Changes in MySQL 5.7.34 (2021-04-20, General Availability)

• Configuration Notes

• Packaging Notes

• Security Notes

• Functionality Added or Changed

• Bugs Fixed

Configuration Notes

• The CMAKE_BUILD_TYPE CMake option now supports a Release build type, which is like the RelWithDebInfo build type but omits debugging information to reduce the build size. (Bug #27874068, Bug #32287863)

Packaging Notes

• The bundled libedit library was upgraded to version 20190324-3.1. (Bug #32433089)

• Binary packages that include curl rather than linking to the system curl library have been upgraded to use curl 7.74.0.

Security Notes

• The linked OpenSSL library for MySQL Server has been updated to version 1.1.1k. Issues fixed in the new OpenSSL version are described at https://www.openssl.org/news/cl111.txt and https://www.openssl.org/news/vulnerabilities.html. (Bug #32680637)

Functionality Added or Changed

• Group Replication: It is now possible to use START REPLICA SQL_THREAD and STOP REPLICA SQL_THREAD statements for the group_replication_applier channel when Group Replication is stopped. This enables an operator to apply any remaining unapplied transactions on a server that left the group, without having to rejoin the server to the group. (Bug #32027612, Bug #32414767)

• Microsoft Windows: The named_pipe_full_access_group system variable now defaults to an empty string (''), making named pipe connections secure. Previously, '*everyone*' was the default value. A valid Windows local group name may be substituted. (WL #12671)

Bugs Fixed

• InnoDB: The introduction of sharded rw_lock_stats counters in MySQL 5.7 caused a regression in CPU cache efficiency. To address this issue in MySQL 5.7, the sharding method was changed. For optimal performance, the rw_lock_stats counter is removed in MySQL 8.0. (Bug #32225367)

• InnoDB: A delete operation on a parent table that initiated a cascading update on a child table with an indexed virtual column and indexed foreign key constraint column caused a virtual column corruption. (Bug #32124113)

• InnoDB: An adaptive hash index (AHI) latch was held in shared mode by a thread truncating a large table, causing mutex waits for other threads. The AHI latch was not required and has been removed. (Bug #32032897)

• InnoDB: The open and close sequence for table share instances (m_share objects) and dictionary table instances was modified to prevent accessing old m_share objects that could point to stale dictionary indexes.

  Thanks to Yuxiang Jiang for the contribution. (Bug #31899685)

• InnoDB: An online ALTER TABLE operation failed with an Incorrect key file for table error due to an unnecessary encryption status check that was performed when reading online DDL row logs. (Bug #31529221, Bug #99938)

• Replication: If all previous binary log files were purged at startup because their retention period had expired, the new binary log file contained an empty Previous_gtids event, which could cause errors in replication. The order of initialization has now been changed so that previous binary log files are only purged after the previous GTID set has been written to the new binary log file that is created at startup. (Bug #32134875, Bug #101533)

• Replication: An assertion was raised in debug builds relating to lost GTIDs if binary log files were removed at startup because their retention period had expired. (Bug #32008512, Bug #101137)

• Replication: A deadlock could occur if the binary log file was rotated while system variables were being updated and read by different clients. (Bug #31774422)

• Replication: The output of a SHOW PROCESSLIST statement for a replica’s SQL thread sometimes showed the last query as currently being applied when the replica was actually caught up. (Bug #30521198, Bug #97560)

• Docker containers for MySQL Enterprise Edition no longer need to run with root privileges. (Bug #32472242)

• A query string was displayed before it had been rewritten. (Bug #32335263, Bug #32628376)

• For builds compiled using the libedit library, if the mysql client was invoked with the --default-character-set=utf8 option, libedit rejected input of multibyte characters. (Bug #32329078, Bug #32583436, Bug #102806)

• On Windows, large result sets could cause the mysql client to exit unexpectedly. (Bug #32316323, Bug #102051)

• Improper locking on an internal queue could cause mysqlpump to exit unexpectedly. (Bug #32067013)

• When the mysql client was used in batch mode, its parser could be confused by USE followed by DROP DATABASE when the USE database name was quoted. (Bug #32015466, Bug #101124)

• While optimizing the ORDER BY clause of a subquery there was a possibility of cleaning up a subquery tree referenced in the outer SELECT, which could lead to a premature exit. (Bug #31721430)

• A malformed name in the mysql.func system table could cause unexpected server behavior. (Bug #31674599)

• Sessions could disable their own auditing. (Bug #31630954)

• Mishandling of stored program local variables could lead to unexpected server behavior. (Bug #30366310)

• Uninstalling a plugin could affect subsequent execution of prepared statements. (Bug #29363867)