diff --git a/migrations/2019-03-22-174825_remove_version_downloads_pk/down.sql b/migrations/2019-03-22-174825_remove_version_downloads_pk/down.sql
new file mode 100644
index 00000000000..3e2458b0b86
--- /dev/null
+++ b/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;
diff --git a/migrations/2019-03-22-174825_remove_version_downloads_pk/up.sql b/migrations/2019-03-22-174825_remove_version_downloads_pk/up.sql
new file mode 100644
index 00000000000..cecb134929a
--- /dev/null
+++ b/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;
diff --git a/mirage/fixtures/version-downloads.js b/mirage/fixtures/version-downloads.js
index 7d3d7fa2409..f7a144d14ae 100644
--- a/mirage/fixtures/version-downloads.js
+++ b/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,
     },
 ];
diff --git a/src/bin/update-downloads.rs b/src/bin/update-downloads.rs
index b31394d5e57..f78f074b014 100644
--- a/src/bin/update-downloads.rs
+++ b/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)?;
 
diff --git a/src/models/download.rs b/src/models/download.rs
index e15db4c62bd..827e32b65a0 100644
--- a/src/models/download.rs
+++ b/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(),
diff --git a/src/schema.rs b/src/schema.rs
index c89bd7d4eba..0830970c53d 100644
--- a/src/schema.rs
+++ b/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`.
diff --git a/src/views.rs b/src/views.rs
index 00a14a4cddd..9506ac00a05 100644
--- a/src/views.rs
+++ b/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,