Fixing slowness in saved post fetching. #4756 (#4758)

* Fixing slowness in saved post fetching. #4756

* Also fix comment_view.rs

crates/db_views/src/comment_view.rs

@@ -1,5 +1,4 @@
 use crate::structs::{CommentView, LocalUserView};
-use chrono::{DateTime, Utc};
 use diesel::{
   dsl::{exists, not},
   pg::Pg,
@@ -63,17 +62,6 @@ fn queries<'a>() -> Queries<
     )
   };
 
-  let is_saved = |person_id| {
-    comment_saved::table
-      .filter(
-        comment::id
-          .eq(comment_saved::comment_id)
-          .and(comment_saved::person_id.eq(person_id)),
-      )
-      .select(comment_saved::published.nullable())
-      .single_value()
-  };
-
   let is_community_followed = |person_id| {
     community_follower::table
       .filter(
@@ -147,14 +135,6 @@ fn queries<'a>() -> Queries<
       Box::new(None::<bool>.into_sql::<sql_types::Nullable<sql_types::Bool>>())
     };
 
-    let is_saved_selection: Box<
-      dyn BoxableExpression<_, Pg, SqlType = sql_types::Nullable<sql_types::Timestamptz>>,
-    > = if let Some(person_id) = my_person_id {
-      Box::new(is_saved(person_id))
-    } else {
-      Box::new(None::<DateTime<Utc>>.into_sql::<sql_types::Nullable<sql_types::Timestamptz>>())
-    };
-
     let is_creator_blocked_selection: Box<dyn BoxableExpression<_, Pg, SqlType = sql_types::Bool>> =
       if let Some(person_id) = my_person_id {
         Box::new(is_creator_blocked(person_id))
@@ -167,6 +147,13 @@ fn queries<'a>() -> Queries<
       .inner_join(post::table)
       .inner_join(community::table.on(post::community_id.eq(community::id)))
       .inner_join(comment_aggregates::table)
+      .left_join(
+        comment_saved::table.on(
+          comment::id
+            .eq(comment_saved::comment_id)
+            .and(comment_saved::person_id.eq(my_person_id.unwrap_or(PersonId(-1)))),
+        ),
+      )
       .select((
         comment::all_columns,
         person::all_columns,
@@ -178,7 +165,7 @@ fn queries<'a>() -> Queries<
         creator_is_moderator,
         creator_is_admin,
         subscribed_type_selection,
-        is_saved_selection.is_not_null(),
+        comment_saved::person_id.nullable().is_not_null(),
         is_creator_blocked_selection,
         score_selection,
       ))
@@ -260,8 +247,8 @@ fn queries<'a>() -> Queries<
     // If its saved only, then filter, and order by the saved time, not the comment creation time.
     if options.saved_only {
       query = query
-        .filter(is_saved(person_id_join).is_not_null())
-        .then_order_by(is_saved(person_id_join).desc());
+        .filter(comment_saved::person_id.is_not_null())
+        .then_order_by(comment_saved::published.desc());
     }
 
     if let Some(my_id) = my_person_id {

crates/db_views/src/post_view.rs

@@ -1,5 +1,4 @@
 use crate::structs::{LocalUserView, PaginationCursor, PostView};
-use chrono::{DateTime, Utc};
 use diesel::{
   debug_query,
   dsl::{exists, not, IntervalDsl},
@@ -100,17 +99,6 @@ fn queries<'a>() -> Queries<
     ),
   );
 
-  let is_saved = |person_id| {
-    post_saved::table
-      .filter(
-        post_aggregates::post_id
-          .eq(post_saved::post_id)
-          .and(post_saved::person_id.eq(person_id)),
-      )
-      .select(post_saved::published.nullable())
-      .single_value()
-  };
-
   let is_read = |person_id| {
     exists(
       post_read::table.filter(
@@ -162,14 +150,6 @@ fn queries<'a>() -> Queries<
       Box::new(false.into_sql::<sql_types::Bool>())
     };
 
-    let is_saved_selection: Box<
-      dyn BoxableExpression<_, Pg, SqlType = sql_types::Nullable<sql_types::Timestamptz>>,
-    > = if let Some(person_id) = my_person_id {
-      Box::new(is_saved(person_id))
-    } else {
-      Box::new(None::<DateTime<Utc>>.into_sql::<sql_types::Nullable<sql_types::Timestamptz>>())
-    };
-
     let is_read_selection: Box<dyn BoxableExpression<_, Pg, SqlType = sql_types::Bool>> =
       if let Some(person_id) = my_person_id {
         Box::new(is_read(person_id))
@@ -237,6 +217,13 @@ fn queries<'a>() -> Queries<
       .inner_join(person::table)
       .inner_join(community::table)
       .inner_join(post::table)
+      .left_join(
+        post_saved::table.on(
+          post_aggregates::post_id
+            .eq(post_saved::post_id)
+            .and(post_saved::person_id.eq(my_person_id.unwrap_or(PersonId(-1)))),
+        ),
+      )
       .select((
         post::all_columns,
         person::all_columns,
@@ -247,7 +234,7 @@ fn queries<'a>() -> Queries<
         creator_is_admin,
         post_aggregates::all_columns,
         subscribed_type_selection,
-        is_saved_selection.is_not_null(),
+        post_saved::person_id.nullable().is_not_null(),
         is_read_selection,
         is_hidden_selection,
         is_creator_blocked_selection,
@@ -426,10 +413,10 @@ fn queries<'a>() -> Queries<
     };
 
     // If its saved only, then filter, and order by the saved time, not the comment creation time.
-    if let (true, Some(person_id)) = (options.saved_only, my_person_id) {
+    if let (true, Some(_person_id)) = (options.saved_only, my_person_id) {
       query = query
-        .filter(is_saved(person_id).is_not_null())
-        .then_order_by(is_saved(person_id).desc());
+        .filter(post_saved::person_id.is_not_null())
+        .then_order_by(post_saved::published.desc());
     }
     // Only hide the read posts, if the saved_only is false. Otherwise ppl with the hide_read
     // setting wont be able to see saved posts.

crates/federate/src/util.rs

@@ -59,13 +59,13 @@ pub struct CancellableTask {
 
 impl CancellableTask {
   /// spawn a task but with graceful shutdown
-  pub fn spawn<F, R: Debug>(
+  pub fn spawn<F, R>(
     timeout: Duration,
     task: impl FnOnce(CancellationToken) -> F + Send + 'static,
   ) -> CancellableTask
   where
     F: Future<Output = LemmyResult<R>> + Send + 'static,
-    R: Send + 'static,
+    R: Send + Debug + 'static,
   {
     let stop = CancellationToken::new();
     let stop2 = stop.clone();

docker/docker-compose.yml

@@ -53,7 +53,7 @@ services:
 
   lemmy-ui:
     # use "image" to pull down an already compiled lemmy-ui. make sure to comment out "build".
-    image: dessalines/lemmy-ui:0.19.3
+    image: dessalines/lemmy-ui:0.19.4-rc.3
     # platform: linux/x86_64 # no arm64 support. uncomment platform if using m1.
     # use "build" to build your local lemmy ui image for development. make sure to comment out "image".
     # run: docker compose up --build