Release notes for minor AliSQL versions

• New features:
  • If the value of innodb_buffer_pool_size is less than 1 GB, the value of innodb_buffer_pool_instances can be greater than 1.
  • If the Native Flashback feature is enabled for an RDS instance, the impact on the performance of the RDS instance is reduced.
• Bug fixes:
  • The bug that causes the Unknown thread id message to be displayed when a user kills a session is fixed.
  • The bug that the settings of the rds_expose_priv_list parameter do not take effect after an RDS instance restarts is fixed.
  • The bug that the Binlog in Redo feature blocks the checkpoint push is fixed.
  • The fixes for Bug#33341080 and Bug#32962511 in MySQL 8.0.25 of MySQL Community Edition are incorporated.

• New features:
  • The updates to the features in MySQL 8.0.25 are incorporated. For more information, see Changes in MySQL 8.0.25.
  • The recovery_apply_binlog mechanism is provided. This mechanism enables the crash-safe feature for XA transactions.
  • The audit log feature is upgraded to version 3. In version 3, a column is added to store transaction IDs, and a field named ext is added to store the identifiers that are used to mark where SQL statements are truncated.
  • A new sequence can be defined as a timestamp sequence. The format of a timestamp sequence is different from the format of a digital sequence. Digital sequences are an outdated type of sequence.

    Users can use the following syntax to create a timestamp sequence: CREATE SEQUENCE seq CACHE [Cache size] TIMESTAMP;.

  • The TRUNCATE permission on the mysql.slow_log table and the mysql.general_log table is granted to privileged accounts.
  • The Native Falshback Query feature is supported. This feature allows users to query the data that is rolled back and restore the data by using SQL statements.
  • A proprietary X-tree structure is provided. This structure is used to create indexes in X-Engine MemTable. This structure also supports writes, point queries, and range queries at high performance.
  • The size of the buffer pool can be adjusted. The adjustment process is optimized to prevent impacts on instance performance.
  • Multiple blocks can be asynchronously read at a time. Users can add the /*+ MULTI_BLOCKS(n) */ hint to SQL statements to prefetch multiple data pages.
  • The logic that is used to scan the linked list of the buffer pool and obtain idle pages is optimized. The least recently used (LRU) algorithm is used to manage the linked list.
  • The UPDATE and DELETE statements that contain a primary key or a unique key can automatically enter a concurrency control (CCL) queue.
  • The amount of time that an RDS instance needs to wait before the RDS instance can process a TCP-based write request can be recorded in the performance_schema.events_statements_summary_by_digest_supplement table.
  • DDL operations that are performed by using the in-place method can be recorded in the redo log.
  • By default, MyISAM is added to the value of the disabled_storage_engines parameter to prevent you from creating MyISAM tables.
• Bug fixes:
  • The bug due to which the execution result of the SHOW GLOBAL STATUS statement is abnormal is fixed.
  • The bug due to which an RDS instance cannot start when the profiling feature of JeMalloc is enabled for the RDS instance is fixed.
  • The bug due to which an RDS instance for which the sequence feature is enabled unexpectedly exits when the INSERT INTO SELECT statement is executed is fixed.
  • The dbms_recycle.restore_table permission is removed. If you need the permission, you can submit a ticket.
  • The number of index scans is added to the I_S.INDEX_STATISTICS table.
  • More metrics that are used to measure the performance of an RDS instance are added to the I_S.PERF_STATISTICS table.
  • The bug that affects the performance of an RDS instance when the user-defined function nextval or currval conflicts with the system function SEQUENCE on the RDS instance is fixed.
  • The bug due to which X-Engine cannot immediately respond to KILL SESSION requests is fixed.
  • The bug that causes inconsistency errors if specific DDL operations fail in extreme circumstances is fixed.
  • The bug that causes a stack overflow is fixed by using a protection mechanism.
  • The bug that prevents the mysqld program from starting when the Binlog in Redo feature and X-Engine are used at the same time is fixed. A system variable named persist_binlog_to_redo is used to specify whether to enable the Binlog in Redo feature.
  • The bug that causes memory leaks when the pthread_getattr_np function is invoked is fixed.
  • The bug due to which ApsaraDB RDS deletes cached pages that are generated by the performance agent feature is fixed.
  • The bug of the Statement outline feature is fixed.
  • The bug due to which ApsaraDB RDS resets the used session tracker when errors occur during the execution of statements is fixed.
  • The ccl_wait_timeout variable is renamed.
  • The bug that prevents ApsaraDB RDS from deleting socket files when the database process stops is fixed. This bug prevents the database process from starting.
  • The priorities of the user-defined functions nextval and currval are adjusted.
  • The bug due to which the net_length_size function returns error 251 is fixed.

• New features:
  • Tables can be restored from the recycle bin. For more information, see Recycle bin.
  • The slow query log files of an RDS instance can be automatically restored when the instance is initialized.
• Performance improvements:

  If X-Engine is used, the Binlog in Redo feature cannot be enabled. For more information, see Binlog in Redo.

• Bug fixes:
  • The bug that causes errors during the execution of the ASSERT statement when the value of the key for the unique index is abnormally large is fixed.
  • The bug that prevents the COM_DAEMON process from stopping is fixed.
  • The bug that causes a cache overflow when Full-Text Search (FTS)-based queries are run is fixed.
  • The bug that causes errors in rollbacks when instant DDL operations become abnormal is fixed.

• New features:
  • The innodb_parallel_read_threads parameter is added to specify whether to allow the count(*) function to run scans in parallel. If this parameter is set to 0, this function cannot run scans in parallel. For more information, see Modify the parameters of an ApsaraDB RDS for MySQL instance.
  • Start global transaction identifiers (GTIDs) and end GTIDs are supported by the mysqlbinlog plug-in.
  • LSNs are supported in the redo log.
    • innodb_lsn: the LSN of each record in the redo log.
    • innodb_log_checkpoint_lsn: the LSN of the last checkpoint.
    • innodb_log_write_lsn: the LSN of each record that is written to the redo log.
    • innodb_log_ready_for_write_lsn: the LSN of the last record that is written to the log buffer.
    • innodb_log_flush_lsn: the LSN of each record that is flushed from the redo log to the disk.
    • innodb_log_dirty_pages_added_up_to_lsn: the LSN of each record that logs a page as dirty.
    • innodb_log_oldest_lsn: the LSN of each record that logs an update to a page.
• Performance improvements:
  • The CCL feature is optimized to schedule and concurrently run transactions in a more efficient manner.
  • The CCL feature is optimized to prioritize stored procedures in a more efficient manner.
• Bug fixes:
  • The bug due to which the recursively called interpreter does not check the memory size is fixed.
  • The bug due to which table definitions cannot be modified when Transparent Data Encryption (TDE) is enabled is fixed.
  • The bug due to which the event scheduler causes memory leaks is fixed.

• New features:
  • The faster DDL feature is supported. This feature provides an optimized buffer pool management mechanism to reduce the impacts of DDL operations on database performance and to increase the number of online DDL operations that can be concurrently run. For more information, see Faster DDL.
  • The maximum number of connections that are allowed is increased to 500,000.
• Performance improvements:
  • The thread pool feature is optimized.
  • The memory allocation mechanism is optimized. Users can specify the maximum memory consumption that is allowed for PERFORMANCE SCHEMA based on the instance type.
  • Audit log files are no longer analyzed.
  • TDE is optimized to cache the keys that are provided by Key Management Service (KMS).
  • The statuses of threads that are managed by the CCL feature are renamed. For more information, see Statement concurrency control.
• Bug fixes:
  • The bug due to which ApsaraDB RDS considers semicolons (;) as part of the statements that are used to create outlines is fixed.
  • The bug due to which an RDS instance unexpectedly exits when tables are modified is fixed.
  • The bug due to which earlier versions do not support the keywords that are supported in later versions is fixed. The keywords are memory and array.
  • The bug due to which ApsaraDB RDS incorrectly counts the number of waits when commands are read from a database client is fixed.
  • The bug that causes failures in updating the minor engine version of an RDS instance is fixed.

• New features:
  • The Binlog in Redo feature is supported. This feature allows ApsaraDB RDS to write binary log records to the redo log before the binary log records are flushed to the disk. This reduces the consumption of I/O resources and improves database performance. For more information, see Binlog in Redo.
  • A restructured row caching mechanism is supported for X-Engine.
  • The XA_RECOVER_ADMIN permission is supported.
• Performance improvements:
  • The code that is used to scan data when operations are performed on a temporary InnoDB table is optimized. This allows ApsaraDB RDS to scan only dirty pages rather than all pages in the buffer pool.
  • The global parameter opt_readonly_trans_implicit_commit is renamed as rds_disable_explicit_trans to ensure compatibility with MySQL 5.6.
  • The upgrades to an RDS instance are no longer recorded by the audit log feature.
  • The memory resources that are consumed by DDL operations on X-Engine tables are reduced.
• Bug fixes:
  • The bug due to which the sizes of X-Engine tables on the disk are inconsistent with the statistics in the INFORMATION_SCHEMA database is fixed.
  • The bug due to which ApsaraDB RDS initializes X-Engine logs when the error log file is re-opened is fixed.

• New features:

  The TRUNCATE TABLE statement is supported. After the statement is executed on a table, ApsaraDB RDS moves the table to a dedicated directory that is used for the recycle bin, and then creates a table that uses the same schema as the truncated table. For more information, see Recycle bin.

• Performance improvements:
  • The output of TCP errors is disabled by default.
  • The thread pool feature is optimized to provide higher performance when the default configurations are used.
• Bug fixes:
  • The bug that causes invalid databases and tables is fixed. This bug is triggered when the names of partitioned tables are separated by the combination of a pound key and a letter p (#p).
  • The bug due to which CCL-managed statements are case-sensitive is fixed.
• The updates to the features in open source MySQL 8.0.17 and MySQL 8.0.18 are incorporated. For more information, see Changes in MySQL 8.0.17 and Changes in MySQL 8.0.18.

• New features:
  • The performance agent feature is supported. For more information, see Performance Agent. This feature is provided as a MySQL plug-in. This feature allows ApsaraDB RDS to compute and analyze the metrics that are used to measure the performance of an RDS instance.
  • A metric is provided to measure the round trip time over the network. This metric helps users monitor the performance of an RDS instance that runs in semi-synchronous mode.
  • Online DDL operations are supported by X-Engine.
• Performance improvements:
  • The CCL feature is optimized to control the concurrency of statements on read-only RDS instances.
  • The outline feature is optimized to support outlines on secondary RDS instances.
  • The database proxy feature is enhanced to optimize short-lived connections.
  • The amount of time that is required to execute the PAUSE statement is reduced in various CPU architectures.
  • A memory summary table is added to provide the statuses of thread pools.
• Bug fixes:
  • The bug due to which ApsaraDB RDS forbids the ppoll function and replaces the ppoll function with the poll function is fixed. This bug is found in Linux kernel versions earlier than 4.9.
  • The bug that causes errors when the wrap_sm4_encrypt function is invoked is fixed.
  • The bug due to which ApsaraDB RDS locks global variables during the rotation of audit logs is fixed.
  • The bug that causes errors during restoration inconsistency checks is fixed.
  • The bug that causes inaccurate time values in the io_statistics table is fixed.
  • The bug due to which an RDS instance unexpectedly exits when invalid compression algorithms are used is fixed.
  • The bug that causes user columns in MySQL 8.0 and MySQL 5.6 to be incompatible is fixed.
• Optimized programs:
  • The faster DDL feature is supported. This feature provides an optimized buffer pool management mechanism to reduce the impacts of DDL operations on database performance and to increase the number of online DDL operations that can be concurrently run. For more information, see Faster DDL.
  • The thread pool feature is optimized to improve database performance.
  • The mechanism that is used for reference counting is optimized to prevent memory leaks in buffers.

• New features:

  Three hints are added. These hints can be used in the following statements to commit transactions and roll transactions back at high speeds: SELECT, UPDATE, INSERT, and DELETE. This increases the throughput of applications. For more information, see Inventory Hint.

• Performance improvements:
  • The CCL feature is optimized. When an RDS instance starts, CCL queue structures are initialized before CCL rules are initialized.
  • The file deletion mechanism is optimized. When ApsaraDB RDS asynchronously deletes files, the links to small files are removed.
  • The thread pool feature is optimized. For more information, see Thread Pool.
  • The restoration inconsistency check feature is disabled by default.
  • The permissions that are required to configure variables are changed.
    • Standard accounts can be granted the permissions to configure the following variables:
      • auto_increment_increment
      • auto_increment_offset
      • bulk_insert_buffer_size
      • binlog_rows_query_log_events
    • Superuser accounts and system variable administrators can be granted the permissions to configure the following variables:
      • binlog_format
      • binlog_row_image
      • binlog_direct
      • sql_log_off
      • sql_log_bin

• New features:

  The recycle bin feature is supported. All tables that are deleted are moved to the recycle bin. Users can specify a retention period within which tables can be retrieved from the recycle bin. For more information, see Recycle bin.

• Performance improvements:
  • The mechanism that is used to process short-lived connections is optimized.
  • A dedicated thread is used for the maintain_user variable. This prevents high-availability failures.
  • The locking mechanism is optimized. If an error occurs when the redo mechanism is used to flush binary log records, ApsaraDB RDS can explicitly release the locks that are triggered by file synchronization.
  • Unnecessary TCP error logs can be deleted.
  • The thread pool feature is enabled by default.
• Bug fixes:
  • The bug that causes errors during the updates of slow query logs is fixed.
  • The bug that causes an inappropriate lock scope is fixed.
  • The bug that causes errors in core dumps when the select() function is invoked for TDE is fixed.

New features:

The statement queue feature is supported. This feature allows statements to be queued in the same bucket. These statements can be executed on the same resources. For example, these statements can be executed on the same row of a table. This feature helps reduce the overhead that is caused by conflicts. For more information, see Statement Queue.

• New features:
  • The SM4 encryption algorithm is supported for TDE. For more information, see Configure TDE for an ApsaraDB RDS for MySQL instance.
  • Data protection is supported for secondary RDS instances. Only the accounts that have the SUPER permission or the REPLICATION_SLAVE_ADMIN permission are authorized to insert, delete, and modify data in the slave_master_info, slave_relay_log_info, and slave_worker_info tables.
  • A mechanism is provided to increase the priorities of auto-increment keys. If a table does not have a primary key or the table does not have a unique key without a null value, the auto-increment key without a null value is assigned the highest priority.
  • A mechanism is provided to prevent the automatic conversion of tables from the MEMORY storage engine to the MyISAM storage engine. These tables include system tables and the tables that are called by threads in the initializing state.
  • A mechanism is provided to flush binary log records to the disk before redo log records.
  • A mechanism is provided to stop the creation of temporary tables on an RDS instance when the RDS instance is locked.
  • X-Engine that is based on a log-structured merge (LSM) tree is provided to store transactions.
• Performance improvements:
  • The thread pool feature is optimized to reduce mutual exclusions (mutexes). For more information, see Thread Pool.
  • The performance insight feature is optimized to monitor thread pools. For more information, see Performance Insight.
  • The following parameters are adjusted:
    • primary_fast_lookup: a session parameter. The default value is true.
    • thread_pool_enabled: a global parameter. Default value: true.

• New features:
  • The TDE feature is provided to support real-time I/O encryption and decryption of data files. This feature encrypts data before the data is written to the disk and decrypts data before the data is read from the disk and written to the memory. For more information, see Configure TDE for an ApsaraDB RDS for MySQL instance.
  • The returning feature is provided. This feature allows DML statements to return result sets. The DBMS_TRANS package is provided for users to use this feature with ease. For more information, see Returning.
  • Forced conversion from the MyISAM or MEMORY storage engine to the InnoDB storage engine is supported. If the global variable force_mysiam_to_innodb or force_memory_to_innodb is set to ON, tables are automatically converted from the MyISAM or MEMORY storage engine to the InnoDB storage engine when the tables are created or modified.
  • A mechanism is provided to prevent accounts that are not privileged accounts from performing primary/secondary switchovers. Only privileged accounts are granted the permissions to perform primary/secondary switchovers.
  • A performance proxy plug-in is provided. This plug-in obtains performance data and saves the data as TXT files to on-premises computers. A round-robin algorithm is used to retain only the most recent files that contains performance data at the single-digit second level.
  • A timeout period can be configured for mutexes in InnoDB. Users can change the timeout period by using the global variable innodb_fatal_semaphore_wait_threshold. The default value of the global variable is 600.
  • Index hint errors can be ignored. Users can configure an RDS instance to ignore index hint errors by using the global variable ignore_index_hint_error. The default value of the global variable is false.
  • The SSL encryption feature can be disabled. For more information, see Configure SSL encryption for an ApsaraDB RDS for MySQL instance.
  • The output of TCP errors is supported. TCP read, read-wait, and write-wait errors are returned together with error codes in end_connection events. Log records that contain the information about the errors are also generated.
• Bug fixes:
  • The bug due to which a Linux operating system cannot merge local asynchronous I/O (AIO) requests before linear Read Ahead is triggered is fixed.
  • The bug due to which ApsaraDB RDS inaccurately collects statistics about tables and indexes is fixed.
  • The bug that prevents direct access to the primary key index of a table when a primary key is specified for the table is fixed.

Bug fixes:

The bug that causes memory leaks when the Cmd_set_current_connection process runs is fixed.

• New features:
  • The thread pool feature is provided to separate threads from sessions. If a large number of sessions are created, ApsaraDB RDS can run a small number of threads to complete the tasks in active sessions. For more information, see Thread Pool.
  • The CCL feature is supported. Users can specify the maximum number of concurrent requests that are allowed for an RDS instance. This way, the RDS instance can handle traffic bursts, process statements that consume an excessive number of resources, and adapt to the changes in SQL models. The CCL feature helps ensure the continuity and stability of RDS instances. For more information, see Statement concurrency control.
  • The statement outline feature is provided to support optimizer hints and index hints. These hints are used to ensure that ApsaraDB RDS can run query plans in a stable manner. For more information, see Statement outline.
  • The Sequence engine is provided to simplify the generation of sequence values. For more information, see Sequence Engine.
  • The Purge Large File Asynchronously feature is provided to asynchronously delete files. Before a tablespace is deleted, ApsaraDB RDS renames the files in the tablespace as temporary files. Then, ApsaraDB RDS starts background threads to asynchronously delete the temporary files. For more information, see Purge Large File Asynchronously.
  • The performance insight feature is provided to support load monitoring, association analysis, and performance optimization at the instance level. This feature allows users to evaluate the loads on an RDS instance and troubleshoot performance issues. This way, the stability of the RDS instance can be ensured. For more information, see Performance Insight.
  • An optimized instance locking mechanism is provided. This mechanism allows users to drop or truncate tables on an RDS instance even if the RDS instance is locked.
• Bug fixes:
  • The bug due to which ApsaraDB RDS incorrectly calculates file sizes is fixed.
  • The bug due to which irrelevant processes can reuse idle memory resources is fixed.
  • The bug due to which a host unexpectedly exits when the available cache size on the host is 0 is fixed.
  • The bug that causes conflicts between implicit primary keys and CTS statements is fixed.
  • The bug due to which ApsaraDB RDS incorrectly generates logs for slow queries is fixed.

• Performance improvements:
  • Metadata locking on logging tables is reduced.
  • The code for termination options is restructured.
• Bug fixes:
  • The bug due to which precompiled statements are not recorded by the audit log feature is fixed.
  • The bug due to which ApsaraDB RDS cannot mask error log records in logging tables when the names of the logging tables are invalid is fixed.

The bug that causes memory leaks for PERFORMANCE SCHEMA is fixed.

SSL encryption can be enabled for the dedicated proxy of an RDS instance.

A metadata-related bug is fixed.

• New features:

  The TRUNCATE TABLE statement is supported. After the statement is executed on a table, ApsaraDB RDS moves the table to a dedicated directory that is used for the recycle bin, and then creates a table that uses the same schema as the truncated table. For more information, see Recycle bin.

• Performance improvements:
  • The output of TCP errors is disabled by default.
  • The thread pool feature is optimized to provide higher performance when the default configurations are used.
• Bug fixes:
  • The bug that causes invalid databases and tables is fixed. This bug is triggered when the names of partitioned tables are separated by the combination of a pound key and a letter p (#p).
  • The bug due to which CCL-managed statements are case-sensitive is fixed.
• The updates to the features in open source MySQL 8.0.17 and MySQL 8.0.18 are incorporated. For more information, see Changes in MySQL 8.0.17 and Changes in MySQL 8.0.18.

• New features:
  • The performance agent feature is supported. For more information, see Performance Agent. This feature is provided as a MySQL plug-in. This feature allows ApsaraDB RDS to compute and analyze the metrics that are used to measure the performance of an RDS instance.
  • A metric is provided to measure the round trip time over the network. This metric helps users monitor the performance of an RDS instance that runs in semi-synchronous mode.
• Performance improvements:
  • The CCL feature is optimized to control the concurrency of statements on read-only RDS instances.
  • The outline feature is optimized to support outlines on secondary RDS instances.
  • The database proxy feature is enhanced to optimize short-lived connections.
  • The amount of time that is required to execute the PAUSE statement is reduced in various CPU architectures.
  • A memory summary table is added to provide the statuses of thread pools.
• Bug fixes:
  • The bug due to which ApsaraDB RDS forbids the ppoll function and replaces the ppoll function with the poll function is fixed. This bug is found in Linux kernel versions earlier than 4.9.
  • The bug that causes errors when the wrap_sm4_encrypt function is invoked is fixed.
  • The bug due to which ApsaraDB RDS locks global variables during the rotation of audit logs is fixed.
  • The bug that causes errors during restoration inconsistency checks is fixed.
  • The bug that causes inaccurate time values in the io_statistics table is fixed.
  • The bug due to which an RDS instance unexpectedly exits when invalid compression algorithms are used is fixed.
  • The bug that causes user columns in MySQL 8.0 and MySQL 5.6 to be incompatible is fixed.
• Optimized programs:
  • The faster DDL feature is supported. This feature provides an optimized buffer pool management mechanism to reduce the impacts of DDL operations on database performance and to increase the number of online DDL operations that can be concurrently run. For more information, see Faster DDL.
  • The thread pool feature is optimized to improve database performance.
  • The mechanism that is used for reference counting is optimized to prevent memory leaks in buffers.

• New features:
  • The updates to the features in MySQL 5.7.37 are incorporated. For more information, see Changes in MySQL 5.7.37.
  • The SSL encryption feature is optimized, and a few bugs of the feature are fixed.
  • The permissions to manage the system or performance_schema database are revoked from standard accounts.
• Bug fixes:

  The bug that causes the level of the FLUSH TABLES WITH READ LOCK and UNLOCK TABLES logs to be warning in error logs is fixed. This fix facilitates online troubleshooting.

• New features:
  • The updates to the features in MySQL 5.7.35 are incorporated. For more information, see Changes in MySQL 5.7.35.
  • The InnoDB buffer pool can be flexibly resized. The impact of a resizing operation is reduced, and user experience is improved.
  • The two-way replication mechanism is optimized. Unnecessary binary logs are no longer replicated. In addition, heartbeat events are no longer generated when events are skipped.
  • Users no longer need to restart their RDS instance after they reconfigure the log_slave_updates parameter.
  • The FLUSH TABLES WITH READ LOCK and UNLOCK TABLES logs are added to error logs.
  • The innodb_control_index_page_reserve parameter is added. If this parameter is set to ON, page splitting and storage usage are reduced.
• Bug fixes:
  • The bug due to which the performance agent feature cannot collect CPU usage statistics as expected in the new docker architecture is fixed.
  • The bug due to which session tracker type numbers retained in ApsaraDB RDS are incorrect is fixed.
  • The bug due to which an RDS instance unexpectedly exits and cannot be restored to normal when the size of MTR logs exceeds the size of the log parsing buffer is fixed.
  • Memory pages can be marked as MADV_DONTDUMP. If the innodb_buffer_pool_in_core_file parameter is set to off, core dumps no longer contain the InnoDB buffer pool. This way, the storage that is occupied by core dumps is reduced.
  • The bug due to which the value of the start_time field in the mysql.slow_log table is incorrect is fixed. After the bug is fixed, the field records the time at which the execution of an SQL statement starts rather than the time at which the execution of an SQL statement ends.
  • The Show_db_priv permission is available to standard accounts.
  • The bug due to which memory leaks may occur when the LF_HASH_INSERT function is invoked is fixed.
  • The bug due to which the recycle bin does not support tables that contain virtual columns is fixed.

• New features:
  • The audit log format MYSQL_V3 is supported.
  • Slow query logs and general logs can be truncated.
  • A mechanism is provided to detect out of memory (OOM) exceptions in the thread stack.
  • The thread_pool_strict_mode parameter is supported. This parameter is used to limit the maximum number of worker threads.
• Bug fixes:
  • The bug due to which ApsaraDB RDS deletes outdated socket lock files when the mysqld_safe script is run to start the mysqld process is fixed.
  • The bug that causes memory leaks in the recycle bin is fixed.

• New features:
  • The recycle bin feature is supported. For more information, see Recycle bin.
  • The Sequence engine feature is supported. For more information, see Sequence Engine.
• Performance improvements:
  • More metrics that are used to measure the performance of an RDS instance are added to the I_S.PERF_STATISTICS table.
  • The number of index scans is added to the I_S.INDEX_STATISTICS table.
  • The TDE feature is optimized to improve database performance.
• Bug fixes:

  The bug that causes column generation exceptions during a rollback is fixed. This bug is found in MySQL Community Edition.

Bug fixes:

• The bug due to which the ROW_SEARCH_MVCC function unexpectedly exits when concurrent updates are performed is fixed.
• The bug due to which an RDS instance cannot start when the innodb_undo_tablespaces parameter is reconfigured for the RDS instance is fixed.
• The bug that causes a cache overflow when FTS-based queries are run is fixed.

• New features:
  • The updates to the features in open source MySQL 5.7.30 are incorporated. For more information, visit GitHub.
  • The CCL feature is optimized to schedule and concurrently run transactions in a more efficient manner.
  • Start GTIDs and end GTIDs are supported by the mysqlbinlog plug-in.
  • LSNs are supported in the redo log.
    • innodb_lsn: the LSN of each record in the redo log.
    • innodb_log_write_lsn: the LSN of each record that is written to the redo log.
    • innodb_log_checkpoint_lsn: the LSN of the last checkpoint.
    • innodb_log_flushed_lsn: the LSN of each record that is flushed from the redo log to the disk.
    • innodb_log_Pages_flushed: the LSN of each record that logs an update to a page.
• Performance improvements:

  The CCL feature is optimized to prioritize stored procedures in a more efficient manner.

• Bug fixes:

  The bug due to which an RDS instance may incorrectly count the number of pages that are referenced from temporary tables is fixed. This bug may cause inefficient flushing of dirty blocks from the buffer pool to the disk. As a result, no idle pages are available in the buffer pool, and database performance deteriorates. For more information, see the official MySQL documentation.

• New features:
  • Three hints are added. These hints can be used in the following statements to commit transactions and roll transactions back at high speeds: SELECT, UPDATE, INSERT, and DELETE. This increases the throughput of applications. For more information, see Inventory Hint.
  • The CCL feature is supported. Users can specify the maximum number of concurrent requests that are allowed for an RDS instance. This way, the RDS instance can handle traffic bursts, process statements that consume an excessive number of resources, and adapt to the changes in SQL models. The CCL feature helps ensure the continuity and stability of RDS instances. For more information, see Statement concurrency control.
  • The statement queue feature is supported. This feature allows statements to be queued in the same bucket. These statements can be executed on the same resources. For example, these statements can be executed on the same row of a table. This feature helps reduce the overhead that is caused by conflicts. For more information, see Statement Queue.
  • The statement outline feature is provided to support optimizer hints and index hints. These hints are used to ensure that ApsaraDB RDS can run query plans in a stable manner. For more information, see Statement outline.
  • The faster DDL feature is supported. This feature provides an optimized buffer pool management mechanism to reduce the impacts of DDL operations on database performance and to increase the number of online DDL operations that can be concurrently run. For more information, see Faster DDL.
  • The maximum number of connections that are allowed is increased to 500,000.
• Performance improvements:
  • The call dbms_admin.show_native_procedure(); command can be run to display all procedures of an RDS instance.
  • A new function is provided to delete orphan tables.
  • The thread pool feature is optimized.
  • Query caching is optimized.
  • The memory allocation mechanism is optimized. Users can specify the maximum memory consumption that is allowed for PERFORMANCE SCHEMA based on the instance type.
• Bug fixes:

  The bug due to which an audit update thread enters an infinite loop is fixed.

• Performance improvements:

  Read-write locks are no longer supported in the query cache. The default hash function is changed from LF_hash to murmur3 hash.

• Bug fixes:

  Two bugs that occur when ApsaraDB RDS hits the requested data in the query cache are fixed. These bugs are triggered if transactions at the REPEATABLE_READ isolation level are run.

• New features:
  • The fast query cache is supported. The fast query cache is developed by Alibaba Cloud based on the native MySQL query cache. The fast query cache uses a new design and a new query mechanism to improve query performance. For more information, see Fast query cache.
  • Two metadata locks from Percona Server 5.7 are supported: LOCK TABLES FOR BACKUP (LTFB) and LOCK BINLOG FOR BACKUP (LBFB).
• Performance improvements:
  • The thread pool feature is optimized to ensure compatibility with earlier MySQL versions.
  • The output of TCP errors is disabled by default.
  • The thread pool feature is optimized to provide higher performance when the default configurations are used.
• Bug fixes:
  • The bug due to which ApsaraDB RDS deletes temporary files when large files are deleted is fixed.
  • The bug due to which dump threads in thread pools time out is fixed.
  • The bug due to which ApsaraDB RDS incorrectly counts the value of the IPK field in the procedure context is fixed.
  • The bug that causes the leak and release of PFS threads when the rds_change_user command is run is fixed.
• The updates to the features in open source MySQL 5.7.28 are incorporated. For more information, visit GitHub.

• New features:
  • The performance agent feature is supported. For more information, see Performance Agent. This feature is provided as a MySQL plug-in. This feature allows ApsaraDB RDS to compute and analyze the metrics that are used to measure the performance of an RDS instance.
  • A metric is provided to measure the round trip time over the network. This metric helps users monitor the performance of an RDS instance that runs in semi-synchronous mode.
• Performance improvements:
  • The amount of time that is required to execute the PAUSE statement is reduced in various CPU architectures.
  • The database proxy feature is enhanced to optimize short-lived connections.
  • A memory summary table is added to provide the statuses of thread pools.
• Bug fixes:
  • The bug that compromises the security of DDL-related redo log records is fixed.
  • The bug that causes inaccurate time values in the io_statistics table is fixed.
  • The bug due to which an RDS instance unexpectedly exits when tables are modified is fixed.
  • The bugs in MySQL test cases are fixed.

Performance improvements:

• The file deletion mechanism is optimized. When ApsaraDB RDS asynchronously deletes files, the links to small files are removed.
• The thread pool feature is optimized. For more information, see Thread Pool.
• The default value of the thread_pool_enabled parameter is changed to OFF.

• New features:

  The management of internal accounts is supported. This allows users to manage permissions and protect data in a more efficient manner.

• Performance improvements:
  • The mechanism that is used to process short-lived connections is optimized.
  • A dedicated thread is used for the maintain_user variable. This prevents high-availability failures.
  • Unnecessary TCP error logs can be deleted.
  • The thread pool feature is optimized.
• Bug fixes:
  • The bug due to which the mysqld process unexpectedly exits when the read/write splitting feature is enabled is fixed.
  • The bug that causes errors in core dumps when a keyring is used is fixed.

Bug fixes:

The bug due to which ApsaraDB RDS displays variables in audit logs when a primary/secondary switchover is performed is fixed.

• New features:
  • The SM4 encryption algorithm is supported for TDE. For more information, see Configure TDE for an ApsaraDB RDS for MySQL instance.
  • The bug that prevents direct access to the primary key index of a table when a primary key is specified for the table is fixed.
  • A mechanism is provided to prevent the automatic conversion of tables from the MEMORY storage engine to the MyISAM storage engine. These tables include system tables and the tables that are called by threads in the initializing state.
• Performance improvements:
  • The thread pool feature is optimized to reduce mutexes. For more information, see Thread Pool.
  • An audit log caching mechanism is provided to improve logging performance.
  • The performance insight feature is optimized to monitor thread pools. For more information, see Performance Insight.
  • The thread pool feature is enabled by default. For more information, see Thread Pool.
• Bug fixes:
  • The bug due to which locks on user tables are released when the user tables are being managed or maintained is fixed.
  • More TCP errors are added.

• New features:
  • The rotation of slow query logs is supported. Each CSV slow query log file is assigned a unique name and saved as a new file. This prevents data loss during the collection of slow query logs. Users can run the show variables like '%rotate_log_table%'; command to check whether the rotation of slow query logs is enabled.
  • A performance proxy plug-in is provided. This plug-in obtains performance data and saves the data as TXT files to on-premises computers. A round-robin algorithm is used to retain only the most recent files that contains performance data at the single-digit second level.
  • Forced conversion from the MEMORY storage engine to the InnoDB storage engine is supported. If the global variable rds_force_memory_to_innodb is set to ON, tables are automatically converted from the MEMORY storage engine to the InnoDB storage engine when the tables are created or modified.
  • The keyring-rds plug-in is supported for TDE. This plug-in allows ApsaraDB RDS to communicate with the administration system or KMS.
  • The output of TCP errors is supported. TCP read, read-wait, and write-wait errors are returned together with error codes in end_connection events. Log records that contain the information about the errors are also generated.
• Bug fixes:

  The bug that causes error 1290 in DDL operations is fixed.

Adjusted parameters:

• The default value of the system variable auto_generate_certs is changed from true to false.
• The global read-only variable auto_detact_certs is added. Valid values: true and false. Default value: false. This variable is supported for an RDS instance only when OpenSSL is used to compile code on the RDS instance. This variable specifies whether the RDS instance automatically searches for SSL certificate files and key files in the data directory of the host on which the RDS instance resides.

New features:

The thread pool feature is provided to separate threads from sessions. If a large number of sessions are created, ApsaraDB RDS can run a small number of threads to complete the tasks in active sessions. For more information, see Thread Pool.

• New features:
  • The Purge Large File Asynchronously feature is provided to asynchronously delete files. Before a tablespace is deleted, ApsaraDB RDS renames the files in the tablespace as temporary files. Then, ApsaraDB RDS starts background threads to asynchronously delete the temporary files. For more information, see Purge Large File Asynchronously.
  • The performance insight feature is provided to support load monitoring, association analysis, and performance optimization at the instance level. This feature allows users to evaluate the loads on an RDS instance and troubleshoot performance issues. This way, the stability of the RDS instance can be ensured. For more information, see Performance Insight.
  • An optimized instance locking mechanism is provided. This mechanism allows users to drop or truncate tables on an RDS instance even if the RDS instance is locked.
• Bug fixes:
  • The bug that allows users to set the rds_prepare_begin_id parameter in the set rds_current_connection command is fixed.
  • The bug due to which ApsaraDB RDS cannot update the information about locked accounts is fixed.
  • The bug due to which actual can be used as a keyword in table names is fixed.
  • The bug that causes an overflow of timestamps in slow query logs is fixed.

New features:

The creation of temporary tables in transactions is supported.

New features:

The configuration of thread IDs for proxies in handshake packets is supported.

• Performance improvements:
  • Open source MySQL 5.7.25 is supported.
  • JeMalloc that is used for memory management is disabled.
• Bug fixes:

  The bug due to which ApsaraDB RDS incorrectly calculates the value of the internal variable net_lenth_size is fixed.

• New features:

  Dynamic modifications to the system variable binlog-row-event-max-size are supported. This accelerates the replication of tables that do not have a primary key.

• Bug fixes:

  The bug due to which the proxy instances of an RDS instance cannot apply for memory resources is fixed.

Performance improvements:

• Implicit primary keys are supported.
• The replication of tables that do not have a primary key between a primary RDS instance and its secondary RDS instance is accelerated.
• Native AIO is provided to improve I/O performance.

New features:

• RDS High-availability Edition is supported.
• The SQL Audit feature is supported. For more information, see Connect to the RDS instance. For more information, see SQL audit.
• The protection for RDS instances on which snapshot backups are being created is enhanced.

• The bug due to which an RDS instance unexpectedly exits or is unexpectedly stuck is fixed.
• The bug due to which prefix indexes are considered to be invisible indexes is fixed.
• The bug due to which a logger RDS instance is in an abnormal state based on the consensus protocol is fixed. If this bug persists, ApsaraDB RDS may fail to elect an eligible RDS instance as the primary RDS instance.

• New features:

  The read/write splitting feature is supported.

• Bug fixes:
  • The bug due to which ApsaraDB RDS incorrectly calculates the value of the Second_Behind_Master metric for a follower is fixed.
  • The bug that causes deadlocks when users run specific table-level parallel replication transactions for a second time is fixed.
  • XA-related bugs are fixed.

• New features:
  • The upgrade from RDS High-availability Edition to RDS Enterprise Edition is supported for RDS instances that use local SSDs.
  • GTIDs that are provided by open source MySQL are supported. GTIDs are disabled by default.
  • All proprietary AliSQL features that are released by Alibaba Cloud for RDS Basic Edition and RDS High-availability Edition in 20190915 and earlier minor engine versions are incorporated.
• Bug fixes:

  The bug due to which binary logs are disabled for a primary RDS instance when the secondary RDS instance of the primary RDS instance is reset is fixed.

• New features:
  • A mechanism is provided to ensure that large transactions are run at high speeds when data is replicated between a primary RDS instance, its secondary RDS instance, and its logger RDS instance in synchronous mode.
  • Binary log records can be dumped from a leader or a follower.
  • Read-only RDS instances can be created.
  • The InnoDB storage engine is used for system tables by default.
• Bug fixes:
  • The bug that invalidates the commands that are run by a follower to delete logs is fixed.
  • The bug due to which slave threads unexpectedly exit is fixed. This bug is triggered when the slave_sql_verify_checksum parameter is set to OFF and the binlog_checksum parameter is set to crc32.

New features:

• RDS Enterprise Edition is supported.
• The semi-sync plug-in can be disabled.
• Table-level parallel replication and write set-level parallel replication are supported.
• The pk_access module is provided to accelerate queries that are run based on primary keys.
• The thread pool feature is supported.
• All proprietary AliSQL features that are released by Alibaba Cloud for RDS Basic Edition and RDS High-availability Edition in 20190510 and earlier minor engine versions are incorporated.

• New features:

  A mechanism is provided to detect OOM exceptions in the thread stack.

• Bug fixes:
  • The bugs in MySQL 5.6 Community Edition are fixed.
  • The operation limits on the SHOW CREATE statement in the mysql system database are removed.

• Performance improvements:

  More metrics that are used to measure the performance of an RDS instance are added to the I_S.PERF_STATISTICS table.

• Bug fixes:

  The bugs that cause memory leaks in MySQL Community Edition are fixed.

• The bug that invalidates the subqueries that are nested in IN clauses is fixed.
• The bug that causes errors in the permissions on processes is fixed.
• The bug that causes errors in the permissions of users in the kill_user_list table is fixed.
• The bug that causes errors when the DROP DATABASE statement is executed is fixed.
• The bug due to which ApsaraDB RDS incorrectly calculates the value of the SECONDS_BEHIND_MASTER parameter due to PREVIOUS_GTID events is fixed.

• New features:

  LSNs are supported in the redo log.

  • innodb_lsn: the LSN of each record in the redo log.
  • innodb_log_write_lsn: the LSN of each record that is written to the redo log.
  • innodb_log_checkpoint_lsn: the LSN of the last checkpoint.
  • innodb_log_flushed_lsn: the LSN of each record that is flushed from the redo log to the disk.
  • innodb_log_Pages_flushed: the LSN of each record that logs an update to a page.
• Bug fixes:
  • The bug due to which the SHOW_HA_ROWS statement returns invalid enumeration types is fixed.
  • The bug due to which ApsaraDB RDS incorrectly counts the value of the IPK field in the procedure context is fixed.
  • The bug due to which an RDS instance unexpectedly exits when data is queried from the INFORMATION_SCHEMA database is fixed.
  • The bug due to which an audit update thread enters an infinite loop is fixed.
  • The bug due to which secondary RDS instances cannot report data replication latencies is fixed.

• New features:
  • The performance agent feature is supported. For more information, see Performance Agent. This feature is provided as a MySQL plug-in. This feature allows ApsaraDB RDS to compute and analyze the metrics that are used to measure the performance of an RDS instance.
  • The maximum number of connections that are allowed is increased to 500,000.
  • The faster DDL feature is supported. This feature provides an optimized buffer pool management mechanism to reduce the impacts of DDL operations on database performance and to increase the number of online DDL operations that can be concurrently run. For more information, see Faster DDL.
• Performance improvements:
  • The global parameter max_execution_time is supported. If the amount of time that is required to execute an SQL statement exceeds the value of this parameter, the SQL statement is paused.
  • The thread pool feature is optimized.
• Bug fixes:
  • The bug due to which ApsaraDB RDS incorrectly counts the number of waits when commands are read from a database client is fixed.
  • The bug due to which standard accounts cannot be granted the permissions to execute the DROP DATABASE statement is fixed.

• New features:

  The mdl_info table is provided to store the information about metadata locks.

• Bug fixes:

  The bug that causes conflicts between the thread pool feature and the ic_reduce feature is fixed.

Performance improvements:

• The thread pool feature is optimized to provide higher performance when the default configurations are used.
• The output of TCP errors is disabled by default.

• New features:

  The read/write splitting feature is supported for database proxies.

• Performance improvements:
  • The thread pool feature is optimized.
  • The amount of time that is required to execute the PAUSE statement is reduced in various CPU architectures.
• Bug fixes:

  The bug due to which ApsaraDB RDS partially commits XA transactions is fixed.

• New features:

  The thread pool feature is provided to separate threads from sessions. If a large number of sessions are created, ApsaraDB RDS can run a small number of threads to complete the tasks in active sessions. For more information, see Thread Pool.

• Performance improvements:

  The file deletion mechanism is optimized. When ApsaraDB RDS asynchronously deletes files, the links to small files are removed.

• Bug fixes:
  • The bug due to which ApsaraDB RDS incorrectly calculates the sleep time of the page cleaner is fixed.
  • The bug due to which the SELECT @@global.gtid_executed statement triggers failover failures is fixed.
  • The bug that causes the "IF CLIENT KILLED AFTER ROLLBACK TO SAVEPOINT PREVIOUS STMTS COMMITTED" error is fixed. For more information, see IF CLIENT KILLED AFTER ROLLBACK TO SAVEPOINT PREVIOUS STMTS COMMITTED.

Unnecessary TCP error logs can be deleted.

The bug that causes an overflow of timestamps in slow query logs is fixed.

• The bug due to which ApsaraDB RDS rotates slow query logs when logs are updated is fixed.
• Some display-related bugs are fixed.

• New features:
  • The rotation of slow query logs is supported. Each CSV slow query log file is assigned a unique name and saved as a new file. This prevents data loss during the collection of slow query logs. Users can run the show variables like '%rotate_log_table%'; command to check whether the rotation of slow query logs is enabled.
  • A new SM4 encryption algorithm is provided to replace the previously used SM4 encryption algorithm.
  • The Purge Large File Asynchronously feature is provided to asynchronously delete files. Before a tablespace is deleted, ApsaraDB RDS renames the files in the tablespace as temporary files. Then, ApsaraDB RDS starts background threads to asynchronously delete the temporary files. For more information, see Purge Large File Asynchronously.
  • The output of TCP errors is supported. TCP read, read-wait, and write-wait errors are returned together with error codes in end_connection events. Log records that contain the information about the errors are also generated.
  • An audit log caching mechanism is provided to improve logging performance.
• Bug fixes:
  • The bug that prevents responses to the pstack command when a large number of connections are established is fixed by disabling the pstack command.
  • The bug that causes conflicts between implicit primary keys and the CREATE TABLE AS SELECT statement is fixed.
  • The bug due to which ApsaraDB RDS cannot delete temporary files that are created from binary log files is fixed.

An optimized instance locking mechanism is provided. This mechanism allows users to drop or truncate tables on an RDS instance even if the RDS instance is locked.

The bugs that compromise database stability are fixed.

The rocksdb_ddl_commit_in_the_middle parameter is supported by MyRocks. If this parameter is set to on, some DDL statements call the COMMIT operation when they are executed.

Slow query logs can be collected at the microsecond level.

• New features:

  Invisible indexes are supported. For more information, see AliSQL 5.6.32 Release Notes (2017-07-16).

• Bug fixes:
  • The bug due to which ApsaraDB RDS applies threads on secondary RDS instances is fixed.
  • The bug that compromises database performance when updates to partitioned tables are applied on secondary RDS instances is fixed.
  • The bug due to which TokuDB rebuilds tables when the ALTER TABLE COMMENT statement is executed on these tables is fixed. For more information, see AliSQL 5.6.32 Release Note (2018-05-01).
  • The bug that causes deadlocks when the SHOW SLAVE STATUS statement or the SHOW STATUS statement is executed is fixed.

• The bug that causes deadlocks when the OPTIMIZE TABLE statement and the ONLINE ALTER TABLE statement are executed at the same time is fixed.
• The bug that causes conflicts between sequences and implicit primary keys is fixed.
• The bug due to which ApsaraDB RDS cannot correctly execute the SHOW CREATE SEQUENCE statement is fixed.
• The bug due to which ApsaraDB RDS inaccurately collects statistics about TokuDB tables is fixed.
• The bug that causes deadlocks when the OPTIMIZE statement is executed on multiple tables in parallel is fixed.
• The bug due to which ApsaraDB RDS inaccurately records character sets in QUERY_LOG_EVENT is fixed.
• The bug due to which an RDS instance cannot stop if signal processing errors occur is fixed. For more information, see AliSQL 5.6.32 Release Notes (2017-10-10).
• The bug that causes errors when the RESET MASTER statement is executed is fixed.
• The bug due to which secondary RDS instances are stuck in the waiting state is fixed.
• The bug due to which the statuses of a primary RDS instance and its secondary RDS instance are incorrect after a primary/secondary switchover is fixed. This bug is found in RDS Enterprise Edition.
• The bug due to which the database process may unexpectedly exit when the SHOW CREATE TABLE statement is executed is fixed.

The bug due to which ApsaraDB RDS queries TokuDB tables based on inappropriate indexes is fixed.

• New features:
  • The update of SSL encryption to TLS 1.2 is supported. For more information, see AliSQL 5.6.32 Release Notes (2017-10-10).
  • Sequences are supported.
• Bug fixes:

  The bug due to which ApsaraDB RDS returns an inaccurate result set for a NOT IN query is fixed.

The privileged account of an RDS instance is granted the permissions to close all connections that are established by the standard accounts of the RDS instance.

The read/write splitting feature is supported. For more information, see Enable the proxy terminal feature for an ApsaraDB RDS for MySQL instance.

The bug due to which the gettimeofday(2) function returns an inaccurate time value is fixed. The returned time value is used to calculate the timeout period. If the time value that is returned is inaccurate, some operations never time out.