fix db update error

Author: hggq

frameworks/C++/paozhu/paozhu_benchmark/conf/orm.conf

@@ -6,7 +6,8 @@ dbname=hello_world
 user=benchmarkdbuser
 password=benchmarkdbpass
 pretable=
-maxpool=5
+maxpool=120
+minpool=20
 dbtype=mysql
 
 type=second
@@ -16,5 +17,6 @@ dbname=hello_world
 user=benchmarkdbuser
 password=benchmarkdbpass
 pretable=
-maxpool=20
+maxpool=120
+minpool=20
 dbtype=mysql