Struct db_dump::Loader [−][src]
pub struct Loader<'a> { /* fields omitted */ }Expand description
Perform a streaming load of only relevant database tables.
Example
This example loads just the version_downloads.csv table, in which each row is the download count for a single version of a single crate on a single day. We do not store the rows individually in memory but instead stream from the csv to accumulate just a total count per day across all crates, which requires far less memory.
use chrono::NaiveDate;
use std::collections::BTreeMap as Map;
fn main() -> db_dump::Result<()> {
let mut downloads = Map::<NaiveDate, u64>::new();
db_dump::Loader::new()
.version_downloads(|row| {
*downloads.entry(row.date).or_default() += row.downloads;
})
.load("./db-dump.tar.gz")?;
for (date, count) in downloads {
println!("{},{}", date, count);
}
Ok(())
}