Currently we don't reset the file read offset if ZCR fails. Due to this, when we switch to the normal read path, we hit the eosr of the scan-range even before reading the expected data length. This results in re-issuing the whole set of scan ranges and hence a severe
This has been observed while debugging
IMPALA-3679, where zero-copy reads don't work with encryption zones. However this situation can apply to any general case where the ZCRs fail.