CQL TinyText

This crate implements various CqlType derivatives for storing String values of up to (and including) 255 chars in a CQL database.

Will allocate 1020 bytes per value linked.

Benchmarks

Benchmarks supplied below are fairly rudimentary (and rounded) and are there to give a rough idea of relative costs. Full benchmark code can be found in github and can be run with rustup run nightly cargo bench, but please be aware that they will allocate ~102MB of disk space. The readtostream benchmarks also differ slightly from other CqlType derivatives as they stream into a Vector, not an Array.

Operation | Database dimensions | Mean time (ns) --- | --- | --- Single point read | 1 | 3 060 (+/- 200) Single point read | 4 | 15 800 (+/- 1 100) Single point write | 1 | 2 800 (+/- 300) Single point write | 4 | 15 400 (+/- 1 000) Stream read 1 point | 1 | 3 500 (+/- 300) Stream read 1 point | 4 | 15 500 (+/- 1 100) Stream read 50 000 points | 1 | 56 700 000 (+/- 800 000) Stream read 50 000 points | 4 | 56 400 000 (+/- 150 000)

Getting started

To get started, add the below dependencies to your Cargo.toml:

[dependencies] //... (any existing dependencies you may have) cql_db = "^0.2.4" cql_tiny_text = "^0.2"

Then need to create a folder where you want the database to live, and then try out the below:

``` use std::convert::TryFrom; use std::io::{ Cursor, SeekFrom, Seek }; use std::error::Error; use cqltinytext::{ TinyText, unpack_stream };

const DATABASELOCATION: &str = "PATHTOYOURDATABASE_DIRECTORY";

pub fn example_cql() -> Result<(), Box> { let value1 = "item one"; let value3 = "شماره ۳";

cql_db::create_db::<TinyText>(
    DATABASE_LOCATION,
    &[3]
)?;

cql_db::write_value::<TinyText>(
    DATABASE_LOCATION,
    &[1],
    TinyText::try_from(value1)?
)?;

cql_db::write_value::<TinyText>(
    DATABASE_LOCATION,
    &[3],
    TinyText::try_from(value3)?
)?;

let mut result = Vec::with_capacity(3);
let mut stream = Cursor::new(Vec::new());

cql_db::read_to_stream::<TinyText>(
    DATABASE_LOCATION,
    &mut stream,
    &[1],
    3
)?;

stream.seek(SeekFrom::Start(0));
unpack_stream(&mut stream, 3, |_, value| {
    result.push(value)
})?;

assert_eq!(result[0], TinyText::try_from(value1)?);
assert_eq!(result[1], TinyText::new());
assert_eq!(result[2], TinyText::try_from(value3)?);
Ok(())

} ```

More info

For further information and more examples, please see the rustdocs. Additional storage types are documented in the cql_db crate.