> I believe it's an indicator to signal the preferred size for
> applications to fetch blobs per segment. As far as I know, no
> Delphi/CBuilder component set uses it.

Accrding to Ann this is just an indicator for embedded SQL processors
about the buffer to allocate. Actual segment size of the segmented
blob is different for each segment (max. 64k - 1) and is equal to the
number of bytes that were passed into isc_put_segment. Maximum size of
the segment can be obtained from the blob info request.

Best regards,
Roman Rokytskyy