perf(*): bound list queries, batch fetches, harden media downloads

backend/src/utils/read/chats.py

@@ -62,6 +62,18 @@ _ONE_ID = """
     WHERE account_id = $1 AND scope_type = 'chat' AND scope_id = $2
 """
 
+_MANY_IDS = """
+    SELECT chat_id FROM chat_stats
+    WHERE account_id = $1 AND chat_id = ANY($2::bigint[])
+    UNION
+    SELECT chat_id FROM dialogs
+    WHERE account_id = $1 AND chat_id = ANY($2::bigint[])
+    UNION
+    SELECT scope_id AS chat_id FROM capture_policy
+    WHERE account_id = $1 AND scope_type = 'chat'
+      AND scope_id = ANY($2::bigint[])
+"""
+
 _CHAT_ROWS = """
 WITH ids AS ({ids})
 SELECT ids.chat_id,
@@ -171,6 +183,15 @@ async def get_chat(
     return _chat_item(row) if row is not None else None
 
 
+async def get_chats(
+    pool: asyncpg.Pool, account_id: int, ids: list[int]
+) -> list[ChatListItem]:
+    if not ids:
+        return []
+    rows = await pool.fetch(_CHAT_ROWS.format(ids=_MANY_IDS), account_id, ids)
+    return [_chat_item(row) for row in rows]
+
+
 async def get_chat_history(  # noqa: PLR0913
     pool: asyncpg.Pool,
     account_id: int,
@@ -308,7 +329,7 @@ async def get_message_versions(
     rows = await pool.fetch(
         "SELECT observed_at, edit_date, text FROM message_versions "
         "WHERE account_id = $1 AND chat_id = $2 AND message_id = $3 "
-        "ORDER BY observed_at",
+        "ORDER BY observed_at LIMIT 500",
         account_id,
         chat_id,
         message_id,