[IMPALA-534] Selective queries over large tables produce unnecessary memory consumption

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 1.1
• Fix Version/s: Impala 1.1.1
• Assignee: Skye Wanderman-Milne
• Reporter: Skye Wanderman-Milne
• Created: 14/Aug/13 17:50
• Updated: 15/Aug/13 02:18
• Resolved: 15/Aug/13 02:18

Description

The scanners only release IO buffers when they have produced rows, so running a very selective query over a large table causes the scanners to accumulate many IO buffers that aren't actually being used. Scanners should release IO buffers periodically regardless of how many rows were produced.