Server core dump querying over Transparent Gateway

[amannering]

We are in the process of proving a migration of a Delphi application from Sybase to Oracle using the DOA components to access data migrated fully to Oracle and some legacy data in Sybase over TG4SYBS.

We have setup Transparent Gateway for Sybase from Oracle 10.1.0.3. Queries to remote tables work correctly from PL/SQL Developer provided they do not contain Sybase "text" fields (which Oracle maps to a long).
As soon as a text/long field is included in the query in PL/SQL Developer, a server core dump terminates the session. As the same query works correctly in SQL*Plus (including the text field returning content) Oracle are saying it must be a problem with PL/SQL developer.

We've tried running with client software from 9.2.0.6, 10.1.0.3 and Instant Client - all get the same result.

Any ideas?

Andrew Mannering

 

[Marco Kalter]

My guess is that the transparent gateway cannot handle the way that PL/SQL Developer accesses the long field. Long fields are fetched "piecewise", and perhaps SQL*Plus fetches differently sized pieces than PL/SQL Developer.

How Oracle Support can claim this is an application issue is beyond me, but it is unfortunately no untypical for their behavior. An Oracle Server core dump is of course by definition an Oracle bug.

I would love to help, but I'm not sure how we can tackle this server-related issue.

 

[amannering]

I've managed to get this to a workround - if I force OCI7 mode the longs are read successfully. I used DOA in Delphi 6 to start going through options one at a time to see if I could get at least a change in behaviour, but struck lucky within a few minutes.

I agree it is plainly a server bug, but is it possible to get some kind of test case of the OCI8 calls you use for retrieving longs that I can pass to Oracle? I know from my own experience in writing OCI wrappers in Objective-C that they only accept test cases in plain C.

Andrew

 

[Marco Kalter]

If you send me an e-mail can provide you with this information.