Struct Bucket

Source

pub struct Bucket { /* private fields */ }

Expand description

A bucket is a named collection of key-value pairs.

Implementations§

Source §

impl Bucket

Source

pub fn begin(&self) -> Result<TxnKV<'_>, OpCode>

Begins a new read-write transaction.

Examples found in repository ?

examples/observer.rs (line 19)

8fn main() -> Result<(), OpCode> {
9    let path = std::env::temp_dir().join(format!("mace_observer_{}", std::process::id()));
10    let _ = std::fs::remove_dir_all(&path);
11
12    let observer = Arc::new(InMemoryObserver::new(256));
13    let mut opt = Options::new(&path);
14    opt.observer = observer.clone();
15
16    let db = Mace::new(opt.validate()?)?;
17    let bucket = db.new_bucket("observe", BucketOptions::default())?;
18
19    let tx = bucket.begin()?;
20    tx.put("k1", "v1")?;
21
22    let r = tx.put("k1", "v2");
23    assert_eq!(r.err(), Some(OpCode::AbortTx));
24    drop(tx);
25
26    let tx = bucket.begin()?;
27    tx.put("k2", "v2")?;
28    tx.commit()?;
29
30    let snapshot = observer.snapshot();
31    print_snapshot(&snapshot);
32    Ok(())
33}

More examples

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examples/demo.rs (line 11)

3fn main() -> Result<(), OpCode> {
4    let path = std::env::temp_dir().join("mace");
5    let _ = std::fs::remove_dir_all(&path);
6    let opt = Options::new(path).validate()?;
7    let db = Mace::new(opt)?;
8    let bucket = db.new_bucket("test", BucketOptions::default())?;
9
10    // start a read-write transaction
11    let kv = bucket.begin()?;
12    kv.put("foo", "bar")?;
13    kv.put("fool", "+1s")?;
14    kv.put("foolish", "elder")?;
15
16    // can't create two identical keys
17    let r = kv.put("foolish", "114514").err();
18    assert_eq!(r.unwrap(), OpCode::AbortTx);
19
20    // use `update` for exist key or use `upsert` when unsure
21    let r = kv.update("foolish", "114514");
22    assert!(r.is_ok());
23
24    let r = kv.get("foo")?;
25    assert_eq!(r.slice(), "bar".as_bytes());
26    kv.del("foolish")?;
27    kv.commit()?;
28
29    // rollback
30    let kv = bucket.begin()?;
31    kv.put("mo", "ha")?;
32    drop(kv);
33
34    // start a read-only transaction
35    let view = bucket.view()?;
36    let r = view.get("foo")?;
37    assert_eq!(r.slice(), "bar".as_bytes());
38    let r = view.get("mo");
39    assert_eq!(r.err().unwrap(), OpCode::NotFound);
40
41    // prefix scan
42    let r = view.get("foolish");
43    assert!(r.is_err() && r.err().unwrap() == OpCode::NotFound);
44    let iter = view.seek("foo");
45    assert_eq!(iter.count(), 2);
46
47    Ok(())
48}

Source

pub fn view(&self) -> Result<TxnView<'_>, OpCode>

Begins a new read-only transaction (view).

Examples found in repository ?

examples/demo.rs (line 35)

3fn main() -> Result<(), OpCode> {
4    let path = std::env::temp_dir().join("mace");
5    let _ = std::fs::remove_dir_all(&path);
6    let opt = Options::new(path).validate()?;
7    let db = Mace::new(opt)?;
8    let bucket = db.new_bucket("test", BucketOptions::default())?;
9
10    // start a read-write transaction
11    let kv = bucket.begin()?;
12    kv.put("foo", "bar")?;
13    kv.put("fool", "+1s")?;
14    kv.put("foolish", "elder")?;
15
16    // can't create two identical keys
17    let r = kv.put("foolish", "114514").err();
18    assert_eq!(r.unwrap(), OpCode::AbortTx);
19
20    // use `update` for exist key or use `upsert` when unsure
21    let r = kv.update("foolish", "114514");
22    assert!(r.is_ok());
23
24    let r = kv.get("foo")?;
25    assert_eq!(r.slice(), "bar".as_bytes());
26    kv.del("foolish")?;
27    kv.commit()?;
28
29    // rollback
30    let kv = bucket.begin()?;
31    kv.put("mo", "ha")?;
32    drop(kv);
33
34    // start a read-only transaction
35    let view = bucket.view()?;
36    let r = view.get("foo")?;
37    assert_eq!(r.slice(), "bar".as_bytes());
38    let r = view.get("mo");
39    assert_eq!(r.err().unwrap(), OpCode::NotFound);
40
41    // prefix scan
42    let r = view.get("foolish");
43    assert!(r.is_err() && r.err().unwrap() == OpCode::NotFound);
44    let iter = view.seek("foo");
45    assert_eq!(iter.count(), 2);
46
47    Ok(())
48}