[Oracle] Schema switch fails with clientClosedConnection on a healthy connection

[JX-WANG117]

What happened?

When I open a saved Oracle connection and TablePro restores or switches to another accessible schema, it shows this dialog:

Schema switch failed
OracleSQLError(code: clientClosedConnection, triggeredFromRequestInFile: *******, line: *******, statement: *******) - Some information has been reducted to prevent accidental leakage of sensitive data.

The Oracle server and network path were healthy at the time.

Diagnostics performed on the same Mac and network:

• macOS network logs show the TCP connections to the Oracle listener reached the ready state in about 0.1 seconds over the VPN.
• There was no remote READ_CLOSE before the error. TablePro cancelled an auxiliary connection after reporting the failure.
• An independent python-oracledb test using the same network and credentials connected in 0.296 seconds.
• SELECT ... FROM dual, ALTER SESSION SET CURRENT_SCHEMA to the target schema, and restoring the original schema all succeeded.
• TablePro's query timeout is 180 seconds. This error appeared about 17.5 seconds after the sockets became ready, so it does not appear to be a query timeout.

No persistent database changes were made during the diagnostic test.

Steps to reproduce

1. Open a saved Oracle connection that has a previously selected schema.
2. Wait for the initial connection and object tree to begin loading.
3. Let TablePro restore the last schema, or select another accessible schema.
4. Observe the Schema switch failed dialog with clientClosedConnection.

I observed this on an existing saved connection. I have not yet confirmed whether a newly created connection reproduces it.

Expected behavior

TablePro should restore or switch the Oracle session schema and load its objects.

If the existing session is stale or closed locally, TablePro should reconnect and retry once, or show an actionable connection error instead of surfacing the raw clientClosedConnection driver error.

Database type

Oracle

TablePro version

0.75.0 (131), Oracle plugin 1.2.29

macOS version & chip

macOS 27.0 / Apple Silicon (arm64)

Screenshots / Logs

Observed at 2026-09-22 19:16:53 local time.

Redacted unified-log entry:

Failed to switch schema: OracleSQLError(code: clientClosedConnection, triggeredFromRequestInFile: ********, line: ********, statement: ********)

The attached screenshot contains only the redacted error dialog.