This topic describes the kernel version updates of AliSQL.

MySQL 8.0

20190915

Bug fixed:

Memory is no longer leaked when the system runs the Cmd_set_current_connection process.

20190816

  • New features:
    • Thread pool: Threads are separated from sessions. When a large number of sessions exist, the system can run only a small number of threads to complete the tasks specified by the active sessions.
    • Statement concurrency control: You can control the number of concurrent requests to reduce traffic bursts, better process statements that consume an abnormally large number of resources, and adapt to changes to the SQL access model. This feature helps to guarantee continuous, stable operation of MySQL instances.
    • Statement outline: You can use optimizer hints and index hints to make MySQL stably run the planned statements.
    • Recycle bin: You can temporarily transfer deleted tables to the recycle bin. You can also specify a retention period, during which you can retrieve the deleted tables.
    • Sequence engine: This feature makes it easier to obtain sequence values.
    • Purge Large File Asynchronously: When you delete a tablespace, the system renames the tablespace file as a temporary file. The asynchronous deletion process then deletes the temporary file.
    • Performance Insight: The system supports instance load monitoring, correlative analysis, and performance optimization, helping you to evaluate database loads, locate performance problems, and improve database stability.
    • Instance lock status optimization: You can drop or truncate a table in an instance even when the instance is locked.
  • Bugs fixed:
    • The bug that causes the system to incorrectly calculate the size of a file has been fixed.
    • The bug due to which some memory resources become idle and then are used again occasionally has been fixed.
    • The but that causes the system to break down when the host cache size is 0 has been fixed.
    • The bug that causes conflicts between implicit primary keys and CTS statements has been fixed.
    • The bug due to which slow queries cause errors in slow logs has been fixed.

20190601

  • Performance optimization:
    • The range of MDL log tables has been shrinked to reduce the possibility of MDL blocking.
    • The code for terminating options has been reconstructed.
  • Bugs fixed:
    • The system no longer fails to record precompiled statements in audit logs.
    • The system now can shield error logs that contain invalid table names.

MySQL 5.7

20190925

Parameter reconfiguration:

  • The default value of the system variable auto_generate_certs has been changed from true to false.
  • The default value of the global read-only variable auto_detact_certs is false while the valid values are true and false. This variable is available when OpenSSL is used for compilation on the server. It specifies whether the server automatically searches for SSL certificates and key files in the data directory when the server starts up. In other words, this variable specifies whether to enable the function of automatically searching for certificates and keys on the server.

20190915

New feature:

Thread pool: Threads are separated from sessions. When a large number of sessions exist, the system can run only a small number of threads to complete the tasks specified by the active sessions.

20190815

  • New features:
    • Purge Large File Asynchronously: When you delete a tablespace, the system renames the tablespace file as a temporary file. The asynchronous deletion process then deletes the temporary file.
    • Performance Insight: The system supports instance load monitoring, correlative analysis, and performance optimization, helping you to evaluate database loads, locate performance problems, and improve database stability.
    • Instance lock status optimization: You can drop or truncate a table in an instance even when the instance is locked.
  • Bugs fixed:
    • You can no longer set the rds_prepare_begin_id parameter in the set rds_current_connection command.
    • You are now allowed to modify the information of a locked user.
    • The keyword actual can no longer be used in a table name.
    • Slow logs no longer cause the overflow of time fields.

20190510

New feature: You can create temporary tables in transactions.

20190319

New feature: You can set thread IDs in the proxy information of handshake packets.

20190131

  • The DB engine version has been upgraded to the official version 5.7.25.
  • The memory management feature JeMalloc has been disabled.
  • The bug that causes the system to incorrectly calculate the value of the internal variable net_lenth_size has been fixed.

20181226

  • New feature: The system can dynamically change the value of the binlog-row-event-max-size parameter to expedite the replication of tables that do not have primary keys.
  • Bug fixed: The bug due to which you cannot apply for memory resources for a proxy instance has been fixed.

20181010

  • The system supports implicit primary keys.
  • The system replicates tables that do not have primary keys between the master and slave instances faster.
  • The system supports Native AIO to improve I/O performance.

20180431

New features:

  • The system supports the High-availability Edition.
  • The system supports the SQL audit function.
  • The protection for instances that are being backed up by using snapshots has been enhanced.

MySQL 5.6

20190815

Instance lock status optimization: You can drop or truncate a table in an instance even when the instance is locked.

20190130

Some bugs that may cause system instability have been fixed.

20181010

The rocksdb_ddl_commit_in_the_middle (MyRocks) parameter has been introduced. If this parameter is enabled, the COMMIT statement is run during the execution of the some DDL operations.

201806** (5.6.16)

New feature: The time precision of slow logs is accurate to microsecond.

20180426 (5.6.16)

  • New feature: You can hide indexes. For more information, see Changes in AliSQL.
  • The bug that causes threads to be applied in the slave instance has been fixed.
  • The bug that causes the system performance to deteriorate when the updates to the partition table are applied to the slave instance has been fixed.
  • The bug that causes the TokuDB engine to run the alter table comment command to reconstruct an entire table has been fixed. For more information, see Changes in AliSQL.
  • The bug that causes a dead lock when you run the show slave status or show status command has been fixed.

20171205 (5.6.16)

  • The bug that causes a dead lock when you run the OPTIMIZE TABLE and ONLINE ALTER TABLE statements at the same time has been fixed.
  • The bug that causes conflicts between sequence values and implicit primary keys has been fixed.
  • The bug in the SHOW CREATE SEQUENCE statement has been fixed.
  • The bug that causes the TokuDB engine to incorrectly collect statistics of table information has been fixed.
  • The bug that causes a dead lock when the system optimizes tables concurrently has been fixed.
  • The bug in the character set recorded in QUERY_LOG_EVENT has been fixed.
  • The signal processing bug due to which the database cannot be stopped has been fixed. For more information, see Changes in AliSQL.
  • The bug that causes an error when you run the RESET MASTER command has been fixed.
  • The bug that causes the slave instance to enter the waiting state has been fixed.
  • The bug due to which the database status cannot be properly maintained after services are switched over between the master and slave instances in the Enterprise Edition has been fixed.
  • The bug that causes a breakdown in the invoked process when you run the SHOW CREATE TABLE command has been fixed.

20170927 (5.6.16)

The bug that causes the TokuDB engine to query tables by using incorrect indexes has been fixed.

20170901 (5.6.16)

  • New features:
    • The SSL version has been upgraded to TLS 1.2. For more information, see Changes in AliSQL.
    • Sequences are supported.
  • Bug fixed: The bug that causes the system to return incorrect results in certain circumstances when you use the NOT IN clause to query data has been fixed.

20170530 (5.6.16)

New feature: You can use the premier account in an instance to terminate the connections established by the other accounts in the same account.

20170221 (5.6.16)

New feature: The system supports the read/write splitting feature.

MySQL 5.5

20181212

The bug that causes the system to return an inaccurate value when you call the gettimeofday(2) function has been fixed. This function is used to calculate whether the waiting time of an operation times out. If the returned time is inaccurate, some operations may never time out.