FireDAC TFDConnection DriverName and SSLMode Behavior After PostgreSQL ODBC Driver Upgrade in RAD Studio 12.0

DriverName and ODBC Versioning

No, TFDConnection does not require a manual DriverName update when the PostgreSQL ODBC driver version is upgraded. In FireDAC, DriverName='ODBC' acts as a generic identifier that tells the framework to use the ODBC bridge. The actual version of the PostgreSQL driver is managed by the Windows ODBC Data Source Administrator (odbcad32.exe). As long as the driver name registered in the system (e.g., "PostgreSQL Unicode") remains consistent, FireDAC will utilize the updated binary without code changes.

Pooling and SSLMode Compatibility

Yes, Pooling=False is safe to use with SSLMode=Require. When pooling is disabled, TFDConnection.Close triggers the release of the connection handle back to the ODBC Driver Manager, which in turn signals the PostgreSQL driver to terminate the physical session and tear down the SSL tunnel.

Likely Behavior and Trade-offs

While Pooling=False effectively minimizes idle connections on the server, it introduces a performance penalty for low-traffic workloads. Every Open call requires a full TCP handshake and a complete SSL negotiation. For a Community Edition deployment, this is functionally correct but may result in noticeable latency during the initial connection phase of each request.

Implementation Steps

1. Verify Driver Registration: Ensure the upgraded PostgreSQL ODBC driver is installed and visible in the 64-bit (or 32-bit, depending on your target platform) ODBC Administrator.
2. Configure Connection Params: Set the following in your TFDConnection.Params:
   • DriverName=ODBC
   • SSLMode=Require (This is passed directly to the ODBC driver string)
   • Pooling=False
3. Validate Connection: Execute a simple TFDConnection.Connected := True to ensure the driver accepts the SSLMode parameter.

Verification Method

To confirm that idle connections are being closed and not held by a hidden pool, run the following query on your PostgreSQL server while opening and closing the connection in your application:

SELECT count(*) FROM pg_stat_activity WHERE datname = 'your_db_name';

If Pooling=False is working as intended, the count should drop to zero immediately after TFDConnection.Close is called.

Diagnostic Detail Needed: Are you using a System DSN or a DSN-less connection string? If using a DSN, verify that the SSLMode is configured within the DSN setup itself, as some older DSN configurations may override parameters passed via FireDAC.