LiteKV

LiteKV is a simple key-value storage implementation.

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Build

mkdir build
cd build
cmake ..
make

Supported data types

• integer
• string
• list
• hash
• set

Supported modes

• Pub/Sub

Supported persistence

• AOF
• LiteKV Binary Format

Supported Commands

Type	Command	Usage	Description
Generic
	ping	ping	Ping the server
	del	del key [key...]	Remove the specified keys
	exists	exists key [key...]	Return if specified keys exist
	type	type key	Return data type of specified key
	expire	expire key seconds	Set expiration for key
	expireat	expireat key unix-timestamp	Set key expire in unix-timestamp
	ttl	ttl key	Get the time to live (TTL) in seconds of key
Integer or String
	set	set key value	Set key to store string or integer value
	get	get key	Get the value of key
Integer
	incr	incr key	Increase int value by 1 on given key
	decr	decr key	Decrease int value by 1 on given key
	incrby	incrby key value	Increase int value by n on given key
	decrby	decry key value	Decrease int value by n on given key
String
	strlen	strlen key	Return the length of value at key
	append	append key value	Append value to existing value at key
List
	llen	llen key	Return the size of list at key
	lpop	lpop key	Remove and return the first item of list at key
	lpush	lpush key value [value...]	Insert all values at the head of list at key
	rpop	rpop key	Remove and return the last item of list at key
	rpush	rpush key value [value...]	Insert all values at the end of list at key
	lrange	lrange key begin end	Return all items in specified range of list at key
	lsetindex	lsetindex key index value	Set the item to value at index.
	lindex	lindex key index	Return the item at index
Hash
	hset	hset key field value [field value...]	Set field-value pair in hash at key
	hget	hget key field [field...]	Get values of fields in hash at key
	hdel	hdel key field [field...]	Remove fields in hash at key
	hexists	hexists key field	Check the existence of field in hash at key
	hgetall	hgetall key	Return all field-value pairs in hash at key
	hkeys	hkeys key	Return all fields in hash at key
	hvals	hvals key	Return all values in hash at key
	hlen	hlen key	Return the number of pairs in hash at key
Set
	sadd	sadd key member [member...]	Add members into set at key
	sismember	sismember key member	Check a member is inside set at key
	smismember	smismember key member [member...]	Check multiple members are inside set at key
	smembers	smembers key	Return all members inside set at key
	srem	srem key member [member...]	Remove the specified members inside set at key
	scard	scard key	Return the number of members inside set at key
Pub/Sub
	publish	publish chan msg	Publish a message to specific channel
	subscribe	subscribe chan1 [chan2...]	Subscribe to specific channels
	unsubscribe	unsubscribe chan1 [chan2...]	Unsubscribe from specific channels

Benchmark Results

Since our communication protocol is based on RESP, the redis-benchmark tool from redis can be used to benchmark this repository.

The following command is used for benchmarking. We make N_CLIENTS and N_THREADS as two variables;

redis-benchmark -h 127.0.0.1 -p 9527 \
	-c $N_CLIENTS \
	-n 100000 \
	-t set,get,incr,lpush,rpush,lpop,rpop,lrange,hset \
	--threads $N_THREADS \
	-r 10000 \
	--csv

Results (server and clients run in the same local machine)

Environments

Server

Machine: 64bit AMD 3600 CPU + 16G RAM

System: Ubuntu 16.04

Compiler: gcc 5.4.0

Client

redis-benchmark version: 7.0.2

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Single thread case

Multiple threads case

Future Works

• Performance Optimization
  • string object optimization (COW or SSO)
  • dlist optimization (redesign and reconstruct)
• Features
  • support more data structure, such as set, sorted sets, etc.
  • transaction
  • make it distributed
  • master-slave mode
  • pub/sub mode
  • sentinel
  • use connection pool