FireflyDB

FireflyDB is a fast, thread-safe, JVM-based key-value storage engine with microsecond latency. FireflyDB is 20x faster for reads and 10x faster for writes than Bitcask, which has a similar architecture.

FireflyDB is hash-based and gives up range queries to achieve high throughput and low latency. As a result, it is about 100x faster at writes than LevelDB (Google) and RocksDB (Facebook).

FireflyDB relies on sensible defaults and does not expose many configuration options. FireflyDB is designed with educated tradeoffs to achieve high performance:

1. All the keys must fit in memory. This is a tradeoff with all hash-based storage engines. Even with the largest key size of 32KB, FireflyDB can store 32,000+ keys per 1GB of memory.
2. FireflyDB does not support range queries.
3. Maximum key size is 32768 bytes or 32KB.
4. Maximum value size is 2,147,483,647 bytes or 2.14 GB.

Installation

Maven

<dependency>
    <groupId>com.sahilbondre</groupId>
    <artifactId>fireflydb</artifactId>
    <version>0.1.1</version>
</dependency>

Gradle

implementation 'com.sahilbondre:fireflydb:0.1.1'

API

FireflyDB fireflyDB=FireflyDB.getInstance("path/to/db");
    fireflyDB.start();

// Write
    byte[]key="testKey".getBytes();
    byte[]value="testValue".getBytes();

    fireflyDB.put(key,value);

// Read
    byte[]result=fireflyDB.get(key);

// Compaction 
// FireflyDB will compact automatically but can be triggered on demand.
    fireflyDB.compact();

    fireflyDB.stop();

Benchmarks

iterations: 100,000
cpu: 1
memory: 1GB
key-size: 8 bytes
value-size: 100 bytes

Random Write Test

Test: Generate a random key and value and write it to the database.

Database	Avg Time (microseconds)	P90 Latency (microseconds)
In-Memory	0.53	1
LevelDB	445.94	811
Bitcask	71.33	48
RocksDB	568.60	872
FireflyDB	7.10	5

Random Read Test

Test: Pick a random key from the ones written in the previous test and read it from the database.

Database	Avg Time (microseconds)	P90 Latency (microseconds)
In-Memory	0.49	1
LevelDB	1.55	2
Bitcask	108.03	62
RocksDB	0.94	2
FireflyDB	4.97	4

Alternating Read-Write Test

Test: Perform a read and write operation alternately.

Database	Avg Time (microseconds)	P90 Latency (microseconds)
In-Memory (read)	0.61	1
In-Memory (write)	0.57	1
LevelDB (read)	3.43	5
LevelDB (write)	441.38	814
Bitcask (read)	120.15	60
Bitcask (write)	66.78	57
RocksDB (read)	4.54	7
RocksDB (write)	567.14	971
FireflyDB (read)	3.89	4
FireflyDB (write)	3.91	4

Potential Improvements

• Add an explicit delete operation.
• Expose compaction size as a configuration option.
• Expose compaction interval as a configuration option.
• Allow larger key size as a configuration option.
• Expose read only mode.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

Apache 2.0