Crate transient_btree_index

Expand description

Transient Index using B-Trees

transient-btree-index allows you to create a BTree index backed by temporary files. This is helpful if you

need to index large datasets (thus only working on disk) by inserting entries in unsorted order,
want to query entries (get and range queries) while the index is still constructed, e.g. to check existence of a previous entry, and
need support for all serde-serializable key and value types with varying key-size.

Because of its intended use case, it is therefore not possible to

delete entries once they are inserted (you can use Option values and set them to Option::None, but this will not reclaim any used space),
persist the index to a file (you can use other crates like sstable to create immutable maps), or
load an existing index file (you might want to use an immutable map file and this index can act as an “overlay” for all changed entries).

Example

use transient_btree_index::{BtreeConfig, BtreeIndex, Error};

fn main() -> std::result::Result<(), Error> {
    let mut b = BtreeIndex::<u16,u16>::with_capacity(BtreeConfig::default(), 10)?;
    b.insert(1,2)?;
    b.insert(200, 4)?;
    b.insert(20, 3)?;

    assert_eq!(true, b.contains_key(&200)?);
    assert_eq!(false, b.contains_key(&2)?);  

    assert_eq!(3, b.get(&20)?.unwrap());  

    for e in b.range(1..30)? {
        let (k, v) = e?;
        dbg!(k, v);
    }
    Ok(())
}

Structs

BtreeConfig
Configuration for a B-tree index.
BtreeIndex
B-tree index backed by temporary memory mapped files.

Enums

Error