There are times when CLI sends a request to the database for the next buffer-full of a response and it conflicts with a more recent request of the database. The rule is that a session may have the database active on its behalf for only one request at a time. This applies to the requests the application knows about as well as to the re-stocking requests done “behind the scenes.” If CLI is re-stocking response buffers, CLI returns “busy” from a call to DBCHCL for the Fetch function if Wait For Response is set to 'N'. This phenomenon is a possibility when a new request has been “refused.”
If CLIv2 is running a FastExport application that set a buffer length (using keyword BLOCKSIZE in the FastExport script) that is too small, CLIv2 will automatically try to fix the problem. The CLIv2 software, in this event, expands the buffer by between 70 and 100 bytes, depending on parcel overhead. If the buffer expansion is sufficient, the FastExport job runs to completion. The database returns the error:
3691: Specified Buffer Size is too small in FastExport
only if the buffer remains too small after the expansion has taken place.