diff --git a/packages/server/src/integrations/postgres.ts b/packages/server/src/integrations/postgres.ts
index a3e49687b6..220f35dae5 100644
--- a/packages/server/src/integrations/postgres.ts
+++ b/packages/server/src/integrations/postgres.ts
@@ -208,6 +208,7 @@ module PostgresModule {
      */
     async buildSchema(datasourceId: string, entities: Record<string, Table>) {
       let tableKeys: { [key: string]: string[] } = {}
+      await this.openConnection()
       try {
         const primaryKeysResponse = await this.client.query(
           this.PRIMARY_KEYS_SQL