RocksDB

Language: CPP

Database

RocksDB was developed at Facebook in 2012 to handle data-intensive applications that required low-latency and high-throughput storage. Built on Google’s LevelDB, it was enhanced with features like column families, transactions, bloom filters, and better multi-threading. Today, it powers large-scale systems at Facebook, LinkedIn, and other enterprises.

RocksDB is an embeddable, high-performance, persistent key-value store developed by Facebook. It is based on LevelDB but optimized for fast storage, low-latency access, and high throughput on flash drives and SSDs.

Installation

linux: sudo apt install librocksdb-dev

mac: brew install rocksdb

windows: vcpkg install rocksdb or build from source with CMake

Usage

RocksDB provides an API for storing and retrieving key-value pairs, supporting advanced features like column families, snapshots, iterators, batch writes, and transactions. It is designed for write-heavy workloads.

Opening a database and writing data

#include <rocksdb/db.h>
#include <iostream>

int main() {
    rocksdb::DB* db;
    rocksdb::Options options;
    options.create_if_missing = true;

    rocksdb::Status status = rocksdb::DB::Open(options, "testdb", &db);
    if (!status.ok()) {
        std::cerr << status.ToString() << std::endl;
        return 1;
    }

    status = db->Put(rocksdb::WriteOptions(), "key1", "value1");
    std::cout << "Write Status: " << status.ToString() << std::endl;

    delete db;
    return 0;
}

Creates a RocksDB database, writes a key-value pair, and closes it.

Reading data

std::string value;
status = db->Get(rocksdb::ReadOptions(), "key1", &value);
if (status.ok()) std::cout << "Value: " << value << std::endl;

Reads the value of a key from the database.

Batch writes

rocksdb::WriteBatch batch;
batch.Put("key2", "value2");
batch.Delete("key1");
db->Write(rocksdb::WriteOptions(), &batch);

Performs multiple operations in a single atomic batch.

Using iterators

rocksdb::Iterator* it = db->NewIterator(rocksdb::ReadOptions());
for (it->SeekToFirst(); it->Valid(); it->Next()) {
    std::cout << it->key().ToString() << " => " << it->value().ToString() << std::endl;
}
delete it;

Iterates through all key-value pairs in the database.

Transactions

rocksdb::TransactionDB* txn_db;
rocksdb::TransactionDBOptions txn_options;
rocksdb::DBOptions db_options;
db_options.create_if_missing = true;
rocksdb::TransactionDB::Open(db_options, txn_options, "testdb_txn", &txn_db);

Opens RocksDB in transaction mode for ACID-compliant operations.

Column Families

std::vector<rocksdb::ColumnFamilyDescriptor> column_families;
column_families.push_back(rocksdb::ColumnFamilyDescriptor(
    rocksdb::kDefaultColumnFamilyName, rocksdb::ColumnFamilyOptions()));

Uses column families to organize different logical databases within the same RocksDB instance.

Error Handling

Status::NotFound: Indicates the requested key does not exist. Always check `status.ok()` before using results.

Corruption errors: May happen if the database files are corrupted. Run RocksDB repair tools or restore from backup.

Performance degradation: Adjust compaction strategy, memory tables, and background thread settings to match workload.

Best Practices

Use `WriteBatch` for grouped writes to improve performance.

Leverage column families for data partitioning and better management.

Use Bloom filters for fast point-lookups.

Monitor compaction and tune it for your workload to avoid performance bottlenecks.

Enable compression (e.g., Snappy, Zstd) to save storage space.

Official Docs Github