Heaven

This project is still in beta, and is not adviced to be used in production.

Keynote: There is no max memory limit, the DB will keep growing untill OOM.

Heaven is an RESP2-compliant in-memory database completely written in safe Rust.

It does not support all the commands, but as for the commands that are supported, it is a drop-in replacement for redis.

What it supports right now

Note: Every command is supposed to work just like how it would in Redis.

Command	Category	Usage	Description
SET	String	SET key value [EX seconds]	Stores a string; supports optional TTL
GET	String	GET key	Retrieves a value; handles passive expiry
APPEND	String	APPEND key value	Appends to a key; acts like SET
INCR / DECR	String	INCR key	Atomic integer math on string values
STRLEN	String	STRLEN key	Retrieves length of string
LPUSH / RPUSH	List	LPUSH key val [val...]	Pushes to the Front (Left) or Back (Right)
LPOP / RPOP	List	LPOP key [count]	Pops element(s) from the Front or Back
LRANGE	List	LRANGE key start stop	Returns a slice of the list
LREM	List	LREM key count element	Removes elements based on directional search
LINDEX	List	LINDEX key index	Retrieves one element at given index in a list
LLEN	List	LLEN key	Retrieves number of elements in a list
LSET	List	LSET key index element	Replaces an element at a specific index
HSET	Hash	HSET key field val [val ...]	Sets fields within a hash map
HMGET	Hash	HMGET key field [field ...]	Gets fields within a hash map
HGET	Hash	HGET key field	Gets fields within a hash map
HDEL	Hash	HDEL key field...	Removes one or more fields from a hashmap
HEXISTS	Hash	HEXISTS key field	Checks for one field in a hashmap
HLEN	Hash	HLEN key	Retrieves the hashmap's size
HGETALL	Hash	HGETALL key	Returns all field value pairs in a hashmap at key
SADD	Set	SADD key val [val ...]	Addes value to a (new) set at key
SREM	Set	SREM key val [val ...]	Removes value from a set at key
SISMEMBER	Set	SISMEMBER key val	Checks if value is in a set at key
SMEMBERS	Set	SMEMBERS key	Returns all the values in a set at key
EXISTS	Generic	EXISTS key [key...]	Checks for the presence of keys
DEL	Generic	DEL key [key...]	Removes keys of any data type
TTL	Generic	TTL key	Returns the expiry of the entry at key
EXPIRE	Generic	EXPIRE key expiry	Sets the expiry of the entry at key
SUBSCRIBE	Broadcast	SUBSCRIBE event [event ...]	Subscribes you to event(s)
UNSUBSCRIBE	Broadcast	UNSUBSCRIBE event [event ...]	Unsubscribes you from the event(s)
PUBLISH	Broadcast	PUBLISH event message	Sends a message to all the clients subscribed to event
PING	System	PING	Returns PONG
COMMAND	System	COMMAND	Returns information about all the commands supported

Support for snapshots

As it stands Heaven only supports .rdb style snapshots using rkyv. AOF is not yet supported.

A Note on PING

Currently, Heaven requires the standard RESP array protocol format for all commands. Some clients may attempt to send a "naked" PING during pipelining without the array marker (*). This is currently not supported to keep the parser logic clean and focused on standard protocol adherence.

Usage

cargo r --release

Note: If you want to handle more than 508 concurrent connections, you may have to set ulimit to a higher number than 1024.

Crates used

https://crates.io/crates/mio

https://crates.io/crates/crossbeam

https://crates.io/crates/jemallocator

https://crates.io/crates/itoa

https://crates.io/crates/rkyv

https://crates.io/crates/ctrlc

Future plans

std::bytes Io_uring Metacommands Sharding