Remove the id column from version_downloads

migrations/2019-03-22-174825_remove_version_downloads_pk/down.sql

@@ -0,0 +1,28 @@
+-- Diesel always runs migrations in a transaction, and we can't create indexes
+-- concurrently in a transaction. We can't block crate downloads on this, so
+-- just raise if we try to run this in production
+DO $$
+DECLARE
+  tmp_index_exists boolean;
+BEGIN
+  tmp_index_exists := (SELECT EXISTS (
+      SELECT * FROM pg_index
+        INNER JOIN pg_class
+          ON pg_class.oid = pg_index.indexrelid
+        WHERE relname = 'version_downloads_tmp'
+  ));
+  IF NOT tmp_index_exists THEN
+    IF (SELECT COUNT(*) FROM version_downloads) > 1000 THEN
+      RAISE EXCEPTION 'Indexes need to be created concurrently in production, manually create them and try again';
+    ELSE
+      ALTER TABLE version_downloads ADD COLUMN id SERIAL;
+      CREATE UNIQUE INDEX version_downloads_tmp ON version_downloads (id);
+      CREATE UNIQUE INDEX version_downloads_unique ON version_downloads (version_id, date);
+      CREATE UNIQUE INDEX index_version_downloads_not_processed ON version_downloads (id) WHERE processed = false;
+    END IF;
+  END IF;
+END $$;
+
+ALTER TABLE version_downloads
+  DROP CONSTRAINT version_downloads_pkey,
+  ADD CONSTRAINT version_downloads_pkey PRIMARY KEY USING INDEX version_downloads_tmp;

migrations/2019-03-22-174825_remove_version_downloads_pk/up.sql

@@ -0,0 +1,6 @@
+-- ALERT! DESTRUCTIVE MIGRATION
+-- DO NOT DEPLOY UNTIL PREVIOUS COMMIT IS DEPLOYED
+ALTER TABLE version_downloads
+  DROP CONSTRAINT version_downloads_pkey,
+  ADD CONSTRAINT version_downloads_pkey PRIMARY KEY USING INDEX version_downloads_unique,
+  DROP COLUMN id;

mirage/fixtures/version-downloads.js

@@ -3,19 +3,16 @@ export default [
     {
         date: '2017-02-10T00:00:00Z',
         downloads: 2,
-        id: 3023900,
         version: 40905,
     },
     {
         date: '2017-02-10T00:00:00Z',
         downloads: 1,
-        id: 3024236,
         version: 18445,
     },
     {
         date: '2017-02-11T00:00:00Z',
         downloads: 1,
-        id: 3027018,
         version: 40905,
     },
 ];

src/bin/update-downloads.rs

@@ -12,8 +12,6 @@ use cargo_registry::{
 
 use diesel::prelude::*;
 
-static LIMIT: i64 = 1000;
-
 fn main() -> CargoResult<()> {
     let conn = db::connect_now()?;
     update(&conn)?;
@@ -25,18 +23,11 @@ fn update(conn: &PgConnection) -> QueryResult<()> {
     use diesel::dsl::now;
     use diesel::select;
 
-    let mut max = Some(0);
-    while let Some(m) = max {
-        let rows = version_downloads
-            .filter(processed.eq(false))
-            .filter(id.gt(m))
-            .filter(downloads.ne(counted))
-            .order(id)
-            .limit(LIMIT)
-            .load(conn)?;
-        collect(conn, &rows)?;
-        max = rows.last().map(|d| d.id);
-    }
+    let rows = version_downloads
+        .filter(processed.eq(false))
+        .filter(downloads.ne(counted))
+        .load(conn)?;
+    collect(conn, &rows)?;
 
     // Anything older than 24 hours ago will be frozen and will not be queried
     // against again.
@@ -62,7 +53,7 @@ fn collect(conn: &PgConnection, rows: &[VersionDownload]) -> QueryResult<()> {
 
         conn.transaction::<_, diesel::result::Error, _>(|| {
             // increment the number of counted downloads
-            update(version_downloads::table.find(download.id))
+            update(version_downloads::table.find(download.id()))
                 .set(version_downloads::counted.eq(version_downloads::counted + amt))
                 .execute(conn)?;
 

src/models/download.rs

@@ -7,8 +7,8 @@ use crate::views::EncodableVersionDownload;
 
 #[derive(Queryable, Identifiable, Associations, Debug, Clone, Copy)]
 #[belongs_to(Version)]
+#[primary_key(version_id, date)]
 pub struct VersionDownload {
-    pub id: i32,
     pub version_id: i32,
     pub downloads: i32,
     pub counted: i32,
@@ -34,7 +34,6 @@ impl VersionDownload {
 
     pub fn encodable(self) -> EncodableVersionDownload {
         EncodableVersionDownload {
-            id: self.id,
             version: self.version_id,
             downloads: self.downloads,
             date: self.date.to_string(),

src/schema.rs

@@ -815,13 +815,7 @@ table! {
     /// Representation of the `version_downloads` table.
     ///
     /// (Automatically generated by Diesel.)
-    version_downloads (id) {
-        /// The `id` column of the `version_downloads` table.
-        ///
-        /// Its SQL type is `Int4`.
-        ///
-        /// (Automatically generated by Diesel.)
-        id -> Int4,
+    version_downloads (version_id, date) {
         /// The `version_id` column of the `version_downloads` table.
         ///
         /// Its SQL type is `Int4`.

src/views.rs

@@ -66,7 +66,6 @@ pub struct EncodableDependency {
 
 #[derive(Serialize, Deserialize, Debug)]
 pub struct EncodableVersionDownload {
-    pub id: i32,
     pub version: i32,
     pub downloads: i32,
     pub date: String,