diff --git a/appveyor.yml b/appveyor.yml
index 2347c2c5..4c2f9385 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,3 +1,5 @@
+clone_depth: 1
+
 image:
   - Visual Studio 2017
 
@@ -15,8 +17,8 @@ environment:
   MYSQL_PWD: Password12!
 
 before_build:
-  - psql -d postgresql://%VNPY_TEST_POSTGRESQL_USER%:%VNPY_TEST_POSTGRESQL_PASSWORD%@localhost -c "create database vnpy;"
-  - ps: . "C:\Program Files\MySQL\MySQL Server 5.7\bin\mysql" -u $VNPY_TEST_MYSQL_USER " -e 'CREATE DATABASE vnpy;'
+  - ps: psql -d "postgresql://$VNPY_TEST_POSTGRESQL_USER:$VNPY_TEST_POSTGRESQL_PASSWORD@localhost" -c "create database vnpy;"
+  - ps: . "C:\Program Files\MySQL\MySQL Server 5.7\bin\mysql" -u $VNPY_TEST_MYSQL_USER -e 'CREATE DATABASE vnpy;'
   - python -m pip install --upgrade pip wheel setuptools
 
 install: