[IMPALA-4577] Adjust maximum size of row batch queue for non-Parquet scans with MT_DOP>0.

• Type: Sub-task
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Impala 2.8.0
• Fix Version/s: Impala 2.8.0
• Component/s: Backend
• Labels: performance resource-management
• Target Version: Impala 2.8.0
• Assignee: Alexander Behm
• Reporter: Alexander Behm
• Created: 02/Dec/16 20:02
• Updated: 03/Dec/16 06:50
• Resolved: 03/Dec/16 06:50

Description

When MT_DOP is set, non-Parquet scans are run with the old scan node with a fixed NUM_SCANNER_THREADS=1

We should adjust the maximum size of the row batch queue based on MT_DOP for each such scan instance to avoid a significant increase in
the memory consumption of such scans.