Thread performance optimization

app/src/main/java/eu/faircode/email/DaoMessage.java

@@ -217,11 +217,15 @@ public interface DaoMessage {
             " WHERE message.account = :account" +
             " AND message.thread = :thread" +
             " AND (:id IS NULL OR message.id = :id)" +
-            " AND (NOT :filter_archive OR folder.type <> '" + EntityFolder.ARCHIVE +
-            "' OR (SELECT COUNT(m.id) FROM message m" +
-            "   WHERE m.account = message.account" +
+            " AND (NOT :filter_archive" +
+            "  OR folder.type <> '" + EntityFolder.ARCHIVE + "'" +
+            "  OR NOT EXISTS" +
+            "   (SELECT * FROM message m" +
+            "   WHERE m.id <> message.id" +
+            "   AND m.account = message.account" +
+            "   AND m.thread = message.thread" +
             "   AND (m.hash = message.hash OR m.msgid = message.msgid)" +
-            "   AND NOT m.ui_hide) = 1)" +
+            "   AND NOT m.ui_hide))" +
             " AND (NOT message.ui_hide OR :debug)" +
             " ORDER BY CASE WHEN :ascending THEN message.received ELSE -message.received END" +
             ", CASE" +