[IMPALA-9410] Support resolving ORC file columns by names

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Impala 4.2.0, Impala 4.1.1
• Component/s: Backend
• Labels: orc
• Epic Link: Basic ORC Support
• Epic Color: ghx-label-5
• Assignee: Gergely Fürnstáhl
• Reporter: Quanlong Huang
• Created: 21/Feb/20 01:15
• Updated: 26/Aug/22 00:07
• Resolved: 29/Jun/22 01:05

Description

Currently we resolve ORC file columns by indices. We should provide an query option like PARQUET_FALLBACK_SCHEMA_RESOLUTION for Parquet (IMPALA-2835), to resolve ORC file columns by names.

Note that Hive only writes column names to ORC files after Hive-2.x (HIVE-4243). For older versions of Hive, the column names in ORC files are something like _col0, _col1,....,_col99. So this feature is only required when deployed with Hive 2+.