ApsaraDB for Redis Enhanced Edition (Tair)

• Performance-enhanced instances use the multi-threading model to provide approximately three times the performance of ApsaraDB for Redis Community Edition instances with the same specifications.
• Performance-enhanced instances provide multiple enhanced data structure modules such as TairString (including CAS and CAD commands), TairHash, TairGIS, TairBloom, TairDoc, TairTS, TairCpc, TairZset, and TairRoaring. Performance-enhanced instances eliminate concerns about storage structure and timeliness and allow you to focus on business development.
• Performance-enhanced instances provide high compatibility. Performance-enhanced instances are fully compatible with open source Redis. You can switch from open source Redis to ApsaraDB for Redis without the need to modify application code.
• Performance-enhanced instances provide a variety of enterprise-grade features such as data flashback, proxy query cache, and Global Distributed Cache for Redis. For more information, see Use data flashback to restore data by point in time, Use proxy query cache to address issues caused by hotkeys, and Overview.

• TairRoaring V2 is released. For more information, see TairRoaring commands.

• The performance of TairRoaring is optimized.

• The following issue is fixed: Cluster instances may be unable to restart in some scenarios.

• The following issue is fixed: Statistics of SPOP commands are not collected when the real-time key analysis feature is used.

• Transparent Data Encryption (TDE) information is included in the output of the INFO command.
• Stability is enhanced.

• The autonomous capabilities of implementing imperceptible slot migration during cluster configuration changes are enhanced.

• The ray casting algorithm is optimized for the TairGIS data structure to yield more precise search results when you run the GIS.CONTAINS command.

• TairRoaring is supported. For more information, see TairRoaring commands.
• Stability is enhanced.

• Memory leaks that may occur during the append-only file (AOF) persistence of rewrites are fixed.
• Statistical data of queries per second (QPS) is classified. Three types of QPS can be calculated: read QPS, write QPS, and other QPS.

• The reliability of imperceptible slot migration is enhanced to strengthen stability.

• The following issue is fixed: Configuration changes may fail when the direct connection mode is enabled for cluster instances.

• Stability is enhanced.

• TDE can be used to perform real-time I/O encryption and decryption on Redis Database (RDB) files.

• The memory usage of TairHash is optimized. For more information, see TairHash commands.

• Stability is enhanced.

• Latency histograms are supported.

• Stability is enhanced.

• Some functions of keys are retained based on keys or key patterns when data is cleared. This feature can be used in the following scenarios:
  • Restore some keys or key patterns when you use the data flashback feature to restore data to a point in time. For more information, see Use data flashback to restore data by point in time.
  • Delete or retain the keyspace content based on keys or key patterns.

• The performance and migration speed during imperceptible scaling operations are optimized.
• Virtual IP addresses (VIPs) can be obtained over the Internet. This provides better support for clients in direct connection mode. For more information, see Enable the direct connection mode.
• The large key pattern is optimized.

• By default, the statistics feature is enabled for large keys.
• TairString commands are available in the gt version. For more information, see TairString commands.

• The capabilities to migrate slots and implement imperceptible scaling are improved.

• The issue that the real-time statistics of large keys become inaccurate when keys with the same name are written is fixed.

• Statistics of large keys can be collected in real time.

• The liveness detection capability of high-availability (HA) systems is improved when you call fork() in memory-intensive scenarios. This prevents long pauses that may occur.

• Metadata is cleared after an active geo-redundancy link is released. The link is built based on Global Distributed Cache for Redis or Data Transmission Service (DTS). This accelerates subsequent synchronization operations. For more information, see Overview and Configure two-way data synchronization between ApsaraDB for Redis Enhanced Edition (Tair) instances.

• Memory leaks that may occur when the FLUSHALL command is frequently run in TairHash scenarios are fixed. For more information, see TairHash commands.

• When the illegal address error message is returned, the IP address of the client is included in the error message. An IP address whitelist can be configured for your instance based on the IP address prompt.

  

• Flags such as FLAGS are used in the syntax of TairString commands. This syntax is compatible with Memcached semantics.

• The liveness detection capability of HA systems is improved.
  Note We recommend that you update the minor version to 1.5.0 or later to obtain the latest optimization for this feature.

• Correct binlogs are generated when TairString commands expire. This prevents data inconsistency between the master and replica nodes.
• Abnormal switchover of HA systems is fixed. This issue occurs when TairHash commands still use the active expire algorithm in read-only scenarios.
• The following issue is fixed: The system may not respond when an instance is restarted after it is forcibly stopped.
• The following issue is fixed: Expired keys are deleted when RDB files are loaded to ApsaraDB for Redis instances that have the data flashback feature enabled. For more information about the data flashback feature, see Use data flashback to restore data by point in time.

• Memory leaks that may occur when some modules are loaded are fixed.

• The output of the CLUSTER NODES command is stored in the cache. This optimizes the command execution speed.

• The processing capabilities of some modules in special scenarios are improved.

• Proxy nodes can pass through the IP addresses of clients to operational logs and audit logs. This helps you interpret logs and identify clients that have issues.

• The data collection capability is improved. This minimizes the impact on data shards when a large number of connections are queued up and I/O threads are busy.

• The communication latency is reduced when DTS is used to implement two-way data synchronization. For more information, see Configure two-way data synchronization between ApsaraDB for Redis Enhanced Edition (Tair) instances.

• The security group feature provided by Elastic Compute Service (ECS) is supported to simplify Q&M. You can grant permissions to ApsaraDB for Redis instances when you add the instances to security groups to which ECS instances belong. You do not need to manually enter the IP addresses of the ECS instances. For more information, see Step 2: Configure whitelists.
• The TairString module is updated to support more API operations (flags) that are compatible with Memcached semantics.

• The following issue is fixed: The BGREWRITEAOF command is interrupted when you use the data flashback feature to restore data to a point in time. For more information about the data flashback feature, see Use data flashback to restore data by point in time.
• Latency flag bits in audit logs are modified to help you identify these bits in master and replica audit logs.

• Saved point metadata is automatically cleared when data is cleared. This way, replicators are quickly restored in scenarios where multi-way data synchronization is implemented based on Global Distributed Cache for Redis or DTS. For more information, see Overview and Configure two-way data synchronization between ApsaraDB for Redis Enhanced Edition (Tair) instances.

• The Replication part in the output of the INFO command shows role information, such as role:master. This allows Redisson clients to call the role information in some scenarios.

• Statistics about hotkeys are regularly recorded in logs.
• The data statistics feature is available for performance metrics. This feature allows the system to differentiate the QPS that are generated in read, write, and read/write synchronization operations. This improves the accuracy of the statistics.

• The kernel capabilities for restoring data to a point in time are improved to simplify the data restoration process. For more information, see Use data flashback to restore data by point in time.
• Commands such as AUTH, ADMINAUTH, and CONFIG are used. These commands do not record sensitive information, which improves data security.

• The issue that deadlocks may occur when multi-threaded engines asynchronously disable client connections is fixed.
• The issue that file descriptors in engines cannot linearly expand is fixed.

• The 64-bit hash algorithm is applied to TairBloom commands.
• The final memory usage of TairBloom commands can be estimated to allow the system to record more accurate memory statistics.
• The exhgetAll2 interface is used in TairHash commands to revise command output formats.

• The error message that is returned by ApsaraDB for Redis when a whitelist is improperly configured is changed from (error) ERR invalid password to (error) ERR illegal address.
• Memory leaks that may occur when you use TairGIS commands to manage multiple polygons are fixed.
• The issue that the default path for TairDoc commands is incorrect is fixed.
• The issue that Pub and Sub commands may compete in multi-threaded engines is fixed.

• The data flashback feature is supported. This feature allows you to restore instance data to a point in time within the last seven days. This helps prevent data loss caused by accidental operations, simplify O&M, and protect databases in real time. For more information, see Use data flashback to restore data by point in time.
• TairGIS commands are compatible with Redis GEO commands.
• TairBloom commands can be used in capacity security validation for the BFRESERVE interface.
• TairHash commands support the following new features:
  • The NOACTIVE option is added to multiple commands including EXHSET, EXHEXPIRE, EXHINCRBY, and EXHINCRBYFLOAT. This option can reduce memory overheads in some scenarios.
  • The MAX and MIN options are added to the EXHINCRBY command to define the upper and lower boundaries of the value range.
  • The noexp option is added to the EXHLEN command to return the true length of the EXHLEN command.
• The HINCRBY and HINCRBYFLOAT commands in the hash structure are supported. The transaction processing capability of these commands can be used to increase and decrease different fields that constitute a key at the same time.

• Data structure modules are improved. For more information, see Integration with multiple Redis modules.
• The JedisCluster client can run the MGET and MSET commands on cluster instances with much higher performance.

• Binlog overflows are fixed.
• The issue that the system may not respond when hotkeys are evicted is fixed.
• The issue that the system may not respond due to double deallocation in TairHash commands is fixed.
• The issue that the system may not respond due to use-after-free (UAF) is fixed. The issue occurs when the audit log feature is disabled.

• The BITFIELD_RO command is added. This command significantly optimizes the performance of the BITFIELD command in read/write splitting scenarios.
  Note If BITFIELD commands contain only the get option, proxy nodes convert the commands to BITFIELD_RO commands and route these new commands to multiple backend data shards.

• The following issue is fixed: The replication process stops when some sophisticated commands in Lua scripts are run.

• The algorithm and performance related to traffic throttling are improved.

• The issue that the service stops because the congestion of client output buffers triggers server overload protection is fixed.

• Global Distributed Cache for Redis is supported. Global Distributed Cache for Redis is an active geo-redundancy database system that is developed based on ApsaraDB for Redis. Global Distributed Cache for Redis supports business scenarios in which multiple sites in different regions provide services at the same time. It helps enterprises replicate the active geo-redundancy architecture of Alibaba. For more information, see Overview.
• Binlogs and their protocols are available to support capabilities such as active geo-redundancy.

• The issue that the output of the INFO command can contain the cluster_enabled information when the direct connection mode is used is fixed. This allows some SDKs to automatically negotiate to enter the cluster mode. For more information, see Enable the direct connection mode.
• The issue that the number of controlled clients is inaccurately calculated is fixed.
• The issue that the system may not respond when a client is released is fixed.
• The issue that the system may not respond when a pipeline contains sophisticated commands is fixed.

• The memory usage of TairHash commands is optimized.

• The issue that the system may not respond when traffic throttling is executed is fixed.

• The direct connection mode is supported. Clients can bypass proxies to connect to ApsaraDB for Redis instances by using private endpoints. This is similar to the connection to open source Redis clusters. The direct connection mode can reduce communication overheads and further improve the response speed of ApsaraDB for Redis. For more information, see Enable the direct connection mode.
• The identification logic for hotkeys is supported. This allows hotkeys of engines to be accurately found. The memory usage of hotkeys is also optimized.
• EXCAS commands are supported in optimistic locking scenarios. For more information about how to use EXCAS commands, see EXCAS and Reduce resource consumption for optimistic locking.

• The core dump issue that may occur when pipelines are used is fixed.

• Performance-enhanced instances use the multi-threading model and provide read and write performance approximately three times that of ApsaraDB for Redis Community Edition instances with the same specifications.
• Performance-enhanced instances provide multiple enhanced data structure modules such as TairString (including CAS and CAD commands), TairHash, TairGIS, TairBloom, and TairDoc. These modules do not have strict requirements for the structure or validity period of storage and improve the efficiency of business development.

• TairString is supported. For more information, see TairString commands.
• Streams are supported.
• The intset encoding is supported for SETs to reduce memory overheads.
• Data eviction policies are supported.
• Performance is optimized, and stability is enhanced.

• The following issue is fixed: Statistics of SPOP commands are not collected when the real-time key analysis feature is used.

• Storage space occupied by large values is optimized to reduce used persistent storage.

• Tail latency that takes place during data writes is optimized.
• Stability is enhanced.

• The following issue is fixed: In special scenarios, the usage of lists and hashes is incorrectly calculated.

• Stability is enhanced.

• The speed at which cluster instances are scaled can be adaptively controlled.
  Note During scaling operations, the speed at which old data is cleared is well adapted to instance loads. For example, more CPU cores are used for clearance in low-load scenarios to increase the clearance speed. This feature keeps the CPU utilization at a high level during scaling operations but does not affect service availability.
• The performance of commands such as CLUSTER NODES is optimized for large cluster instances.

• The issue that abnormal slow logs are generated during scaling of cluster instances is fixed.
• Stability is enhanced.

• The storage of the list, hash, set, and ZSET data structures is optimized to reduce their usage of memory and persistent memory.

• When memory is exhausted in some scenarios, persistent memory can be fully utilized.
• Stability is enhanced.

• Semi-synchronous data replication is supported. By default, this feature is disabled. If you want to enable this feature, submit a ticket.
  Note If this feature is enabled, logs are transmitted from a master node to a replica node after the data update that the client initiates is complete on the master node. After the replica node receives all logs, the master node returns the log transmission information to the client. If a replica node is unavailable or the communication between a master node and a replica node is abnormal, semi-synchronous replication degrades to the asynchronous mode.
• In the output of the INFO command, the return value of the redis_version parameter is changed to 4.9.9 and the pena_version parameter is added to indicate the minor version.

• Stability is enhanced.

• Imperceptible scaling operations are supported, which allows slots to be migrated without perceptible impacts on your business.

• The hash and ZSET data structures support ziplist encoding to reduce memory overheads.
• The liveness detection capability of HA systems is improved.
• Data migration of large cluster instances is optimized. Large cluster instances indicate instances that have a large number of data shards.
• The scaling stability of the cluster architecture is improved.

• Cluster instances are supported. This eliminates performance bottlenecks caused by the single-threading model of open source Redis. You can use high-performance cluster instances to process large-capacity workloads.
• The minor version of an instance is used as the value of the redis_version parameter in the output of the INFO command.

• The stability is enhanced.

• When you run the INFO command by using a standard account, the usage of persistent memory is included in the command output.

• The space occupied by embstr encoding is decreased to reduce memory overheads.
• The stability is enhanced.

Persistent memory-optimized instances of ApsaraDB for Redis Enhanced Edition (Tair) are equipped with the Intel Optane DC Persistent Memory Module (AEP) to provide in-memory databases that have a large capacity and are compatible with open source Redis. Persistent memory-optimized instances have the following benefits:

• A persistent memory-optimized instance costs about 30% less than an ApsaraDB for Redis Community Edition instance.
• In scenarios where advanced memory specifications are used, issues such as high latency, high network jitter, and slow service data loading during fork operations triggered by AOF rewrites are resolved. You do not need to choose between performance and persistence.
• Persistent memory-optimized instances support command-level persistence. A response is returned after data persistence is complete for each write operation.
• Persistent memory-optimized instances are compatible with most of the data structures and interfaces of open source Redis. The persistence of data structures except for Redis Streams is supported.
  Note For more information about command limits, see Limits on commands supported by ApsaraDB for Redis Enhanced Edition (Tair).

• The speed of master-replica switchover is optimized to improve stability. Master-replica switchover is also known as proactive HA.

• The issue that binlogs occupy a large amount of space is fixed.

• The storage parameters of storage-optimized instances with terabytes of capacity are optimized to improve performance.
• Stability is enhanced.

• The MULTI and EXEC transaction commands are supported.
• The EVAL, EVALSHA, and SCRIPT Lua script commands are supported.

• Notifications about keyspace events can be sent.

• The following issue is fixed: In extreme cases, the FLUSHALL command may cause data inconsistency between master and replica nodes.

• The following issue is fixed to ensure data consistency between master and replica nodes: In extreme cases, a master node and a replica node cannot be automatically reconnected after a disconnection.

• The cmd_slowlog_count metric is added to collect historical statistics of slow logs.

• Protection capabilities are improved in scenarios where disk space is fully occupied.

• Data verification for master and replica nodes is added.

• The defects of the RESTORE command that emerge in specific scenarios are fixed.

• The FLUSHALL and FLUSHDB commands cannot be run in serial.

• Memory management is optimized.

• You can access ApsaraDB for Redis instances that are deployed in virtual private clouds (VPCs) without using passwords. For more information, see Enable password-free access.
• The size of a single transaction is limited by using the max-write-batch-size option to prevent memory overflows caused by large transactions.

• To make the Redis-shake tool available for data migration scenarios, the value of the redis_version parameter is added to the output of the INFO command.

• The issue that the number of connections is incorrectly calculated is fixed.
• The issue that the number of keys is incorrectly calculated when the RESTORE command is run is fixed.

• The issue that unexpected quits occur when the SETRANGE command is run is fixed.
• The issue that exceptions occur when keys are empty strings is fixed.

• The issue of a sharp increase in connection management logs is fixed.

• The issue of a sharp increase in operational logs is fixed.

• The stability of data synchronization between master and replica nodes is improved.
• The scanning performance for members that have sophisticated data structures is optimized.

• The following issue is fixed to prevent semantic errors that may occur when multiple duplicate members are managed: The ZADD and ZINCR commands are inconsistent with those of open source Redis.
• The following issue is fixed: nil is returned for empty strings when the MGET command is run.

• Storage-optimized instances store data in cloud disks to implement data persistence at a cost that can be as low as 15% that of ApsaraDB for Redis Community Edition instances.
• Storage-optimized instances use multiple I/O threads and worker nodes to improve throughput on each server and support replication of binlogs between master and replica nodes.
• Storage-optimized instances are compatible with most of the open source Redis commands.
• Storage-optimized instances reduce the amount of reserved memory that is required for the forks of open source Redis.