Attempt to optimize query for subscription feed

src/invidious.cr

@@ -1282,10 +1282,7 @@ post "/login" do |env|
       PG_DB.exec("INSERT INTO session_ids VALUES ($1, $2, $3)", sid, email, Time.utc)
 
       view_name = "subscriptions_#{sha256(user.email)}"
-      PG_DB.exec("CREATE MATERIALIZED VIEW #{view_name} AS \
+      PG_DB.exec("CREATE MATERIALIZED VIEW #{view_name} AS #{MATERIALIZED_VIEW_SQL.call(user.email)}")
-        SELECT * FROM channel_videos WHERE
-        ucid IN (SELECT unnest(subscriptions) FROM users WHERE email = E'#{user.email.gsub("'", "\\'")}')
-        ORDER BY published DESC")
 
       if Kemal.config.ssl || config.https_only
         secure = true

src/invidious/helpers/jobs.cr

@@ -75,7 +75,7 @@ def refresh_feeds(db, logger, config)
                 end
               end
 
-              if db.query_one("SELECT pg_get_viewdef('#{view_name}')", as: String).includes? "ucid = ANY"
+              if !db.query_one("SELECT pg_get_viewdef('#{view_name}')", as: String).includes? "WHERE ((cv.ucid = ANY (u.subscriptions))"
                 logger.puts("Materialized view #{view_name} is out-of-date, recreating...")
                 db.exec("DROP MATERIALIZED VIEW #{view_name}")
               end
@@ -95,10 +95,7 @@ def refresh_feeds(db, logger, config)
                   # While iterating through, we may have an email stored from a deleted account
                   if db.query_one?("SELECT true FROM users WHERE email = $1", email, as: Bool)
                     logger.puts("CREATE #{view_name}")
-                    db.exec("CREATE MATERIALIZED VIEW #{view_name} AS \
+                    db.exec("CREATE MATERIALIZED VIEW #{view_name} AS #{MATERIALIZED_VIEW_SQL.call(email)}")
-                      SELECT * FROM channel_videos WHERE
-                      ucid IN (SELECT unnest(subscriptions) FROM users WHERE email = E'#{email.gsub("'", "\\'")}')
-                      ORDER BY published DESC")
                     db.exec("UPDATE users SET feed_needs_update = false WHERE email = $1", email)
                   end
                 rescue ex

src/invidious/users.cr

@@ -1,5 +1,8 @@
 require "crypto/bcrypt/password"
 
+# Materialized views may not be defined using bound parameters (`$1` as used elsewhere)
+MATERIALIZED_VIEW_SQL = ->(email : String) { "SELECT cv.* FROM channel_videos cv WHERE EXISTS (SELECT subscriptions FROM users u WHERE cv.ucid = ANY (u.subscriptions) AND u.email = E'#{email.gsub("'", "\\'")}') ORDER BY published DESC" }
+
 struct User
   module PreferencesConverter
     def self.from_rs(rs)
@@ -166,10 +169,7 @@ def get_user(sid, headers, db, refresh = true)
 
       begin
         view_name = "subscriptions_#{sha256(user.email)}"
-        db.exec("CREATE MATERIALIZED VIEW #{view_name} AS \
+        db.exec("CREATE MATERIALIZED VIEW #{view_name} AS #{MATERIALIZED_VIEW_SQL.call(user.email)}")
-          SELECT * FROM channel_videos WHERE
-          ucid IN (SELECT unnest(subscriptions) FROM users WHERE email = E'#{user.email.gsub("'", "\\'")}')
-          ORDER BY published DESC")
       rescue ex
       end
     end
@@ -188,10 +188,7 @@ def get_user(sid, headers, db, refresh = true)
 
     begin
       view_name = "subscriptions_#{sha256(user.email)}"
-      db.exec("CREATE MATERIALIZED VIEW #{view_name} AS \
+      db.exec("CREATE MATERIALIZED VIEW #{view_name} AS #{MATERIALIZED_VIEW_SQL.call(user.email)}")
-        SELECT * FROM channel_videos WHERE
-        ucid IN (SELECT unnest(subscriptions) FROM users WHERE email = E'#{user.email.gsub("'", "\\'")}')
-        ORDER BY published DESC")
     rescue ex
     end
   end