diff --git a/plugins/simdht/index.py b/plugins/simdht/index.py
index 0cbf7afa6..819576e45 100755
--- a/plugins/simdht/index.py
+++ b/plugins/simdht/index.py
@@ -72,7 +72,7 @@ def getSqlFile():
 
 
 def getDbConf():
-    file = getServerDir() + "/workers/db.cfg"
+    file = getServerDir() + "/db.cfg"
     return file
 
 
@@ -88,6 +88,12 @@ def initDreplace():
         sdir = getPluginDir() + '/workers'
         public.execShell('cp -rf ' + sdir + ' ' + getServerDir())
 
+    cfg = getServerDir() + '/db.cfg'
+    if not os.path.exists(cfg):
+        cfg_tpl = getPluginDir() + '/workers/db.cfg'
+        content = public.readFile(cfg_tpl)
+        public.writeFile(cfg, content)
+
     file_tpl = getInitDTpl()
     service_path = os.path.dirname(os.getcwd())
 
diff --git a/plugins/simdht/workers/db.cfg b/plugins/simdht/workers/db.cfg
index 6be5cc806..df3a289e3 100755
--- a/plugins/simdht/workers/db.cfg
+++ b/plugins/simdht/workers/db.cfg
@@ -5,6 +5,10 @@ DB_PORT = 3306
 DB_PASS = ssbc
 DB_NAME = ssbc
 
+#UNIT(G)
+DB_SIZE_LIMIT = 1
+DB_SIZE_TICK = 3
+
 [queue]
 MAX_QUEUE_LT = 30
 MAX_QUEUE_PT = 200
diff --git a/plugins/simdht/workers/simdht_worker.py b/plugins/simdht/workers/simdht_worker.py
index 88d1515a5..c93a515a5 100755
--- a/plugins/simdht/workers/simdht_worker.py
+++ b/plugins/simdht/workers/simdht_worker.py
@@ -56,6 +56,8 @@ DB_USER = cp.get(section_db, "DB_USER")
 DB_PORT = cp.getint(section_db, "DB_PORT")
 DB_PASS = cp.get(section_db, "DB_PASS")
 DB_NAME = cp.get(section_db, "DB_NAME")
+DB_SIZE_LIMIT = cp.get(section_db, "DB_SIZE_LIMIT")
+DB_SIZE_TICK = cp.getint(section_db, "DB_SIZE_TICK")
 BLACK_FILE = 'black_list.txt'
 
 BOOTSTRAP_NODES = (
@@ -323,6 +325,12 @@ class Master(Thread):
         self.visited = set()
         self.black_list = load_res_blacklist(BLACK_FILE)
 
+    def query(self, sql):
+        self.dbcurr.execute(sql)
+        result = self.dbcurr.fetchall()
+        data = map(list, result)
+        return data
+
     def got_torrent(self):
         binhash, address, data, dtype, start_time = self.metadata_queue.get()
         if dtype == 'pt':
@@ -341,6 +349,7 @@ class Master(Thread):
         self.name = threading.currentThread().getName()
         print self.name, 'started'
         while True:
+
             while self.metadata_queue.qsize() > 0:
                 self.got_torrent()
             address, binhash, dtype = self.queue.get()
@@ -389,6 +398,8 @@ class Master(Thread):
                 print 'n_d_pt', self.n_downloading_pt, 'n_d_lt', self.n_downloading_lt,
                 self.n_reqs = self.n_valid = self.n_new = 0
 
+                self.check_db_size()
+
     def log_announce(self, binhash, address=None):
         self.queue.put([address, binhash, 'pt'])
 
@@ -414,6 +425,48 @@ def rpc_server():
     print 'Starting xml rpc server...'
     rpcserver.serve_forever()
 
+
+class DBCheck(Master):
+
+    def __init__(self, master):
+        Master.__init__(self)
+        self.setDaemon(True)
+
+    def delete_db(self, line=1):
+        sql = 'select id, info_hash from search_hash order by id limit ' + \
+            str(line)
+        data = self.query(sql)
+        for x in range(len(data)):
+            iid = data[x][0]
+            infohash = data[x][1]
+
+            sqldel = "delete from search_hash where id='" + str(iid) + "'"
+            self.query(sqldel)
+
+            sqldel2 = "delete from search_filelist where info_hash='" + \
+                str(infohash) + "'"
+            self.query(sqldel2)
+            print 'delete ', iid, infohash, 'done'
+
+    def check_db_size(self):
+        sql = "select (concat(round(sum(DATA_LENGTH/1024/1024),2),'M') + concat(round(sum(INDEX_LENGTH/1024/1024),2),'M') ) \
+            as sdata from information_schema.tables where TABLE_SCHEMA='" + DB_NAME + "' and TABLE_NAME in('search_hash','search_filelist', 'search_statusreport')"
+
+        db_size_limit = int(DB_SIZE_LIMIT) * 1024
+        data = self.query(sql)
+        db_size = data[0][0]
+
+        if db_size > db_size_limit:
+            self.delete_db()
+
+        # print 'db size limit:', int(DB_SIZE_LIMIT) * 1024, db_size
+        # self.delete_db()
+
+    def run(self):
+        while True:
+            self.check_db_size()
+            time.sleep(DB_SIZE_TICK)
+
 if __name__ == "__main__":
     # max_node_qsize bigger, bandwith bigger, spped higher
     master = Master()
@@ -423,6 +476,9 @@ if __name__ == "__main__":
     rpcthread.setDaemon(True)
     rpcthread.start()
 
+    check = DBCheck(master)
+    check.start()
+
     dht = DHTServer(master, "0.0.0.0", 6881, max_node_qsize=MAX_NODE_QSIZE)
     dht.start()
     dht.auto_send_find_node()