:Parameters that can be configured for Tair instances

Specifies whether to check that the IP address of a client is added to a whitelist of your Tair instance after password-free access is enabled for the instance. The client is deployed in the same virtual private cloud (VPC) as the instance. Valid values:

• yes: After you enable password-free access for the Tair instance, you must also add the IP address of a client that is deployed in the same VPC as the Tair instance to a whitelist of the instance before the client can connect to the instance.

  If the (error) ERR illegal address error is returned, the whitelist is improperly configured.

• no (default): After you enable password-free access for the Tair instance, you can connect a client that is deployed in the same VPC as the Tair instance to the instance without adding the IP address of the client to a whitelist of the instance.

The disabled commands. You can use this parameter to disable the commands that may have high risks or high time complexity based on your business requirements, such as FLUSHALL, FLUSHDB, KEYS, HGETALL, EVAL, EVALSHA, and SCRIPT.

Specifies whether to improve the throughput of the Tair instance when the PUBLISH command is run on the instance. The output of this command is always 0. Valid values:

• no (default)

• yes

Specifies whether to enable the Sentinel-compatible mode for cluster instances in proxy mode or read/write splitting instances. Valid values:

• 1: enables the Sentinel-compatible mode.

• 0 (default): disables the Sentinel-compatible mode.

Specifies whether to enable the Sentinel-compatible mode for standard instances or cluster instances in direct connection mode. Valid values:

• yes

• no (default)

This parameter is related to the observability of Tair. After you specify this parameter for an instance, you must also enable the audit log feature for the instance. Audit logs must be collected at an interval of 5 seconds. For more information about the observability of Tair and audit logs, see Observability and Enable the audit log feature.

• #no_loose_statistics-cmds: specifies the commands whose statistics you want to collect. The source IP addresses from which the commands are issued and the frequencies at which the commands are run are collected. This parameter is empty by default, which indicates that no statistics are collected. Separate the commands with commas (,).

• #no_loose_statistics-ip-enable: specifies whether to enable the collection of statistics about IP addresses or whether to record IP addresses of established connections. Valid values: yes and no. Default value: no.

• #no_loose_statistics-keys: specifies the keys whose statistics you want to collect. The source IP addresses and the frequencies at which these keys are queried or updated are collected. This parameter is empty by default, which indicates that no statistics are collected. Separate the keys with commas (,).

The earliest Transport Layer Security (TLS) version supported by the instance. Valid values:

• TLSv1 (default)

• TLSv1.1

• TLSv1.2

The level of activeness in cleaning up expired keys. If you specify a larger value for this parameter, the engine becomes more active in cleaning up expired keys. In this case, memory consumed by expired keys decreases but CPU utilization and latency increase. Valid values: 1 to 10. Default value: 1.

Specifies whether to enable AOF persistence for master nodes. Valid values:

• yes (default)

• no

  Note

  By default, data persistence by using Redis Database (RDB) snapshots is performed once a day. For more information, see Automatic or manual backup.

The output buffer limits of publisher and subscriber clients. The clients are disconnected when the specified limits are reached. Specify this parameter in the following format: <hard limit> <soft limit> <soft seconds>. Default value: 33554432 8388608 60.

• <hard limit>: the hard limit. A client is disconnected if its output buffer size is larger than or equal to the hard limit value. The hard limit value is measured in bytes.

• <soft limit>: the soft limit. <soft seconds>: the maximum number of seconds during which the soft limit value is reached or exceeded. A client is disconnected if its output buffer size remains larger than or equal to the soft limit value for a period of time that is longer than or equal to the soft seconds value. The soft limit value is measured in bytes. The soft seconds value is measured in seconds.

Specifies whether to enable the support for the syntax of native Redis clusters for cluster instances in proxy mode or read/write splitting instances. Valid values:

• 0: disables the support for the syntax of native Redis clusters.

• 1 (default): enables the support for the syntax of native Redis clusters.

Specifies whether to enable dynamic frequency control for background tasks. Valid values:

• yes (default)

• no

The maximum number and size of key-value pairs stored in a hash. Ziplist encoding is used only if a hash meets both of the following conditions:

• The number of key-value pairs stored in the hash is smaller than the value of the hash-max-ziplist-entries parameter.

• The keys and values of key-value pairs stored in the hash are all smaller than the value of the hash-max-ziplist-value parameter. The keys and values are measured in bytes.

Specifies how frequently tasks are performed in the background for the Tair instance. For example, you can specify how frequently tasks are performed to evict expired keys. Valid values: 1 to 500. The default value is 10, which specifies that each task is performed 10 times per second.

Specifies whether to enable the eviction feature based on the lazy free mechanism. Valid values:

• yes

• no (default)

Specifies whether to delete expired keys based on the lazy free mechanism. Valid values:

• yes (default)

• no

Specifies whether to asynchronously delete data based on the lazy free mechanism for an implicit DEL operation. Valid values:

• yes (default)

• no

The number of nodes that are not compressed at both ends of a list. Valid values: 0 to 65535.

• 0 (default): does not compress nodes of a list.

• A value in the range of 1 to 65535: does not compress the specified number of nodes at both ends of a list but compresses in-between nodes.

The policy used to evict keys if memory is exhausted. If the memory usage of your Tair instance reaches the value of Maxmemory, data eviction is triggered. You can choose a data eviction policy based on your needs. Valid values:

• volatile-lru (default for Tair DRAM-based instances and ApsaraDB for Redis Community Edition instances): evicts the LRU keys from keys that have a TTL configured regardless of whether the keys have expired.

• noeviction (default for Tair persistent memory-optimized instances): does not evict keys to make space when the memory limit is reached, but returns errors for write operations.

• volatile-lfu: evicts the LFU keys from keys that have a TTL configured.

• volatile-random: randomly evicts keys from keys that have a TTL configured.

• volatile-ttl: evicts the keys that have the shortest TTL from keys that have a TTL configured.

• allkeys-lru: evicts the LRU keys from all keys.

• allkeys-lfu: evicts the LFU keys from all keys.

• allkeys-random: randomly evicts keys from all keys.

The types of events of which the server can notify clients. The value of this parameter is a combination of the following characters. This parameter setting applies to all databases in the instance. These notifications consume CPU resources. For more information, see Redis keyspace notifications.

• K: keyspace events. All events are published with a _keyspace@<db>_ prefix.

• E: keyevent events. All events are published with a _keyevent@<db>_ prefix.

• g: generic events that are not related to specific commands, such as DEL, EXPIRE, and RENAME.

• $: events of string commands. Clients are notified of operations to create, modify, and delete strings.

• l: events of list commands.

• s: events of set commands.

• h: events of hash commands.

• z: events of sorted set commands.

• x: expiration events. Clients may be notified when an expired key is deleted instead of when a key expires.

• e: eviction events. Clients are notified when a key is evicted based on maxmemory policies.

• A: all the preceding event types. This parameter is the alias for the g$lshzxe parameter. Example: AKE.

Specifies whether to enable the support for the MOVE and RENAME commands. The time complexity of these commands is O(n), which differs from O(1) of native Redis commands. If the MOVE or RENAME command is used to manage large keys, the command takes an extended period of time to run. Valid values:

• no (default): disables the support.

• yes: enables the support. You can run these commands by using syntax similar to that of native Redis commands.

Specifies whether to pass through client IP addresses to data nodes by using proxy nodes for cluster instances in proxy mode or read/write splitting instances. Valid values:

• 0 (default): does not pass through client IP addresses to data nodes.

• 1: passes through client IP addresses to data nodes.

Specifies whether to enable the proxy query cache feature. For more information, see Use proxy query cache to address issues caused by hotkeys. Valid values:

• 0 (default): disables the proxy query cache feature.

• 1: enables the proxy query cache feature.

The validity period of cached data. Unit: milliseconds. Valid values: 100 to 60000. Default value: 1000.

• If the cached data is modified within the validity period, the modified data is not synchronized to the cache. In this case, dirty data is returned for identical read requests until the cache expires.

• You must evaluate the value of this parameter based on your business requirements and your tolerance for dirty data. If the value is smaller than required, the cache hit ratio is reduced. If the value is greater than required, the client reads dirty data for an extended period of time.

The proxy query cache mode. Valid values:

• 0 (default): caches data of only the hotkeys pushed by data shards.

• 1: caches data of all keys. The cached keys are evicted based on the LRU algorithm.

Specifies whether to enable Lua scripting on read replicas. Valid values:

• 0 (default): disables Lua scripting. Lua scripts are processed by master nodes instead of read replicas.

• 1: enables Lua scripting. Lua scripts that involve only read requests are forwarded to read replicas.

Specifies whether to enable unidirectional forwarding for requests from accounts that have read-only permissions. Valid values:

• 0 (default): disables unidirectional forwarding. Requests from accounts that have read-only permissions are forwarded based on weights to all nodes including master nodes.

• 1: enables unidirectional forwarding. Requests from accounts that have read-only permissions are forwarded only to read replicas.

The threshold for logging slow queries of a proxy node. Unit: milliseconds. If the proxy node processes a request for a period of time longer than the specified threshold, the request is recorded in a slow query log.

Specifies whether to check that the keys used in Lua scripts are mapped to the same slot for cluster instances in proxy mode or read/write splitting instances. For more information, see Additional checks on Lua scripts in proxy mode. Valid values:

• 0: does not check whether the keys are mapped to the same slot. If your database account of the Tair instance has read-only permissions, the system still performs the check.

• 1 (default): checks whether the keys are mapped to the same slot.

The maximum number of data entries for which a set supports intset encoding. Intset encoding is used only if a set meets both of the following conditions:

• All data entries in the set are strings.

• The set contains only radix-10 integers in the range of 64-bit signed integers.

The maximum amount of memory that each macro node in a stream can consume. Valid values: 0 to 999999999999999. Unit: bytes.

The maximum number of entries that can be stored on each macro node in a stream. Valid values: 0 to 999999999999999.

The timeout period. The system closes a connection to a client for the Tair instance if the connection remains idle for the specified period of time. Valid values: 0 to 100000. Unit: seconds. The default value is 0, which indicates that no timeout period is specified.

Specifies whether to enable the feature of converting SUBSCRIBE to PSUBSCRIBE. Valid values:

• 0 (default): disables this feature. Proxy nodes cannot convert SUBSCRIBE to PSUBSCRIBE.

• 1: enables this feature. Proxy nodes can convert SUBSCRIBE to PSUBSCRIBE.

  Note

  If you use Pub/Sub commands in Lua scripts and the channel to which you have subscribed cannot receive messages, you can enable this feature to fix the issue.

The maximum number and size of key-value pairs stored in a sorted set. Ziplist encoding is used only if a sorted set meets both of the following conditions:

• The keys and values of key-value pairs stored in the sorted set are all smaller than the value of the zset-max-ziplist-value parameter. The keys and values are measured in bytes.

• The number of key-value pairs stored in the sorted set is smaller than the value of the zset-max-ziplist-entries parameter.

The disabled commands. You can use this parameter to disable the commands that may have high risks or high time complexity based on your business requirements, such as FLUSHALL, FLUSHDB, KEYS, HGETALL, EVAL, EVALSHA, and SCRIPT.

Specifies whether to enable transactional locking. If you set this parameter to yes, you can run the MULTI, EXEC, and Lua commands on an ESSD/SSD-based instance. In this case, the instance performance may degrade by 10%. Valid values:

• no (default): disables transactional locking.

• yes: enables transactional locking. You can run these commands by using syntax similar to that of native Redis commands.