmysqld-libs, --embedded-libs, and --embedded options

    • The CMake WITH_EMBEDDED_SERVER, WITH_EMBEDDED_SHARED_LIBRARY, and INSTALL_SECURE_FILE_PRIV_EMBEDDEDDIR options

    • The (undocumented) mysql --server-arg option

    • The mysqltest --embedded-server, --server-arg, and --server-file options

    • The mysqltest_embedded and mysql_client_test_embedded test programs

  • The deprecated replace utility has been removed. If you wish to continue using this utility, be sure to retain a copy from an installed version of MySQL before upgrading to the current version.

  • The removal of the mysql_shutdown() C API function in MySQL 8.0.0 has been reverted. It is still to be removed in a future MySQL release, but that removal has been deferred.

  • Work was done to clean up the source code base, including: Removal of unneeded CMake checks; removing unused macros from source files; reorganizing header files to reduce the number of dependencies and make them more modular, removal of function declarations without definitions.

Bugs Fixed

  • Incompatible Change: The stored definition of a view for which an explicit column name list was provided could be invalid. For example, for this statement:

    CREATE VIEW v1 (name2) AS SELECT 1 AS name1 UNION SELECT 2 ORDER BY name1;
    

    The stored definition looked like this, which is invalid:

    CREATE VIEW v1 AS SELECT 1 AS name2 UNION SELECT 2 AS 2 ORDER BY name1;
    

    Now column names within the stored definition are not replaced by the column name list:

    CREATE VIEW v1 (name2) AS SELECT 1 AS name1 UNION SELECT 2 AS 2 ORDER BY name1;
    

    An incompatibility resulting from this change is that the CREATE VIEW statement can no longer be recreated solely from the INFORMATION_SCHEMA VIEWS table, because the VIEW_DEFINITION value does not show the column name list. Instead, you must also consult the COLUMNS table to get the column name list. Alternatively (and more simply), use SHOW CREATE VIEW. (Bug #23265335, Bug #81377)

  • InnoDB: In debug builds, a call that initialized latch debugging raised an assertion due to a race condition. (Bug #25700405)

  • InnoDB: InnoDB did not set the compression algorithm when opening a partitioned table. (Bug #25685868)

  • InnoDB: The restriction that required the first undo tablespace to use space ID 1 was removed. The first undo tablespace may now be assigned a space ID other than 1. Space ID values for undo tablespaces are still assigned in a consecutive sequence. (Bug #25551311)

  • InnoDB: A DROP TABLE operation raised an assertion on a server with an innodb_force_recovery setting of 5 or 6. DROP TABLE is no longer permitted with these innodb_force_recovery settings. (Bug #25385590)

    References: This issue is a regression of: Bug #19779113.

  • InnoDB: Compiling the server without the Performance Schema caused a build failure. (Bug #25348787)

  • InnoDB: During read-ahead, the wrong page size was used to calculate the tablespace size. (Bug #25330449)

  • InnoDB: Compiling on Fedora 25 using DWITH_LZ4=system resulted in a build failure due to a deprecated LZ4_COMPRESS_LIMITEDOUTPUT function. (Bug #25297593)

  • InnoDB: Disabling macros such as UNIV_PFS_MUTEX, UNIV_PFS_RWLOCK, and UNIV_PFS_THREAD caused compilation errors. (Bug #25251082)

  • InnoDB: A NULL virtual column field name in a virtual index caused a server exit during a field name comparison that occurs while populating virtual columns affected by a foreign key constraint. (Bug #25222337)

  • InnoDB: The file handle type name for InnoDB file I/O Performance Schema instrumentation was changed from os_pfs_file_t to pfs_os_file_t. (Bug #25220118)

  • InnoDB: Transactions with subqueries on INFORMATION_SCHEMA tables could block concurrent DDL operations. (Bug #25200952)

  • InnoDB: During a range comparison, a secondary index field number was passed instead of clustered index field number, eventually causing the retrieval of an incorrect field. (Bug #25175249)

  • InnoDB: A server exit on restart was caused by missing my_thread_init() and my_thread_exit() functions for background threads that initialize the st_my_thread_var structure. (Bug #25167032)

  • InnoDB: A memcached read operation with a non-default read batch size configuration resulted in a server exit. (Bug #25147515)

  • InnoDB: The INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS table reported NULL for a foreign key constraint name (UNIQUE_CONSTRAINT_NAME) after restarting the server. (Bug #25126722)

  • InnoDB: A gap lock was taken unnecessarily during foreign key validation while using the READ COMMITTED isolation level. (Bug #25082593)

  • InnoDB: Loading InnoDB tables required more memory in MySQL 5.7 due primarily to the addition of in-memory structure members introduced with temporary table optimizations. The in-memory structure members, only used for temporary tables, are now only allocated as needed. (Bug #25080442)

  • InnoDB: After a TRUNCATE TABLE operation on a table with a FULLTEXT index, space size was incorrectly calculated resulting in an invalid read. (Bug #25053705)

  • InnoDB: A prepared XA transaction was rolled back by a high priority transaction. The high priority transaction should wait if the blocking transaction is in a prepared state. (Bug #25032066)

  • InnoDB: InnoDB passed an invalid argument to syscall(SYS_futex). (Bug #24923840, Bug #83375)

  • InnoDB: After redo log recovery, the node size of an undo tablespace object could sporadically be zero, eventually causing an error. Additionally, the undo tablespace object was incorrectly placed on the LRU list, and the header page of the undo tablespace could be present the buffer cache when the tablespace object is freed, causing a file-open failure on the first page read. (Bug #24916359)

  • InnoDB: During a checkpoint, all MLOG_FILE_NAME redo log records were written in a single mini-transaction (mtr), causing a log parsing buffer overflow. (Bug #24793413, Bug #83245)

  • InnoDB: On a MySQL 64-bit build on Windows, a file I/O retry result was misinterpreted due to a missing cast necessary for the correct operation of the retry path, resulting in a failing assertion and operating system error. (Bug #24711351)

  • InnoDB: The GCC mach_parse_compressed function should load one to five bytes depending on the value of the first byte. Due to a GCC bug, GCC 5 and 6 emit code to load four bytes before the first byte value is checked (GCC Bug #77673). A workaround prevents this behavior. Thanks to Laurynas Biveinis for the patch. (Bug #24707869, Bug #83073)

  • InnoDB: Code related to tablespace type functions was improved to address issues with naming consistency, function distribution, and function usage. (Bug #24706739, Bug #83092)

  • InnoDB: A mechanism was added to debug builds to ensure that keys for InnoDB Performance Schema instrumentation are registered with Performance Schema. The mechanism causes startup to fail on debug builds if the number of Performance Schema keys does not match the number of registered Performance Schema keys. (Bug #24686908)

  • InnoDB: A race condition while updating table statistics could result in an estimated row count of 1 and an incorrect query execution plan. (Bug #24666839, Bug #82968)

  • InnoDB: Due to a glibc bug, short-lived detached threads could exit before the caller had returned from pthread_create(), causing a server exit. Thanks to Laurynas Biveinis for the patch. (Bug #24605956, Bug #82886)

  • InnoDB: An error in code related to table statistics raised an assertion in the dict0stats.cc source file. (Bug #24585978)

  • InnoDB: The list of module base names representing modules in the InnoDB code base that allocate memory using ut_malloc or ut_new was incomplete. The list is used by the Performance Schema for reporting of InnoDB memory allocation event data. (Bug #24571816)

  • InnoDB: Some InnoDB rw-lock and mutex keys were not registered for use with the Performance Schema. (Bug #24571597)

  • InnoDB: After increasing the value of innodb_undo_logs and restarting the server, the number of active undo tablespaces was not increased when assigning undo tablespaces to newly allocated rollback segments. (Bug #24488141)

  • InnoDB: The unused MLOG_UNDO_HDR_DISCARD redo log record type and related functions were removed. (Bug #24482001)

  • InnoDB: An assertion was raised when the purge thread started due to the server not recognizing a tablespace ID as an undo tablespace ID. (Bug #24479773)

    References: This issue is a regression of: Bug #23517560.

  • InnoDB: InnoDB incorrectly reported an error about missing encryption when restoring pages from the doublewrite buffer during recovery. (Bug #24471076)

  • InnoDB: InnoDB reported an incorrect estimate for the number of pages in the buffer pool for a table. The number of pages was not decremented correctly when pages were removed. (Bug #24464147)

    References: This issue is a regression of: Bug #21747906.

  • InnoDB: The following code changes related to undo tablespace management were implemented:

    • An in-memory array for temporary tablespace rollback segments was added, freeing 32 slots in the TRX_SYS page for use by redo-enabled rollback segments.

    • Code comments related to undo logs and rollback segments were revised.

    • Fixed arrays that list rollback segments and undo tablespaces were replaced by dynamic size arrays.

    • The function that initializes undo tablespaces was refactored.

    • A class was added for managing just-in-time creation of undo and undo file names.

    (Bug #24462978)

  • InnoDB: A cached undo segment was not removed from the rollback segment history during a slow shutdown. (Bug #24450908)

  • InnoDB: An error during a table-rebuilding operation on a table with only a generated clustered index (GEN_CLUST_INDEX) raised and assertion due to an error called with an invalid key name. (Bug #24444831)

  • InnoDB: MySQL did not build with GCC 6.1.1. (Bug #24438752)

  • InnoDB: Rotating the tablespace encryption master key while the server is in read-only mode raised an assertion instead of displaying an error message. (Bug #24404091)

  • InnoDB: On a table without an explicitly defined primary key, InnoDB did not replace the implicit clustered index (GEN_CLUST_INDEX) when a unique key was defined on a NOT NULL column. (Bug #24397406)

  • InnoDB: handler::keys_to_use_for_scanning() was removed from the handler API. The function was no longer used. The HA_READ_ORDER index flag provides the same information for each index. (Bug #24364448)

  • InnoDB: Page cleaner threads asserted due to a regression related to the adaptive hash index feature. (Bug #24346574)

    References: This issue is a regression of: Bug #21407023.

  • InnoDB: InnoDB failed to free memory used by the full-text optimizer thread. (Bug #24331265)

  • InnoDB: During recovery, InnoDB attempted to fetch LOB pages using a null reference. (Bug #23615208)

  • InnoDB: When adding a new index, the server dropped an internally defined foreign key index and attempted to use a secondary index defined on a generated virtual column as the foreign key index, causing a server exit. InnoDB now permits a foreign key constraint to reference a secondary index defined on a generated virtual column. (Bug #23533396)

  • InnoDB: An INFORMATION_SCHEMA.FILES query resulted in a server exit due to a race condition with a concurrent tablespace creation operation. (Bug #23477214)

  • InnoDB: A concurrent DML operation during an in in-place ALTER TABLE operation that rebuilt the table did not update a virtual index, resulting in a mismatch between the virtual index and clustered index. (Bug #23219499)

  • InnoDB: A TRUNCATE TABLE operation held the dict_sys mutex while scanning for and removing pages from the buffer pool, causing concurrent DDL operations to stall. The mutex is now released during the scan and acquired again when the scan is completed. (Bug #23070734, Bug #80060)

  • InnoDB: Inserting GIS data into an r-tree raised an assertion due to a missing page number field that was encountered when storing the b-tree cursor. (Bug #23044098)

  • InnoDB: Writing to an InnoDB internal temporary table did not increment the Handler_write counter. (Bug #23024178)

  • InnoDB: Changes to the InnoDB recovery process in MySQL 5.7 could require up to three scans of the redo log during recovery. To reduce the number of scans, the first and second scans are were merged. With this change, there is only one scan unless the redo log record hash table that is populated by the scan reaches its memory threshold. In this case, a second scan is initiated that performs a simultaneous scan and apply. (Bug #22963951, Bug #80788)

  • InnoDB: A table-copying online ALTER TABLE operation on a ROW_FORMAT=REDUNDANT table with indexed virtual columns raised an assertion. (Bug #22018745)

  • InnoDB: After a server restart, concurrent INSERT operations a table with an auto-increment primary key resulted in a duplicate entry error. The current auto-increment value was not changed after auto_increment_increment and auto_increment_offset settings were modified. (Bug #20989615, Bug #76872)

  • InnoDB: Performance Schema instrumentation for InnoDB file I/O was disabled on Windows. (Bug #14025581)

  • InnoDB: The row_search_mvcc() function unnecessarily traversed the entire table for a range query, which occurred when the record was not in the transaction read view. (Bug #84202, Bug #23481444, Bug #25251375)

  • Packaging: The my_create_minidump function in the mysys library called the Windows API function MiniDumpWriteDump with an incorrect value (NULL) for the ExceptionParam parameter. This resulted in exception information being omitted from the minidump file. (Bug #24505650, Bug #82695)

  • Partitioning: For a partitioned table, dropping a partition dropped triggers for the table as well. (Bug #24449174)

  • Partitioning: Updating a row of a table that had partitioning on a generated column could raise an assertion failure for debug builds, and return incorrect results in nondebug builds. (Bug #22574695, Bug #80080)

  • Replication: Using an unresolvable host name in group_replication_group_seeds caused START GROUP_REPLICATION to fail. The fix ensures that host names in group_replication_group_seeds are validated when starting Group Replication and the list must contain at least one valid address. Invalid addresses are ignored. (Bug #25460324, Bug #84674)

  • Replication: When using XA transactions, if a lock wait timeout or deadlock occurred for the applier (SQL) thread on a replication slave, the automatic retry did not work. The cause was that while the SQL thread would do a rollback, it would not roll the XA transaction back. This meant that when the transaction was retried, the first event was XA START which was invalid as the XA transaction was already in progress, leading to an XAER_RMFAIL error. (Bug #24764800)

    References: See also: Bug #24923091, Bug #24966941.

  • Replication: The group commit update of GTIDs has been refactored to improve performance on workloads with many small transactions. (Bug #24398760)

  • Replication: If the relay_log option was not specified in a configuration file, the relay_log_basename variable was being internally constructed on the fly using hostname but the relay_log_basename variable was not set. When a slave tried to access this uninitialized variable it resulted in an unexpected halt of the server. (Bug #24352667)

  • Replication: For servers built with yaSSL, using group replication with secure connections could result in timeout failures waiting for view delivery. (Bug #23592214)

  • Replication: When using a multi-threaded slave (slave_parallel_workers greater than 0) the value of Seconds_Behind_Master was incorrect when rotating a relay log. (Bug #23532304)

  • Replication: An XA PREPARE statement that failed during the intermediate steps could lead to an inconsistent XA transaction state, where ID = -1 but the binlogged flag was set to true. This caused asserts while executing XA COMMIT and XA ROLLBACK queries. (Bug #22915670)

  • Replication: The number of generated unwanted fseeks into the binary log file being replicated to a slave has been reduced. (Bug #83226, Bug #24763579)

  • Replication: The fix for Bug #81657 was not correctly merged into MySQL 8.0. Thanks to Laurynas Biveinis for alerting us. (Bug #83124, Bug #24715790)

  • Replication: The rpl.rpl_binlog_errors test was failing sporadically on Windows. (Bug #82302, Bug #24330138)

  • Replication: When binlog_group_commit_sync_delay was set to a value between 1 and 9, if binlog_group_commit_sync_no_delay_count was set to a value greater than 1, and the number of transaction commits was less than binlog_group_commit_sync_no_delay_count, these commits hung forever if no more commits were received; and if binlog_group_commit_sync_no_delay_count was set to 0, all transaction commits hung forever. (Bug #80652, Bug #22891628)

  • Microsoft Windows: On Windows, SHOW TABLES FROM db_name hung if db_name was given in uppercase. (Bug #24800048, Bug #83262)

  • Microsoft Windows: 32-bit builds are no longer supported on Windows, but CMake failed to detect when a 32-built build would be attempted, resulting in compilation errors later. Now CMake detects 32-bit build attempts and produces an appropriate error message. (Bug #24487483, Bug #82645)

  • JSON: When a JSON value consisted of a large sub-document wrapped in many levels of JSON arrays, objects, or both, serialization of the JSON value sometimes required an excessive amount time to complete. (Bug #23031146)

  • JSON: When a NULL value existed in a JSON column, the result from a query using GROUP_CONCAT() together with the ORDER BY clause was not always correct. (Bug #22992666)

  • JSON: The internal rapid_json_handler used its own data structures to represent a partially-built DOM; these had to be converted into a Json_dom graph before returning the result. Now this handler builds the graph directly, which reduces the amount of work required to build it, and thus to parse a JSON document. (Bug #22900110)

  • JSON: The internal function Item_func_case::val_json() did not always set the null value flag as expected when a CASE expression evaluated to NULL, leading to an assertion in debug builds of the server. (Bug #22887227)

  • JSON: The SUM() function truncated decimal values extracted from JSON documents, producing an integer result. (Bug #84935, Bug #25530204)

  • JSON: A JSON document that contained a double value slightly greater than the maximum value that can be represented by a double silently replaced it with zero instead of rejecting the value and raising an error. Such values are now handled correctly in MySQL JSON documents.

    The underlying issue was traced to a problem with RapidJSON, which has been reported to that library's developers as Issue #849. (Bug #84891, Bug #25518504)

  • JSON: The JSON_SEARCH() and JSON_CONTAINS_PATH() functions did not work when the one_or_all argument was specified using UTF-16 encoding. For both of these functions, this argument is now converted to utfmb4 if need be before its value is checked. (Bug #84880, Bug #22516960)

  • JSON: The JSON_UNQUOTE() function did not work with strings that used UTF-16 encoding. Now these strings are converted to utfmb4 internally before being processed. (Bug #84878, Bug #25516881)

  • JSON: Updating the same JSON column in a single statement could cause incorrect values to be written into the table. This occurred when the second update overwrote the column value with a subset of itself. An example of such a statement is shown here:

    UPDATE t SET col = JSON_ARRAY(value), col = col->'$[0]';
    

    (Bug #84694, Bug #25461627)

  • JSON: The functions JSON_QUOTE() and JSON_UNQUOTE() did not work correctly with multibyte character sets such as utf8mb4. (Bug #84680, Bug #25455065)

    References: See also: Bug #77234, Bug #21193273.

  • JSON: The error message for Error 3152 ER_JSON_USED_AS_KEY has been changed from JSON column '%s' cannot be used in key specification to the less confusing and more accurate JSON column '%s' supports indexing only via generated columns on a specified JSON path. (Bug #81364, Bug #23274244)

  • JSON: Internal tests for MySQL JSON functionality ran out of stack space on some platforms when run against a debug-enabled server. Because timely checks were not made for stack usage, the server did not detect this situation, leading to a server exit.

    The fix for this issue is twofold:

    • Stack overrun checks are now made before attempting to serialize a nested array or object, so that the operation fails gracefully when processing deeply nested JSON documents, rather than causing an exit.

    • Serialization of JSON documents has been reorganized so that it requires less use of the stack when compiled without optimization.

    (Bug #81083, Bug #23106330)

  • MySQL did not compile with GCC 7. (Bug #25643811)

  • The (undocumented) WINDOWS_RUNTIME_MD CMake option has been removed. (Bug #25611359)

  • If --skip-innodb or one of its variants was used, a spurious warning about avoid_temporal_upgrade was generated. (Bug #25573578)

  • mysqld_safe failed to restart the server if a PID_FILE.shutdown file was present. (Bug #25572504)

    References: This issue is a regression of: Bug #11751149.

  • For Debian/Ubuntu packages, user-defined collation files could be overwritten during MySQL upgrades. Charset files are now marked as conffiles so that user customizations generate a prompt during upgrades whether to overwrite them. (Bug #25525628, Bug #84761)

  • For CREATE TABLE statements that specified the table name with a database qualifier and included a DATA DIRECTORY or INDEX DIRECTORY option, an error occurred if there was no default database. (Bug #25514146, Bug #84861)

  • referenced_table_schema and referenced_table_name field values in the mysql.foreign_keys data dictionary table were not stored in lowercase when lower_case_table_names was enabled. (Bug #25495714)

  • Starting the server with performance_schema_digests_size=1 caused an abnormal exit. (Bug #25492129, Bug #84786)

  • For clients linked against yaSSL, connections became invalid when a read timeout occurred, rather than retrying the read. (Bug #25444075)

  • MySQL compilation in different directories produced different builds to leakage of absolute paths into debug information and __FILE__. (Bug #25436469)

  • Calculations for UCA 9.0.0 collations were inefficient for tailoring rules containing contraction characters. (Bug #25426632)

  • A negative internal connection timeout value caused the connection to go idle and abort. A negative value now causes the connection to block indefinitely in the absence of I/O. (Bug #25408557)

  • A mutex Performance Schema name was too long and produced a warning at server startup. (Bug #25406915)

  • MySQL failed to compile on some platforms with -DWITH_LIBWRAP=ON. CMake support now checks whether tcpd.h has proper function prototypes. (Bug #25395543, Bug #84495)

  • An index defined on a data dictionary table column exceeded the maximum index key length when the instance was initiated with innodb_page_size=4k. (Bug #25384527)

  • mysqld_safe did not check whether the directory named by the --basedir option existed. (Bug #25365194)

  • Configuring CMake with -G ninja resulted in build output that was inappropriate for build platforms other than Xcode or Visual Studio. (Bug #25358460)

  • mysqld_safe failed if the error log file named by the --log-error option was a FIFO. (Bug #25356221, Bug #84427)

  • For prepared statements, an alias within a subquery or derived table might cause incorrect behavior during statement execution if another alias depended on it. (Bug #25343335, Bug #84398, Bug #25171608)

  • mysqld_safe could fail if the --datadir option value ended with a / character. (Bug #25319457)

  • A recent change to mysqld_safe caused the mysql.server script to be unable to start it if the base directory was specified as an absolute path that differed from the compiled-in default absolute path. (Bug #25319392, Bug #84263)

  • The connection_control plugin failed to compile if the Performance Schema was disabled. (Bug #25308357, Bug #84304)

  • Passwords did not expire correctly for accounts created using MySQL Workbench. (Bug #25299309)

  • For System V init scripts for RPMs, the [mysqld] option-file section was being ignored for some options, such as pid-file. (Bug #25287707, Bug #84172)

  • Init scripts failed to launch mysqld_safe if a non-default base directory was used. (Bug #25261472, Bug #84219)

  • CMake now detects whether a GCC 5.3.0 loop optimization bug occurs and attempts a workaround if so. (Bug #25253540)

  • mysqld_safe --no-defaults did not work (inadvertent consequence of an earlier bug fix). (Bug #25244898, Bug #84173)

  • Semicolon (;) characters within or between statements could cause distinct digests to be generated from identical statements. (Bug #25244533, Bug #83253)

  • Components could not register services without referring to their private implementation. A SERVICE_IMPLEMENTATION(component,service) macro now enables this to be avoided. (Bug #25238906)

  • Certain stored functions, if used in a query WHERE clause, could be handled using Index Condition Pushdown (which should not happen), resulting in a server exit. (Bug #25196653, Bug #25174454)

  • For ai_ci collations based on Unicode Collation Algorithm 9.0.0, accented characters that compare equal were treated as different by LIKE comparisons. (Bug #25167284, Bug #83999)

  • For a client linked against libmysqlclient, invalid memory access could occur during use of prepared statements. (Bug #25164932)

  • Some Linux startup scripts did not process the datadir setting correctly. (Bug #25159791)

  • If a character set is specified for a column of a partitioned table, a segmentation fault could occur while upgrading. (Bug #25153261)

  • LOAD DATA failed to accept multibyte characters that followed an escape sequence. (Bug #25147988, Bug #83950)

  • The fix for Bug #25088048 caused the command used by mysqld_safe to start the MySQL server to no longer include the mysqld path. (Bug #25144379)

    References: This issue is a regression of: Bug #25088048.

  • For UCA collations, LIKE comparisons against a pattern that ended with the escape character returned incorrect results. (Bug #25140629, Bug #83930)

  • The default character set and collation were used instead of the character set and collation defined in db.opt file when upgrading the schema from MySQL 5.7 to MySQL 8.0. (Bug #25139901)

  • Instead of updating the data dictionary cache at the end of DDL statements using separate function calls, the data dictionary cache is now updated as part of transaction commit. (Bug #25095798, Bug #83818)

  • CREATE TABLE now requires the FILE privilege if DATA DIRECTORY or INDEX DIRECTORY is specified explicitly as a table or partition option. ALTER TABLE requires the FILE privilege if either option is specified explicitly as a partition option (it ignores them if specified as table options). (Bug #25092566)

  • There were some differences between ICU order and MySQL Unicode collations for Hungarian contractions and ligatures. MySQL now follows ICU order. (Bug #25090543)

  • The data dictionary failed to initialize and start when using a binary collation. The query string generated to create the data dictionary schema did not add quotes to the binary collation name. (Bug #25054104, Bug #83706)

  • Executing a stored procedure containing a query that accessed a view could allocate memory that was not freed until the session ended. (Bug #25053286)

  • Compilation on FreeBSD 11 failed attempting to check MAP_NORESERVE, which is no longer defined. (Bug #25048128, Bug #83689)

  • mysql-test-run.pl now checks whether the TSAN_OPTIONS environment variable is set. If so, the value is taken as the path name of a file containing ThreadSanitizer suppressions (errors to be ignored during test runs). Additionally, the --sanitize option now causes mysql-test-run.pl to scan the server error logs for ThreadSanizer messages. (Bug #24970905, Bug #83601)

  • After starting the server with a non-zero --lower-case-table-names setting, an assertion was raised when USE INFORMATION_SCHEMA; was the first instruction from the first client. (Bug #24963580)

  • For case-insensitive Unicode collations, the various space characters did not hash to the same value, resulting in incorrect comparisons between them. (Bug #24956750)

  • Dictionary clients now track uncommitted dictionary objects that are being modified by DDL statements, making uncommitted changes by the same session visible to a dictionary client without affecting the dictionary object cache prior to commit time. (Bug #24956365, Bug #83548)

  • Simultaneous dictionary object cache misses were not handled correctly. An object retrieved by one thread could be evicted from the cache before a waiting thread attempted to access it. (Bug #24949179)

  • CMake now avoids configuring the -fexpensive-optimizations option for GCC versions for which the option triggers faulty shift-or optimizations. (Bug #24947597, Bug #83517)

  • CMake support was added for compiling using the -std=c++03 option under Developer Studio 12.5. This is now used rather than stlport by default. (Bug #24947136, Bug #83512, Bug #25229424)

  • NCHAR and NATIONAL CHAR are synonyms, but CAST(expr AS NCHAR) succeeded, whereas CAST(expr AS NATIONAL CHAR) did not. Now both work. (Bug #24934161)

  • OEL RPM packages now better detect which platforms have multilib support (for which 32-bit and 64-bit libraries can be installed). Thanks to Alexey Kopytov for the patch. (Bug #24925181, Bug #83457)

  • OEL RPM packages now better detect which platforms do not have multilib support (for which 32-bit and 64-bit libraries can be installed). Thanks to Alexey Kopytov for the patch. (Bug #24916428, Bug #83428)

  • The LOCATE() function returned NULL if the substr or str argument was NULL, but not if the pos argument was NULL. Now it returns NULL if any argument is NULL. (Bug #24911350, Bug #83427)

  • Bit operations could cause a server exit to occur if argument nullability was mishandled. (Bug #24910958, Bug #24930038, Bug #24930829)

  • The Block Nested Loop algorithm could allocate too much memory during query execution. (Bug #24909223)

  • Information about building MySQL 5.6 compatibility libraries in the MySQL 5.7 and higher .spec file is needed only for building libmysqlclient and libmysqld. Information about building the InnoDB memcached plugin was removed. (Bug #24908345, Bug #83409)

  • Incorrect updating of view metadata could raise an assertion. (Bug #24834622)

  • Initialization of the keyring_okv plugin failed if the STANDBY_SERVER setting was missing from the okvclient.ora configuration file, effectively making this a mandatory setting. STANDBY_SERVER is now optional. (Bug #24816271)

  • Data dictionary objects acquired by Dictionary_client::acquire_uncached() are now owned by the current auto-releaser instead of the caller. Also, acquisition of TABLE_SHARE view objects is performed by acquire() and clone() instead of acquire_uncached(). (Bug #24813358, Bug #83296)

  • Privilege checking could be incorrect for a derived table used within a multiple-table UPDATE invoked within a stored procedure or view object, for the second or subsequent execution of the object, if the derived table was merged into the outer query. (Bug #24810564)

  • The Created_tmp_tables status variable was incremented in some cases when no temporary table was created. (Bug #24808970, Bug #83287)

  • An in-place upgrade from MySQL 5.7 to MySQL 8.0 failed if parsing of a stored routine body failed while migrating the routine. Now a warning is reported and the routine is created without parsing its body. Also, warnings are now reported when dependency resolution fails for a view during view migration. (Bug #24805140, Bug #83275)

  • For compilation, mysql_upgrade is dependent on the dynamically generated sql_commands_system_tables_data_fix.h file, but a missing dependency could cause that file not to be generated. (Bug #24802377, Bug #83272)

  • A race condition between transactions accessing the access-control list (ACL) cache and use of the ACL cache to populate INFORMATION_SCHEMA tables could cause a server exit. (Bug #24786029)

  • For debug builds, EXPLAIN or DESCRIBE for a table with a database or table name longer than the maximum permitted length raised an assertion rather than displaying an appropriate error. (Bug #24751177, Bug #83114)

  • The implementation of several INFORMATION_SCHEMA tables as views on data dictionary tables introduced a number of native SQL functions intended only for internal use by the server, but they could be invoked by users. Those functions now produce an error if invoked by users. (Bug #24749248, Bug #83189)

  • CASE, COALESCE(), IF() and IFNULL() could merge a mix of signed and unsigned arguments incorrectly and produce an incorrect result type. (Bug #24733658, Bug #83148)

  • Connections from a client to a server with SSL enabled succeeded even if --ssl-mode had a value of VERIFY_CA or VERIFY_IDENTITY and the client did not provide a CA certificate. (Bug #24732452, Bug #23189252)

  • Manual creation of a directory in the data directory resulted in USE dir_name succeeding even though the directory was not registered as a database in the data dictionary. (Bug #24732194, Bug #83140)

  • If InnoDB statistics were incorrect, FOUND_ROWS() could return 1 even when the previous SELECT returned no rows. (Bug #24714857, Bug #83110)

  • ALTER TABLE on a temporary table could raise an assertion if a nontemporary table with the same name existed. (Bug #24713918, Bug #83117)

  • CMake now sets -DWITH_NUMA=ON for Debian platforms where possible. (Bug #24689101)

  • To better provide atomic file creation, Debian packaging scripts now use the coreutils install command rather than touch, chmod, and chown. (Bug #24688682)

  • Enabling the DISABLE_SHARED CMake option caused compilation failure. (Bug #24687701, Bug #83039)

    References: This issue is a regression of: Bug #24481181.

  • The BIN(), OCT(), and HEX() functions could mishandle values of the BIT data type. (Bug #24686658, Bug #83031)

  • For debug builds, an invalid utf8 character in the comment of a CREATE EVENT or ALTER EVENT statement raised an assertion. This now produces an ER_INVALID_CHARACTER_STRING error. (Bug #24679962)

  • The encoding for the utf8 character set permitted characters between U+D800 and U+DFFF as valid, though they are reserved for surrogate pairs and do not directly represent characters. They are now considered invalid. (Bug #24672415)

  • A query could produce incorrect results if the WHERE clause contained a dependent subquery, the table had a secondary index on the columns in the select list followed by the columns in the subquery, and GROUP BY or DISTINCT permitted the query to use a Loose Index Scan. (Bug #24671968, Bug #83005)

  • After a RENAME TABLE operation on a table with a foreign key, the generated constraint name was not updated in TABLE_CONSTRAINTS. (Bug #24666169)

  • On macOS, CMake AddressSanitizer support did not work. (Bug #24661626, Bug #82976)

    References: This issue is a regression of: Bug #23759968.

  • Compilation failed on macOS 10.11 with Xcode 8.0. (Bug #24661523, Bug #82975)

  • Index hints applied to invisible indexes produced no error. (Bug #24660093, Bug #82960)

  • In some cases, INFORMATION_SCHEMA.KEY_COLUMN_USAGE did not report data for all foreign key constraints. (Bug #24655803, Bug #82961)

  • REPLACE() on large strings could be slow and unkillable. (Bug #24652792)

  • The DebugPrintTest and DebugPrintDeathTest unit tests did not handle divide-by-zero testing properly on the Aarch64 platform. Thanks to Alexey Kopytov for the patch. (Bug #24624555, Bug #82889)

  • Compilation on FreeBSD using GCC 6 did not work. (Bug #24619561, Bug #82922)

  • Changes made to mysqld_safe in recent MySQL releases require the --ledir, --mysqld, --mysqld-version options to be specified on the command line; they can no longer be specified in option files. This could cause failure of init scripts that invoke mysqld_safe. Such scripts now pass the value of the MYSQLD_OPTS environment variable as the first command-line argument to mysqld_safe, with the value set to such command line-only mysqld_safe option values as may be required. On platforms that use /etc/sysconfig/mysqld, the MYSQLD_OPTS value can be set in that file with a line such as this:

    MYSQLD_OPTS=" --ledir=/mysqld_ledir --mysqld=my_wrapper "
    

    The value of MYSQLD_OPTS can also include mysqld options for mysqld_safe to pass to mysqld. (Bug #24619033, Bug #82920)

    References: This issue is a regression of: Bug #24464380, Bug #24483092, Bug #25088048, Bug #25378439, Bug #25378565.

  • SET PERSIST innodb_buffer_pool_size = value stored the original value of innodb_buffer_pool_size to mysqld-auto.cnf, not the new value. (Bug #24613005, Bug #82905)

  • For SLES packages, a typo in the installation script postamble prevented some cleanup from occurring. (Bug #24605300, Bug #82389)

  • Some messages written by the server to the error log while upgrading the data directory were missing the standard timestamp and process ID information. (Bug #24600054, Bug #82874)

  • It was possible for the session values of the Last_query_cost and Last_query_partial_plans status variables to be accessed before they had been initialized. (Bug #24596263)

  • Warnings occurring during CREATE TABLE ... SELECT could cause a server exit. (Bug #24595992)

  • For LOAD DATA used to insert data into an updateable view, the check to verify whether a column is actually updatable was missing. (Bug #24595937)

  • The server could dereference a null pointer when a deterministic function returning LONGTEXT was used in a subquery. (Bug #24595581)

  • A view altered with ALTER VIEW might be dropped if the statement failed with an error. (Bug #24594140)

  • Conversion of JSON documents to string could be slow if the document was large and contained many signed integers. (Bug #24586888)

  • The data dictionary can contain entries for temporary tables (names beginning with #sql). These tables were exposed to INFORMATION_SCHEMA queries and through SHOW statements. This could cause mysqldump and mysqlpump to fail when they attempted to dump such tables. Temporary tables are now hidden to INFORMATION_SCHEMA queries and SHOW statements. (Bug #24580599, Bug #24571427)

  • When a view was defined, the character set of the definition was not considered. If this differed from the default character set, table names used in the view might not be recognized, causing the view to be marked invalid.

    For debug builds, an assertion could be raised if an error occurred while parsing an ALTER VIEW statement and the diagnostics area was empty. (Bug #24580586)

  • For LOAD DATA statements, input data with too many column values produced only a warning, rather than an error as in MySQL 5.6. An error now occurs. (Bug #24577194, Bug #82830)

  • Using SET PERSIST with the global_log system variable was ineffective. (Bug #24569624, Bug #82807)

  • In the Performance Schema variables_info table, the VARIABLE_SOURCE column was not set properly for some boolean options specified in option files without a variable. (Bug #24567960)

  • The .mylogin.cnf option file is intended for use by client programs, but the server was reading it as well. The server no longer reads it. (Bug #24557925)

  • Use of boost::chrono was replaced with std::chrono because the former was causing link errors. (Bug #24556808, Bug #82781)

  • The X Plugin was built with compilation options different from other plugins. (Bug #24555770, Bug #82777)

  • When populating the variables_by_thread table, the Performance Schema could attempt to access session variables of other threads that were being deinitialized. (Bug #24555658)

  • Users without proper privileges could load and unload server components. (Bug #24528148)

  • Concurrent execution of INSTALL COMPONENT and UNINSTALL COMPONENT statements could cause a server exit. (Bug #24527148)

  • On Debian/Ubuntu platforms, the systemd startup script for MySQL ignored datadir settings in /etc/mysql/my.cnf. (Bug #24517024, Bug #82709)

  • With a LOCK TABLES statement in effect, DML statements on a table that had triggers could cause a server exit. (Bug #24506766)

  • When the WITH_INNODB_MEMCACHED CMake option is enabled, memcached now can be built on Solaris 11 and 12 using the Developer Studio 12.5 compiler. (Bug #24504155, Bug #82692)

  • Parallel slave threads running account-management statements could fail due to a race condition in handling privilege cache locks. (Bug #24503606)

  • Executing ALTER TABLE on a table that has triggers concurrently with other DDL operations could result in a corrupted data dictionary. (Bug #24497803)

  • If mysqladmin shutdown encountered an error determining the server process ID file, it displayed an error message that did not clearly indicate the error was nonfatal. It now indicates that execution continues. (Bug #24496214)

  • For the null_audit plugin, setting the null_audit_event_record system variable improperly could cause a server exit. This variable should be set only from within the null_audit plugin, so it is now read only. (Bug #24493829, Bug #82670)

  • In certain contexts, an expression such as IF(col_name > 5000, (1 / col_name), 5000) could get a type of DECIMAL(6,4), which would truncate results. (Bug #24492965, Bug #82668)

  • The data structure used for ZEROFILL columns could experience memory corruption, leading eventually to a server exit. (Bug #24489302)

  • Library search path handling on Solaris was incorrect. (Bug #24487934, Bug #82646)

  • Operation of the mysql-multi.server.sh script was based on my.cnf in the data directory. That option file is no longer used, so mysql-multi.server.sh has been removed. (Bug #24487870)

  • A query could produce incorrect results if MIN() or MAX() in a subquery referred to an indexed column. (Bug #24484060, Bug #82638, Bug #24657798, Bug #82965)

  • SHOW TRIGGERS output order could differ on Linux and Windows. (Bug #24482919, Bug #82637)

  • mysqld_safe attempted to read my.cnf in the data directory, although that is no longer a standard option file location. (Bug #24482156)

  • After running mysql_upgrade, executing an INSTALL COMPONENT statement could cause a server exit. (Bug #24453571)

  • A regular expression pattern match into a large string could result in a server exit due to memory allocation failure or integer overflow. (Bug #24449076, Bug #24449090)

  • Starting the server with a MySQL 5.7 data directory resulted in failure due to absence of the default_roles and role_edges system tables. (Bug #24447771)

  • An incorrect error was reported for CREATE TABLE statements with a large value for the CONNECTION table option. The value is now limited to 1024 bytes. (Bug #24437124)

  • An assertion could be raised if an ER_LOCK_WAIT_TIMEOUT error occurred during execution of SHOW CREATE TRIGGER. (Bug #24420809, Bug #82483)

  • Constant folding could produce incorrect results for large unsigned integers. (Bug #24401273, Bug #82425)

  • Use of very long subpartition names could result in a server exit. Now partition or subpartition names larger than 64 characters produce an ER_TOO_LONG_IDENT error. (Bug #24400628, Bug #82429)

  • The Gis_wkb_vector<Gis_point> copy constructor was not explicitly instantiated, causing build problems for the Intel compiler. (Bug #24397833, Bug #82358)

  • Privilege escalation was possible by exploiting the way REPAIR TABLE used temporary files. (Bug #24388746)

  • A race condition between UNINSTALL PLUGIN and SHOW PLUGINS could result in a server exit. (Bug #24344026)

  • With ROW mode binary logging, component installation raised an assertion. (Bug #24343582)

  • A potential memory leak related to roles was fixed. (Bug #24337928)

  • Subqueries that were converted to semi-joins and programmatically generated an INFORMATION_SCHEMA table could incorrectly treat the INFORMATION_SCHEMA table as empty.

    A workaround for this problem prior to the bug fix: SET optimizer_switch='semijoin=off'; (Bug #24287772, Bug #82214)

  • mysqldumpslow failed to parse timestamps in the slow query log; it had not been updated to track a change in log timestamp format. (Bug #24007040)

  • The AppArmor profile installed by Ubuntu packages was missing an entry permitting libnuma to read a /sys hierarchy path, resulting in server startup failure. (Bug #23854929)

  • The optimizer could incorrectly treat RAND() as a constant for queries subjected to semi-join transformation. (Bug #23854015)

  • For debug builds, unequal-length binary operands for bit operators could raise an assertion. (Bug #23853628)

  • If a transaction rollback request rolled back only a statement and not the whole transaction, any attempt at attaching another operation to the transaction raised an assertion. (Bug #23753319, Bug #82143)

  • STRCMP() for arguments with the utf8mb4_unicode_ci collation could return results different from ORDER BY. STRCMP() has been corrected. (Bug #23752284, Bug #82132)

  • Complete logical backups made with mysqlpump could not be restored if GTIDs were enabled. (Bug #23748432)

  • Infinite recursion could occur if the audit_log plugin signalled an error while handling an error. (Bug #23717558, Bug #82052)

  • Messages written by the audit_log plugin to the error log regarding MYSQL_AUDIT_CONNECT event failures now print the underlying error cause as well to aid debugging. (Bug #23710632)

  • MySQL now uses readdir() rather than readdir_r(). The latter has been deprecated since glibc 2.24 and caused debug builds of MySQL and builds using GCC 6.1 to fail.

    Additionally, several problems resulting in GCC 6.1 compiler warnings were corrected. (Bug #23708395, Bug #24437737, Bug #82515, Bug #24459890, Bug #25103242)

  • FORCE INDEX was ineffective for SELECT COUNT(*) queries. (Bug #23596760, Bug #81854)

  • During startup, the server creates a lock file for the Unix socket file (for example, mysql.sock.lock as a lock file for mysql.sock). If the server failed to write the process ID to the lock file, it failed to remove that file, which could cause subsequent server startups to fail until the file was removed manually. (Bug #23582603, Bug #81838)

  • For debug builds, queries executed using Item_func_spatial_collection::val_str() could raise an assertion. (Bug #23573720)

  • For audit log events in the connection class, the connection_type value was available only for connect events. The value is now available in connect, disconnect, and change-user events. (Bug #23541550)

  • The audit_log plugin audit_log_filter_remove_filter() function caused a server exit if given a NULL argument. (Bug #23522793)

  • Attempts to configure MySQL without the FEDERATED storage engine failed (the CMake -DWITH_FEDERATED_STORAGE_ENGINE=0 option did not work). (Bug #23508203, Bug #81665)

  • On Solaris, gettimeofday() could return an invalid value and cause a server shutdown. (Bug #23499695)

  • The keyring_file plugin could attempt to write keys to its storage file when the file did not exist. To ensure that keys are flushed only when the correct storage file exists, keyring_file now stores a SHA-256 checksum of the keyring in the file. Before updating the file, the plugin verifies that it contains the expected checksum. (Bug #23498254)

  • START GROUP REPLICATION uses stacked Srv_session and did not return to the correct thread. START GROUP REPLICATION and STOP GROUP REPLICATION are now removed from the list of permitted commands. (Bug #23337984)

  • A union query resulting in tuples larger than max_join_size could result in a server exit. (Bug #23303485)

  • Grant tables with incorrect structure may cause problems in user management operations. As a consequence of the fix for this, for any operation that modifies a grant table, the server now checks whether the table has the expected structure and produces an error if not. mysql_upgrade must be run to update the tables to the expected structure. (Bug #23295423, Bug #25095876, Bug #25448037)

  • ST_ExteriorRing() could cause a server exit due to being passed an invalid WKB string believed to be valid. (Bug #23280574)

  • For debug builds, failure to prepare a branch of an XA transaction could lead to a server exit. (Bug #23264552, Bug #81375)

  • The optimizer could choose ref access on a secondary index rather than range access on the primary key, even when the cost was higher. (Bug #23259872, Bug #81341)

  • An instance of the disk-full error message contained the wrong error code. (Bug #23247332, Bug #81346)

  • For a query with ORDER BY and LIMIT, an optimizer trace did not record the optimizer's switch to a different index. (Bug #23227428, Bug #81250)

  • Improper handling of a lock used by the version_tokens plugin and user-defined functions could result in a server exit if a UDF was called while version_tokens was being uninstalled. (Bug #23210850)

  • The QUOTE() function could allocate excessive memory. A limit of max_allowed_packet bytes is now imposed and returns NULL with a warning for attempts to allocate more. (Bug #23195404)

  • For some deeply nested expressions, the optimizer failed to detect stack overflow, resulting in a server exit. (Bug #23135667)

  • For sessions created through the X Plugin, incorrect thread attachment/detachment could cause a server exit. (Bug #23057045)

  • When attempting to locate the data directory, mysqld_safe incorrectly considered $MY_BASEDIR_VERSION/var as one of the possible locations. (Bug #23013510, Bug #80866)

  • For some generated columns, character set conversion of the column definition for table rebuilds could change column values. (Bug #22991924)

  • If a query performed a GROUP BY on a column of a derived table and the select list contained an expression mixing an aggregate function and the group column, an error was raised if the ONLY_FULL_GROUP_BY SQL mode was enabled. (Bug #22924183, Bug #80726)

  • A binary (in-place) upgrade from MySQL 5.6 to 5.7 followed by a data export performed using mysqlpump resulted in an Invalid default value for date_column error for attempts to reload the dump file. (Bug #22919028, Bug #80706)

  • A failed cast of a long float to integer could cause a server exit. (Bug #22907691)

  • On Unix and Unix-like systems, the error log file resulting from specifying --log-error without an option value was incorrectly created in the directory of the PID file if the --pid-file option was also given. (Bug #22900354)

  • The main.log_tables-big test case could be unstable on highly loaded hosts. Thanks to Laurynas Biveinis for the patch. (Bug #22874167, Bug #80607)

  • SQL statements executed through the X Plugin were not instrumented in the Performance Schema. (Bug #22859462)

  • The rpl.rpl_key_rotation test case did not synchronize properly with the master server. Thanks to Laurynas Biveinis for the patch. (Bug #22838596, Bug #80531)

  • DROP INDEX operations could fail due to inconsistent handling of index prefix lengths for TEXT-type columns (TINYTEXT and so forth). (Bug #22740093, Bug #80392)

  • Metadata locking on stored routine names was performed on a case-sensitive basis, but routine names are not case sensitive. (Bug #22700385)

  • Queries that used an aggregate function with DISTINCT could produce incorrect results. (Bug #22686994, Bug #80310)

  • The innodb_numa_interleave system variable was erroneously available on some systems that were not NUMA-enabled. Thanks to Tomislav Plavcic for the patch.

    CMake now sets the default WITH_NUMA value based on whether the current platform has NUMA support. For platforms without NUMA support, CMake behaves as follows:

    • With no NUMA option (the normal case), CMake continues normally, producing only this warning: NUMA library missing or required version not available

    • With -DWITH_NUMA=ON, CMake aborts with this error: NUMA library missing or required version not available

    (Bug #22678436, Bug #80288)

  • Certain SQL queries involving complex WHERE conditions could cause warnings, memory corruption, or a server exit. (Bug #22671573)

  • When taking the server offline, a race condition within the Performance Schema could lead to a server exit. (Bug #22551677)

  • On macOS, if a table with an associated trigger was renamed to a new name containing both lowercase and uppercase characters, DROP TRIGGER for the trigger resulted in an ER_NO_SUCH_TABLE error for the table. (Bug #22512899, Bug #79873)

  • In the MYSQL_FIELD C API structure, the org_table value for derived tables was *, which could cause failure for queries that depend on this value. The org_table value for views and derived tables now is set as follows: If the column is selected from a view, org_table names the view. If the column is selected from a derived table, org_table names the base table. If a derived table wraps a view, org_table still names the base table. If the column is an expression, org_table is the empty string. (Bug #22364401, Bug #79641)

  • For RPM packages, the default error-log location in the deployed /etc/my.cnf file differed from the location in the installed logrotate script, causing logrotate to fail. (Bug #22322685)

  • The Performance Schema events_statements_summary_by_digest table could contain multiple rows for the same statement digest and schema combination, rather than the expected single (unique) row. (Bug #22320066, Bug #79533)

  • For Performance Schema system and status variable tables, variable values expressed in a character set different from utf8 could be truncated or incorrect. (Bug #22313205)

  • For debug builds, altering a table partitioning expression using an expression attribute with an invalid UTF-8 name caused an assertion to be raised. (Bug #22152229)

  • After performing inserts in a table containing an AUTO_INCREMENT column and then performing a SELECT operation, the LAST_INSERT_ID() returns the correct value, but the value of the mysql_insert_id() C API function was being reset to 0. (Bug #22028117, Bug #78778)

  • On Ubuntu, error messages were displayed during upgrades from Community to Commercial packages that made it appear as though mysqld and my_print_defaults had not been installed. Those messages were spurious and have been silenced. (Bug #21807248)

  • With the use_index_extensions flag of the optimizer_switch system variable disabled, some SELECT DISTINCT queries could return incorrect results. (Bug #21749123, Bug #78244)

  • An invalid string value in the WHERE clause of an UPDATE statement, caused an index scan rather than a range scan to be used. For values not present in the index, this could be much slower. Now the optimizer determines this to be an impossible WHERE condition. (Bug #21032418, Bug #76933)

  • Debian packages were missing an AppArmor-related include file and incorrectly were marked dependent on AppArmor (making it impossible to disable AppArmor by uninstalling it). (Bug #20768958)

  • When the automatic_sp_privileges system variable was enabled, it did not have the expected effect for anonymous users. (Bug #20266641)

  • In a replication environment, SET PASSWORD or ALTER USER could fail to execute on the slave due to failure to parse the hash string correctly. (Bug #20228478)

  • The optimizer resolve_const_item() function called Item_decimal() with the last two arguments in the wrong order. (Bug #19062566)

  • An in-place ALTER TABLE operation failed to report an error when adding a DATE or DATETIME column under these conditions: a) the column was NOT NULL and no default value was supplied; b) strict and NO_ZERO_DATE SQL modes were enabled; c) the table was not empty.

    An ALTER TABLE operation failed with an error rather than a warning when adding a DATE or DATETIME column under these conditions: a) the column was NOT NULL and no default value was supplied; b) strict SQL mode was enabled and NO_ZERO_DATE SQL mode was not enabled; c) the table was not empty. (Bug #16888677)

  • Inserting a TIME, DATE, or TIMESTAMP value with a fractional seconds part into a column having the same type but fewer fractional digits resulted in rounding. This differs from MySQL 5.5, which used truncation rather than rounding. To enable control over this behavior, a new TIME_TRUNCATE_FRACTIONAL SQL mode is available. The default is to use rounding. If this mode is enabled, truncation occurs instead. (Bug #16583910, Bug #68760)

  • NOT IN subqueries could produce incorrect results when an index prefix of an inner table was used. (Bug #13915291)

  • On non-Linux Unix systems, the mysql.server startup script used the Linux command pidof rather than pgrep. (Bug #13788154, Bug #64342)

  • Starting multiple instances of mysqld_safe after an abnormal server exit could result in one mysqld_safe instance killing another. As a consequence of the bug fix, the mysqld_safe.pid file is no longer used. (Bug #11751149, Bug #41908)

  • The --help message for mysqld_safe was corrected to mention that the --no-defaults, --defaults-file, and --defaults-extra-file options, if given, must be the first argument. (Bug #11745176, Bug #11192)

  • The bounds check for the XML parser position stack for each level (which has a fixed depth) used the size of the array as the upper limit, and so was off by one. This is fixed by decreasing the allowable depth by one, which actually matches the maximum number of elements in the position stack. (Bug #83871, Bug #25111907)

    References: See also: Bug #14040071, Bug #15948580.