Fix issue where credentials from import foreign schema were lost after restarting session. Closes #504

Author: pskrbasu

fdw.go

@@ -133,9 +133,21 @@ func goFdwGetRelSize(state *C.FdwPlanState, root *C.PlannerInfo, rows *C.double,
 
 	pluginHub := hub.GetHub()
 
+	// get connection name
+	connName := GetSchemaNameFromForeignTableId(types.Oid(state.foreigntableid))
+
+	log.Println("[TRACE] connection name:", connName)
+
+	// here we are loading the server options(again) so that they are not lost after the session is restarted
+	serverOpts := GetForeignServerOptionsFromFTableId(types.Oid(state.foreigntableid))
+	err := pluginHub.ProcessImportForeignSchemaOptions(serverOpts, connName)
+	if err != nil {
+		FdwError(sperr.WrapWithMessage(err, "failed to process options"))
+	}
+
 	// reload connection config
 	// TODO remove need for fdw to load connection config
-	_, err := pluginHub.LoadConnectionConfig()
+	_, err = pluginHub.LoadConnectionConfig()
 	if err != nil {
 		log.Printf("[ERROR] LoadConnectionConfig failed %v ", err)
 		FdwError(err)

hub/hub_local.go

@@ -68,6 +68,14 @@ func (l *HubLocal) SetConnectionConfig(connectionName, configString string) erro
 
 func (l *HubLocal) UpdateConnectionConfig(connectionName, configString string) error {
 	log.Printf("[INFO] HubLocal UpdateConnectionConfig: connection: %s, config: %s", connectionName, configString)
+
+	// if the connection already exists and the config is the same, do nothing
+	// this situation could arise when a session is restarted, the server options are loaded again, and
+	// the connection config is set again which results in the cache getting cleared
+	if conn, ok := l.connections[connectionName]; ok && conn.Config == configString {
+		return nil
+	}
+
 	l.connections[connectionName] =
 		&proto.ConnectionConfig{
 			Connection:      connectionName,