diff --git a/weed/filer/mysql/mysql_store.go b/weed/filer/mysql/mysql_store.go
index cb96dea1d..2e83e7a4d 100644
--- a/weed/filer/mysql/mysql_store.go
+++ b/weed/filer/mysql/mysql_store.go
@@ -33,6 +33,8 @@ func (store *MysqlStore) GetName() string {
 }
 
 func (store *MysqlStore) Initialize(configuration util.Configuration, prefix string) (err error) {
+	// Absent key keeps a pooled default; an explicit 0 disables the idle pool.
+	configuration.SetDefault(prefix+"connection_max_idle", 2)
 	return store.initialize(
 		configuration.GetString(prefix+"dsn"),
 		configuration.GetString(prefix+"upsertQuery"),
diff --git a/weed/filer/mysql2/mysql2_store.go b/weed/filer/mysql2/mysql2_store.go
index 2bce3c063..82d0c86c2 100644
--- a/weed/filer/mysql2/mysql2_store.go
+++ b/weed/filer/mysql2/mysql2_store.go
@@ -33,6 +33,8 @@ func (store *MysqlStore2) GetName() string {
 }
 
 func (store *MysqlStore2) Initialize(configuration util.Configuration, prefix string) (err error) {
+	// Absent key keeps a pooled default; an explicit 0 disables the idle pool.
+	configuration.SetDefault(prefix+"connection_max_idle", 2)
 	return store.initialize(
 		configuration.GetString(prefix+"createTable"),
 		configuration.GetString(prefix+"upsertQuery"),
diff --git a/weed/filer/postgres/postgres_store.go b/weed/filer/postgres/postgres_store.go
index 6778bc59e..fa6cb7df6 100644
--- a/weed/filer/postgres/postgres_store.go
+++ b/weed/filer/postgres/postgres_store.go
@@ -28,6 +28,8 @@ func (store *PostgresStore) GetName() string {
 }
 
 func (store *PostgresStore) Initialize(configuration util.Configuration, prefix string) (err error) {
+	// Absent key keeps a pooled default; an explicit 0 disables the idle pool.
+	configuration.SetDefault(prefix+"connection_max_idle", 2)
 	return store.initialize(
 		configuration.GetString(prefix+"upsertQuery"),
 		configuration.GetBool(prefix+"enableUpsert"),
diff --git a/weed/filer/postgres2/postgres2_store.go b/weed/filer/postgres2/postgres2_store.go
index d563ec322..64e86b9da 100644
--- a/weed/filer/postgres2/postgres2_store.go
+++ b/weed/filer/postgres2/postgres2_store.go
@@ -33,6 +33,8 @@ func (store *PostgresStore2) GetName() string {
 }
 
 func (store *PostgresStore2) Initialize(configuration util.Configuration, prefix string) (err error) {
+	// Absent key keeps a pooled default; an explicit 0 disables the idle pool.
+	configuration.SetDefault(prefix+"connection_max_idle", 2)
 	return store.initialize(
 		configuration.GetString(prefix+"createTable"),
 		configuration.GetString(prefix+"upsertQuery"),