diff --git a/db/ckdb.py b/db/ckdb.py
index 6f3cb76..397f111 100644
--- a/db/ckdb.py
+++ b/db/ckdb.py
@@ -5,13 +5,13 @@ import pandas as pd
 
 
 class CKDrive:
-    ClientPool = dict()
+    ClientPool = set()
 
     @classmethod
     async def _execute(cls, *args, **kwargs):
-        key, client = cls.ClientPool.popitem()
+        client = cls.ClientPool.pop()
         res = await client.execute(*args, **kwargs)
-        CKDrive.ClientPool[key] = client
+        CKDrive.ClientPool.add(client)
         return res
 
     async def execute(self, sql) -> dict:
diff --git a/db/ckdb_utils.py b/db/ckdb_utils.py
index 0f04dcc..51ca270 100644
--- a/db/ckdb_utils.py
+++ b/db/ckdb_utils.py
@@ -7,8 +7,9 @@ from .ckdb import CKDrive
 async def connect_to_ck(pool_size=100):
     for i in range(pool_size):
         client = Client(**settings.CK_CONFIG)
-        CKDrive.ClientPool[i] = client
+        CKDrive.ClientPool.add(client)
 
 
 async def close_ck_connection():
-    await CKDrive.client.disconnect()
+    for c in CKDrive.ClientPool:
+        await c.disconnect()