[dependencies.rocksdb] git = "https://github.com/tikv/rust-rocksdb.git"

extern crate rocksdb; use rocksdb::{DB, Writable}; fn main() { let mut db = DB::open_default("/path/for/rocksdb/storage").unwrap(); db.put(b"my key", b"my value"); match db.get(b"my key") { Ok(Some(value)) => println!("retrieved value {}", value.to_utf8().unwrap()), Ok(None) => println!("value not found"), Err(e) => println!("operational problem encountered: {}", e), } db.delete(b"my key"); }

extern crate rocksdb; use rocksdb::{DB, WriteBatch, Writable}; fn main() { // NB: db is automatically freed at end of lifetime let mut db = DB::open_default("/path/for/rocksdb/storage").unwrap(); { let batch = WriteBatch::new(); // WriteBatch and db both have trait Writable batch.put(b"my key", b"my value"); batch.put(b"key2", b"value2"); batch.put(b"key3", b"value3"); db.write(&batch).unwrap(); // Atomically commits the batch } }

extern crate rocksdb; use rocksdb::{DB, Direction, IteratorMode}; fn main() { // NB: db is automatically freed at end of lifetime let mut db = DB::open_default("/path/for/rocksdb/storage").unwrap(); let mut iter = db.iterator(IteratorMode::Start); // Always iterates forward for (key, value) in iter { println!("Saw {} {}", key, value); //actually, need to convert [u8] keys into Strings } iter = db.iterator(IteratorMode::End); // Always iterates backward for (key, value) in iter { println!("Saw {} {}", key, value); } iter = db.iterator(IteratorMode::From(b"my key", Direction::forward)); // From a key in Direction::{forward,reverse} for (key, value) in iter { println!("Saw {} {}", key, value); } // You can seek with an existing Iterator instance, too iter.set_mode(IteratorMode::From(b"another key", Direction::reverse)); for (key, value) in iter { println!("Saw {} {}", key, value); } }

extern crate rocksdb; use rocksdb::{DB, Direction}; fn main() { // NB: db is automatically freed at end of lifetime let mut db = DB::open_default("/path/for/rocksdb/storage").unwrap(); let snapshot = db.snapshot(); // Creates a longer-term snapshot of the DB, but freed when goes out of scope let mut iter = snapshot.iterator(IteratorMode::Start); // Make as many iterators as you'd like from one snapshot }

extern crate rocksdb; use rocksdb::{Options, DB, MergeOperands, Writable}; fn concat_merge(new_key: &[u8], existing_val: Option<&[u8]>, operands: &mut MergeOperands) -> Vec<u8> { let mut result: Vec<u8> = Vec::with_capacity(operands.size_hint().0); existing_val.map(|v| { for e in v { result.push(*e) } }); for op in operands { for e in op { result.push(*e) } } result } fn main() { let path = "/path/to/rocksdb"; let mut opts = Options::new(); opts.create_if_missing(true); opts.add_merge_operator("test operator", concat_merge); let mut db = DB::open(&opts, path).unwrap(); let p = db.put(b"k1", b"a"); db.merge(b"k1", b"b"); db.merge(b"k1", b"c"); db.merge(b"k1", b"d"); db.merge(b"k1", b"efg"); let r = db.get(b"k1"); assert!(r.unwrap().unwrap().to_utf8().unwrap() == "abcdefg"); }

use rocksdb::{Options, DB}; use rocksdb::DBCompactionStyle::DBUniversalCompaction; fn badly_tuned_for_somebody_elses_disk() -> DB { let path = "_rust_rocksdb_optimizetest"; let mut opts = Options::new(); opts.create_if_missing(true); opts.set_max_open_files(10000); opts.set_use_fsync(false); opts.set_bytes_per_sync(8388608); opts.set_disable_data_sync(false); opts.set_block_cache_size_mb(1024); opts.set_table_cache_num_shard_bits(6); opts.set_max_write_buffer_number(32); opts.set_write_buffer_size(536870912); opts.set_target_file_size_base(1073741824); opts.set_min_write_buffer_number_to_merge(4); opts.set_level_zero_stop_writes_trigger(2000); opts.set_level_zero_slowdown_writes_trigger(0); opts.set_compaction_style(DBUniversalCompaction); opts.set_max_background_compactions(4); opts.set_max_background_flushes(4); opts.set_disable_auto_compactions(true); DB::open(&opts, path).unwrap() }