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Switch most recently downloaded summary query to be faster #1312

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Merged
merged 1 commit into from
Apr 5, 2018
Merged

Switch most recently downloaded summary query to be faster #1312

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31 changes: 18 additions & 13 deletions src/controllers/krate/metadata.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,8 +16,7 @@ use models::krate::ALL_COLUMNS;

/// Handles the `GET /summary` route.
pub fn summary(req: &mut Request) -> CargoResult<Response> {
use diesel::dsl::*;
use diesel::sql_types::{BigInt, Nullable};
use diesel::sql_query;
use schema::crates::dsl::*;

let conn = req.db_conn()?;
Expand Down Expand Up @@ -57,17 +56,23 @@ pub fn summary(req: &mut Request) -> CargoResult<Response> {
.limit(10)
.load(&*conn)?;

let recent_downloads = sql::<Nullable<BigInt>>("SUM(crate_downloads.downloads)");
let most_recently_downloaded = crates
.left_join(
crate_downloads::table.on(id.eq(crate_downloads::crate_id)
.and(crate_downloads::date.gt(date(now - 90.days())))),
)
.group_by(id)
.order(recent_downloads.desc().nulls_last())
.limit(10)
.select(ALL_COLUMNS)
.load::<Crate>(&*conn)?;
// This query needs to be structured in this way to have the LIMIT
// happen before the joining/sorting for performance reasons.
// It needs to use sql_query because Diesel doesn't have a great way
// to join on subselects right now :(
let most_recently_downloaded = sql_query(
"SELECT crates.* \
FROM crates \
JOIN ( \
SELECT crate_downloads.crate_id, SUM(crate_downloads.downloads) \
FROM crate_downloads \
WHERE crate_downloads.date > date(CURRENT_TIMESTAMP - INTERVAL '90 days') \
GROUP BY crate_downloads.crate_id \
ORDER BY SUM(crate_downloads.downloads) DESC NULLS LAST \
LIMIT 10 \
) cd ON crates.id = cd.crate_id \
ORDER BY cd.sum DESC NULLS LAST",
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I believe NULLS LAST can be dropped because this is an INNER JOIN which should not include any null sums. Doesn't hurt to be explicit though.

).load::<Crate>(&*conn)?;

let popular_keywords = keywords::table
.order(keywords::crates_cnt.desc())
Expand Down
3 changes: 2 additions & 1 deletion src/models/krate.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,8 @@ pub struct CrateDownload {
pub date: NaiveDate,
}

#[derive(Debug, Clone, Queryable, Identifiable, Associations, AsChangeset)]
#[derive(Debug, Clone, Queryable, Identifiable, Associations, AsChangeset, QueryableByName)]
#[table_name = "crates"]
pub struct Crate {
pub id: i32,
pub name: String,
Expand Down