use CTE for message mention query

Author: jay3332

migrations/20260226000000_mention_query_indexes.down.sql

@@ -0,0 +1,3 @@
+DROP INDEX IF EXISTS idx_messages_channel_message;
+DROP INDEX IF EXISTS idx_role_data_user_guild;
+DROP INDEX IF EXISTS idx_messages_mentions;

migrations/20260226000000_mention_query_indexes.up.sql

@@ -0,0 +1,3 @@
+CREATE INDEX IF NOT EXISTS idx_messages_channel_message ON messages (channel_id, id);
+CREATE INDEX IF NOT EXISTS idx_role_data_user_guild ON role_data (user_id, guild_id);
+CREATE INDEX IF NOT EXISTS idx_messages_mentions ON messages USING GIN (mentions);

src/db/message.rs

@@ -666,7 +666,7 @@ pub trait MessageDbExt<'t>: DbExt<'t> {
     /// Edits a message in the given channel. This turns the current message into a revision of the
     /// message, and creates a new message with the new data.
     ///
-    /// If provided, ``user_id``` will be checked against the author of the message and throw a
+    /// If provided, ``user_id`` will be checked against the author of the message and throw a
     /// forbidden error if they do not match.
     ///
     /// # Note
@@ -832,22 +832,23 @@ pub trait MessageDbExt<'t>: DbExt<'t> {
             .collect_vec();
 
         let res = sqlx::query!(
-            r"SELECT m.id, m.channel_id FROM messages m
+            r"WITH user_roles AS (
+                SELECT guild_id, array_agg(role_id) AS role_ids
+                FROM role_data
+                WHERE user_id = $1
+                GROUP BY guild_id
+            )
+            SELECT m.id, m.channel_id FROM messages m
             INNER JOIN channels c ON m.channel_id = c.id
             LEFT JOIN channel_acks a ON m.channel_id = a.channel_id AND a.user_id = $1
+            LEFT JOIN user_roles r ON r.guild_id = c.guild_id
             WHERE
                 m.channel_id = ANY($2::BIGINT[])
-            AND (
-                a.last_message_id IS NULL
-                OR m.id > a.last_message_id
-            )
+            AND m.id > COALESCE(a.last_message_id, 0)
             AND (
                 $1 = ANY(m.mentions)
                 OR c.guild_id = ANY(m.mentions)
-                OR m.mentions && (
-                    SELECT array_agg(role_id) FROM role_data 
-                    WHERE guild_id = c.guild_id AND user_id = $1
-                )
+                OR m.mentions && r.role_ids
             )",
             user_id as i64,
             &channel_ids,