# vecdb
High-performance mutable persistent vectors built on [`rawdb`](../rawdb/README.md).
It features:
- `Vec` based API: push, update, truncate, delete by index
- Multiple variants: `raw`, `compressed`, `computed`
- Rollback via stamped change deltas
- Sparse deletions with holes
- Thread-safe with concurrent reads
- Blazing fast ([benchmark](../vecdb_bench/README.md))
- Persistence only on `flush`
It is not:
- A key-value store (consider [`fjall`](https://crates.io/crates/fjall) or [`redb`](https://crates.io/crates/redb))
- Suited for variable-sized types (`String`, `Vec<T>`, etc.)
## Install
```bash
cargo add vecdb
```
## Usage
```rust
use vecdb::{AnyStoredVec, Database, GenericStoredVec, RawVec, Result, Version};
fn main() -> Result<()> {
// create
let temp_dir = tempfile::TempDir::new()?;
let db = Database::open(temp_dir.path())?;
let mut vec: RawVec<usize, u64> = RawVec::import(&db, "vec", Version::ONE)?;
// push
for i in 0..1_000_000 {
vec.push(i);
}
// flush
vec.flush()?;
db.flush()?;
// read (sequential)
let mut sum = 0u64;
for value in vec.iter()? {
sum = sum.wrapping_add(value);
}
// read (random)
let indices: Vec<usize> = vec![500, 1000, 10];
let reader = vec.create_reader();
for i in indices {
if let Ok(value) = vec.read_at(i, &reader) {
sum = sum.wrapping_add(value);
}
}
Ok(())
}
```
## Constraints
Data must be fixed-size types: numbers, fixed arrays, structs with `#[repr(C)]`.
Compression via Pcodec works for numeric types only.
## When to use it
- Need to store `Vec`s on disk
- Append-only or append-mostly workloads
- Need very high read speeds
- Space-efficient storage for numeric data
- Sparse deletions without reindexing
- Rollback without full snapshots
## Examples
See [examples/](examples/) for usage.