Pika Currently Supported Redis Interfaces

Pika supports the interfaces for Redis's five types (string, hash, list, set, zset). Below is a compatibility summary for the five Redis data structures.

Legend for the table:

Icon	Meaning
o	Fully supported; usage is identical to Redis
!	Functionally supported, but usage or output has some differences from Redis; please note
×	Not yet supported

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Keys

Interface	DEL	DUMP	EXISTS	EXPIRE	EXPIREAT	KEYS	MIGRATE	MOVE	OBJECT
Status	o	x	o	o	o	o	x	x	x
Interface	PERSIST	PEXPIRE	PEXPIREAT	PTTL	RANDOMKEY	RENAME	RENAMENX	RESTORE	SORT
Status	o	!	!	o	x	x	x	x	x
Interface	TOUCH	TTL	TYPE	UNLINK	WAIT	SCAN
Status	x	o	!	o	x	!

Notes:

• PEXPIRE: Cannot be precise to milliseconds; the underlying layer automatically truncates to second-level precision.
• PEXPIREAT: Cannot be precise to milliseconds; the underlying layer automatically truncates to second-level precision.
• SCAN: Iterates through a snapshot of the current DB sequentially. Since Pika allows duplicate names five times, scan has a priority output order: string -> hash -> list -> zset -> set.
• TYPE: Since Pika allows duplicate names five times, type has a priority output order: string -> hash -> list -> zset -> set. If this key exists in string, only "string" is output; if not, hash is output, and so on.
• KEYS: The KEYS command supports scanning specific data types via a parameter, e.g., keys * [string, hash, list, zset, set].

Strings

Interface	APPEND	BITCOUNT	BITFIELD	BITOP	BITPOS	DECR	DECRBY	GET	GETBIT
Status	o	o	x	!	o	o	o	o	!
Interface	GETRANGE	GETSET	INCR	INCRBY	INCRBYFLOAT	MGET	MSET	MSETNX	STRLEN
Status	o	o	o	o	o	o	o	o	o
Interface	PSETEX	SET	SETBIT	SETEX	SETNX	SETRANGE
Status	o	o	!	o	o	o

Notes:

• BIT operations: Unlike Redis, Pika's bit operation range is 2^21, with a maximum bitmap size of 256 KB. Redis setbit only updates the key's value. But Pika uses RocksDB as the storage engine, which only writes new data and only deletes old data from disk during compaction. If Pika's bit operation range matched Redis's 2^32, each setbit on the same key might store a 512 MB value in RocksDB. This creates a serious performance risk, so Pika's bit operation range has been reduced.

Hashes

Interface	HDEL	HEXISTS	HGET	HGETALL	HINCRBY	HINCRBYFLOAT	HKEYS	HLEN	HMGET	HMSET
Status	o	o	o	o	o	o	o	o	o	o
Interface	HSET	HSETNX	HVALS	HSCAN	HSTRLEN
Status	!	o	o	o	o

Notes:

• HSET operation: Setting multiple field-value pairs with a single command is temporarily not supported. Please use HMSET instead.

Lists

Interface	LINDEX	LINSERT	LLEN	LPOP	LPUSH	LPUSHX	LRANGE	LREM	LSET	LTRIM
Status	o	o	o	o	o	x	o	o	o	o
Interface	RPOP	RPOPLPUSH	RPUSH	RPUSHX	BLPOP	BRPOP	BRPOPLPUSH
Status	o	o	o	o	o	o	x

Sets

Interface	SADD	SCARD	SDIFF	SDIFFSTORE	SINTER	SINTERSTORE	SISMEMBER	SMEMBERS	SMOVE	SPOP
Status	o	o	o	o	o	o	o	o	o	o
Interface	SRANDMEMBER	SREM	SUNION	SUNIONSTORE	SSCAN
Status	!	o	o	o	o

Notes:

• SRANDMEMBER: Time complexity O(n), relatively slow.

Sorted Sets

Interface	ZADD	ZCARD	ZCOUNT	ZINCRBY	ZRANGE	ZRANGEBYSCORE	ZRANK	ZREM	ZREMRANGEBYRANK	ZREMRANGEBYSCORE
Status	o	o	o	o	o	o	o	o	o	o
Interface	ZREVRANGE	ZREVRANGEBYSCORE	ZREVRANK	ZSCORE	ZUNIONSTORE	ZINTERSTORE	ZSCAN	ZRANGEBYLEX	ZLEXCOUNT	ZREMRANGEBYLEX
Status	o	o	o	o	o	o	o	o	o	o
Interface	ZPOPMAX	ZPOPMIN	ZREVERANGEBYLEX
Status	o	o	o

• ZADD options [NX|XX] [CH] [INCR] are temporarily not supported.

HyperLogLog

Interface	PFADD	PFCOUNT	PFMERGE
Status	o	o	o

Notes:

• Error within 1% for under 500k, less than 3% for under 1 million, but at the cost of additional time.

GEO

Interface	GEOADD	GEODIST	GEOHASH	GEOPOS	GEORADIUS	GEORADIUSBYMEMBER
Status	o	o	o	o	o	o

BitMap

Interface	SETBIT	GETBIT	BITPOS	BITOP	BITCOUNT
Status	o	o	o	o	o

Pub/Sub

Interface	PSUBSCRIBE	PUBSUB	PUBLISH	PUNSUBSCRIBE	SUBSCRIBE	UNSUBSCRIBE
Status	o	o	o	o	o	o

Notes:

• Keyspace notifications are temporarily not supported.

Admin Commands (only those compatible with Pika are listed)

Interface	INFO	CONFIG	CLIENT	PING	BGSAVE	SHUTDOWN	SELECT	TYPE	HELLO
Status	!	o	!	o	o	o	!	!	o

Notes:

• info: Supports full output and pattern-matched output. For example, info stats shows statistics. Note that key space differs from Redis — Pika displays key space by type rather than by DB (since Pika has no concept of databases). Pika's key space statistics are passive and must be manually triggered. Pika's key space statistics are accurate. To trigger: execute keyspace command, then Pika will count in the background. You can use keyspace readonly to view without re-triggering. If current data is 0, it's still being counted. info commandstats can query call count and time statistics (average time) for each command. Unlike Redis, the time unit we use is milliseconds.

• client: The current client command supports client list, client kill, and client setname. client list shows less information than Redis.

• select: This command had no effect before version 3.1.0; since 3.1.0 it is consistent with Redis.

• ping: This command only supports use without parameters, i.e., PING, and the client returns PONG.

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Pika Pub/Sub Documentation

Available version: >= 2.3.0

Note: Keyspace notification functionality is not currently supported.

Pika Publish/Subscribe Commands

The following Pub/Sub commands are fully compatible with Redis:

• PUBSUB subcommand [argument [argument ...]]
• PUBLISH channel message
• SUBSCRIBE channel [channel ...]
• PSUBSCRIBE pattern [pattern ...]
• UNSUBSCRIBE [channel [channel ...]]
• PUNSUBSCRIBE [pattern [pattern ...]]

For usage details, refer to Redis's Pub/Sub documentation.

Important Notes

• Key duplication: Since each Pika type operates independently, duplicate keys are allowed. For example, key abc can exist in both string and hash at the same time. A key can be duplicated at most 5 times (for the 5 major types), but cannot be duplicated within the same interface. Therefore, it is recommended to avoid using exactly the same key across different types.

• Multi-DB: Pika supports multiple databases since version 3.1.0. For changes to related commands and parameters, refer to the Pika 3.1.0 multi-DB version command/parameter change reference document.

• Data display: Pika displays key space by type rather than by DB (since Pika has no concept of databases). Key statistics in Pika are passive and must be manually triggered; they do not output immediately. The command is: info keyspace [0|1], defaulting to 0 (no trigger). Pika's keyspace statistics are accurate.