- Supports millions of operations per second
- Suitable for real-time collaboration
- Supports delta updates
- It is a CRDT, which means it possesses strong eventual consistency and can be easily used in distributed environments. It allows for syncing tabular data via peer-to-peer connections, supports end-to-end encryption, and facilitates the development of local-first applications.
Currently, it functions solely as an in-memory table with a unique persistence format and is not a comprehensive database solution. It is not suitable for sparse tables yet.
use lww_table::LwwDb;
use std::collections::HashSet;
pub fn main() {
let mut db = LwwDb::new();
db.set("my_table", "row1", "col1", 1);
db.set("my_table", "row1", "col2", 2);
db.set("my_table", "row2", "col1", 3);
db.set("my_table", "row2", "col2", 4);
assert_eq!(db.get_cell("my_table", "row1", "col1").unwrap(), &1.into());
assert_eq!(
db.iter_row("my_table", "row1").collect::<HashSet<_>>(),
HashSet::from([("col1", &1.into()), ("col2", &2.into())])
);
println!("{}", db);
db.delete_row("my_table", "row1");
println!("{}", db);
}Output:
LwwDb {
# my_table
-------- ------ ------
| row_id | col2 | col1 |
-------- ------ ------
| row1 | 2 | 1 |
-------- ------ ------
| row2 | 4 | 3 |
-------- ------ ------
}
LwwDb {
# my_table
-------- ------ ------
| row_id | col2 | col1 |
-------- ------ ------
| row1 | null | null |
-------- ------ ------
| row2 | 4 | 3 |
-------- ------ ------
}
use lww_table::{LwwDb, VectorClock};
pub fn main() {
let mut db = LwwDb::new();
db.set("my_table", "row1", "col1", 1);
db.set("my_table", "row1", "col2", 2);
db.set("my_table", "row2", "col1", 3);
db.set("my_table", "row2", "col2", 4);
let mut db2 = LwwDb::new();
db2.set("my_table", "row3", "col1", 3);
db2.set("my_table", "row3", "col2", 5);
let version: Vec<u8> = db2.version().encode();
// you can send version via network, save to disk, etc.
let bytes: Vec<u8> = db.export_updates(VectorClock::decode(&version));
// you can send bytes via network, save to disk, etc.
db2.import_updates(&bytes);
// sync in the other direction
db.import_updates(&db2.export_updates(db.version().clone()));
// now two databases are in sync
assert!(db.check_eq(&mut db2));
println!("{}", db);
println!("{}", db2);
}Output:
LwwDb {
# my_table
-------- ------ ------
| row_id | col2 | col1 |
-------- ------ ------
| row1 | 2 | 1 |
-------- ------ ------
| row2 | 4 | 3 |
-------- ------ ------
| row3 | 5 | 3 |
-------- ------ ------
}
LwwDb {
# my_table
-------- ------ ------
| row_id | col2 | col1 |
-------- ------ ------
| row1 | 2 | 1 |
-------- ------ ------
| row2 | 4 | 3 |
-------- ------ ------
| row3 | 5 | 3 |
-------- ------ ------
}
For a table created by the following code:
let mut db = lww_table::LwwDb::new();
for i in 0..100_000 {
for j in 0..10 {
db.set("table", &i.to_string(), j.to_string().as_str(), i j);
}
}The benchmark is conducted on MacBook Pro (13-inch, M1, 2020).
| Set | 344.884ms |
|---|---|
| Export updates | 272.93475ms |
| Updates size | 2552394 bytes |
| Import updates | 329.477459ms |
| Export snapshot | 26.450417ms |
| Snapshot size | 323420 bytes |
| Import snapshot | 143.268833ms |