Subject Re: [IBO] Cursor unknown error -504
Author Helen Borrie
At 08:55 AM 8/08/2004 +0000, you wrote:
>Thanks Helen.
>The problem seems to happen when you return to the application after
>switching to another task or if the application has been idle for a
>period of time. The error message is sitting there when the screen
>appears. And it happens on stand alone machines as well as when
>using a server. I have never seen it happen when actively using the

Why I asked about the conditions is that this error occurs when the app
asks to fetch a row from an open cursor and the client has either lost the
cursor or was unable to obtain it. The client manages open cursors by way
of the cursor handle it assigns when the cursor is first opened. (We are
talking about server-side set cursors here, not IBO's ib_cursor component.)

In your conditions, it looks like the former case: the application had the
handle but the connection timed out and the handle assignment was gone when
the application tried to refer to it. Do you know whether the user
reporting the error was able to go on and do something else?

Do we have an XP box involved here? What network protocol is being
used? If it's TCP/IP, is the server subject to being randomly assigned a
dynamic IP address during idle time? etc. etc.

>The app has a timer that refreshes the data displayed in a grid
>every minute in case someone adds a new record but this doesn't seem
>to be the cause. I put a try - except around the refresh but it
>doesn't trap the error.

So are you saying the error is *also* likely to occur during active usage?

>If I knew what the error message means it might point me in the
>right direction.

If I understood what the error conditions really were I might be able to do
more to point you there....