fix

.woodpecker.yml

@@ -185,44 +185,6 @@ steps:
       - cargo test --workspace --no-fail-fast
     when: *slow_check_paths
 
-  check_diesel_migration:
-    # TODO: use willsquire/diesel-cli image when shared libraries become optional in lemmy_server
-    image: *rust_image
-    environment:
-      LEMMY_DATABASE_URL: postgres://lemmy:password@database:5432/lemmy
-      RUST_BACKTRACE: "1"
-      CARGO_HOME: .cargo_home
-      DATABASE_URL: postgres://lemmy:password@database:5432/lemmy
-      PGUSER: lemmy
-      PGPASSWORD: password
-      PGHOST: database
-      PGDATABASE: lemmy
-    commands:
-      - cargo install diesel_cli
-      - export PATH="$CARGO_HOME/bin:$PATH"
-      # Run all migrations
-      - diesel migration run
-      # Dump schema to before.sqldump (PostgreSQL apt repo is used to prevent pg_dump version mismatch error)
-      - apt update && apt install -y lsb-release
-      - sh -c 'echo "deb https://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'
-      - wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
-      - apt update && apt install -y postgresql-client-16
-      - psql -c "DROP SCHEMA IF EXISTS r CASCADE;"
-      - pg_dump --no-owner --no-privileges --no-table-access-method --schema-only --no-sync -f before.sqldump
-      # Make sure that the newest migration is revertable without the `r` schema
-      - diesel migration redo
-      # Run schema setup twice, which fails on the 2nd time if `DROP SCHEMA IF EXISTS r CASCADE` drops the wrong things
-      - alias lemmy_schema_setup="target/lemmy_server --disable-scheduled-tasks --disable-http-server --disable-activity-sending"
-      - lemmy_schema_setup
-      - lemmy_schema_setup
-      # Make sure that the newest migration is revertable with the `r` schema
-      - diesel migration redo
-      # Check for changes in the schema, which would be caused by an incorrect migration
-      - psql -c "DROP SCHEMA IF EXISTS r CASCADE;"
-      - pg_dump --no-owner --no-privileges --no-table-access-method --schema-only --no-sync -f after.sqldump
-      - diff before.sqldump after.sqldump
-    when: *slow_check_paths
-
   run_federation_tests:
     image: node:20-bookworm-slim
     environment:

crates/db_schema/src/lib.rs

@@ -11,11 +11,6 @@ extern crate diesel_derive_newtype;
 #[macro_use]
 extern crate diesel_derive_enum;
 
-// this is used in tests
-#[cfg(feature = "full")]
-#[macro_use]
-extern crate diesel_migrations;
-
 #[cfg(feature = "full")]
 #[macro_use]
 extern crate async_trait;

crates/db_schema/src/schema_setup.rs

@@ -1,9 +1,8 @@
 use crate::schema::previously_run_sql;
-use anyhow::Context;
+use anyhow::{anyhow, Context};
 use diesel::{
-  backend::Backend,
   connection::SimpleConnection,
-  migration::{Migration, MigrationSource},
+  migration::{Migration, MigrationSource, MigrationVersion},
   pg::Pg,
   select,
   update,
@@ -14,12 +13,25 @@ use diesel::{
   QueryDsl,
   RunQueryDsl,
 };
-use diesel_migrations::{EmbeddedMigrations, MigrationHarness};
+use diesel_migrations::MigrationHarness;
 use lemmy_utils::error::{LemmyError, LemmyResult};
 use std::time::Instant;
 use tracing::info;
 
-const MIGRATIONS: EmbeddedMigrations = embed_migrations!();
+// In production, include migrations in the binary
+#[cfg(not(debug_assertions))]
+fn get_migration_source() -> diesel_migrations::EmbeddedMigrations {
+  // Using `const` here is required by the borrow checker
+  const MIGRATIONS: diesel_migrations::EmbeddedMigrations = diesel_migrations::embed_migrations!();
+  MIGRATIONS
+}
+
+// Avoid recompiling when migrations are changed
+#[cfg(debug_assertions)]
+fn get_migration_source() -> diesel_migrations::FileBasedMigrations {
+  diesel_migrations::FileBasedMigrations::find_migrations_directory()
+    .expect("failed to find migrations dir")
+}
 
 /// This SQL code sets up the `r` schema, which contains things that can be safely dropped and replaced
 /// instead of being changed using migrations. It may not create or modify things outside of the `r` schema
@@ -30,35 +42,103 @@ const REPLACEABLE_SCHEMA: &[&str] = &[
   include_str!("../replaceable_schema/triggers.sql"),
 ];
 
-fn get_pending_migrations(conn: &mut PgConnection) -> LemmyResult<Vec<Box<dyn Migration<Pg>>>> {
-  Ok(
-    conn
-      .pending_migrations(MIGRATIONS)
-      .map_err(|e| anyhow::anyhow!("Couldn't determine pending migrations: {e}"))?,
-  )
+struct MigrationHarnessWrapper<'a> {
+  conn: &'a mut PgConnection,
+}
+
+impl<'a> MigrationHarness<Pg> for MigrationHarnessWrapper<'a> {
+  fn run_migration(
+    &mut self,
+    migration: &dyn Migration<Pg>,
+  ) -> diesel::migration::Result<MigrationVersion<'static>> {
+    let start_time = Instant::now();
+
+    let result = self.conn.run_migration(migration);
+
+    let duration = start_time.elapsed().as_millis();
+    let name = migration.name();
+    info!("{duration}ms run {name}");
+
+    result
+  }
+
+  fn revert_migration(
+    &mut self,
+    migration: &dyn Migration<Pg>,
+  ) -> diesel::migration::Result<MigrationVersion<'static>> {
+    let start_time = Instant::now();
+
+    let result = self.conn.revert_migration(migration);
+
+    let duration = start_time.elapsed().as_millis();
+    let name = migration.name();
+    info!("{duration}ms revert {name}");
+
+    result
+  }
+
+  fn applied_migrations(&mut self) -> diesel::migration::Result<Vec<MigrationVersion<'static>>> {
+    self.conn.applied_migrations()
+  }
+}
+
+// TODO: remove when diesel either adds MigrationSource impl for references or changes functions to take reference
+#[derive(Clone, Copy)]
+struct MigrationSourceRef<T>(
+  // If this was `&T`, then the derive macros would add `Clone` and `Copy` bounds for `T`
+  T,
+);
+
+impl<'a, T: MigrationSource<Pg>> MigrationSource<Pg> for MigrationSourceRef<&'a T> {
+  fn migrations(&self) -> diesel::migration::Result<Vec<Box<dyn Migration<Pg>>>> {
+    self.0.migrations()
+  }
 }
 
 #[derive(Default)]
 pub struct Options {
-  /// Only for testing
   enable_forbid_diesel_cli_trigger: bool,
+  revert: bool,
+  revert_amount: Option<u64>,
+  redo_after_revert: bool,
 }
 
-pub fn run(db_url: &str, options: &Options) -> LemmyResult<()> {
+impl Options {
+  #[cfg(test)]
+  fn enable_forbid_diesel_cli_trigger(mut self) -> Self {
+    self.enable_forbid_diesel_cli_trigger = true;
+    self
+  }
+
+  pub fn revert(mut self, amount: Option<u64>) -> Self {
+    self.revert = true;
+    self.revert_amount = amount;
+    self
+  }
+
+  pub fn redo(mut self, amount: Option<u64>) -> Self {
+    self.redo_after_revert = true;
+    self.revert(amount)
+  }
+}
+
+pub fn run(db_url: &str, options: Options) -> LemmyResult<()> {
   // Migrations don't support async connection, and this function doesn't need to be async
   let mut conn = PgConnection::establish(db_url).with_context(|| "Error connecting to database")?;
 
-  let test_enabled = std::env::var("LEMMY_TEST_MIGRATIONS")
-    .map(|s| !s.is_empty())
-    .unwrap_or(false);
-
   let new_sql = REPLACEABLE_SCHEMA.join("\n");
 
-  let pending_migrations = get_pending_migrations(&mut conn)?;
+  let migration_source = get_migration_source();
+
+  let migration_source_ref = MigrationSourceRef(&migration_source);
 
   // If possible, skip locking the migrations table and recreating the "r" schema, so
   // lemmy_server processes in a horizontally scaled setup can start without causing locks
-  if pending_migrations.is_empty() {
+  if !(options.revert
+    || conn
+      .has_pending_migration(migration_source_ref)
+      .map_err(|e| anyhow!("Couldn't check pending migrations: {e}"))?)
+  {
     // The condition above implies that the migration that creates the previously_run_sql table was already run
     let sql_unchanged: bool = select(
       previously_run_sql::table
@@ -75,47 +155,62 @@ pub fn run(db_url: &str, options: &Options) -> LemmyResult<()> {
   }
 
   conn.transaction::<_, LemmyError, _>(|conn| {
-    // Use the table created by `MigrationHarness::pending_migrations` as a lock target to prevent multiple
-    // lemmy_server processes from running this transaction concurrently. This lock does not block
-    // `MigrationHarness::pending_migrations` (`SELECT`) or `MigrationHarness::run_migration` (`INSERT`).
+    let mut wrapper = MigrationHarnessWrapper { conn };
+
+    // * Prevent other lemmy_server processes from running this transaction simultaneously by repurposing
+    // the table created by `MigrationHarness::pending_migrations` as a lock target (this doesn't block
+    // normal use of the table)
+    // * Drop `r` schema, so migrations don't need to be made to work both with and without things in
+    // it existing
+    // * Disable the trigger that prevents the Diesel CLI from running migrations
     info!("Waiting for lock...");
-    conn.batch_execute("LOCK __diesel_schema_migrations IN SHARE UPDATE EXCLUSIVE MODE;")?;
-    info!("Running Database migrations (This may take a long time)...");
 
-    // Check pending migrations again after locking
-    let pending_migrations = get_pending_migrations(conn)?;
-
-    // Drop `r` schema and disable the trigger that prevents the Diesel CLI from running migrations
     let enable_migrations = if options.enable_forbid_diesel_cli_trigger {
       ""
     } else {
       "SET LOCAL lemmy.enable_migrations TO 'on';"
     };
-    conn.batch_execute(&format!(
-      "DROP SCHEMA IF EXISTS r CASCADE;{enable_migrations}"
-    ))?;
 
-    for migration in &pending_migrations {
-      let name = migration.name();
-      let start_time = Instant::now();
-      conn
-        .run_migration(migration)
-        .map_err(|e| anyhow::anyhow!("Couldn't run migration {name}: {e}"))?;
-      let duration = start_time.elapsed().as_millis();
-      info!("{duration}ms run {name}");
+    wrapper.conn.batch_execute(&format!("LOCK __diesel_schema_migrations IN SHARE UPDATE EXCLUSIVE MODE;DROP SCHEMA IF EXISTS r CASCADE;{enable_migrations}"))?;
+
+    info!("Running Database migrations (This may take a long time)...");
+
+    (|| {
+      if options.revert {
+        if let Some(amount) = options.revert_amount {
+          for _ in 0..amount {
+            wrapper.revert_last_migration(migration_source_ref)?;
+          }
+          if options.redo_after_revert {
+            for _ in 0..amount {
+              wrapper.run_next_migration(migration_source_ref)?;
+            }
+          }
+        } else {
+          wrapper.revert_all_migrations(migration_source_ref)?;
+          if options.redo_after_revert {
+            wrapper.run_pending_migrations(migration_source_ref)?;
+          }
+        }
+      } else {
+        wrapper.run_pending_migrations(migration_source_ref)?;
+      }
+      diesel::migration::Result::Ok(())
+    })().map_err(|e| anyhow!("Couldn't run DB Migrations: {e}"))?;
+
+    // Run replaceable_schema if newest migration was applied
+    if !(options.revert && !options.redo_after_revert) {
+      wrapper.conn
+        .batch_execute(&new_sql)
+        .context("Couldn't run SQL files in crates/db_schema/replaceable_schema")?;
+
+      let num_rows_updated = update(previously_run_sql::table)
+        .set(previously_run_sql::content.eq(new_sql))
+        .execute(wrapper.conn)?;
+
+      debug_assert_eq!(num_rows_updated, 1);
     }
 
-    // Run replaceable_schema
-    conn
-      .batch_execute(&new_sql)
-      .context("Couldn't run SQL files in crates/db_schema/replaceable_schema")?;
-
-    let num_rows_updated = update(previously_run_sql::table)
-      .set(previously_run_sql::content.eq(new_sql))
-      .execute(conn)?;
-
-    debug_assert_eq!(num_rows_updated, 1);
-
     Ok(())
   })?;
 
@@ -126,16 +221,31 @@ pub fn run(db_url: &str, options: &Options) -> LemmyResult<()> {
 
 #[cfg(test)]
 mod tests {
+  use super::*;
   use lemmy_utils::{error::LemmyResult, settings::SETTINGS};
+  use serial_test::serial;
 
   #[test]
+  #[serial]
   fn test_schema_setup() -> LemmyResult<()> {
-    let mut options = super::Options::default();
-    let db_url = SETTINGS.get_database_url();
+    let url = SETTINGS.get_database_url();
+    let mut conn = PgConnection::establish(&url)?;
 
-    // Test the forbid_diesel_cli trigger
-    options.enable_forbid_diesel_cli_trigger = true;
-    super::run(&db_url, &options).expect_err("forbid_diesel_cli trigger should throw error");
+    // Start with consistent state by dropping everything
+    conn.batch_execute("DROP OWNED BY CURRENT_USER;")?;
+
+    // Run and revert all migrations, ensuring there's no mistakes in any down.sql file
+    run(&url, Options::default())?;
+    run(&url, Options::default().revert(None))?;
+
+    // TODO also don't drop r, and maybe just directly call the migrationharness method here
+    assert!(matches!(
+      run(&url, Options::default().enable_forbid_diesel_cli_trigger()),
+      Err(e) if e.to_string().contains("lemmy_server")
+    ));
+
+    // Previous run shouldn't stop this one from working
+    run(&url, Options::default())?;
 
     Ok(())
   }

crates/db_schema/src/utils.rs

@@ -427,7 +427,7 @@ pub async fn build_db_pool() -> LemmyResult<ActualDbPool> {
     }))
     .build()?;
 
-  crate::schema_setup::run(&db_url, &Default::default())?;
+  crate::schema_setup::run(&db_url, Default::default())?;
 
   Ok(pool)
 }

migrations/2020-03-26-192410_add_activitypub_tables/down.sql

@@ -1,5 +1,11 @@
 DROP TABLE activity;
 
+DROP VIEW community_view, community_mview;
+
+DROP MATERIALIZED VIEW community_aggregates_mview;
+
+DROP VIEW community_aggregates_view;
+
 ALTER TABLE user_
     DROP COLUMN actor_id,
     DROP COLUMN private_key,
@@ -15,3 +21,126 @@ ALTER TABLE community
     DROP COLUMN local,
     DROP COLUMN last_refreshed_at;
 
+-- Views are the same as before, except `*` does not reference the dropped columns
+CREATE VIEW community_aggregates_view AS
+SELECT
+    c.*,
+    (
+        SELECT
+            name
+        FROM
+            user_ u
+        WHERE
+            c.creator_id = u.id) AS creator_name,
+    (
+        SELECT
+            avatar
+        FROM
+            user_ u
+        WHERE
+            c.creator_id = u.id) AS creator_avatar,
+    (
+        SELECT
+            name
+        FROM
+            category ct
+        WHERE
+            c.category_id = ct.id) AS category_name,
+    (
+        SELECT
+            count(*)
+        FROM
+            community_follower cf
+        WHERE
+            cf.community_id = c.id) AS number_of_subscribers,
+    (
+        SELECT
+            count(*)
+        FROM
+            post p
+        WHERE
+            p.community_id = c.id) AS number_of_posts,
+    (
+        SELECT
+            count(*)
+        FROM
+            comment co,
+            post p
+        WHERE
+            c.id = p.community_id
+            AND p.id = co.post_id) AS number_of_comments,
+    hot_rank ((
+        SELECT
+            count(*)
+        FROM community_follower cf
+        WHERE
+            cf.community_id = c.id), c.published) AS hot_rank
+FROM
+    community c;
+
+CREATE MATERIALIZED VIEW community_aggregates_mview AS
+SELECT
+    *
+FROM
+    community_aggregates_view;
+
+CREATE UNIQUE INDEX idx_community_aggregates_mview_id ON community_aggregates_mview (id);
+
+CREATE VIEW community_view AS
+with all_community AS (
+    SELECT
+        ca.*
+    FROM
+        community_aggregates_view ca
+)
+SELECT
+    ac.*,
+    u.id AS user_id,
+    (
+        SELECT
+            cf.id::boolean
+        FROM
+            community_follower cf
+        WHERE
+            u.id = cf.user_id
+            AND ac.id = cf.community_id) AS subscribed
+FROM
+    user_ u
+    CROSS JOIN all_community ac
+UNION ALL
+SELECT
+    ac.*,
+    NULL AS user_id,
+    NULL AS subscribed
+FROM
+    all_community ac;
+
+CREATE VIEW community_mview AS
+with all_community AS (
+    SELECT
+        ca.*
+    FROM
+        community_aggregates_mview ca
+)
+SELECT
+    ac.*,
+    u.id AS user_id,
+    (
+        SELECT
+            cf.id::boolean
+        FROM
+            community_follower cf
+        WHERE
+            u.id = cf.user_id
+            AND ac.id = cf.community_id) AS subscribed
+FROM
+    user_ u
+    CROSS JOIN all_community ac
+UNION ALL
+SELECT
+    ac.*,
+    NULL AS user_id,
+    NULL AS subscribed
+FROM
+    all_community ac;
+

migrations/2020-04-03-194936_add_activitypub_for_posts_and_comments/down.sql

@@ -1,3 +1,15 @@
+DROP VIEW post_mview;
+
+DROP MATERIALIZED VIEW post_aggregates_mview;
+
+DROP VIEW post_view, post_aggregates_view;
+
+DROP VIEW user_mention_view, comment_view, user_mention_mview, reply_view, comment_mview;
+
+DROP MATERIALIZED VIEW comment_aggregates_mview;
+
+DROP VIEW comment_aggregates_view;
+
 ALTER TABLE post
     DROP COLUMN ap_id,
     DROP COLUMN local;
@@ -6,3 +18,526 @@ ALTER TABLE comment
     DROP COLUMN ap_id,
     DROP COLUMN local;
 
+-- Views are the same as before, except `*` does not reference the dropped columns
+CREATE VIEW post_aggregates_view AS
+SELECT
+    p.*,
+    (
+        SELECT
+            u.banned
+        FROM
+            user_ u
+        WHERE
+            p.creator_id = u.id) AS banned,
+    (
+        SELECT
+            cb.id::bool
+        FROM
+            community_user_ban cb
+        WHERE
+            p.creator_id = cb.user_id
+            AND p.community_id = cb.community_id) AS banned_from_community,
+    (
+        SELECT
+            name
+        FROM
+            user_
+        WHERE
+            p.creator_id = user_.id) AS creator_name,
+    (
+        SELECT
+            avatar
+        FROM
+            user_
+        WHERE
+            p.creator_id = user_.id) AS creator_avatar,
+    (
+        SELECT
+            name
+        FROM
+            community
+        WHERE
+            p.community_id = community.id) AS community_name,
+    (
+        SELECT
+            removed
+        FROM
+            community c
+        WHERE
+            p.community_id = c.id) AS community_removed,
+    (
+        SELECT
+            deleted
+        FROM
+            community c
+        WHERE
+            p.community_id = c.id) AS community_deleted,
+    (
+        SELECT
+            nsfw
+        FROM
+            community c
+        WHERE
+            p.community_id = c.id) AS community_nsfw,
+    (
+        SELECT
+            count(*)
+        FROM
+            comment
+        WHERE
+            comment.post_id = p.id) AS number_of_comments,
+    coalesce(sum(pl.score), 0) AS score,
+    count(
+        CASE WHEN pl.score = 1 THEN
+            1
+        ELSE
+            NULL
+        END) AS upvotes,
+    count(
+        CASE WHEN pl.score = - 1 THEN
+            1
+        ELSE
+            NULL
+        END) AS downvotes,
+    hot_rank (coalesce(sum(pl.score), 0), (
+            CASE WHEN (p.published < ('now'::timestamp - '1 month'::interval)) THEN
+                p.published -- Prevents necro-bumps
+            ELSE
+                greatest (c.recent_comment_time, p.published)
+            END)) AS hot_rank,
+    (
+        CASE WHEN (p.published < ('now'::timestamp - '1 month'::interval)) THEN
+            p.published -- Prevents necro-bumps
+        ELSE
+            greatest (c.recent_comment_time, p.published)
+        END) AS newest_activity_time
+FROM
+    post p
+    LEFT JOIN post_like pl ON p.id = pl.post_id
+    LEFT JOIN (
+        SELECT
+            post_id,
+            max(published) AS recent_comment_time
+        FROM
+            comment
+        GROUP BY
+            1) c ON p.id = c.post_id
+GROUP BY
+    p.id,
+    c.recent_comment_time;
+
+CREATE VIEW post_view AS
+with all_post AS (
+    SELECT
+        pa.*
+    FROM
+        post_aggregates_view pa
+)
+SELECT
+    ap.*,
+    u.id AS user_id,
+    coalesce(pl.score, 0) AS my_vote,
+    (
+        SELECT
+            cf.id::bool
+        FROM
+            community_follower cf
+        WHERE
+            u.id = cf.user_id
+            AND cf.community_id = ap.community_id) AS subscribed,
+    (
+        SELECT
+            pr.id::bool
+        FROM
+            post_read pr
+        WHERE
+            u.id = pr.user_id
+            AND pr.post_id = ap.id) AS read,
+    (
+        SELECT
+            ps.id::bool
+        FROM
+            post_saved ps
+        WHERE
+            u.id = ps.user_id
+            AND ps.post_id = ap.id) AS saved
+FROM
+    user_ u
+    CROSS JOIN all_post ap
+    LEFT JOIN post_like pl ON u.id = pl.user_id
+        AND ap.id = pl.post_id
+    UNION ALL
+    SELECT
+        ap.*,
+        NULL AS user_id,
+        NULL AS my_vote,
+        NULL AS subscribed,
+        NULL AS read,
+        NULL AS saved
+    FROM
+        all_post ap;
+
+CREATE MATERIALIZED VIEW post_aggregates_mview AS
+SELECT
+    *
+FROM
+    post_aggregates_view;
+
+CREATE UNIQUE INDEX idx_post_aggregates_mview_id ON post_aggregates_mview (id);
+
+CREATE VIEW post_mview AS
+with all_post AS (
+    SELECT
+        pa.*
+    FROM
+        post_aggregates_mview pa
+)
+SELECT
+    ap.*,
+    u.id AS user_id,
+    coalesce(pl.score, 0) AS my_vote,
+    (
+        SELECT
+            cf.id::bool
+        FROM
+            community_follower cf
+        WHERE
+            u.id = cf.user_id
+            AND cf.community_id = ap.community_id) AS subscribed,
+    (
+        SELECT
+            pr.id::bool
+        FROM
+            post_read pr
+        WHERE
+            u.id = pr.user_id
+            AND pr.post_id = ap.id) AS read,
+    (
+        SELECT
+            ps.id::bool
+        FROM
+            post_saved ps
+        WHERE
+            u.id = ps.user_id
+            AND ps.post_id = ap.id) AS saved
+FROM
+    user_ u
+    CROSS JOIN all_post ap
+    LEFT JOIN post_like pl ON u.id = pl.user_id
+        AND ap.id = pl.post_id
+    UNION ALL
+    SELECT
+        ap.*,
+        NULL AS user_id,
+        NULL AS my_vote,
+        NULL AS subscribed,
+        NULL AS read,
+        NULL AS saved
+    FROM
+        all_post ap;
+
+CREATE VIEW comment_aggregates_view AS
+SELECT
+    c.*,
+    (
+        SELECT
+            community_id
+        FROM
+            post p
+        WHERE
+            p.id = c.post_id), (
+        SELECT
+            co.name
+        FROM
+            post p,
+            community co
+        WHERE
+            p.id = c.post_id
+            AND p.community_id = co.id) AS community_name,
+    (
+        SELECT
+            u.banned
+        FROM
+            user_ u
+        WHERE
+            c.creator_id = u.id) AS banned,
+    (
+        SELECT
+            cb.id::bool
+        FROM
+            community_user_ban cb,
+            post p
+        WHERE
+            c.creator_id = cb.user_id
+            AND p.id = c.post_id
+            AND p.community_id = cb.community_id) AS banned_from_community,
+    (
+        SELECT
+            name
+        FROM
+            user_
+        WHERE
+            c.creator_id = user_.id) AS creator_name,
+    (
+        SELECT
+            avatar
+        FROM
+            user_
+        WHERE
+            c.creator_id = user_.id) AS creator_avatar,
+    coalesce(sum(cl.score), 0) AS score,
+    count(
+        CASE WHEN cl.score = 1 THEN
+            1
+        ELSE
+            NULL
+        END) AS upvotes,
+    count(
+        CASE WHEN cl.score = - 1 THEN
+            1
+        ELSE
+            NULL
+        END) AS downvotes,
+    hot_rank (coalesce(sum(cl.score), 0), c.published) AS hot_rank
+FROM
+    comment c
+    LEFT JOIN comment_like cl ON c.id = cl.comment_id
+GROUP BY
+    c.id;
+
+CREATE MATERIALIZED VIEW comment_aggregates_mview AS
+SELECT
+    *
+FROM
+    comment_aggregates_view;
+
+CREATE UNIQUE INDEX idx_comment_aggregates_mview_id ON comment_aggregates_mview (id);
+
+CREATE VIEW comment_mview AS
+with all_comment AS (
+    SELECT
+        ca.*
+    FROM
+        comment_aggregates_mview ca
+)
+SELECT
+    ac.*,
+    u.id AS user_id,
+    coalesce(cl.score, 0) AS my_vote,
+    (
+        SELECT
+            cf.id::boolean
+        FROM
+            community_follower cf
+        WHERE
+            u.id = cf.user_id
+            AND ac.community_id = cf.community_id) AS subscribed,
+    (
+        SELECT
+            cs.id::bool
+        FROM
+            comment_saved cs
+        WHERE
+            u.id = cs.user_id
+            AND cs.comment_id = ac.id) AS saved
+FROM
+    user_ u
+    CROSS JOIN all_comment ac
+    LEFT JOIN comment_like cl ON u.id = cl.user_id
+        AND ac.id = cl.comment_id
+    UNION ALL
+    SELECT
+        ac.*,
+        NULL AS user_id,
+        NULL AS my_vote,
+        NULL AS subscribed,
+        NULL AS saved
+    FROM
+        all_comment ac;
+
+CREATE VIEW reply_view AS
+with closereply AS (
+    SELECT
+        c2.id,
+        c2.creator_id AS sender_id,
+        c.creator_id AS recipient_id
+    FROM
+        comment c
+        INNER JOIN comment c2 ON c.id = c2.parent_id
+    WHERE
+        c2.creator_id != c.creator_id
+        -- Do union where post is null
+    UNION
+    SELECT
+        c.id,
+        c.creator_id AS sender_id,
+        p.creator_id AS recipient_id
+    FROM
+        comment c,
+        post p
+    WHERE
+        c.post_id = p.id
+        AND c.parent_id IS NULL
+        AND c.creator_id != p.creator_id
+)
+SELECT
+    cv.*,
+    closereply.recipient_id
+FROM
+    comment_mview cv,
+    closereply
+WHERE
+    closereply.id = cv.id;
+
+CREATE VIEW user_mention_mview AS
+with all_comment AS (
+    SELECT
+        ca.*
+    FROM
+        comment_aggregates_mview ca
+)
+SELECT
+    ac.id,
+    um.id AS user_mention_id,
+    ac.creator_id,
+    ac.post_id,
+    ac.parent_id,
+    ac.content,
+    ac.removed,
+    um.read,
+    ac.published,
+    ac.updated,
+    ac.deleted,
+    ac.community_id,
+    ac.community_name,
+    ac.banned,
+    ac.banned_from_community,
+    ac.creator_name,
+    ac.creator_avatar,
+    ac.score,
+    ac.upvotes,
+    ac.downvotes,
+    ac.hot_rank,
+    u.id AS user_id,
+    coalesce(cl.score, 0) AS my_vote,
+    (
+        SELECT
+            cs.id::bool
+        FROM
+            comment_saved cs
+        WHERE
+            u.id = cs.user_id
+            AND cs.comment_id = ac.id) AS saved,
+    um.recipient_id
+FROM
+    user_ u
+    CROSS JOIN all_comment ac
+    LEFT JOIN comment_like cl ON u.id = cl.user_id
+        AND ac.id = cl.comment_id
+    LEFT JOIN user_mention um ON um.comment_id = ac.id
+UNION ALL
+SELECT
+    ac.id,
+    um.id AS user_mention_id,
+    ac.creator_id,
+    ac.post_id,
+    ac.parent_id,
+    ac.content,
+    ac.removed,
+    um.read,
+    ac.published,
+    ac.updated,
+    ac.deleted,
+    ac.community_id,
+    ac.community_name,
+    ac.banned,
+    ac.banned_from_community,
+    ac.creator_name,
+    ac.creator_avatar,
+    ac.score,
+    ac.upvotes,
+    ac.downvotes,
+    ac.hot_rank,
+    NULL AS user_id,
+    NULL AS my_vote,
+    NULL AS saved,
+    um.recipient_id
+FROM
+    all_comment ac
+    LEFT JOIN user_mention um ON um.comment_id = ac.id;
+
+CREATE VIEW comment_view AS
+with all_comment AS (
+    SELECT
+        ca.*
+    FROM
+        comment_aggregates_view ca
+)
+SELECT
+    ac.*,
+    u.id AS user_id,
+    coalesce(cl.score, 0) AS my_vote,
+    (
+        SELECT
+            cf.id::boolean
+        FROM
+            community_follower cf
+        WHERE
+            u.id = cf.user_id
+            AND ac.community_id = cf.community_id) AS subscribed,
+    (
+        SELECT
+            cs.id::bool
+        FROM
+            comment_saved cs
+        WHERE
+            u.id = cs.user_id
+            AND cs.comment_id = ac.id) AS saved
+FROM
+    user_ u
+    CROSS JOIN all_comment ac
+    LEFT JOIN comment_like cl ON u.id = cl.user_id
+        AND ac.id = cl.comment_id
+    UNION ALL
+    SELECT
+        ac.*,
+        NULL AS user_id,
+        NULL AS my_vote,
+        NULL AS subscribed,
+        NULL AS saved
+    FROM
+        all_comment ac;
+
+CREATE VIEW user_mention_view AS
+SELECT
+    c.id,
+    um.id AS user_mention_id,
+    c.creator_id,
+    c.post_id,
+    c.parent_id,
+    c.content,
+    c.removed,
+    um.read,
+    c.published,
+    c.updated,
+    c.deleted,
+    c.community_id,
+    c.community_name,
+    c.banned,
+    c.banned_from_community,
+    c.creator_name,
+    c.creator_avatar,
+    c.score,
+    c.upvotes,
+    c.downvotes,
+    c.hot_rank,
+    c.user_id,
+    c.my_vote,
+    c.saved,
+    um.recipient_id
+FROM
+    user_mention um,
+    comment_view c
+WHERE
+    um.comment_id = c.id;
+

migrations/2021-02-02-153240_apub_columns/down.sql

@@ -1,3 +1,5 @@
+DROP VIEW user_alias_1, user_alias_2;
+
 ALTER TABLE community
     DROP COLUMN followers_url;
 
@@ -13,3 +15,16 @@ ALTER TABLE user_
 ALTER TABLE user_
     DROP COLUMN shared_inbox_url;
 
+-- Views are the same as before, except `*` does not reference the dropped columns
+CREATE VIEW user_alias_1 AS
+SELECT
+    *
+FROM
+    user_;
+
+CREATE VIEW user_alias_2 AS
+SELECT
+    *
+FROM
+    user_;
+

migrations/2021-02-25-112959_remove-categories/down.sql

@@ -34,3 +34,5 @@ INSERT INTO category (name)
 ALTER TABLE community
     ADD category_id int REFERENCES category ON UPDATE CASCADE ON DELETE CASCADE NOT NULL DEFAULT 1;
 
+CREATE INDEX idx_community_category ON community (category_id);
+

migrations/2021-03-09-171136_split_user_table_2/down.sql

@@ -260,6 +260,8 @@ FROM
 WHERE
     lu.person_id = u.id;
 
+CREATE UNIQUE INDEX idx_user_email_lower ON user_ (lower(email));
+
 CREATE VIEW user_alias_1 AS
 SELECT
     *

migrations/2022-05-20-135341_embed-url/down.sql

@@ -1,6 +1,6 @@
 ALTER TABLE post
-    DROP COLUMN embed_url;
+    DROP COLUMN embed_video_url;
 
 ALTER TABLE post
-    ADD COLUMN embed_video_url text;
+    ADD COLUMN embed_html text;
 

migrations/2022-11-20-032430_sticky_local/down.sql

@@ -65,3 +65,15 @@ CREATE TRIGGER post_aggregates_stickied
     WHEN (OLD.stickied IS DISTINCT FROM NEW.stickied)
     EXECUTE PROCEDURE post_aggregates_stickied ();
 
+CREATE INDEX idx_post_aggregates_stickied_newest_comment_time ON post_aggregates (stickied DESC, newest_comment_time DESC);
+
+CREATE INDEX idx_post_aggregates_stickied_comments ON post_aggregates (stickied DESC, comments DESC);
+
+CREATE INDEX idx_post_aggregates_stickied_hot ON post_aggregates (stickied DESC, hot_rank (score, published) DESC, published DESC);
+
+CREATE INDEX idx_post_aggregates_stickied_active ON post_aggregates (stickied DESC, hot_rank (score, newest_comment_time_necro) DESC, newest_comment_time_necro DESC);
+
+CREATE INDEX idx_post_aggregates_stickied_score ON post_aggregates (stickied DESC, score DESC);
+
+CREATE INDEX idx_post_aggregates_stickied_published ON post_aggregates (stickied DESC, published DESC);
+

migrations/2023-01-17-165819_cleanup_post_aggregates_indexes/down.sql

@@ -8,7 +8,7 @@ CREATE INDEX idx_post_aggregates_comments ON post_aggregates (comments DESC);
 
 CREATE INDEX idx_post_aggregates_hot ON post_aggregates (hot_rank (score, published) DESC, published DESC);
 
-CREATE INDEX idx_post_aggregates_active ON post_aggregates (hot_rank (score, newest_comment_time) DESC, newest_comment_time DESC);
+CREATE INDEX idx_post_aggregates_active ON post_aggregates (hot_rank (score, newest_comment_time_necro) DESC, newest_comment_time_necro DESC);
 
 CREATE INDEX idx_post_aggregates_score ON post_aggregates (score DESC);
 

migrations/2023-05-10-095739_force_enable_undetermined_language/down.sql

@@ -0,0 +1,3 @@
+SELECT
+    1;
+

migrations/2023-06-17-175955_add_listingtype_sorttype_hour_enums/down.sql

@@ -1,3 +1,6 @@
+ALTER TABLE local_user
+    ALTER default_sort_type DROP DEFAULT;
+
 -- update the default sort type
 UPDATE
     local_user
@@ -29,6 +32,9 @@ ALTER TABLE local_user
     ALTER COLUMN default_sort_type TYPE sort_type_enum
     USING default_sort_type::text::sort_type_enum;
 
+ALTER TABLE local_user
+    ALTER default_sort_type SET DEFAULT 'Active';
+
 -- drop the old enum
 DROP TYPE sort_type_enum__;
 

migrations/2023-06-20-191145_add_listingtype_sorttype_3_6_9_months_enums/down.sql

@@ -1,3 +1,6 @@
+ALTER TABLE local_user
+    ALTER default_sort_type DROP DEFAULT;
+
 -- update the default sort type
 UPDATE
     local_user
@@ -32,6 +35,9 @@ ALTER TABLE local_user
     ALTER COLUMN default_sort_type TYPE sort_type_enum
     USING default_sort_type::text::sort_type_enum;
 
+ALTER TABLE local_user
+    ALTER default_sort_type SET DEFAULT 'Active';
+
 -- drop the old enum
 DROP TYPE sort_type_enum__;
 

migrations/2023-07-11-084714_receive_activity_table/down.sql

@@ -26,3 +26,5 @@ DROP TABLE sent_activity;
 
 DROP TABLE received_activity;
 
+CREATE UNIQUE INDEX idx_activity_ap_id ON activity (ap_id);
+

migrations/2023-08-01-101826_admin_flag_local_user/down.sql

@@ -14,3 +14,7 @@ WHERE
 ALTER TABLE local_user
     DROP COLUMN admin;
 
+CREATE INDEX idx_person_admin ON person (admin)
+WHERE
+    admin;
+

migrations/2023-08-02-174444_fix-timezones/down.sql

@@ -328,7 +328,9 @@ ALTER TABLE captcha_answer
     ALTER COLUMN published TYPE timestamp
     USING published;
 
-CREATE OR REPLACE FUNCTION hot_rank (score numeric, published timestamp without time zone)
+DROP FUNCTION hot_rank;
+
+CREATE FUNCTION hot_rank (score numeric, published timestamp without time zone)
     RETURNS integer
     AS $$
 DECLARE

src/lib.rs

@@ -129,13 +129,11 @@ pub async fn start_lemmy_server(args: CmdArgs) -> LemmyResult<()> {
   println!("Lemmy v{VERSION}");
 
   if let Some(CmdSubcommand::Migration { subcommand }) = args.subcommand {
-    let mut options = schema_setup::Options::default();
+    let options = match subcommand {
+      MigrationSubcommand::Run => schema_setup::Options::default(),
+    };
 
-    match subcommand {
-      MigrationSubcommand::Run => {}
-    }
-
-    schema_setup::run(&SETTINGS.get_database_url(), &options)?;
+    schema_setup::run(&SETTINGS.get_database_url(), options)?;
 
     return Ok(());
   }