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From:Bjorn Munch Date:April 25 2019 11:31am
Subject:MySQL Community Server 8.0.16 has been released [part 2]
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[This is part 2 of the announcement]

Bugs Fixed, continued

     * InnoDB: Write-ahead did not work as expected due to an
       incorrectly initialized variable.
       Thanks to Yuhui Wang for the contribution. (Bug
       #29028838, Bug #93442)

     * InnoDB: The base column information for a generated
       column was not stored. (Bug #29021730)

     * InnoDB: An implicit lock check on secondary indexes
       needlessly compared columns using collation rules. (Bug
       #29010725)

     * InnoDB: Assertion code related to the innodb_flush_method
       O_DIRECT_NO_FSYNC setting was no longer valid due to a
       recent modification to that setting. Assertion code was
       revised. (Bug #29007731)
       References: See also: Bug #27309336.

     * InnoDB: When starting the server with undo log encryption
       enabled, the master key for newly created undo
       tablespaces was generated without a server UUID. Undo
       tablespaces should use the DefaultMasterKey if the server
       UUID is not yet generated. (Bug #29006275)

     * InnoDB: Data dictionary code did not check for a returned
       data dictionary object, which could potentially cause the
       server to exit due to a null pointer access. (Bug
       #28977444, Bug #93362)

     * InnoDB: An undo tablespace file was left behind by a
       failed CREATE UNDO TABLESPACE operation. (Bug #28966457)

     * InnoDB: A CREATE UNDO TABLESPACE statement failed on
       Windows due to an invalid character in the file name. The
       failure resulted in a hang condition due to a missing
       OS_FILE_ON_ERROR_NO_EXIT attribute in the call that
       creates the undo tablespace file. (Bug #28955676)

     * InnoDB: Modifying the value of the
       innodb_undo_log_encrypt variable was not a blocking
       operation, which could lead to the modification being
       reverted by a background thread after the operation
       appeared to have been completed successfully. (Bug
       #28952870)

     * InnoDB: An invalid debug assertion was removed from the
       temptable::Handler::primary_key_is_clustered function.
       (Bug #28949332)

     * InnoDB: An ALTER TABLE ... EXCHANGE PARTITION operation
       did not properly update column table_id values in the
       data dictionary. (Bug #28927005)

     * InnoDB: Memory leaks discovered in the innochecksum
       utility were removed. (Bug #28917614, Bug #93164)

     * InnoDB: A DDL operation that followed a failed attempt to
       create an index on a virtual column resulted in an
       assertion failure. (Bug #28825718)

     * InnoDB: A performance regression was observed for partial
       update operations on compressed BLOBs less than or equal
       to 128KB in size. (Bug #28784301)

     * InnoDB: Running aggregated queries raised Valgrind
       warnings. (Bug #28711717)

     * InnoDB: A CHECK TABLE operation raised an assertion
       failure. A pointer to a local call stack variable was not
       set back to null before a function exit. (Bug #28525110)

     * InnoDB: DDL log functions were modified to handle
       ER_TOO_MANY_CONCURRENT_TRXS errors. (Bug #28523127, Bug
       #92071)

     * InnoDB: The purge thread failed to free LOB data pages.
       (Bug #28510599)

     * InnoDB: Some DDL log table transactions were not rolled
       back prior to DDL log recovery. (Bug #28494969)

     * InnoDB: A function invoked during SHOW CREATE TRIGGER
       processing that retrieves the table name did not perform
       the expected lowercase conversion. (Bug #28351038)

     * InnoDB: The INFORMATION_SCHEMA.INNODB_FOREIGN TYPE column
       reported incorrect values. (Bug #28315651, Bug #91577)

     * InnoDB: A Linux AIO handler function failed to check if
       completed I/O events succeeded. Thanks to Wei Zhao for
       the contribution. (Bug #27850600, Bug #90402)

     * InnoDB: An assertion failure was raised in a check that
       determines if a transaction holds an implicit lock on a
       secondary index. A transaction that does not change the
       columns of a secondary index that includes virtual
       columns could be incorrectly determined to hold an
       implicit lock. (Bug #27491839)

     * InnoDB: A function called by a CREATE TABLE thread
       attempted to access a table object after it was freed by
       a background thread.
       Thanks to Yan Huang for the patch. (Bug #27373959, Bug
       #89126)

     * InnoDB: Two sessions concurrently executing an INSERT ...
       ON DUPLICATE KEY UPDATE operation generated a deadlock.
       During partial rollback of a tuple, another session could
       update it. The fix for this bug reverts fixes for Bug
       #11758237, Bug #17604730, and Bug #20040791. (Bug
       #25966845)

     * InnoDB: When the method used to access a joined table was
       const, InnoDB attempted to unlock the matching row
       multiple times. (Bug #20939184)

     * InnoDB: The INDEX_LENGTH value in
       INFORMATION_SCHEMA.TABLES was not updated when adding an
       index. (Bug #19811005)

     * Partitioning: Some partitioning DDL statements were
       improperly rejected due to name validation checks which
       used the wrong table identifier. (Bug #29317007)

     * Partitioning: While rolling back ALTER TABLE ... COALESCE
       PARTITION, the server sometimes attempted to lock and
       close partitions which had been dropped as a result of
       this statement. (Bug #28517446)

     * Partitioning: An AUTO_INCREMENT key added to a
       partitioned table by an ALTER TABLE statement using
       ALGORITHM=INPLACE restarted on each partition. (Bug
       #92241, Bug #28573894)

     * Replication: Group Replication did not correctly handle
       the situation where START GROUP REPLICATION was issued
       when the port specified for the member's Group
       Replication local address was currently busy. (Bug
       #29347285)

     * Replication: If the WAIT_FOR_EXECUTED_GTID_SET() function
       was used with a timeout value including a fractional part
       (for example, 1.5), an error in the casting logic meant
       that the timeout was rounded down to the nearest whole
       second, and to zero for values less than 1 second (for
       example, 0.1). The casting logic has now been corrected
       so that the timeout value is applied as originally
       specified with no rounding. Thanks to Dirkjan Bussink for
       the contribution. (Bug #29324564, Bug #94247)

     * Replication: The consistency level AFTER for the system
       variable group_replication_consistency did not include
       the consistency guarantees provided by
       BEFORE_ON_PRIMARY_FAILOVER. These consistency guarantees,
       which were already implicitly present with the BEFORE and
       BEFORE_AND_AFTER consistency levels, are now provided
       with AFTER. (Bug #29315752)

     * Replication: On Debian-based platforms (such as Ubuntu),
       if the hostname resolved to 127.0.1.1 - which is the
       default on these platforms - it was not possible to
       create a cluster using the default settings. Now, in such
       situations a proper validation of the instance is
       performed before creating a cluster and adding instances
       to it. (Bug #29246110)

     * Replication: In a blocked group, if you set an invalid
       value for group_replication_force_members and then issued
       STOP GROUP_REPLICATION, the server could stop
       unexpectedly. (Bug #29119961)

     * Replication: MySQL Server's behavior when the
       mysql.gtid_executed table cannot be accessed has been
       refactored to provide appropriate error responses and
       actions. The MySQL server now ensures that writes are
       permitted to the mysql.gtid_executed table when the
       server is in read only or super read only mode, so that
       the binary log file can still be rotated in these modes.
       If the mysql.gtid_executed table cannot be accessed for
       writes, and the binary log file is rotated for any reason
       other than reaching the maximum file size
       (max_binlog_size), the current binary log file continues
       to be used. An error message is returned to the client
       that requested the rotation, and a warning is logged on
       the server. If the mysql.gtid_executed table cannot be
       accessed for writes and max_binlog_size is reached, the
       server responds according to its binlog_error_action
       setting. If IGNORE_ERROR is set, an error is logged on
       the server and binary logging is halted, or if
       ABORT_SERVER is set, the server shuts down. (Bug
       #29111514)

     * Replication: When issuing STOP GROUP_REPLICATION while
       the member was trying to assess whether or not it had
       lost majority, the server could stop unexpectedly. (Bug
       #29053128)

     * Replication: When a RESET MASTER TO statement is used to
       specify the starting index number for binary log files,
       the maximum number that you can specify has been reduced
       from the maximum integer value to 2000000000. If the
       maximum integer value was specified, the server was not
       able to start up because no further binary log files
       could be created. The server also previously experienced
       a segmentation fault in that situation. (Bug #28980788,
       Bug #28995220)

     * Replication: On overloaded servers there was a
       possibility that when a member joined the group, the
       VIEW_CHANGE_LOG_EVENT event which marks that point was
       not logged in the correct place. This could lead to
       errors in the data transfer to the newly joining server
       and data divergence. Now, the VIEW_CHANGE_LOG_EVENT event
       is logged in the correct place in the binary log. In
       addition, warnings are logged about the delay in logging
       the event. (Bug #28971594)

     * Replication: On a replication slave with GTIDs in use and
       binary logging disabled, an assertion was raised in debug
       mode when a DDL statement was filtered out by a table
       filter. (Bug #28965972)

     * Replication: Two issues with the deserialization of
       statement based replication events in the binary log were
       corrected. (Bug #28889181, Bug #29028491)

     * Replication: If an applier thread was stopped while it
       was in the process of opening a table, no error was set,
       which could result in a segmentation fault or assertion
       depending on the build type. Error handling is now
       correctly activated in this situation. (Bug #28864557)

     * Replication: When a host name was specified in the IP
       address whitelist for Group Replication
       (group_replication_ip_whitelist),IPv6 addresses were used
       for name resolution and whitelist comparison when an IPv4
       address was also available. An IPv4 address should always
       be preferred for Group Replication connections. Now, if
       the host name resolves to an IPv4 address, any IPv6
       addresses are not considered for comparison to the
       whitelist. (Bug #28841543)

     * Replication: With GTIDs in use on the server, the master
       info log on a replication slave was being synchronized
       every time the master skipped a transaction using the
       auto-skip function. The process ends with a dummy
       heartbeat which is sent to the slave and caused a forced
       flush to the log, and this could have a large cumulative
       impact on the write load on the slave. The same issue
       could occur in a circular replication topology with
       events that originated from the same server and were
       therefore ignored, which were also handled by the slave
       with a forced flush to the log. The slave handling code
       has now been changed to remove the forced flush for
       heartbeat events and for ignored events received through
       circular replication, so that the master info log is only
       synchronized when appropriate (for example, when a CHANGE
       MASTER statement is issued, or the binary log is
       rotated). (Bug #28815555, Bug #85158)

     * Replication: When an ALTER TABLE statement is used with a
       DEFAULT clause to specify an expression default value for
       a new column, and the expression default value refers to
       a nondeterministic function, the statement is unsafe for
       statement-based replication. Previously, such statements
       were also evaluated in terms of GTID consistency, which
       was not the appropriate check as the statements do not
       impact GTID consistency. Now, these statements are
       evaluated only for binary logging and are handled
       depending on the binary logging format in use. When
       binlog_format is set to STATEMENT, the statement is
       logged but a warning message is written to the error log.
       When binlog_format is set to MIXED or ROW, the statement
       is not executed and an error message is written to the
       error log. (Bug #28799939)

     * Replication: In a replication group configured in
       single-primary mode
       (group_replication_single_primary_mode=ON, which is the
       default), if severe network delays affected the group, it
       was possible for the primary and the secondaries to reach
       different decisions on a transaction, which could lead to
       divergence in the gtid_executed sets on the members. The
       issue has now been fixed. (Bug #28768550, Bug #28966455,
       Bug #92690)

     * Replication: Previously, relay logs could not be rotated
       manually for the Group Replication
       group_replication_applier channel using the FLUSH RELAY
       LOGS statement. Due to this restriction, when encryption
       was enabled for binary log files and relay log files
       (binlog_encryption=ON), as available from MySQL 8.0.14,
       the relay log file in use on that channel could not be
       rotated immediately if encryption was disabled again. The
       restriction had a similar impact on binary log master key
       rotation, as available from MySQL 8.0.16. The restriction
       has now been removed, and the FLUSH RELAY LOGS statement
       and corresponding internal requests now operate on the
       group_replication_applier channel as for any other
       channel, with the exception that if the request is
       received while a transaction is being applied, the
       request is performed after the transaction ends. The
       requester must wait while the transaction is completed
       and the rotation takes place. This behavior prevents
       transactions from being split, which is not permitted for
       Group Replication. (Bug #28684376)

     * Replication: When you use the
       group_replication_force_members system variable to force
       a new configuration for a group, the group communication
       engine (XCom) now checks that you have not included any
       group members that are currently unreachable. If any are
       found, the reconfiguration is disallowed and an error is
       returned. (Bug #28678845)

     * Replication: GRANT statements that were written to the
       binary log were logged incorrectly in some cases, which
       could result in a GRANT statement that executed
       successfully on the master causing an error on the
       replication slave. (Bug #28643405, Bug #29155451, Bug
       #93750)

     * Replication: When a member joined a group on server
       start, if the join process failed, for example because
       the server was incompatible with the group, there was a
       possibility that the offline member could still see
       another member as being online. Now, in such a situation
       the information shown in the
       performance_schema.replication_group_members table is
       restricted to the local member when it is OFFLINE. (Bug
       #28533993)

     * Replication: If a storage engine has the capability to
       log in STATEMENT format but not in ROW format, when
       binlog_format is set to STATEMENT, an unsafe SQL
       statement should be logged and a warning message should
       be written to the error log. However, such statements
       were instead not executed and an error message was
       written to the error log, which is the correct behavior
       when binlog_format is set to MIXED or ROW. The issue has
       now been corrected so that unsafe statements are logged
       with a warning as expected when binlog_format is set to
       STATEMENT. (Bug #28429993, Bug #73936)

     * Replication: In the event of the recovery channel
       failing, unprocessed relay logs were being erased. (Bug
       #27940732)

     * Replication: It is possible for a replication group
       member to go offline briefly, then attempt to rejoin the
       replication group again before the group has detected its
       failure and been reconfigured to remove the member.
       Previously, in this situation, the rejoining member could
       participate in XCom's consensus protocol if it received
       and processed messages intended for its pre-crash
       incarnation. This could cause XCom to deliver different
       values for the same consensus round, because the
       rejoining member could make a different decision before
       and after failure. To prevent this situation, a rejoining
       member now ignores messages intended for its pre-crash
       incarnation. (Bug #27383487)

     * Replication: A replication group member could trigger a
       local view after being expelled from the group due to a
       loss of majority. This resulted in a message incorrectly
       stating that the member had resumed regular operation
       after the expulsion. Group Replication now checks before
       delivering a local view that the member has not been
       expelled. (Bug #27349236)

     * Replication: If an invalid value was specified for the
       group_replication_communication_debug_options system
       variable, the Group Communication System set its
       corresponding internal variable to GCS_DEBUG_NONE, and
       the server returned the invalid value for a SHOW
       VARIABLES query. The value of the system variable is now
       checked during server initialization, and if an invalid
       value was specified, an error message is logged and Group
       Replication does not start automatically. (Bug #26729404)

     * macOS: CMake 3.12.4 or higher (which forces
       UseModernBuildSystem = NO) is now required on macOS if
       building with Xcode rather than Makefiles. (Bug
       #28893131)

     * Microsoft Windows: Validity testing for the
       named_pipe_full_access_group system variable did not
       account for NULL values. (Bug #29256690)

     * Microsoft Windows: When multiple instances of mysqld were
       started with the --no-monitor option on the same host for
       same user, the SHUTDOWN command shut down the wrong
       server process. This fix creates a unique shutdown event
       name for use with --no-monitor by appending the process
       ID of the process. (Bug #28723675)

     * JSON: The JSON path parser now propagates errors in the
       same way as most other components of the MySQL server,
       returning true on error and false on success. (Bug
       #28851426)

     * JSON: Removed an unneeded type lookup in
       Json_wrapper::get_datetime(). (Bug #28851324)

     * The authentication_ldap_simple plugin could enforce
       authentication incorrectly. (Bug #29637712)

     * RPM package obsoletes were updated to enable successful
       upgrades from MariaDB to MySQL on EL8. (Bug #29413354)

     * It was possible for the result of an outer join to
       contain a non-NULL row where a NULL extended row was
       expected. (Bug #29402481)
       References: This issue is a regression of: Bug #27808758.

     * SET PASSWORD FOR ... could not be executed as a prepared
       statement. (Bug #29387041, Bug #94416)

     * Builds under Visual Studio could fail while building
       MySQL Router libraries. (Bug #29382197)
       References: This issue is a regression of: Bug #29361890.

     * Imported foreign keys did not work if defined before the
       referenced table. (Bug #29379078, Bug #94400)
       References: This issue is a regression of: Bug #28493257.

     * When an error was raised while evaluating the ESCAPE
       clause of a LIKE expression at resolve time, the error
       status was not propagated to the caller. (Bug #29368521)

     * Tablespace files for the innodb_table_stats_backup and
       innodb_index_stats_backup metadata backup tables were not
       removed after an in-place upgrade from MySQL 5.7 to MySQL
       8.0. (Bug #29365552)

     * While flattening a subquery, if a predicate which was
       always false was present, the MySQL Optimizer did not
       perform any kind of transformation, resulting in a
       subquery that was not prepared, and which asserted later
       when it was executed. To resolve this issue, when such a
       predicate is present in a subquery, the subquery's query
       expression is now unlinked from the query block. (Bug
       #29356132)

     * Upgrade from MySQL 8.0.11, 8.0.12, or 8.0.13 to MySQL
       8.0.14 or 8.0.15 failed if an event, routine, or trigger
       was defined with the ALLOW_INVALID_DATES SQL mode. The
       SQL mode identifier in the data dictionary was changed in
       MySQL 8.0.14, causing a migration failure. (Bug
       #29350955)

     * RPM builds ignored the WITH_SSL configuration setting.
       (Bug #29347534)

     * Length metadata for the TO_SECONDS() function was not
       always calculated correctly. (Bug #29321387)

     * Conditions using windowing functions removed due to being
       always true or false were not always handled correctly.
       (Bug #29320484)

     * SET ROLE statements could leak memory. (Bug #29304583)

     * Upgrading from MySQL 5.7 to MySQL 8.0 on Windows failed
       with "Error 197 from SE while migrating tablespaces". The
       error was due to an access share violation that occurred
       when attempting to open a tablespace file. (Bug
       #29292860)
       References: This issue is a regression of: Bug #28642608.

     * The COMPILATION_COMMENT_SERVER value could be incorrect
       in RPM packages. (Bug #29284651)

     * CREATE TABLE IF NOT EXISTS failed even if the table
       already exists if the new table definition had no primary
       key and the sql_require_primary_key system variable was
       enabled. (Bug #29283055, Bug #94134)

     * A delete from a partitioned table from which all
       partitions had been pruned away was not always handled
       correctly. (Bug #29280186)

     * The CMake check for the GNU gold linker could fail with
       Clang. (Bug #29278244)

     * The data dictionary version was incremented for the MySQL
       8.0.16 release. (Bug #29278241)

     * An argument of the wrong type to a function used with
       DISTINCT was not always handled correctly. (Bug
       #29277571)

     * Length metadata for the QUOTE() function was not always
       calculated correctly. (Bug #29276074)

     * When evaluating GREATEST() or LEAST(), MySQL checked for
       correct signedness of the return value before checking it
       for NULL. (Bug #29275835)

     * When strict SQL mode was not in effect, the values of
       some string functions returning NULL to indicate a result
       greater than max_allowed_packet were handled
       inconsistently behaviour, which could result in
       incorrectly sorted output and possibly other
       misbehaviors. (Bug #29272683)
       References: See also: Bug #97301, Bug #29133127.

     * Logic that checks if upgrade is supported to a particular
       server version was inverted to check for server versions
       from which upgrade is not supported. (Bug #29270297)

     * Event creation could store an incorrect repetition
       interval. (Bug #29269819, Bug #94085)

     * A WHERE condition containing a view reference or an item
       created by a transformation was not always handled
       correctly. (Bug #29268867, Bug #29268698, Bug #28723669,
       Bug #29244238)

     * mysql_ssl_rsa_setup failed to compile using GCC 9. (Bug
       #29245251)

     * If CMake finds a libtirpc library that is too old to work
       with MySQL, it tries to use Sun RPC from glibc instead.
       (Bug #29240701)

     * The server could fail to write slow queries to the slow
       query log due to incorrect calculation of query execution
       time. (Bug #29232684, Bug #93963)

     * MySQL regular expression functions using positions
       employed internal indexes based on 16-bit chunks, rather
       than on codepoint positions. (Bug #29231490)

     * On Windows, the MySQL MSI installer could fail to
       correctly detect whether the Visual Studio 2015
       Redistributable was installed. (Bug #29227209)

     * SDI JSON files did not include the m_hidden field of
       Index_impl objects. This made it hard to use the SDI JSON
       to recreate the CREATE statement for the table because
       InnoDB adds a number of hidden indexes. The SDI JSON now
       includes the m_hidden field. This changes SDI format, so
       the SDI version number was increased to the current
       server version number. (Bug #29210646, Bug #93914)

     * The position hint for the last row in a range frame was
       updated to be one row past the actual last row in the
       frame. (Bug #29201831)

     * In a column definition, multiple constraint definitions
       were not accepted when the first was a CHECK constraint.
       (Bug #29191994)

     * Error log information buffered during startup could be
       buffered too long if the server was performing an
       upgrade. (Bug #29189532)

     * For nullable columns, if we find an expression that is
       always true except when the column is NULL, the
       expression is folded to column IS NOT NULL. When such an
       expression was nested, this caused NULL rows to be
       selected in error. To prevent this from happening, such
       an expressions when nested is now instead folded to
       IF(column IS NULL, NULL, TRUE). (Bug #29179604)

     * PERIOD_ADD() did not handle values greater than 32 bits
       in length for the period argument correctly on Windows
       platforms. (Bug #29175262)

     * When sql_auto_is_null is enabled, a WHERE clause of the
       form WHERE auto_increment_col IS NULL is rewritten as
       WHERE auto_increment_col = LAST_INSERT_ID(). This
       transformation was only performed once per
       auto-incremented value, which made it difficult to know
       in advance whether the transformation would be performed.
       Now the transformation is performed unconditionally
       whenever sql_auto_is_null is enabled.
       In addition, the value returned by LAST_INSERT_ID() is
       now treated as unsigned, fixing a failure to match an
       auto-incremented value outside the range of a signed
       BIGINT. (Bug #29171668)

     * The harness_plugin_eventlog declaration caused
       compilation errors in some build environments. (Bug
       #29160214)

     * The logic for truncating or extending a decimal constant
       to the desired number of fractional digits during
       constant folding was lacking. Extra trailing zeros in the
       fraction could trigger an attempt to widen the faction,
       since the decision to widen was based on the number of
       non-zero fractional digits, rather than on total number
       of fractional digits, leading to an assert (in debug
       builds) in the internal function widen_fraction(). This
       issue is fixed by identifying where it is possible merely
       to truncate excess trailing zeroes. In this case, it is
       not necessary to adjust the comparison operator, and the
       constant can be replaced by one having fewer trailing
       zeroes instead. (Bug #29155439)

     * On Windows, the internal function
       get_mysql_time_from_str_no_warn() did not always perform
       proper error checking. (Bug #29155126)
       References: See also: Bug #29175262.

     * Under certain conditions, RENAME TABLE statements that
       renamed the same table multiple times could raise an
       assertion or cause a server exit. (Bug #29140407)

     * For debug builds, starting the server with
       --event-scheduler=DISABLED could result in an assertion
       being raised for certain events. (Bug #29140298, Bug
       #93719)

     * In debug builds, When strict SQL mode was not in effect,
       the CONCAT() and CONCAT_WS() functions raised an
       assertion if the result was longer than
       max_allowed_packet. (Bug #29133127)

     * An out-of-range fractional part could produce incorrect
       timestamps in SET SESSION timestamp statements. (Bug
       #29120569, Bug #93600)

     * The mysql_service_component_sys_variable service could
       access component system variables but not server or
       plugin system variables. (Bug #29113463)

     * ALTER TABLE ... CONVERT TO CHARACTER SET could produce a
       memory-access error. (Bug #29058369, Bug #93603)

     * The mysql.tablespaces.name column limit was 259 bytes,
       which was less than required for permitted identifier
       lengths. The column limit was raised to 268 bytes. (Bug
       #29053560, Bug #93587)

     * For debug builds, for spatial computations that raised an
       assertion, partition-handling code ignored the error,
       resulting in a server exit. (Bug #29047811)

     * A zero length LOB that was stored externally caused an
       assertion failure. (Bug #29047795)

     * Handling of the COMPILE_DEFINITIONS and COMPILE_FLAGS
       CMake options was adjusted to avoid cross-compiling
       failures. (Bug #29041100)

     * The server could try to read the first diagnostics area
       message even when the max_error_count system variable was
       set to zero, resulting in a memory-access error. (Bug
       #29031684)

     * When comparing DATE values with constant strings, MySQL
       first tries to convert the string to a DATE and then to
       perform the comparison. When the conversion failed, MySQL
       executed the comparison treating the DATE as a string,
       which could lead to unpredictable behavior. Now in such
       cases, if the conversion of the string to a DATE fails,
       the comparison fails with ER_WRONG_VALUE. (Bug #29025656)

     * With the --users option, mysqlpump wrote CREATE USER and
       GRANT statements to the output, but too late to apply to
       the other objects created by the dump. Consequently,
       restoring the dump file created the user accounts too
       late to apply to other objects created by the file.
       mysqlpump now writes user accounts to the dump file
       before other objects. (Bug #29023216)

     * For syntax errors at the position of the WITH keyword,
       the parser error message identified the problem at the
       incorrect location. (Bug #29022263)

     * MySQL builds using recent versions of the International
       Components for Unicode (ICU) now return
       ER_REGEXP_ILLEGAL_ARGUMENT rather than the generic error
       ER_REGEXP_ERROR for malformed regular expressions. (Bug
       #29016798)

     * On Windows, the LDAP library could not be found if the
       file system was case sensitive. (Bug #29016220)

     * Values selected from the TABLE_COMMENT column of the
       INFORMATION_SCHEMA.TABLES table could be truncated. (Bug
       #29014272, Bug #93451)

     * Data layer memory leaks related to unfreed schemas were
       discovered in ASAN and Valgrind builds. (Bug #29008688)

     * A GROUP BY query with ROLLUP incorrectly raised
       ER_WRONG_FIELD_WITH_GROUP when used with an ORDER BY
       clause that contained an expression.
       The same issue also led to incorrect ordering of the
       result from a GROUP BY query with ROLLUP when ordering on
       a function. (Bug #29006668, Bug #29054096)

     * The parser accepted multiple COLLATE clauses in generated
       column definitions. It now accepts a single COLLATE
       clause. (Bug #28997518)

     * INSERT ... ON DUPLICATE KEY UPDATE could perform
       incorrect updates. (Bug #28995498, Bug #93410)
       References: This issue is a regression of: Bug #26188578.

     * A damaged mysql.user table could cause a server exit.
       (Bug #28986737)

     * Reading rows from the Performance Schema data_locks or
       data_lock_waits table could return an unbounded number of
       rows during a scan, resulting in a server exit due to
       excessive memory allocation. This situation now produces
       an error. (Bug #28977428, Bug #87748)

     * Calculating the cost of materialization for a LATERAL
       join on an empty table led to an assertion. Now in such
       cases, the query cost is reported as zero. (Bug
       #28976533)

     * For debug builds, an invalid utf8 character in the
       comment string for a column type in CREATE or ALTER DDL
       statements raised an assertion. (Bug #28972424, Bug
       #93321)

     * The CMake check for tirpc headers now falls back to using
       pkgconfig, to enable finding the headers on more Linux
       platforms. This requires that pkgconfig be installed.
       (Bug #28970313, Bug #93341, Bug #28997093)

     * mysqld could undergo an unplanned shutdown when a
       component in the WHERE clause of a subquery was
       non-deterministic, in this particular case due to
       referencing a user variable that was also set in the same
       statement. This issue is fixed by ignoring predicates
       having non-deterministic components.
       In addition, since non-deterministic subqueries as a
       general rule should be evaluated per outer row, these
       should not be targets for materialization strategy. This
       is prevented by not decorrelating the non-deterministic
       predicates. When possible, the same strategy selection
       for non-semijoin and non-deterministic subqueries is also
       now enforced. (Bug #28970261)

     * ALTER TABLE statements to change a table storage engine
       could hang when user-level locks and explicit table locks
       had been acquired earlier. (Bug #28966941)

     * COUNT() with LIMIT ... OFFSET returned a different result
       from that obtained with other aggregate functions used
       with this clause. (Bug #28961843)

     * Extracting the value of the MYSQL_HOME environment
       variable could change the value of the variable stored
       following MYSQL_HOME in the environment. (Bug #28960613)

     * Opening and closing a connection multiple times in a
       client program could cause the client to exit due to
       improper character set reinitialization. (Bug #28956360,
       Bug #93276)

     * Item_subselect::walk_body() now walks FROM clauses. (Bug
       #28955358)

     * An issue was uncovered in query plan for a query with the
       following two IN subqueries:

          + A subquery with a derived table containing an outer
            reference to the topmost query

          + A subquery with a derived table, which was not
            outer-correlated, was semi-joined, and was not
            lateral.
       For the second subquery: calculation of the map of
       dependencies neglected to exclude irrelevant lateral
       tables, and wrongly included dependencies of the derived
       table in the first subquery. (Bug #28954838)

     * An error generated while evaluating a constant expression
       in certain GROUP BY queries was not checked for in a
       timely fashion. (Bug #28949452)

     * When comparing a DATE or DATETIME value with a string
       MySQL first tries to convert the string to the same type
       (DATE or DATETIME) and then to compare the two as values
       of that type. If this conversion fails, MySQL raises an
       Incorrect date value warning and then falls back to
       comparing the values as strings, which is the expected
       behavior. In some cases, even though the converted string
       did not reflect a valid DATE or DATETIME value, no
       warning was issued so and it was compared with the DATE
       or DATETIME value as a value of that type. Now in such
       cases, the converted string is always checked for
       validity as a DATE or DATETIME before being compared,
       unless the ALLOW_INVALID_DATES server SQL mode has been
       set explicitly. (Bug #28940878)

     * Long client host names could cause unexpected server
       behavior. (Bug #28936359)

     * Substitution of a large number of parameters in a single
       prepared statement could lead to excessive and
       unnecessary reallocation of memory. This is fixed by
       having String::replace() use exponential buffer growth as
       String::append() does. (Bug #28929977)

     * The data dictionary cache could become out of sync with
       data dictionary contents due to failure to check the
       result of a transaction-related operation. (Bug
       #28923782, Bug #93196)

     * Determination of the number of online CPUs available to
       the mysqld process is now more accurate. Thanks to Daniel
       Black for the contribution. (Bug #28907677, Bug #93144)

     * The INFORMATION_SCHEMA.TABLES TABLE_COMMENT column
       reported the wrong error message due to an invalid view.
       (Bug #28901919)

     * After upgrading, the INFORMATION_SCHEMA.TABLES view
       reported "View 'view_name' references invalid table(s) or
       column(s) or function(s) or definer/invoker of view lack
       rights to use them" for several sys schema views. The
       upgrade process did not update the referencing view
       state. (Bug #28901821)

     * Creating histograms for large tables (millions of rows)
       having many distinct column values took an excessive
       amount of time.
       The fix make this process marginally slower for data sets
       with few distinct values and consumes slightly more
       memory than previously, but for large data sets with many
       distinct values it is significantly faster. (Bug
       #28888936)

     * Upgrade from MySQL 5.7 to MySQL 8.0 failed for instances
       with a an InnoDB 4K page size due a key length error that
       should be suppressed during upgrade. (Bug #28884503)

     * An incorrectly configured keyring plugin could cause a
       server exit. (Bug #28876033)

     * Two issues were found in cases involving use of the
       COUNT() function:

          + When the argument passed to COUNT() was a nullable
            expression, it was possible for the function to
            return an incorrect result.

          + A query using COUNT() together with an EXISTS
            subquery returned an incorrect result.
       (Bug #28857990, Bug #29240516)

     * Commands for invoking ccache during MySQL builds were
       generated incorrectly. (Bug #28841612, Bug #92927)

     * Previously, for INSERT statements that listed insert
       column names multiple times, only the first duplicated
       name was reported. Now, all duplicated names are
       reported. (Bug #28836669)

     * When using ROLLUP, the GROUP BY may yield NULL in some
       rows. Expressions referencing any of these rows could
       lose the NULL, producing an incorrect result. (Bug
       #28836345)

     * After a failed attempt to open a table, attempts to
       discover the table from the storage engine did not check
       for an error return, which could cause the server to hang
       if an error occurred. (Bug #28828450)

     * The server could exit when trying to drop a user who had
       been granted a particular role. (Bug #28817441)

     * MySQL Router compilation failed if MySQL was configured
       with -DWITH_MYSQLX=0. (Bug #28811356)

     * A function called during data dictionary upgrade
       temporarily modified the avoid_temporal_upgrade parameter
       so that a check for old temporal types is always
       performed. Because multiple threads could call the
       function concurrently, a check was added to ensure that
       the parameter value could be safely modified during data
       dictionary upgrade. (Bug #28805429)

     * An EXISTS subquery is converted to a semi-join operation.
       The optimizer chooses a materialization lookup strategy
       for this semi-join, but because the subquery is not
       correlated with the outer query block, there were no keys
       to use for the lookup, which caused the parent query to
       fail. To solve this issue, we use two equal constant
       items as keys, to ensure that the materialized query gets
       the constant as a key (and so that the materialized table
       consists of at most one row). (Bug #28805105)

     * The Last_query_cost status variable now shows the cost of
       queries which contain multiple blocks such as subqueries
       or unions. (Previously, this variable was set only for
       simple queries consisting of a single query block.) (Bug
       #28786951)

     * The message displayed by mysqld when a fatal signal
       occurred has been simplified and made more informative.
       It also does not display the calculation of memory usage,
       which had become out of date and inaccurate. (Bug
       #28773322, Bug #92731)

     * The skip_name_resolve system variable could be persisted
       using SET PERSIST_ONLY to enable it, but not to disable
       it. (Bug #28749668)

     * Removed obsolete and unnecessary condition pushdown
       handling in iterators except where required by single
       table update and delete queries. (Bug #28745859)

     * IS NOT NULL predicates are added as part of early
       filtering of NULL for ref access performed by the
       Optimizer. For queries having a star-join topology,
       redundant duplicates of these predicates were added,
       which made evaluation of affected WHERE conditions less
       efficient. (Bug #28727717)

     * CMake could generate an incorrect order of system
       includes when MySQL was configured to use the bundled
       version of a system library. (Bug #28727631, Bug #92615)

     * Some numeric operations involving double to long long
       conversions could return different results on Windows and
       Linux. (Bug #28706832)

     * An attempt to access a null pointer could occur during
       prepared statement execution. (Bug #28692136)

     * FROM_UNIXTIME() returned an out-of-range value if passed
       an argument that, when rounded up, exceeded the epoch
       value. Now it returns NULL as for other out-of-range
       values. (Bug #28671811, Bug #92501)

     * A replicated DDL operation could result in a 'duplicate
       entry on primary key' error during recovery on servers
       started with the --slave-parallel-workers option. (Bug
       #28670843)

     * Empty host names in accounts could cause the server to
       misbehave. (Bug #28653104)

     * The MySQL 5.7 to MySQL 8.0 upgrade process did not check
       for the existence of tablespace files, which could result
       in an inconsistent data dictionary. (Bug #28642608)

     * Type casting of ENUM behaved differently in subqueries
       than not in subqueries. (Bug #28547906, Bug #92173)

     * Statements that caused truncation of floating-point
       values could be executed as prepared statements even when
       the server SQL mode included STRICT_TRANS_TABLES. In
       addition, if the binary logging mode was MIXED, such
       statements were propagated to the slave, where they
       caused errors. (Bug #28546855)

     * Reducing the value of thread_cache_size at runtime did
       not reduce the size of the thread cache. (Bug #28508923,
       Bug #92024)

     * Some error messages still referred to the PASSWORD()
       function, which has been removed. (Bug #28498714)

     * The Aborted_connects status variable was not incremented
       for unsuccessful connection attempts, if connections were
       managed by the thread_pool plugin. (Bug #28490126)

     * mysqladmin shutdown did not wait for mysqld to shut down.
       (Bug #28466137, Bug #91803)
       References: This issue is a regression of: Bug #25364806.

     * Specifying CURRENT_USER as the user in GRANT statements
       could fail. (Bug #28454014)

     * Repeated invocations of stored procedures which executed
       queries undergoing short-circuit evaluation were not
       always handled correctly. (Bug #28379655)

     * Keyring migration should require only read access to the
       source keyring, but failed unless the user had write
       access. (Bug #28339014)

     * If a user performing a keyring migration did not have
       write access to the keyring file, the migration failed
       but reported success in its final error log message. (Bug
       #28330922)

     * During FLUSH STATUS execution, the Performance Schema
       unnecessarily aggregated session status to global status,
       causing double counts for some status variables. (Bug
       #28291258, Bug #91541)

     * mysql_secure_installation no longer attempts to read a
       password from the .mysql_secret file. This was was
       created by mysql_install_db, a program that has been
       removed. (Bug #28235716, Bug #91270)

     * Some status variable values could temporarily increase
       before returning to their original value. (Bug #27839644,
       Bug #90351)

     * Client programs did not exit if --ssl-fips-mode was given
       but FIPS mode could not be set to the specified option
       value. (Bug #27809371)

     * Executing ALTER INSTANCE ROTATE INNODB MASTER KEY and
       migrating keys from the keyring_file plugin to the
       keyring_encrypted_file plugin could make encrypted tables
       unusable. (Bug #27760952)

     * When upgrading from MySQL Community to Commercial, the
       root password prompt was shown even when the data
       directory existed. (Bug #27741998)

     * In the client/server protocol, malformed packets for
       prepared statements could go undetected and cause an
       assertion to be raised. (Bug #27627731)

     * Changes were made in session connect and disconnect
       handling for threads in order to speed up query
       throughput when using the X Plugin. Previously, a session
       (Srv_session) was attached to and detached from the
       current thread with every command; now, this thread
       switch takes place only when disconnecting the current
       session, or when the current thread and the thread being
       attached to belong to different plugins. (Bug #27463277)

     * The PERSIST and PERSIST_ONLY keywords were reserved by
       mistake. They are now nonreserved keywords. (Bug
       #25220656)

     * Installing and uninstalling a plugin concurrently with
       client connection activity could cause a server exit.
       (Bug #22980441)

     * The LOAD_FILE() function could fail for files for which
       stat() should be considered only advisory, such as files
       under /proc. (Bug #18394503, Bug #72027)

     * A query using an ORDER BY clause failed silently when the
       table being queried had an implicit full-text index and
       the sort buffer was of insufficient size to contain the
       sorted keys. (Bug #93241, Bug #28940361)

     * A UDF returning a string value now sets an explicit
       return type. Depending on the arguments passed to the
       function, this is one of VARCHAR, MEDIUMBLOB, or
       LONGBLOB. (Bug #92890, Bug #28828169)

     * Made a comparison in the internal method
       Item_result::item_cmp_type() more efficient. Our thanks
       to Daniel Black for the contribution. (Bug #92784, Bug
       #28796107)

     * A windowing function employed in an arithmetic expression
       produced an incorrect result when the query containing it
       used DISTINCT. (Bug #92503, Bug #28672483)

     * Some queries involving complex joins leaked file handles.
       (Bug #90902, Bug #28039829)

Thread
MySQL Community Server 8.0.16 has been released [part 2]Bjorn Munch25 Apr 2019