Zero copy connector between instances - Error executing SQL : Pass-through queries are not enabled

[Christopher Wea]

Hi all,

We've set up a Zero Copy Connector (Instance-to-Instance, ServiceNow connector type, OAuth authentication) between two of our ServiceNow instances using Data Fabric. The connection itself shows as **CONNECTED** in the Zero Copy Connector Hub, schema discovery works fine, and we've successfully created several remote/data fabric tables (mapped via `sys_df_data_dictionary`) from the source instance.

However, when we open the list view for any of these newly created data fabric tables (e.g. `<table>_list.do?sysparm_skip_dbm=true`), we get:

```
Query error: Query failed (#<redacted>): Error executing SQL (Status: 500): Pass-through queries are not enabled for this DB
```

This happens consistently across **every** mapped table on this connection, even simple unfiltered list views. The `df_log` table shows the same error at `log_category: connection`, with `remote_schema_name: default` and the relevant `remote_catalog_name`.

**What we've checked so far:**
- The connection's `sys_df_connection_data.connection_status` = `CONNECTED`, no error message.
- The remote service account has all the standard Data Fabric roles assigned (`df_observer`, `df_connection_admin`, `df_data_steward`, `wdf_admin`, `wdf_builder`, `wdf_operator`, `data_fabric_user`, `wdf_consumer`) — this fixed a separate/earlier "failed to get remote schemas" issue on the same connection, but not this one.
- We compared against another working ZCC connection (different pair of instances, same connector type) — that one does **not** hit this error when querying its mapped data fabric table's list view.
- Checked `sys_properties` on both instances for anything related to `pass_through`, `sql_api`, `egress`, `odbc`, `jdbc`, `trino` — nothing relevant found.
- Reviewed the SQL API documentation (pass-through query support, `sn_odbc_rest_access` / `sn_jdbc_rest_access` / `sn_sql_api_privileged_mode` roles, `egress_sql` ACLs) — but we are **not** using the SQL API plugin/ODBC/JDBC access here, only the native Data Fabric/ZCC list views, so this doesn't seem to directly apply.
- Looked at `sn_df_connector_section` (the connector's config template, e.g. `data_template_json` containing `connector-type`/`sql-type`) and `sn_df_connection_attributes`/`sys_df_connection_data` for any exposed toggle resembling `query.passthrough-enabled` — none of these tables expose a customer-configurable pass-through setting, and the connector section table itself returns "Insufficient rights to update" when we tried adding one, confirming it's locked down as an OOB-managed record.

Our current hypothesis is that this is a backend Trino/query-engine catalog property (something like `query.passthrough-enabled=true`) that needs to be enabled by ServiceNow on their side for the specific catalog/connection, and isn't exposed for customers to configure directly.

**Questions for the community:**
1. Has anyone else hit "Pass-through queries are not enabled for this DB" on a Zero Copy Connector / Data Fabric list view (not the SQL API)?
2. Is there a documented, customer-configurable setting (system property, connection attribute, or plugin) that enables pass-through queries for Data Fabric/ZCC connections?
3. If this does require a ServiceNow-side change, is there a specific HI Support request type or category to make finding/enabling this faster?

Any pointers appreciated — happy to share more (sanitized) log detail if useful.

Thanks!

[Christopher Wea]

It turns out Zero Copy Connectors  between Postgres and  Oracle Instances are not supported.

[Joe Wilmoth]

If the Remote Instance is on Oracle, this connector will not function correctly. What DB is the remote instance using?