diff --git a/src/com/android/providers/telephony/MmsProvider.java b/src/com/android/providers/telephony/MmsProvider.java
index 5acfe13..d7a6803 100644
--- a/src/com/android/providers/telephony/MmsProvider.java
+++ b/src/com/android/providers/telephony/MmsProvider.java
@@ -50,6 +50,7 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.util.HashSet;
 
 /**
  * The class to provide base facility to access MMS related content,
@@ -637,6 +638,8 @@
                                          selectionArgs, uri);
         } else if (TABLE_PART.equals(table)) {
             deletedRows = deleteParts(db, finalSelection, selectionArgs);
+            cleanUpWords(db);
+            updateHasAttachment(db);
         } else if (TABLE_DRM.equals(table)) {
             deletedRows = deleteTempDrmData(db, finalSelection, selectionArgs);
         } else {
@@ -651,12 +654,13 @@
 
     static int deleteMessages(Context context, SQLiteDatabase db,
             String selection, String[] selectionArgs, Uri uri) {
-        Cursor cursor = db.query(TABLE_PDU, new String[] { Mms._ID },
+        Cursor cursor = db.query(TABLE_PDU, new String[] { Mms._ID, Mms.THREAD_ID },
                 selection, selectionArgs, null, null, null);
         if (cursor == null) {
             return 0;
         }
 
+        HashSet<Long> threadIds = new HashSet<Long>();
         try {
             if (cursor.getCount() == 0) {
                 return 0;
@@ -665,12 +669,18 @@
             while (cursor.moveToNext()) {
                 deleteParts(db, Part.MSG_ID + " = ?",
                         new String[] { String.valueOf(cursor.getLong(0)) });
+                threadIds.add(cursor.getLong(1));
             }
+            cleanUpWords(db);
+            updateHasAttachment(db);
         } finally {
             cursor.close();
         }
 
         int count = db.delete(TABLE_PDU, selection, selectionArgs);
+        for (long thread : threadIds) {
+            MmsSmsDatabaseHelper.updateThread(db, thread);
+        }
         if (count > 0) {
             Intent intent = new Intent(Mms.Intents.CONTENT_CHANGED_ACTION);
             intent.putExtra(Mms.Intents.DELETED_CONTENTS, uri);
@@ -682,6 +692,18 @@
         return count;
     }
 
+    private static void cleanUpWords(SQLiteDatabase db) {
+        db.execSQL("DELETE FROM words WHERE source_id not in (select _id from part) AND "
+                + "table_to_use = 2");
+    }
+
+    private static void updateHasAttachment(SQLiteDatabase db) {
+        db.execSQL("UPDATE threads SET has_attachment = CASE "
+                + "(SELECT COUNT(*) FROM part JOIN pdu WHERE part.mid = pdu._id AND "
+                + "pdu.thread_id = threads._id AND part.ct != 'text/plain' "
+                + "AND part.ct != 'application/smil') WHEN 0 THEN 0 ELSE 1 END");
+    }
+
     private static int deleteParts(SQLiteDatabase db, String selection,
             String[] selectionArgs) {
         return deleteDataRows(db, TABLE_PART, selection, selectionArgs);
diff --git a/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java b/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java
index abe7ffd..4f89900 100644
--- a/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java
+++ b/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java
@@ -94,19 +94,6 @@
                         "        AND " + Mms.MESSAGE_BOX + " != 3) " +
                         "  WHERE threads._id = new.thread_id; ";
 
-    private static final String UPDATE_THREAD_COUNT_ON_OLD =
-                        "  UPDATE threads SET message_count = " +
-                        "     (SELECT COUNT(sms._id) FROM sms LEFT JOIN threads " +
-                        "      ON threads._id = " + Sms.THREAD_ID +
-                        "      WHERE " + Sms.THREAD_ID + " = old.thread_id" +
-                        "        AND sms." + Sms.TYPE + " != 3) + " +
-                        "     (SELECT COUNT(pdu._id) FROM pdu LEFT JOIN threads " +
-                        "      ON threads._id = " + Mms.THREAD_ID +
-                        "      WHERE " + Mms.THREAD_ID + " = old.thread_id" +
-                        "        AND (m_type=132 OR m_type=130 OR m_type=128)" +
-                        "        AND " + Mms.MESSAGE_BOX + " != 3) " +
-                        "  WHERE threads._id = old.thread_id; ";
-
     private static final String SMS_UPDATE_THREAD_DATE_SNIPPET_COUNT_ON_UPDATE =
                         "BEGIN" +
                         "  UPDATE threads SET" +
@@ -156,21 +143,6 @@
                         PDU_UPDATE_THREAD_READ_BODY +
                         "END;";
 
-    private static final String UPDATE_THREAD_SNIPPET_SNIPPET_CS_ON_DELETE =
-                        "  UPDATE threads SET snippet = " +
-                        "   (SELECT snippet FROM" +
-                        "     (SELECT date * 1000 AS date, sub AS snippet, thread_id FROM pdu" +
-                        "      UNION SELECT date, body AS snippet, thread_id FROM sms)" +
-                        "    WHERE thread_id = OLD.thread_id ORDER BY date DESC LIMIT 1) " +
-                        "  WHERE threads._id = OLD.thread_id; " +
-                        "  UPDATE threads SET snippet_cs = " +
-                        "   (SELECT snippet_cs FROM" +
-                        "     (SELECT date * 1000 AS date, sub_cs AS snippet_cs, thread_id FROM pdu" +
-                        "      UNION SELECT date, 0 AS snippet_cs, thread_id FROM sms)" +
-                        "    WHERE thread_id = OLD.thread_id ORDER BY date DESC LIMIT 1) " +
-                        "  WHERE threads._id = OLD.thread_id; ";
-
-
     // When a part is inserted, if it is not text/plain or application/smil
     // (which both can exist with text-only MMSes), then there is an attachment.
     // Set has_attachment=1 in the threads table for the thread in question.
@@ -196,28 +168,6 @@
                         "     WHERE part._id=new._id LIMIT 1); " +
                         " END";
 
-
-    // When a part is deleted (with the same non-text/SMIL constraint as when
-    // we set has_attachment), update the threads table for all threads.
-    // Unfortunately we cannot update only the thread that the part was
-    // attached to, as it is possible that the part has been orphaned and
-    // the message it was attached to is already gone.
-    private static final String PART_UPDATE_THREADS_ON_DELETE_TRIGGER =
-                        "CREATE TRIGGER update_threads_on_delete_part " +
-                        " AFTER DELETE ON part " +
-                        " WHEN old.ct != 'text/plain' AND old.ct != 'application/smil' " +
-                        " BEGIN " +
-                        "  UPDATE threads SET has_attachment = " +
-                        "   CASE " +
-                        "    (SELECT COUNT(*) FROM part JOIN pdu " +
-                        "     WHERE pdu.thread_id = threads._id " +
-                        "     AND part.ct != 'text/plain' AND part.ct != 'application/smil' " +
-                        "     AND part.mid = pdu._id)" +
-                        "   WHEN 0 THEN 0 " +
-                        "   ELSE 1 " +
-                        "   END; " +
-                        " END";
-
     // When the 'thread_id' column in the pdu table is updated, we need to run the trigger to update
     // the threads table's has_attachment column, if the message has an attachment in 'part' table
     private static final String PDU_UPDATE_THREADS_ON_UPDATE_TRIGGER =
@@ -550,6 +500,15 @@
                 createSmsTables(db);
             }
         }
+
+        // Improve the performance of deleting Mms.
+        dropMmsTriggers(db);
+    }
+
+    private void dropMmsTriggers(SQLiteDatabase db) {
+        db.execSQL("DROP TRIGGER IF EXISTS update_threads_on_delete_part");
+        db.execSQL("DROP TRIGGER IF EXISTS mms_words_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS pdu_update_thread_on_delete");
     }
 
     // When upgrading the database we need to populate the words
@@ -646,8 +605,18 @@
 
     private void createIndices(SQLiteDatabase db) {
         createThreadIdIndex(db);
+        createPduPartIndex(db);
     }
 
+    private void createPduPartIndex(SQLiteDatabase db) {
+        try {
+            db.execSQL("CREATE INDEX IF NOT EXISTS index_part ON " + MmsProvider.TABLE_PART +
+                        " (mid);");
+        } catch (Exception ex) {
+            Log.e(TAG, "got exception creating indices: " + ex.toString());
+        }
+     }
+
     private void createThreadIdIndex(SQLiteDatabase db) {
         try {
             db.execSQL("CREATE INDEX IF NOT EXISTS typeThreadIdIndex ON sms" +
@@ -779,9 +748,6 @@
         db.execSQL("DROP TRIGGER IF EXISTS update_threads_on_update_part");
         db.execSQL(PART_UPDATE_THREADS_ON_UPDATE_TRIGGER);
 
-        db.execSQL("DROP TRIGGER IF EXISTS update_threads_on_delete_part");
-        db.execSQL(PART_UPDATE_THREADS_ON_DELETE_TRIGGER);
-
         db.execSQL("DROP TRIGGER IF EXISTS update_threads_on_update_pdu");
         db.execSQL(PDU_UPDATE_THREADS_ON_UPDATE_TRIGGER);
 
@@ -857,10 +823,6 @@
                 " SET index_text = NEW.text WHERE (source_id=NEW._id AND table_to_use=2); " +
                 " END;");
 
-        db.execSQL("DROP TRIGGER IF EXISTS mms_words_delete");
-        db.execSQL("CREATE TRIGGER mms_words_delete AFTER DELETE ON part BEGIN DELETE FROM " +
-                " words WHERE source_id = OLD._id AND table_to_use = 2; END;");
-
         // Updates threads table whenever a message in pdu is updated.
         db.execSQL("DROP TRIGGER IF EXISTS pdu_update_thread_date_subject_on_update");
         db.execSQL("CREATE TRIGGER pdu_update_thread_date_subject_on_update AFTER" +
@@ -869,18 +831,6 @@
                    PDU_UPDATE_THREAD_CONSTRAINTS +
                    PDU_UPDATE_THREAD_DATE_SNIPPET_COUNT_ON_UPDATE);
 
-        // Update threads table whenever a message in pdu is deleted
-        db.execSQL("DROP TRIGGER IF EXISTS pdu_update_thread_on_delete");
-        db.execSQL("CREATE TRIGGER pdu_update_thread_on_delete " +
-                   "AFTER DELETE ON pdu " +
-                   "BEGIN " +
-                   "  UPDATE threads SET " +
-                   "     date = (strftime('%s','now') * 1000)" +
-                   "  WHERE threads._id = old." + Mms.THREAD_ID + "; " +
-                   UPDATE_THREAD_COUNT_ON_OLD +
-                   UPDATE_THREAD_SNIPPET_SNIPPET_CS_ON_DELETE +
-                   "END;");
-
         // Updates threads table whenever a message is added to pdu.
         db.execSQL("DROP TRIGGER IF EXISTS pdu_update_thread_on_insert");
         db.execSQL("CREATE TRIGGER pdu_update_thread_on_insert AFTER INSERT ON " +
@@ -1567,9 +1517,8 @@
 
         updateThreadsAttachmentColumn(db);
 
-        // Add insert and delete triggers for keeping it up to date.
+        // Add insert triggers for keeping it up to date.
         db.execSQL(PART_UPDATE_THREADS_ON_INSERT_TRIGGER);
-        db.execSQL(PART_UPDATE_THREADS_ON_DELETE_TRIGGER);
     }
 
     private void upgradeDatabaseToVersion44(SQLiteDatabase db) {