[ORC-758] Avoid decompressing compressed streams if already decompressed

• Type: Sub-task
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.7.0
• Fix Version/s: 1.7.0
• Component/s: Java
• Assignee: Pavan Lanka
• Reporter: Pavan Lanka
• Created: 12/Mar/21 01:41
• Updated: 21/Sep/21 20:44
• Resolved: 23/Mar/21 21:25

Description

The current behavior of `InStream.CompressedStream` does not avoid seek and decompression if the required position is already decompressed and available.

This results in multiple decompressions of the same compression blocks. This can be avoided by tracking the current position and avoid decompression if we are at the required position already.

Issue Links

• is depended upon by: ORC-759 StructBatchReader should always skip processing on the rootReader
• links to: GitHub Pull Request #652