[IMPALA-5595] Impala shouldn't set KuduScanner timestamp feature flag unless necessary

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.9.0
• Fix Version/s: Impala 2.10.0
• Component/s: Backend
• Labels: kudu
• Target Version: Impala 2.10.0
• Epic Color: ghx-label-5
• Assignee: Matthew Jacobs
• Reporter: Matthew Jacobs
• Created: 28/Jun/17 18:59
• Updated: 29/Jun/17 14:39
• Resolved: 29/Jun/17 14:39

Description

To support Kudu timestamps, Impala sets a KuduScanner flag which pads the result tuples: KuduScanner::PAD_UNIXTIME_MICROS_TO_16_BYTES

It is always set, which is correct, but means that newer versions of Impala cannot scan older Kudus even if there are no TIMESTAMP columns.

The flag should just be set when there are TIMESTAMP columns.