6 releases (breaking)
0.5.1 | Nov 14, 2023 |
---|---|
0.5.0 | Jul 19, 2022 |
0.4.0 | Jul 17, 2022 |
0.3.0 | Mar 10, 2022 |
0.1.0 | Feb 10, 2022 |
#4 in #index-file
492 downloads per month
Used in 9 crates
(5 directly)
81KB
1.5K
SLoC
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 toOption::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(())
}
Dependencies
~3–12MB
~152K SLoC