CQL U64

This crate implements various CqlType derivatives for storing u64 values in a CQL database.

Will allocate 8 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.

Operation | Database dimensions | Mean time _unchecked (ns) | Mean time (ns) --- | --- | --- | --- Single point read | 1 | 2 450 (+/- 300) | 7 500 (+/- 600) Single point read | 4 | 14 850 (+/- 1 000) | 37 550 (+/- 2 300) Single point write | 1 | 2 800 (+/- 400) | 7 700 (+/- 400) Single point write | 4 | 15 400 (+/- 2 500) | 37 700 (+/- 3 000) Stream read 1 point | 1 | 2 500 (+/- 300) | 10 000 (+/- 850) Stream read 1 point | 4 | 14 900 (+/- 600) | 42 500 (+/- 6 500) Stream read 50 000 points | 1 | 27 650 000 (+/- 31 000) | 27 630 000 (+/- 180 000) Stream read 50 000 points | 4 | 27 660 000 (+/- 1 200 000) | 27 620 000 (+/- 480 000)

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_u64 = "^0.2"

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

``` use std::io::{ Cursor, SeekFrom, Seek }; use cqldb::error::Error; use cqlu64::{ U64, unpack_stream };

const DATABASELOCATION: &str = "PATHTOYOURDATABASE_DIRECTORY";

pub fn examplecql() -> Result<(), Error> { // create a one dimensional database to hold 3 points cqldb::createdb::( DATABASELOCATION, &[3] )?;

// write '1', to [1]
cql_db::write_value::<U64>(
    DATABASE_LOCATION,
    &[1],
    1
)?;

let mut result = [0; 2];
let mut stream = Cursor::new(Vec::new());

// read 2 values from [1] to 'stream'
cql_db::read_to_stream::<U64>(
    DATABASE_LOCATION,
    &mut stream,
    &[1],
    2
)?;

stream.seek(SeekFrom::Start(0)).unwrap();
unpack_stream(&mut stream, 2, |idx, value| {
    result[idx] = value
})?;

assert_eq!(result[0], 1);
assert_eq!(result[1], 0);
Ok(())

} ```

More info

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